m facebook com login device based update nonce

And all of them operate via Telegram, a cloud-based instant the login via a prompt that pops up on your registered mobile device. For example, it determines when the application can use or refresh stored access For testing, you can specify URIs that refer to the local machine. This document explains how applications installed on devices like phones, tablets, and computers use Google's OAuth 2.0 endpoints to authorize access to. m facebook com login device based update nonce

M facebook com login device based update nonce -

users

Users are entities that are able to log into your system. They can have attributes associated with themselves like email, username, address, phone number, and birth day. They can be assigned group membership and have specific roles assigned to them.

authentication

The process of identifying and validating a user.

authorization

The process of granting access to a user.

credentials

Credentials are pieces of data that Keycloak uses to verify the identity of a user. Some examples are passwords, one-time-passwords, digital certificates, or even fingerprints.

roles

Roles identify a type or category of user. , , , and are all typical roles that may exist in an organization. Applications often assign access and permissions to specific roles rather than individual users as dealing with users can be too fine grained and hard to manage.

user role mapping

A user role mapping defines a mapping between a role and a user. A user can be associated with zero or more roles. This role mapping information can be encapsulated into tokens and assertions so that applications can decide access permissions on various resources they manage.

composite roles

A composite role is a role that can be associated with other roles. For example a composite role could be associated with the and roles. If a user is mapped to the role they also inherit the and roles.

groups

Groups manage groups of users. Attributes can be defined for a group. You can map roles to a group as well. Users that become members of a group inherit the attributes and role mappings that group defines.

realms

A realm manages a set of users, credentials, roles, and groups. A user belongs to and logs into a realm. Realms are isolated from one another and can only manage and authenticate the users that they control.

clients

Clients are entities that can request Keycloak to authenticate a user. Most often, clients are applications and services that want to use Keycloak to secure themselves and provide a single sign-on solution. Clients can also be entities that just want to request identity information or an access token so that they can securely invoke other services on the network that are secured by Keycloak.

client adapters

Client adapters are plugins that you install into your application environment to be able to communicate and be secured by Keycloak. Keycloak has a number of adapters for different platforms that you can download. There are also third-party adapters you can get for environments that we don’t cover.

consent

Consent is when you as an admin want a user to give permission to a client before that client can participate in the authentication process. After a user provides their credentials, Keycloak will pop up a screen identifying the client requesting a login and what identity information is requested of the user. User can decide whether or not to grant the request.

client scopes

When a client is registered, you must define protocol mappers and role scope mappings for that client. It is often useful to store a client scope, to make creating new clients easier by sharing some common settings. This is also useful for requesting some claims or roles to be conditionally based on the value of parameter. Keycloak provides the concept of a client scope for this.

client role

Clients can define roles that are specific to them. This is basically a role namespace dedicated to the client.

identity token

A token that provides identity information about the user. Part of the OpenID Connect specification.

access token

A token that can be provided as part of an HTTP request that grants access to the service being invoked on. This is part of the OpenID Connect and OAuth 2.0 specification.

assertion

Information about a user. This usually pertains to an XML blob that is included in a SAML authentication response that provided identity metadata about an authenticated user.

service account

Each client has a built-in service account which allows it to obtain an access token.

direct grant

A way for a client to obtain an access token on behalf of a user via a REST invocation.

protocol mappers

For each client you can tailor what claims and assertions are stored in the OIDC token or SAML assertion. You do this per client by creating and configuring protocol mappers.

session

When a user logs in, a session is created to manage the login session. A session contains information like when the user logged in and what applications have participated within single-sign on during that session. Both admins and users can view session information.

user federation provider

Keycloak can store and manage users. Often, companies already have LDAP or Active Directory services that store user and credential information. You can point Keycloak to validate credentials from those external stores and pull in identity information.

identity provider

An identity provider (IDP) is a service that can authenticate a user. Keycloak is an IDP.

identity provider federation

Keycloak can be configured to delegate authentication to one or more IDPs. Social login via Facebook or Google+ is an example of identity provider federation. You can also hook Keycloak to delegate authentication to any other OpenID Connect or SAML 2.0 IDP.

identity provider mappers

When doing IDP federation you can map incoming tokens and assertions to user and session attributes. This helps you propagate identity information from the external IDP to your client requesting authentication.

required actions

Required actions are actions a user must perform during the authentication process. A user will not be able to complete the authentication process until these actions are complete. For example, an admin may schedule users to reset their passwords every month. An required action would be set for all these users.

authentication flows

Authentication flows are work flows a user must perform when interacting with certain aspects of the system. A login flow can define what credential types are required. Credential reset flow defines what actions a user must do before they can reset their password.

events

Events are audit streams that admins can view and hook into.

themes

Every screen provided by Keycloak is backed by a theme. Themes define HTML templates and stylesheets which you can override as needed.

Источник: https://www.keycloak.org/docs/latest/server_admin/

Https Facebook Com Login Device Based Update Nonce

It is very rare to see people having troubles with our login system, a guide should still be ready to prevent any mishaps. If you fall into one of those cases where you cannot log into our page, here is a guide for you to fix it on your side.

Step 1 – First, check your Internet connection. This is the primary reason why your login is failing, either due to connection instability or requests timing out. 

Step 2 – Make sure that you are using as well as entering the right login information. Some of our customers have tried using their old passwords and failed. If you can, you can also opt to view your passwords as you type it. However, you should check if anyone is around to see your credentials.

Step 3 – If you have uppercase letters in your passwords, be sure to punch them in at the right place. If all the letters in your passwords are in uppercase, check if you’re using CAPS LOCK.

Step 4 – If the former steps do not help, it is likely that there are cookies in your cache preventing you from logging in. Here is a guide on how to clear your cache on your browser.

Step 5 – Thewebsite might be on the list of restricted sites in your region. You can check it with your Virtual Private Network (VPN) and consider switching your server to another country if you have the option to. If that does not work either, you can switch off VPN completely. 

Step 6 – In case you forget your passwords, here are the instructions to follow to regain it.

Step 7 – If nothing else works, please contact us via our mailbox or our phone number. We will be honored to help you with any problems you run into.

Источник: https://itprospt.com/https-facebook-com-login-device-based-update-nonce/

Open Access

Peer-reviewed

  • Teing Yee Yang,
  • Ali Dehghantanha,
  • Kim-Kwang Raymond Choo ,
  • Zaiton Muda
  • Teing Yee Yang, 
  • Ali Dehghantanha, 
  • Kim-Kwang Raymond Choo, 
  • Zaiton Muda
PLOS

x

Abstract

Instant messaging (IM) has changed the way people communicate with each other. However, the interactive and instant nature of these applications (apps) made them an attractive choice for malicious cyber activities such as phishing. The forensic examination of IM apps for modern Windows 8.1 (or later) has been largely unexplored, as the platform is relatively new. In this paper, we seek to determine the data remnants from the use of two popular Windows Store application software for instant messaging, namely Facebook and Skype on a Windows 8.1 client machine. This research contributes to an in-depth understanding of the types of terrestrial artefacts that are likely to remain after the use of instant messaging services and application software on a contemporary Windows operating system. Potential artefacts detected during the research include data relating to the installation or uninstallation of the instant messaging application software, log-in and log-off information, contact lists, conversations, and transferred files.

Citation: Yang TY, Dehghantanha A, Choo K-KR, Muda Z (2016) Windows Instant Messaging App Forensics: Facebook and Skype as Case Studies. PLoS ONE 11(3): e0150300. https://doi.org/10.1371/journal.pone.0150300

Editor: Muhammad Khurram Khan, King Saud University, Kingdom of Saudi Arabia, SAUDI ARABIA

Received: December 29, 2015; Accepted: February 11, 2016; Published: March 16, 2016

Copyright: © 2016 Yang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the paper.

Funding: These authors have no support or funding to report.

Competing interests: The authors have declared that no competing interests exist.

1. Introduction

Instant messaging (IM) is popular with both traditional computing device users (i.e., personal computers and laptops) and mobile device users by allowing them to exchange information with peers in real time using text messaging, voice messaging, and file sharing. According to the report of Radicati Group [1], the number of worldwide IM accounts (with the exception of mobile messaging) in 2015 amounted to over 3.2 billion which is expected to rise above 3.8 billion by the end of 2019.

Similar to other popular consumer technologies, IM services have also been exploited to commit frauds and scams [2–4], disseminate malware [5], groom children online with the purpose of sexual exploitation [6–9] etc. The chat logs can provide a great deal of information of evidential value to investigators [10, 11], which may often comprise a suspect’s physical location, true identity, transactional information, incriminating conversations, and other person information i.e., email address and bank account number [12].

Due to the increased user privacy requirements [13] and demands for data redundancy, it is increasingly challenging to collect evidential data from the IM service provider (ISP). The data are often protected by proprietary protocols, encryption, etc., making forensic practitioners virtually impossible to collect meaningful information from external network [14]. Moreover, collecting data from a multi-tenancy environment may breach the data privacy policies of the ISPs [15]. Even if the artefacts could be identified, the challenges are compounded by cross-jurisdictional investigations that may prohibit cross-border transfer of information [16–18]. In the worst-case scenario, the ISPs may not even log the incriminating conversations to reduce traffic to the messaging servers [19].

Depending on the IM application in use, the client device can often provide potential for alternative methods for recovery of the IM artefacts [20–22]. In addition to addressing the possible issues in relation to evidence acquisition from the ISPs, the terrestrial artefacts can be useful in establishing whether a suspect has a direct connection to a crime, as the suspect may claim he/she is a victim of identity theft otherwise. While a practitioner should be cognisant of techniques of digital forensics, it is just as important to maintain an up-to-date understanding of the potential artefacts that are recoverable from different types of IM products. Hence, in this paper, we seek to identify potential terrestrial artefacts that may remain after the use of the popular Facebook and Skype Windows Store application software (henceforth the Store app) on a Windows 8.1 client machine. Similar to the approaches of Quick and Choo [23–25], we attempt to answer the following questions in this research:

  1. What data remains on a Windows 8.1 device and their locations on a hard drive after a user has used Facebook app version 1.4.0.9 and Skype app version 3.1.0.1007.
  2. What data remains in Random Access Memory (RAM) after a user has used the above IM services or apps on a Windows 8.1 device?
  3. What data can be seen in network traffic?

Findings from this research will contribute to the forensic community’s understanding of the types of terrestrial artefacts that are likely to remain after the use of IM services and apps on devices running the newer Windows operating system.

The structure of this paper is as follows. Section 2 discusses the background and related work. Section 3 outlines the research methodology and experiment environment and setup. In Sections 4 to 6, we present and discuss the findings from the IM apps. We then conclude the paper and outline potential future research areas in the last section.

2. Literature Review

A Windows Store app (formerly known as Metro app) mimics the touch-screen-friendly mobile apps, while retaining the traditional mouse and keyboard inputs [26]. The installation is handled exclusively by the Windows Store, which bypasses the execution of executable files [27]. The Store apps are licensed to Microsoft account, giving the users the right to install a same app on up to eighty-one different Windows 8 (or newer) desktop clients under the same login [28]. The concept also enables the users to roam the app credentials (stored within the Credential Locker) between the corresponding devices [29].

The Store apps are predominantly built on Windows Runtime. In addition to offering the developers a multi-language programming environment, the architecture isolates the apps from the file system for security and stability [26]. The app itself is a package (.APPX file) that incorporates the app’s code, resources, libraries, and a manifest up to a combined limit of 8GB [26]. Each Store app is represented by a package ID, which is often denoted by the package name followed by its build version, the target platform, and the alphanumeric publisher identification (ID). The installation and application folders can be generally located in %Program Files%\WindowsApps\[Package ID] and %localappdata%\packages\[Package ID] respectively [30, 31].

The application data, correspond to the app states [26], are stored in three (3) categories: local, roaming, and temp states; each of which creates a subfolder in the application folder. The ‘LocalState’ folder holds device-specific data typically loaded to support the app functionality, such as temporary files and caches, recently viewed items, and other behavioural settings. The ‘RoamingState’ folder stores data shared between the same app running on multiple Windows devices under the same login. The data may include account configurations, favourites, game scores and progress, important URIs etc. Meanwhile, the ‘TempState’ folder houses data temporarily suspended or terminated from the memory for restoration purposes, such as page navigation history, unsaved form data etc. The application data persist throughout the lifetime of a Store app, with the exception of the temp data which may be subject to disk clean up [26].

The application cache/data can be stored using caching mechanisms like HTML5 local storage and IndexedDB (for Store apps written in HTML and JavaScript) as well as other third-party database options like SQLite [32]. In the absence of encryption mechanism, the data can aid in reconstruction of user events such as cloud storage [28], emails [30], web browsing history [33], conversations [34], and other user-specific events [35], depending on the Store app in use.

Instant messaging has been the subject of numerous digital forensic studies since the mid 2000’s. In a series of early works, Dickson identified that artefacts of the client-based American Online Messenger version 5.5 (AIM) [16], MSN Messenger version 7.5 [36], Yahoo Messenger version 7.0 [37], and Trillian version 3.1 [38] could be recovered from the registry, user settings, and other application-specific files on the hard drive of a Windows XP machine. By applying keyword search, the author was able to recover portion of the conversation history from unstructured datasets such as memory dumps, slack space, free space, and swap files in plain text, even with the absence of chat logging. The findings were echoed by several others studies with respect to Digsby [39–41], Windows Live Messenger 8.0 [42], and Pidgin 2.0 [43]. However, Levendoski et al. [44] concluded that artefacts of the Yahoo Messenger client produced a different directory structure on Windows Vista/7. Kiley et al. [19] investigated web-based IM apps (i.e., AIM Express, Google Talk, Meebo, and E-Buddy) and found that artefacts of the contact lists, conversations, and approximate time of the last conversation could only be recovered from memory dump and hard disk’s free space, although reference to the URLs, last access times, and view count information could be recovered from the web browsing history.

Wong et al. [45] and Al Mutawa et al. [46] demonstrated that artefacts of the Facebook web-application could be recovered from memory dumps and web browsing cache in Javascript Object Notation (JSON) and Hypertext Markup Language (HTML) formats. Al Mutawa et al. [46] also described a methodology for investigating the Arabic string artefacts on a computer device. In another study, Al Mutawa et al. [47] investigated artefacts of the Facebook and several other IM applications on iPhone 4, Blackberry Torch 9800, and Samsung GT-i9000 Galaxy S. The authors were able to extract records of the contact list and conversation from the logical images, with the exception of the BlackBerry devices.

Said et al. [48] investigated Facebook and other IM applications for iPhone 3G and 3GS, Blackberry Bold 7000 and 900, Samsung Omnia II i8000, Nokia E71, and Ericsson G900. Of all the mobile devices investigated, it was determined that only BlackBerry Bold 9700 and iPhone 3G/3GS provided evidence of Facebooking unencrypted. The study also revealed that artefacts of the Facebook applications were unique to the mobile devices investigated (i.e., iPhone 3GS and iphone 3G had the same version of Facebook v3.4.2 but maintained different files in the application folders). Walnycky et al. [49] added that artefacts of the Facebook Messenger could vary depending on user settings, OS version, and manufacturer. Levinson et al. [50] demonstrated that records of the recent Facebook chats stored in the property list of the Facebook Messenger for iOS can assist forensic practitioners with timeline analysis.

Examining iTunes backups rather than disk images, Norouzizadeh et al. [10] and Tso et al. [51] concluded that it is possible to extract users’ personal data, messages, contact lists and posts Facebook app from the iTunes backup of iPhone 4 and iPhone 5s, respectively. Chu et al. [52] focused on live data acquisition from the desktop personal computer (PC) and was able to identify distinct strings that will assist forensic practitioners with reconstruction of the previous Facebook sessions. Wongyai and Charoenwatana [53] determined that objects recovered from a network analysis of Facebook homepage can be broadly categorised into 24 types based on properties such as file type, naming pattern, IP address, and location or section on the page.

Sgaras et al. [54] analysed Skype and several other VoIP applications for iOS and Android platforms. Although footprints of the installations, user profiles, conversations, contact lists, and network traffic could be located for all the VoIP applications investigated, it was concluded that the Android apps store far less artefacts than of the iOS apps. Simon and Slay [55] found that remnants of Skype communication, communication history, contacts, passwords, and encryption keys could be recovered from physical memory dump. However, Teng and Lin [56] demonstrated that using SQLite editor tools, one could easily modify Skype log files. Unsurprisingly, other studies have suggested that the network traffic behaviour varies among different versions [57, 58].

In the only article on Windows Store apps for instant messaging (at the time of this research), Lee and Chung [34] studied the third party Viber and Line apps and identified that the package identifications (IDs) could be discerned from ‘2414F_C7A.ViberFreePhoneCallsText_p61zvh252yqyr’ and ‘NA_VER.LINEwin8_8ptj331gd3tyt’ respectively. By analysing the app caches, the authors managed to locate records of account logins, contacts, chats, transferred file unencrypted. However, the study is only limited to dead analysis of the hard disk. Hence, there is a need to develop a further understanding of the implications of the Windows Store apps for IM forensics–a gap that this paper aims to contribute to.

3. Research Methodology

The examination procedure in this research is adapted from the four-stage digital forensic framework of McKemmish [59], namely: identification of digital evidence, preservation of digital evidence, analysis, and presentation. The purpose is to enable acquisition of realistic data similar to that found in real world investigations. This paper mainly focuses on the analysis stage, although we also briefly discuss the evidence source identification, preservation, and presentation to demonstrate how the framework could be applied in practice.

The first step of the experiment involved the creation of eight (8) fictional accounts to play the role of suspects and victims in this research–see Table 1. The IM accounts were assigned with a unique ‘display icon’ and username which was not used within the respective IM apps and Windows operating system. This eases identification of the user roles. Next was to create the test environments for the suspects and the victims, which consisted two (2) control base VMware Workstations (VMs) version 9.0.0 build 812388 running Windows 8.1 Professional (Service Pack 1, 64 bit, build 9600). As explained by Quick and Choo [23–25], using physical hardware to undertake setup, erasing, copying, and re-installing would have been an onerous exercise. Moreover, a virtual machine allows room for error by enabling the test environment to be reverted to a restore point should the results are unfavourable. The workstations were configured with the minimal space (2GB of physical memory and 20GB hard drive space) in order to reduce the time required to analyse the considerable amounts of snapshots in the latter stage.

In the third step, we conducted a predefined set of activities to simulate various real world scenarios of using the apps on each workstation/test environment. The base assumptions are that the practitioner encounters a live system running Microsoft Windows 8.1 in a typical home environment. Similar to the approaches of Quick and Choo [23–25], the 3111th email message of the University of California (UC) Berkeley Enron email dataset (downloaded from http://bailando.sims.berkeley.edu/enron_email.html on 24th September 2014) was used to create the sample files and saved as SuspectToVictim.rtf, SuspectToVictim.txt, SuspectToVictim.docx, SuspectToVictim.zip, SuspectToVictim.jpg (printscreen), VictimToSuspect.rtf, VictimToSuspect.txt, VictimToSuspect.docx, VictimToSuspect.jpg (printscreen), and VictimToSuspect.zip to simulate the transferring and receiving of files of different formats using the IM apps. As the filenames suggest, the ‘SuspectToVictim’ (and ‘VictimToSuspect’) files were placed on the suspect’s workstation (and victims’ workstations respectively) and subsequently transferred to the victims’ workstations (and suspect’s workstation respectively).

The experiments were predominantly undertaken in NATed (where NAT stands for Network Address Translation) network environment and without firewall outbound restriction to represent a typical IM situation. Wireshark was deployed on the host machine to capture the network traffic from the suspect’s workstation for each scenario. After each experiment was carried out, we saved a copy of the network capture file in.PCAP format, and acquired a bit-stream (dd) image of the virtual memory (.VMEM) file prior to shutdown. We then took a snapshot of each workstation after being shutdown and made a forensic copy of the virtual disk (.VMDK) file in Encase Evidence (E01) format. This resulted in the creation of fifteen (15) snapshots (each for each environment) as highlighted in Table 2, and Figs 1 and 2. The decision to instantiate the physical memory dumps and hard disks with the virtual disk and memory files was to prevent the datasets from being modified with the use of memory/image acquisition tools [23, 25].

The final step of this research was to analyse the datasets using a range of forensically recognised tools (as highlighted in Table 3) and present the findings. Both indexed and non-indexed as well as Unicode and non-Unicode string searches were included as part of the evidence searches. The experiments were repeated at least thrice (at different dates) to ensure consistency of findings.

4. Analysis of the Facebook App

Facebook (Messenger) is an IM service offered by Facebook–one of the most popular social network platforms with more than one billion daily active users on average [60]. The Store app was officially released on 17th October 2013 in conjunction with the launch of Windows 8.1 [61]. It allows users to view status updates, news feeds, send and receive text and voice, as well as features such as file transfer and image sharing. In this section, we present artefacts of installation, uninstallation, logins, contact lists, conversations, transferred files, and notifications of the Facebook app (version 1.4.0.9) on Windows 8.1.

4.1 Installation of the Facebook App

Examinations of the directory listings observed that the package ID (for the Facebook app) can be differentiated from ‘Facebook.Facebook_1.4.0.9_x64__8xx8rvfyw5nnt’. A closer examination of the registry entries created during the installation observed that the installation time could be identified from the ‘InstallTime’ entry within the HKEY_USERS\<SID>\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\AppModel\Repository\Families\Faceook.Facebook_8xx8rvfyw5nnt\Facebook.Facebook_1.4.0.9_x64_8xx8rvfyw5nnt branch in 64-bit FILETIME Hex value in Big Endian format.

A search for the package ID ‘Facebook.Facebook_1.4.0.9_x64__8xx8rvfyw5nnt’ in the Windows Store logs (resided at %AppData%\Local\Temp\winstore.log and %AppData%\Local\Packages\winstore_cw5n1h2txyewy\AC\Temp\winstore.log) located supporting timestamp information such as the dates when the app was first launched and updated. Moreover, analysis of the prefetch files revealed the last run time and number of times the app has been loaded in ‘FACEBOOK.EXE.pf’. As for event logs, there was additional timestamp information which indicated the accessed times in ‘Application.evtx’, ‘Microsoft-WS-Licensing%4Admin.evtx’, ‘Microsoft-Windows-AppModel-Runtime%4Admin.evtx’, ‘Microsoft-Windows-AppXDeploymentServer%4Operational.evtx’, ‘Microsoft-Windows-Audio%4PlaybackManager.evtx’, ‘Microsoft-Windows-CoreApplication%4Operational.evtx’, ‘Microsoft-Windows-PushNotification-Platform%4Operational.evtx’, ‘Microsoft-Windows-Resource-Exhaustion-Resolver%4Operational.evtx’, ‘Microsoft-Windows-SettingSync%4Debug.evtx’, ‘Microsoft-Windows-Shell-Core%4Operational.evtx’, ‘Microsoft-Windows-TWinUI%4Operational.evtx’, ‘Microsoft-Windows-Windows Firewall With Advanced Security%4Firewall.evtx’, and ‘System.evtx’.

Examinations of the running processes using the ‘pslist’ function of Volatility determined that the process name could be discerned from ‘Facebook.exe’. Fig 3 illustrates that the ‘pslist’ output also included the process identifier (PID), parent process identifiers (PPID), and the process initiation and termination time. The PID could prove useful for correlating data associated with the the app during further analysis of the RAM (i.e., contextualising a string using the ‘Yarascan’ function of Volatility).

4.2 Logins

In our experiments, it was observed that Facebook maintains a wealth of cache data for the Store app in a number of SQLite databases located in %AppData%\Local\Packages\Facebook.Facebook_1.4.0.9_x64__8xx8rvfyw5nnt\LocalState\<User specific Facebook ID>\DB\, such as Analytics.sqlite, FriendRequests.sqlite, Friends.sqlite, Messages.sqlite, Notifications.sqlite, and Stories.sqlite. However, it is noteworthy that these databases will only appear when the user is logged in from the app. The database of interest with the logins is Analytics.sqlite, which contains records of the login time in Unix epoch format. The records can be discerned from the ‘name’ and ‘module’ table columns which reference ‘login’ and ‘login_events’ in the ‘analytics_logs’ table, respectively—see Fig 4. Within %AppData%\Local\Packages\Facebook.Facebook_8xx8rvfyw5nnt\AC\InetCache\<Cache ID>\ and %AppData%\Local\Packages\Facebook.Facebook_8xx8rvfyw5nnt\AC\.local_cache\ there were copies of profile and cover pictures of the user and the contacts, as well as other pictures which appeared on the Facebook timelines. The pictures may provide invaluable leads that lay the groundwork for follow-up via traditional investigative techniques.

A search for the login password produced no matches in the forensic image and memory dump. An examination of the network traffic revealed that the host first established a session with Symantec Certification Authority (i.e., IP address 23.58.43.27) for certificate authentication. Afterwards, the host accessed the nearest Akamai content delivery servers (i.e., IP addresses 23.62.109.*) and Facebook servers from different countries (i.e., IP addresses 31.13.*.* and 115.164.13.* in our research) on port 443 (hence HTTPS), which we theorised to retrieve the profile and timeline information. Although the network traffic was encrypted and the login credentials were not recovered, we were able to correlate the IP addresses with the timestamp information to determine when the app was started up and the duration of Facebook use in our research.

4.3 Friend Lists

Contact (or ‘friend’ in the context of Facebook) lists can be a useful reference point for a suspect’s social network. A search for the suspect’s profile name in the directory listing determined that artefacts of the contact lists can only be located in the Friends.sqlite database. The table of particular interest is the ‘friends’ table, which holds a list of user identifications (UIDs), full names, first names, middle names, last names, email addresses, phone numbers, profile links, communication rank (frequency of communication), and birth dates associated with the friends added by the user as shown in Fig 5. Moreover, the ‘profiles’ table provide supplementary information relating to the profiles viewed by the user such as the profile type (private profile or page), description (if any), URLs to the profiles, cover photo metadata (i.e., photo IDs, sizes, URLs, titles, and creation times for the cover photos), number of mutual friends associated with the profiles (if any), whether a friend request can be sent to the profiles, and the user has liked the page or is a subscriber.

4.4 Conversations and Transferred Files

Facebook allows users to transfer files up to 15MB. When a file is uploaded using the chat window, it will be attached alongside the line of chat messages (if any) and appear as a download link. The sender is allowed to abort a transfer part way through the process. The downloaded files were saved under %Downloads%\ by default, all of which were given an Alternate Data Stream (ADS) ZoneTransfer marker (ZoneID) with reading 'ZoneID = 3', indicating that the files were downloaded from an Internet zone [62]. This also suggests that when a user downloads a file using the Facebook app, there will be records remaining in Windows system files such as $LogFile, $MFT, and $UsnJrnl to indicate the filenames, directory paths, and timestamps for the downloaded files; an excerpt of the $LogFile entries (recovered from the suspect’s workstation) is shown in Fig 6. Analysis of the thumbnail caches stored within %AppData%\Local\Packages\Package ID\AC\INetCache\<Cache ID>\ and %AppData%\Local\Microsoft\Windows\Explorer\ (henceforth thumbcache) determined that copies of the transferred or downloaded can be recovered. This creates potential for alternative methods for recovery of the deleted files, but the results may not be definitive.

Examinations of the cache databases determined that artefacts of the conversations could be recovered from the Analytics.sqlite and Messages.sqlite databases. Within the ‘analytics_logs’ table of the former there were timestamp records which reflected the times when the chat tab was turned on, conversations were initiated by the user, as well as files were downloaded. The entry of which could be discerned from the ‘name’ table column which referenced ‘chat_turned_on’, ‘message_sent_attempt’ or ‘message_send_state’, and ‘file_downloaded’ respectively. Meanwhile, details about the conversations and file transfers were recovered from the ‘messages’ table in the latter. Each thread created an entry which comprised the thread ID, conversation texts (if any), UID and username of the sender and the receiver, a count of the number of times the message was sent, file attachment metadata (i.e., sender’s username and ID as well as filename, file size, and format references for the files transferred as shown in Fig 7), and other relevant information as shown in Fig 8. Additionally, the ‘users’ table (of the Messages.sqlite database) could provide additional information pertaining to the correspondents including the UIDs, email addresses, Facebook names, last active times and other information as detailed in Fig 9.

Undertaking data carving of the memory captures and unallocated space only produced matches to the transferred/downloaded sample files. By searching for terms unique to the app cache databases (i.e., table column names), it was possible to recover complete/partial fragments of the databases in plain text (similar to other IM scenarios). However, there was no common footer information to indicate the file structure. Fig 10 illustrates that records of conversations from the ‘messages’ table (of Messsages.sqlite database) can be located using the table column name ‘m_mid’. Moreover, we were also able to locate copies of Asynchronous JavaScript and XML (AJAX) objects for the Facebook chat in the memory captures. The artefacts could provide a clear indication of contact in Unix epoch format, Facebook usernames and UIDs of the correspondents, and conversation texts as depicted in Fig 11. The JSON coding could be a suitable search keyword for future searches. The presence of the remnants in the memory space of ‘Facebook.exe’ confirmed that the texts were associated with the Facebook app.

Inspecting the network traffic, it was observed that the transferred files were uploaded to IP addresses 31.13.70.*, 31.13.67.*, and 31.13.67.* with URLs referencing ‘upload.facebook.com’. The downloaded files were seen from IP addresses 31.13.70.*, and the URLs were prefixed with ‘cdn.fbsdx.com’. Meanwhile, the IP addresses i.e., 31.13.79.* and 31.13.76.102 were observed in relation to the conversations, with URLs referencing ‘5-edge-chat.facebook.com’—see Table 4 for details. Although the contents were encrypted completely, the IP addresses and URLs highlighted as part of our research may assist a practitioner in scoping the Facebook activities undertaken by a suspect in future investigations. Additionally, the IP addresses can be correlated with the ‘netscan’ output (of Volatility) to obtain information regarding the running process (i.e., PID, process creation time, and socket states) as detailed in Fig 12.

4.5 Real-time Notifications

Facebook notifications prompt users in real-time when activities such as messages and comments were posted on their walls, or wall post tagging took place. Analyses of the directory listings only revealed records of the notifications in the ‘notifications’ table of Notifications.sqlite database. The records contained the senders’ UIDs, notification texts, URLs, update and creation times, whether a notification has been read by the user (‘1’ for read and ‘0’ for unread), and other options useful to aid timeline analysis (see Fig 13).

4.6 Uninstallation of the Facebook App

Uninstallation of the Facebook app did not create uninstallation files. When the uninstallation was taken place, only the installation folder remained, but was moved to %Program Files%\WindowsApps\Deleted. Other footprints such as remnants from RAM, unallocated space, and system files such as pagefile.sys, shortcuts, event logs, prefetch files, $LogFile, $MFT, as well as $UsnJrnl were not affected by uninstallation process. The uninstallation also created additional references to the directory paths and timestamp information for the files removed during the uninstallation in $LogFile, $MFT, as well as $UsnJrnl.

5. Analysis of the Skype App

Skype is a popular IM and Voice over Internet Protocol (VoIP) application that provides free IM services, audio and video calls between computers and other mobile devices [63]. With the recent launch of Windows 8.1, Skype is now an integrated Windows service. The most recent version of Skype uses the Super Wideband Audio Codec (SILK) [64]. The overlay peer-to-peer network consists of a combination of ordinary and supernodes [57]. An ordinary node is a typical Skype application that provides the users the ability to place calls and send text messages. The supernode serves as a proxy to relay information between nodes with firewall restrictions and an intermediary to handle authentication and user lookups during logins [57].

In this section, we present results of our investigation of artefacts left behind after the use of the Skype (Windows store) app version 3.1.0.1007 on Windows 8.1, such as installation directory paths, usernames, passwords, text of conversations, transferred or downloaded files, records of video and voice calls, and the associated timestamps.

5.1 Installation of the Skype App

Analysis of the directory listing identified that the package ID could be discerned from ‘Microsoft.SkypeApp_kzf8qxf38zg5c’. The package ID was then used to correlate the ‘InstallTime’ registry entry, Windows Store logs, and event logs to determine the installation and accessed times. An inspection of the prefetch files determined that the process name (for the Skype app) was masqueraded with ‘WWAHost.exe’—the process name for the Store apps written in Javascript [35]. As the same process name was located for more than one app of the same type, it was not possible to determine exactly which prefetch file was associated with the Skype app.

5.2 Logins

The crucial artefacts were predominantly located in the user-specific %AppData%\Local\Packages\Microsoft.SkypeApp_kzf8qxf38zg5c\LocalState\<Skype name>\main.db database (unless otherwise stated, all tables will henceforth be referred to this database). Of particular interest with respect to the logins is the ‘Accounts’ table, which maintains a list of details about the Skype accounts logged in from the computer under investigation. The details comprise the account registration times in Unix epoch format, Microsoft Live usernames, Skype names, users’ full name, birth dates, gender, registered locations, phone numbers, email addresses, homepage URLs (if any), mood texts and the creation times, time zones, and other information useful for user profiling. To recover the avatars used by the users, the practitioner can access %AppData%\Local\Packages\Microsoft.SkypeApp_kzf8qxf38zg5c\LocalState\avatars\.

Analysis of the Internet Explorer’s web browsing history was able to identify two URLs associated with the logins, which were ‘login.skype.com/login?message=signin_continue&return_url=…’ and ‘login.skype.com/login/sso?nonce=…’). The web browsing history can provide an estimate of the number of times a suspect had accessed Skype as well as the corresponding login times on the computer under investigation.

Examination of the %AppData%\Local\Packages\Microsoft.SkypeApp_kzf8qxf38zg5c\LocalState\shared.xml file indicated the Skype name and node ID of the user in the ‘Default’ and ‘NodeID’ tags, respectively. The Skype name can prove useful for correlating events initiated by the user during further analysis. Meanwhile, it was observed that the ‘HostCache’ tag maintains a string of the supernode IP addresses and port pairs that Skype builds and refreshes regularly [57]. Each of which is recorded in twelve character hexadecimal strings and prefixed with ‘0400050041050200’ [65]. The shared.xml file also held records of the last used external IP address, port number, and last connected supernode IP address and port pair in the ‘LastIP’, ‘ListeningPort’, ‘Supernode’ tags in decimal format, respectively—see Fig 14; useful to support network analysis.

Although the process name was masqueraded with ‘WWAHost.exe’, we could correlate the supernode IP addresses (obtained from the shared.xml file) with the ‘netscan’ output (of Volatility) to determine the PID. For example, when we mapped the supernode IP address of ‘111.221.77.148’ with the ‘netscan’ output recovered from our research (see Fig 15), we obtained the PID ‘656’. The PID could then be used to map the ‘pslist’ output (of Volatility) to obtain additional information such as the PPID and process creation time as shown in Fig 16. Further analysis of the unstructured datasets identified that the config.xml and shared.xml files can be potentially carved from the memory dump and unallocated space using the header and footer values of “3C 3F 78 6D 6C 20 76 65 72 73 69 6F 6E 3D 22… 3C 2F 55 49 3E 0D 0A 3C 2F 63 6F 6E 66 69 67 3E 0D 0A” and “3C 3F 78 6D 6C 20 76 65 72 73 69 6F 6E 3D 22…3C 2F 4C 69 62 3E 0D 0A 3C 2F 63 6F 6E 66 69 67 3E 0D 0A” respectively, but the findings may be subject to software updates.

Upon launching the app, it was observed that the host first established a session with EdgeCast Networks to download Microsoft’s certificate revocation list (CRL) on port 80. The next session was established with the Akamai servers to retrieve the contact (i.e., IP address 23.58.236.138) and advertisement information (i.e., IP address 23.58.154.154) on port 443. Then, a session was established with the Microsoft servers (i.e., IP addresses 168.63.212.78 and 137.116.32.77 on port 443) for the traffic management service. When the logins occurred, the host first established several TCP sessions with random supernodes, which we hypothesised for user lookups [57]. Similar to the observation of Azab et al. [57], the IP addresses were associated with a combination of random and destined (33033) port numbers. The next servers accessed were the Windows Live Messenger server (i.e., IP address 65.54.184.60), Windows Live servers (i.e., IP addresses 65.55.246.*), as well as Hotmail server (i.e., IP address 65.55.68.104) on port 443 for login authentication and buddy list retrieval. The sessions were subsequently seen with random IP addresses on random UDP ports. Also observed were many connections to the IP addresses 91.190.216.* (referencing ‘rstwh.skype-cr.akadns.net’ and ‘1007.0.1.3.9.rst15.r.skype.net’) on random TCP port numbers, but we were unable to identify the actual functions of the IP addresses due to lack of information from the URLs as well as encrypted traffic—see Table 5 for details of the captured network traffic. Rebuilding the network files using Netminer, we only recovered certificates that were used to authenticate the HTTPS sites as well as HTML documents and image files from the HTTP sites. Since the network traffic was encrypted (HTTPS), no credential information was recovered from the network captures.

5.3 Contacts

Artefacts of the contacts were located in the ‘Contacts’ table. The artefacts comprised the Skype names, full names, birth dates, gender details, languages, registered locations, contact numbers, email addresses, homepage URLs (if any), mood texts, time zones, last online times, display names, last accessed times, and other information as depicted in Fig 17. Examination of the %AppData%\Local\Packages\Microsoft.SkypeApp_kzf8qxf38zg5c\LocalState\<Skype name>\config.xml file revealed the user ID for the contact with whom the user last communicated as well as the last accessed time. Each contact formed an opening and closing subtag in the 'u' tag as shown in Fig 18.

When the Skype account was synced with the Microsoft account, additional profile information was recovered for the contacts in the address book located at %Appdata%\Local\Packages\microsoft.windowscommunicationsapps_8wekyb3d8bbwe\LocalState\Indexed\LiveComm\6e4f9dff0b76dd9b\1207120049\People\AddressBook\26000001_bef42d234ebd42.appcontent-ms. Each contact formed an opening and closing ‘properties’ tag to house the search properties such as search keywords, full names, home addresses, birth dates, phone numbers, and other information as detailed in Fig 19, which may be of value for user profiling. Additionally, the similar information could be located for the user in the %Appdata%\Local\Packages\microsoft.windowscommunicationsapps_8wekyb3d8bbwe\LocalState\Indexed\LiveComm\6e4f9dff0b76dd9b\120712-0049\People\Me\24000001_7b20c4c2b2382.appcontent-ms file.

5.4 IM Conversations and Transferred Files

Examinations of the directory listings determined that the files downloaded were saved in %Downloads%\Microsoft.SkypeApp_kzf8qxf38zg5c!App\ and %AppData%\Local\Packages\Microsoft.SkypeApp_kzf8qxf38zg5c\LocalState\<Skype name>\ReceiveStorage\ by default; each of which was given an ADS ZoneID with reading 'ZoneID = 3'. Meanwhile, copies of the transferred files were located in %AppData%\Local\Packages\Microsoft.SkypeApp_kzf8qxf38zg5c\LocalState\<Skype name>\SendingStorage\. The files retained the original filenames and extensions. In addition to the file download or transfer directory paths, we were able to recover copies of thumbnail images for the transferred or downloaded files within the Windows thumbcache.

An inspection of the registry entries observed that each transferred or downloaded file created a Globally Unique Identifier (GUID) key in HKEY_USERS\<SID>\Software\Classes\LocalSettings\Software\Microsoft\Windows\CurrentVersion\AppModel\SystemAppData\Microsoft.SkypeApp_kzf8qxf38zg5c\PersistedStorageItemTable\ManagedByApp\. The entries of particular interest with the key are ‘FilePath’ and ‘LastUpdatedTime’, which hold the directory path and last modified time for the file. When the sample files were opened, references were found for the directory paths and last accessed times in the ‘RecentDocs’ registry key and ‘DLLHOST.EXE.pf’ prefetch file.

An inspection of the main.db database located further details regarding the file transfer or download in the ‘Transfers’ table. The details included the senders’ names, transfer types (where 1 indicates receiving and 2 indicates transferring), reasons for transfer failure (if any), storage paths, the times when the transfers were accepted, started and finished, as well as other file transfer information as shown in Fig 20. Records specific to the conversation or file transfer threads were located in the ‘Messages’ table, which encompassed the senders’ Skype names (authors), whether the correspondents were the user’s permanent contacts, the times when the threads were sent in Unix epoch format, the message sending status and types (as indicated in Table 6), reasons for message sending failure (if any), and other information as shown in Fig 21. The group chat could be discerned from the ‘participant_count’ table column given the value higher than 2. Moreover, it was also possible to recover the conversation texts and metadata associated with the downloaded or transferred files in the ‘body_xml’ table column (of the ‘Messages’ table). As can be seen in Fig 22, each downloaded or transferred file forms an opening and closing XML subtag (in the 'files' tag) to record its file size, transfer index, transfer ID, and filename in the ‘body_xml’ table column.

Another file of forensic interest that will potentially allow a practitioner to recover the conversation history is the ‘Chatsync’ file located in %AppData%\Local\Packages\Microsoft.SkypeApp_kzf8qxf38zg5c\LocalState\<Skype name>\Chatsync\. The ‘Chatsync’ file is stored in the format of <Random sixteen character strings>.DAT and is mainly used to facilitate chat log synchronisation between devices [67]. The ‘Chatsync’ file is chat-session-specific in the sense that a chatsync file is generally created for each chat session. Fig 23 illustrates that the 'Chatsync' files may provide the conversation texts and timestamp information for the chat sessions associated with the Skype user.

Unsurprisingly, a manual search for terms unique to the Enron sample files (i.e., ‘pensive’ and ‘parakeet’) as well as table column names of the main.db database produced matches to the plain text copies of the transferred/downloaded files and main.db database in the unstructured datasets, respectively. However, there was no common footer information that could enable future carving of the main.db database. We also located fragments of the payloads for the conversation threads in the memory dump, which held the conversation times, senders and receivers’ Skype names, and conversation texts as highlighted in Fig 24. When file transfers occurred, additional entries were observed for the filenames, file sizes, and file transfer IDs in the payload. The header fields could be suitable search terms for the remnants; a Yarascan search would attribute the remnants to the Skype’s process.

Examination of the network traffic observed that the host established a direct UDP connection with the correspondents during conversations and file transfers, and hence the IP addresses could be detected. However, there was no definitive port number or URL which could enable future identification of the traffic. Further analysis of the network packets determined that the data were fully encrypted, but we were able to estimate when the conversations were taken place from the corresponding timestamp information.

5.5 Voice and Video Calls

Skype allows users to perform voice calls via the free Skype to Skype calls and in the premium version, users could make Skype to mobile or landline calls using Skype credit. In order to enhance the user’s interactive experience, Skype allows users to share free video calls with anyone who has Skype and a webcam or compatible smartphone.

Examinations of the directory listings determined that the Skype app does not save the voice and video calls. However, we were able to recover a wealth of caches relating to the voice and video calls in the main.db database. Recalling the ‘Messages’ table, it was observed that entries of the voice or video calls could be differentiated from the ‘type’ table column given the value 30, 39, or 67 (see Table 6). Details of the voice or video calls were recovered from the 'Calls' table, which comprised the callers' Skype names, the times when the calls were started, the call durations in seconds, and whether the calls were incoming calls, conference calls, and put on hold—see Fig 25. Additionally, the ‘CallMembers’ table provided additional information associated with the contacts with whom the user had voice or video calls such as the Skype names, full names, call charges, reasons for call failures (if any), graphical user IDs (represented in ‘<User's Skype name>-<Correspondent's Skype name>-<Call name>‘), external IP addresses of the correspondents, call statuses, the times when the calls were started, the call durations, whether the calls were incoming or outgoing, conference calls, and from permanent contacts.

Examinations of the network traffic of the voice and video calls observed that the app established a session with the CloudFlare (GlobalSign) server for Online Certificate Status Protocol (OSCP) stapling and with the Verisign server for certificate authentication. When the calls occurred, the IP addresses were allocated to the supernodes (on random TCP ports) and then to the Windows Live server (i.e., IP address 65.55.246.85) on port 443, which we theorised for user lookups and authentications. The network traffic was subsequently seen with random IP addresses and UDP ports, which were hypothesised from supernodes responsible for bridging the VoIP, but the contents were encrypted completely.

5.6 Video Messages

Skype allows the users to share video messages (video recordings) with other online and offline users. The video messages are sent as a link in Skype version 6.5 or older, which requires a secret code access.

Sending a video message, it was observed that the Skype app stored a copy of the video message in %AppData%\Local\Packages\Microsoft.SkypeApp_kzf8qxf38zg5c\LocalState\<Skype name>\media\ of the sender's device by default. The video message also created a thumbnail image in %AppData%\Local\Packages\Microsoft.SkypeApp_kzf8qxf38zg5c\LocalState\<Skype name>\thumbnails\.

Analysis of the main.db database revealed that the Skype app cached notifications of the video messages in the ‘body_xml’ table column of the 'Messages' table, and the entry of which could be discerned from the XML tag 'videomessage'. The notification records provided the video message IDs, public links, and secret codes (sent from Skype application version 6.5 or older) for the video messages sent or received by the user as highlighted in Fig 26. Meanwhile, details of the video messages sent/received could be located in the ‘VideoMessages’ table, which included the directory paths, public links, titles, descriptions (if any), author names, creation times, transferring or receiving times as illustrated in Fig 27.

5.7 Uninstallation of the Skype App

Uninstallation of the Skype app did not remove the installation folders like as was presented for the Facebook app. However, the application folder was removed from the file system completely. Analysis of the unallocated space, RAM, as well as a variety Windows system files (i.e., $LogFile, $MFT, $UsnJrnl, pagefile.sys, shortcuts, event logs, prefetch files, and thumbcache files) resulted in the recovery of artefacts created prior to uninstallation of the app, with additional references to the directory paths and timestamp information for the files removed during the uninstallation in $LogFile, $MFT, $UsnJrnl.

6. Discussion

In this research, we identified artefacts common to investigating the Windows Store apps for IM. Previous studies only addressed dead analysis of the IM apps, while we focus on both the volatile and non-volatile artefacts. Our experiments showed that the Facebook and Skype apps maintain a wealth of caches of forensic interest within the ‘localstate’ application folder in Sqlite database unencrypted, which seem to agree with the findings of Lee and Chung [34]. This indicated that when a user has used a Windows Store app for IM, there will be records remaining in the application folder to support reconstruction of the logins, contact lists, conversations, file transfers, and other relevant IM activities, assuming that the app is not removed.

Although several registry keys new to the Windows Store apps could be recovered, it was determined that the Windows Store apps record significantly less information of interest to IM forensics in comparison to traditional client desktop application. While artefacts of the user profiles, contact lists and recent communications could be potentially recovered from the registry of the older Windows IM client applications [16, 21, 36–38, 42, 43], only installation metadata (i.e., install paths and times) could be recovered for the Windows Store apps, albeit records of the transferred files could be recovered in some cases. This is likely resulted from the adoption of the app caches. Similar to any other Windows client applications, our examinations of the system files such as $LogFile, $MFT, $UsnJrnl, shortcuts, event logs, thumbnail cache, as well as the ‘recentdocs’ registry key revealed that additional timestamp information could be recovered to support evidence found in all scenarios, but results may not be definitive.

It should be noted, however, that that the significance, amount, and location of artefacts could vary in accordance to the Windows Store apps under investigation. For instance, in our research, it was determined that:

  • both the Facebook and Skype apps maintain a different directory structure in the application folders;
  • the apps hold different database schema for the application caches;
  • caches of the Facebook app appear only when the user is logged in from the app, while caches of the Skype app remain resident throughout the lifetime of the app;
  • the Skype app caches copies of the transferred and downloaded files in the application folder but this is not the case with the Facebook app;
  • only the Skype app holds records of the transferred or downloaded files in HKEY_USERS\<SID>\Software\Classes\LocalSettings\Software\Microsoft\Windows\CurrentVersion\AppModel\SystemAppData\<Package ID>\PersistedStorageItemTable\ManagedByApp\.

The findings suggested that while a method can be generally defined to guide the investigation of the Windows Store apps, a different process may be necessary for investigating the different IM apps.

Our examinations of the physical memory captures indicated that the memory dumps can provide a potential alternative method for recovery of the application caches in plain text, with the exception of the login password. The fact that there was no clear text password in the hard drives and memory dumps should perhaps be unsurprising since the credential information is securely encrypted in the Credential Locker [29]. Nevertheless, a practitioner must keep in mind that memory changes frequently according to users’ activities and will be wiped as soon as the system is shut down.

In some cases, remnants of the caches could be located in the swap file (pagefile.sys) and unallocated space. The most likely explanation for the remnants is that the system swapped inactive memory pages containing the application caches out of the memory to the hard disk during the system’s normal operation. As the remnants were recovered with minimal space configuration in our research, we believe there will be a greater chance of remnants on a typically larger system. Although the network traffic was encrypted, sufficient IP address and URL references could be located for scoping the user activities as well as requesting for assistance from counterparts overseas (i.e., via Interpol). Hence, we recommend that the physical memory and network captures should be undertaken wherever practical. Table 7 summarises the key artefacts located as part of our research.

7. Conclusion and Future Work

Instant messaging (IM), such as VoIP apps, are increasingly popular among individuals 
and business organisations [68], including criminals. To ensure the most effective collection of evidence of relevance, it is important that a practitioner possess an up-to-date understanding of different technologies [69–77]. This paper presented the findings from our forensic examination (acquisition and reconstruction of the terrestrial artefacts left by the use) of two popular Windows Store IM apps, namely Facebook and Skype. The study consisted of installation, uninstallation, logins, conversations, transferred files, and and other IM activities specific to the apps investigated.

The results indicated that use of the Windows Store apps IM apps can leave behind incriminating evidential material useful or critical to an investigation on the hard drive, memory dumps, and network captures. The artefacts located as part of our experiments are likely to be common with other Windows Store IM apps as well as newer Windows OS (i.e., Windows 10), since the apps share a common feature set. While the implementation may vary between different IM apps, we contended that practitioners could use the artefacts identified in this research as a basis for their investigation of the client as a potential evidence source.

Future work would include:

  1. Extending this study to new (version of) apps, including apps popular in other countries (i.e., WeChat and LINE), to have an up-to-date forensic understanding of these technologies that can be used to inform investigations.
  2. Proposing a method for analyzing new (as of yet) unknown apps with similar functionality(ies). If such a method can be developed, evaluation might demonstrate that it can it be applied to a new app, or even implemented into a tool.

Author Contributions

Conceived and designed the experiments: TYY AD KKRC. Performed the experiments: TYY. Analyzed the data: TYY. Contributed reagents/materials/analysis tools: TYY AD KKRC. Wrote the paper: TYY AD KKRC ZM.

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Источник: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0150300

How Does Bitcoin Mining Work?

What Is Bitcoin Mining?

Bitcoin mining is the process by which new bitcoins are entered into circulation; it is also the way that new transactions are confirmed by the network and a critical component of the maintenance and development of the blockchain ledger. "Mining" is performed using sophisticated hardware that solves an extremely complex computational math problem. The first computer to find the solution to the problem is awarded the next block of bitcoins and the process begins again.

Cryptocurrency mining is painstaking, costly, and only sporadically rewarding. Nonetheless, mining has a magnetic appeal for many investors interested in cryptocurrency because of the fact that miners are rewarded for their work with crypto tokens. This may be because entrepreneurial types see mining as pennies from heaven, like California gold prospectors in 1849. And if you are technologically inclined, why not do it?

However, before you invest the time and equipment, read this explainer to see whether mining is really for you. We will focus primarily on Bitcoin (throughout, we'll use "Bitcoin" when referring to the network or the cryptocurrency as a concept, and "bitcoin" when we're referring to a quantity of individual tokens).

Key Takeaways

  • By mining, you can earn cryptocurrency without having to put down money for it.
  • Bitcoin miners receive Bitcoin as a reward for completing "blocks" of verified transactions, which are added to the blockchain.
  • Mining rewards are paid to the miner who discovers a solution to a complex hashing puzzle first, and the probability that a participant will be the one to discover the solution is related to the portion of the total mining power on the network.
  • You need either a GPU (graphics processing unit) or an application-specific integrated circuit (ASIC) in order to set up a mining rig.

Click Play to Learn How Bitcoin Mining Works

A New Gold Rush

The primary draw for many mining is the prospect of being rewarded with Bitcoin. That said, you certainly don't have to be a miner to own cryptocurrency tokens. You can also buy cryptocurrencies using fiat currency; you can trade it on an exchange like Bitstamp using another crypto (as an example, using Ethereum or NEO to buy Bitcoin); you even can earn it by shopping, publishing blog posts on platforms that pay users in cryptocurrency, or even set up interest-earning crypto accounts.

An example of a crypto blog platform is Steemit, which is kind of like Medium except that users can reward bloggers by paying them in a proprietary cryptocurrency called STEEM. STEEM can then be traded elsewhere for Bitcoin.

The Bitcoin reward that miners receive is an incentive that motivates people to assist in the primary purpose of mining: to legitimize and monitor Bitcoin transactions, ensuring their validity. Because these responsibilities are spread among many users all over the world, Bitcoin is a "decentralized" cryptocurrency, or one that does not rely on any central authority like a central bank or government to oversee its regulation.

Mining to Prevent Double Spend

Miners are getting paid for their work as auditors. They are doing the work of verifying the legitimacy of Bitcoin transactions. This convention is meant to keep Bitcoin users honest and was conceived by Bitcoin's founder, Satoshi Nakamoto. By verifying transactions, miners are helping to prevent the "double-spending problem." 

Double spending is a scenario in which a Bitcoin owner illicitly spends the same bitcoin twice. With physical currency, this isn't an issue: once you hand someone a $20 bill to buy a bottle of vodka, you no longer have it, so there's no danger you could use that same $20 bill to buy lotto tickets next door. While there is the possibility of counterfeit cash being made, it is not exactly the same as literally spending the same dollar twice. With digital currency, however, as the Investopedia dictionary explains, "there is a risk that the holder could make a copy of the digital token and send it to a merchant or another party while retaining the original."

Let's say you had one legitimate $20 bill and one counterfeit of that same $20. If you were to try to spend both the real bill and the fake one, someone that took the trouble of looking at both of the bills' serial numbers would see that they were the same number, and thus one of them had to be false. What a Bitcoin miner does is analogous to that—they check transactions to make sure that users have not illegitimately tried to spend the same bitcoin twice. This isn't a perfect analogy—we'll explain in more detail below.

Only 1 megabyte of transaction data can fit into a single bitcoin block. The 1 MB limit was set by Satoshi Nakamoto, and this has become a matter of controversy as some miners believe the block size should be increased to accommodate more data, which would effectively mean that the bitcoin network could process and verify transactions more quickly.

"So after all that work spent mining, I might still not get any bitcoin for it?"

That is correct. To earn bitcoins, you need to be the first miner to arrive at the right answer, or closest answer, to a numeric problem. This process is also known as proof of work (PoW).

"What do you mean, 'the right answer to a numeric problem'?"

The good news: No advanced math or computation is really involved. You may have heard that miners are solving difficult mathematical problems—that's true but not because the math itself is hard. What they're actually doing is trying to be the first miner to come up with a 64-digit hexadecimal number (a "hash") that is less than or equal to the target hash. It's basically guesswork.

The bad news: It's a matter of guesswork or randomness, but with the total number of possible guesses for each of these problems being on the order of trillions, it's incredibly arduous work. And the number of possible solutions only increases the more miners that join the mining network (known as the mining difficulty). In order to solve a problem first, miners need a lot of computing power. To mine successfully, you need to have a high "hash rate," which is measured in terms gigahashes per second (GH/s) and terahashes per second (TH/s).

If you want to estimate how much bitcoin you could mine with your mining rig's hash rate, the site Cryptocompare offers a helpful calculator. Other web resources offer similar tools.

Mining and Bitcoin Circulation

In addition to lining the pockets of miners and supporting the Bitcoin ecosystem, mining serves another vital purpose: It is the only way to release new cryptocurrency into circulation. In other words, miners are basically "minting" currency. For example, as of September 2021, there were around 18.82 million bitcoins in circulation, out of an ultimate total of 21 million.

Aside from the coins minted via the genesis block (the very first block, which was created by founder Satoshi Nakamoto), every single one of those bitcoins came into being because of miners. In the absence of miners, Bitcoin as a network would still exist and be usable, but there would never be any additional bitcoin. However, because the rate of bitcoin "mined" is reduced over time, the final bitcoin won't be circulated until around the year 2140. This does not mean that transactions will cease to be verified. Miners will continue to verify transactions and will be paid in fees for doing so in order to keep the integrity of Bitcoin's network.

Aside from the short-term Bitcoin payoff, being a coin miner can give you "voting" power when changes are proposed in the Bitcoin network protocol. This is known as a BIP (Bitcoin Improvement Protocol). In other words, miners have some degree of influence on the decision-making process on such matters as forking.

How Much a Miner Earns

The rewards for Bitcoin mining are reduced by half roughly every four years. When bitcoin was first mined in 2009, mining one block would earn you 50 BTC. In 2012, this was halved to 25 BTC. By 2016, this was halved again to 12.5 BTC. On May 11, 2020, the reward halved again to 6.25 BTC.

In September of 2021, the price of Bitcoin was about $45,000 per bitcoin, which means you'd have earned $281,250 (6.25 x 45,000) for completing a block. Not a bad incentive to solve that complex hash problem detailed above, it might seem.

If you want to keep track of precisely when these halvings will occur, you can consult the Bitcoin Clock, which updates this information in real-time. Interestingly, the market price of Bitcoin has, throughout its history, tended to correspond closely to the reduction of new coins entered into circulation. This lowering inflation rate increased scarcity and historically the price has risen with it.

If you are interested in seeing how many blocks have been mined thus far, there are several sites, including Blockchain.info, that will give you that information in real-time.

What You Need to Mine Bitcoins

Although early on in Bitcoin's history individuals may have been able to compete for blocks with a regular at-home personal computer, this is no longer the case. The reason for this is that the difficulty of mining Bitcoin changes over time.

In order to ensure the smooth functioning of the blockchain and its ability to process and verify transactions, the Bitcoin network aims to have one block produced every 10 minutes or so. However, if there are one million mining rigs competing to solve the hash problem, they'll likely reach a solution faster than a scenario in which 10 mining rigs are working on the same problem. For that reason, Bitcoin is designed to evaluate and adjust the difficulty of mining every 2,016 blocks, or roughly every two weeks.

When there is more computing power collectively working to mine for bitcoins, the difficulty level of mining increases in order to keep block production at a stable rate. Less computing power means the difficulty level decreases. At today's network size, a personal computer mining for bitcoin will almost certainly find nothing.

All of this is to say that, in order to mine competitively, miners must now invest in powerful computer equipment like a GPU (graphics processing unit) or, more realistically, an application-specific integrated circuit (ASIC). These can run from $500 to the tens of thousands. Some miners—particularly Ethereum miners—buy individual graphics cards (GPUs) as a low-cost way to cobble together mining operations.

An Analogy

Say I tell three friends that I'm thinking of a number between one and 100, and I write that number on a piece of paper and seal it in an envelope. My friends don't have to guess the exact number; they just have to be the first person to guess any number that is less than or equal to the number I am thinking of. And there is no limit to how many guesses they get.

Let's say I'm thinking of the number 19. If Friend A guesses 21, they lose because 21>19. If Friend B guesses 16 and Friend C guesses 12, then they've both theoretically arrived at viable answers, because of 16 < 19 and 12 < 19. There is no "extra credit" for Friend B, even though B's answer was closer to the target answer of 19. Now imagine that I pose the "guess what number I'm thinking of" question, but I'm not asking just three friends, and I'm not thinking of a number between 1 and 100. Rather, I'm asking millions of would-be miners and I'm thinking of a 64-digit hexadecimal number. Now you see that it's going to be extremely hard to guess the right answer.

If B and C both answer simultaneously, then the analogy breaks down.

In Bitcoin terms, simultaneous answers occur frequently, but at the end of the day, there can only be one winning answer. When multiple simultaneous answers are presented that are equal to or less than the target number, the Bitcoin network will decide by a simple majority—51%—which miner to honor.

Typically, it is the miner who has done the most work or, in other words, the one that verifies the most transactions. The losing block then becomes an "orphan block." Orphan blocks are those that are not added to the blockchain. Miners who successfully solve the hash problem but who haven't verified the most transactions are not rewarded with bitcoin.

What Is a "64-Digit Hexadecimal Number"?

Here is an example of such a number: 

0000000000000000057fcc708cf0130d95e27c5819203e9f967ac56e4df598ee

The number above has 64 digits. Easy enough to understand so far. As you probably noticed, that number consists not just of numbers, but also letters of the alphabet. Why is that?

To understand what these letters are doing in the middle of numbers, let's unpack the word "hexadecimal."

The decimal system uses as its base factors of 100 (e.g., 1% = 0.01). This, in turn, means that every digit of a multi-digit number has 100 possibilities, zero through ninety-nine. In computing, the decimal system is simplified to base 10, or zero through nine.

"Hexadecimal," on the other hand, means base 16, as "hex" is derived from the Greek word for six and "deca" is derived from the Greek word for 10. In a hexadecimal system, each digit has 16 possibilities. But our numeric system only offers 10 ways of representing numbers (zero through nine). That's why you have to stick letters in, specifically letters a, b, c, d, e, and f. 

If you are mining Bitcoin, you do not need to calculate the total value of that 64-digit number (the hash). I repeat: You do not need to calculate the total value of a hash. 

So, what do "64-digit hexadecimal numbers" have to do with Bitcoin mining? 

Remember that analogy, where the number 19 was written on a piece of paper and put it in a sealed envelope? In Bitcoin mining terms, that metaphorical undisclosed number in the envelope is called the target hash.

What miners are doing with those huge computers and dozens of cooling fans is guessing at the target hash. Miners make these guesses by randomly generating as many "nonces" as possible, as fast as possible. A nonce is short for "number only used once," and the nonce is the key to generating these 64-bit hexadecimal numbers I keep talking about. In Bitcoin mining, a nonce is 32 bits in size—much smaller than the hash, which is 256 bits. The first miner whose nonce generates a hash that is less than or equal to the target hash is awarded credit for completing that block and is awarded the spoils of 6.25 BTC.

In theory, you could achieve the same goal by rolling a 16-sided die 64 times to arrive at random numbers, but why on earth would you want to do that?

The screenshot below, taken from the site Blockchain.info, might help you put all this information together at a glance. You are looking at a summary of everything that happened when block #490163 was mined. The nonce that generated the "winning" hash was 731511405. The target hash is shown on top. The term "Relayed by Antpool" refers to the fact that this particular block was completed by AntPool, one of the more successful mining pools (more about mining pools below).

As you see here, their contribution to the Bitcoin community is that they confirmed 1768 transactions for this block. If you really want to see all 1768 of those transactions for this block, go to this page and scroll down to the heading "Transactions."

(source: Blockchain.info)

How do I guess at the target hash

All target hashes begin with a string of leading zeroes. There is no minimum target, but there is a maximum target set by the Bitcoin Protocol. No target can be greater than this number:

00000000ffff0000000000000000000000000000000000000000000000000000

The winning hash for a bitcoin miner is one that has at least the minimum number of leading zeroes defined the mining difficulty.

Here are some examples of randomized hashes and the criteria for whether they will lead to success for the miner:

To find such a hash value, you have to get a fast mining rig, or, more realistically, join a mining pool—a group of coin miners who combine their computing power and split the mined Bitcoin. Mining pools are comparable to those Powerball clubs whose members buy lottery tickets en masse and agree to share any winnings. A disproportionately large number of blocks are mined by pools rather than by individual miners.

In other words, it's literally just a numbers game. You cannot guess the pattern or make a prediction based on previous target hashes. At today's difficulty levels, the odds of finding the winning value for a single hash is one in the tens of trillions. Not great odds if you're working on your own, even with a tremendously powerful mining rig.

Not only do miners have to factor in the costs associated with expensive equipment necessary to stand a chance of solving a hash problem. They must also consider the significant amount of electrical power mining rigs utilize in generating vast quantities of nonces in search of the solution. All told, Bitcoin mining is largely unprofitable for most individual miners as of this writing. The site Cryptocompare offers a helpful calculator that allows you to plug in numbers such as your hash speed and electricity costs to estimate the costs and benefits.

(Source: Cryptocompare)

What Are Coin Mining Pools?

Mining rewards are paid to the miner who discovers a solution to the puzzle first, and the probability that a participant will be the one to discover the solution is equal to the portion of the total mining power on the network. 

Participants with a small percentage of the mining power stand a very small chance of discovering the next block on their own. For instance, a mining card that one could purchase for a couple of thousand dollars would represent less than 0.001% of the network's mining power. With such a small chance at finding the next block, it could be a long time before that miner finds a block, and the difficulty going up makes things even worse. The miner may never recoup their investment. The answer to this problem is mining pools. 

Mining pools are operated by third parties and coordinate groups of miners. By working together in a pool and sharing the payouts among all participants, miners can get a steady flow of bitcoin starting the day they activate their miners. Statistics on some of the mining pools can be seen on Blockchain.info.

"I've done the math. Forget mining. Is there a less onerous way to profit from cryptocurrencies?"

As mentioned above, the easiest way to acquire Bitcoin is to simply buy it on one of the many exchanges. Alternately, you can always leverage the "pickaxe strategy." This is based on the old saw that during the 1849 California gold rush, the smart investment was not to pan for gold, but rather to make the pickaxes used for mining.

To put it in modern terms, invest in the companies that manufacture those pickaxes. In a cryptocurrency context, the pickaxe equivalent would be a company that manufactures equipment used for Bitcoin mining. You may consider looking into companies that make ASICs equipment or GPUs instead, for example.

Downsides of Mining 

The risks of mining are often that of financial risk and a regulatory one. As mentioned, Bitcoin mining, and mining in general, is a financial risk since one could go through all the effort of purchasing hundreds or thousands of dollars worth of mining equipment only to have no return on their investment. That said, this risk can be mitigated by joining mining pools. If you are considering mining and live in an area where it is prohibited you should reconsider. It may also be a good idea to research your country's regulation and overall sentiment towards cryptocurrency before investing in mining equipment.

One additional potential risk from the growth of Bitcoin mining (and other proof-of-work systems as well) is the increasing energy usage required by the computer systems running the mining algorithms. While microchip efficiency has increased dramatically for ASIC chips, the growth of the network itself is outpacing technological progress. As a result, there are concerns about the environmental impact and carbon footprint of Bitcoin mining.

There are, however, efforts to mitigate this negative externality by seeking cleaner and green energy sources for mining operations (such as geothermal or solar), as well as utilizing carbon offset credits. Switching to less energy-intensive consensus mechanisms like proof-of-stake (PoS), which Ethereum has transitioned to, is another strategy; however, PoS comes with its own set of drawbacks and inefficiencies such as incentivizing hoarding instead of using coins and a risk of centralization of consensus control.

Why is it called bitcoin "mining"?

Mining is used as a metaphor for introducing new bitcoins into the system, since it requires (computational) work just as mining for gold or silver requires (physical) effort. Of course, the tokens that miners find are virtual and exist only within the digital ledger of the Bitcoin blockchain.

Why do bitcoins need to be mined?

Since they are entirely digital records, there is a risk of copying, counterfeiting, or double-spending the same coin more than once. Mining solves these problems by making it extremely expensive and resource-intensive to try to do one of these things or otherwise "hack" the network. Indeed, it is far more cost-effective to join the network as a miner than to try to undermine it.

What do you mean mining confirms transactions?

In addition to introducing new BTC into circulation, mining serves the crucial role of confirming and validating new transactions on the Bitcoin blockchain. This is important because there is no central authority such as a bank, court, government, or anything else determining which transactions are valid and which are not. Instead, the mining process achieves a decentralized consensus through proof-of-work (PoW).

Why does mining use so much electricity?

In the early days of Bitcoin, anybody could simply run a mining program from their PC or laptop. But, as the network got larger and more people became interested in mining, the difficulty of the mining algorithm became more difficult. This is because the code for Bitcoin targets finding a new block once every ten minutes, on average. If more miners are involved, the chances that somebody will solve the right hash quicker increases, and so the difficulty is raised to restore that 10-minute goal. Now imagine if thousands, or even millions more times of mining power joins the network. That's a lot of new machines consuming energy.

Is Bitcoin Mining Legal?

The legality of Bitcoin mining depends entirely on your geographic location. The concept of Bitcoin can threaten the dominance of fiat currencies and government control over the financial markets. For this reason, Bitcoin is completely illegal in certain places.

Bitcoin ownership and mining are legal in more countries than not. Some examples of places where it was illegal according to a 2018 report were Algeria, Egypt, Morocco, Bolivia, Ecuador, Nepal, and Pakistan. Overall, Bitcoin use and mining remain legal across much of the globe.

Источник: https://www.investopedia.com/tech/how-does-bitcoin-mining-work/

Re-Authentication

The parameter

The parameter is intended to be a completely arbitrary alphanumeric code that your app generates. The process of generation and format of this code is entirely up to you. For example, a hashed version of a timestamp and a secret string may be sufficient, as long as it's completely unique to each Login attempt. This value enables your app to determine whether a user has been re-authenticated.

You will again need to modify your login flow to specify the parameter, for example:

FB.login(function(response) { // Original FB.login code }, { auth_type: 'reauthenticate', auth_nonce: '{random-nonce}' })

In order to check that this nonce hasn't been used before, you need to create a function to communicate with code that checks your app's database to see if it already used a particular nonce.

Below is an example using JavaScript (with the jQuery framework) and PHP as a guide that you can adapt to your own specific setup. For our example we will use a hard-coded string as the nonce. You should replace this with a dynamic call to a generated nonce.

function checkNonce(access_token) { $.post('checkNonce.php', {access_token: access_token}, function(data) { if (data == 1) { console.log('The user has been successfully re-authenticated.'); FB.api('/me', function(response) { console.log('Good to see you, ' + response.name + '.'); }); } else { console.log('The nonce has been used before. Re-authentication failed.'); } }); }

Note: This PHP file only implies, and does not include, the snippet of code which would compare the supplied nonce against the app's database. You should tailor this to your own database and code environment:

<?php $access_token = $_REQUEST['access_token']; $graph_url = 'https://graph.facebook.com/oauth/access_token_info?' . 'client_id=YOUR_APP_ID&amp;access_token=' . $access_token; $access_token_info = json_decode(file_get_contents($graph_url)); function nonceHasBeenUsed($auth_nonce) { // Here you would check your database to see if the nonce // has been used before. For the sake of this example, we'll // just assume the answer is "no". return false; } if (nonceHasBeenUsed($access_token_info->auth_nonce) != true) { echo '1'; } else { echo '0'; } ?>

In this example, the JavaScript function would be called after receiving the access token response from the re-authentication login dialog. Using the JavaScript SDK as an example:

FB.login(function(response) { if (response.authResponse) { // Login success, check auth_nonce... checkNonce(response.authResponse.access_token); } else { // User cancelled } }, { auth_type: 'reauthenticate', auth_nonce: '{random-nonce}' })

Note that the is an optional part of re-authentication. Apps are strongly encouraged to use it, however, especially when requesting as .

Источник: https://developers.facebook.com/docs/facebook-login/reauthentication/

metamask swap error fetching quotes To trade on Balancer: Balancer. MetaMask is a Google Chrome, Vivaldi, Opera and Firefox extension for the browser which makes it easy for web applications to communicate with the Ethereum blockchain. Enter all the details below Network Name: Binance I am following these instructions. 2021-10-14. Set the amount you wish to buy in the "From" box, and press the "Swap" button; Confirm transaction and HODL. Therefore my program must fetch quotes in batches of 50 symbols (if there are more than 50 to get quotes for). You're trying to swap tokens, but your slippage tolerance is too low or liquidity is too low. It should be noted that some wallets charge higher transaction fees, compared to actual network fees, to cover their development cost. And i replace 0x to ronin. 3. A bad or failing ECM may produce any of the following 5 symptoms to alert the driver of a potential problem. MetaMask users can now swap tokens directly from their wallet. It eliminates trusted intermediaries and unnecessary forms of rent extraction, allowing for fast, efficient trading. Prior in selecting “Get Quotes” button, it says “MUNCH is only  Mar 6, 2021 I have been trying to swap my HOGE to ETH since yesterday on Metamask however its giving an error "No quotes available. The Spend Limit permission is the total amount of tokens that are able to move when using MetaMask Swap. 0 (Windows NT 6. Using RPC, you may perform low-level operations like executing ABCI queries, viewing network/consensus state or broadcasting a transaction. If you'r using MetaMask Swap, you'r getting this on-top of the existing 0. Simplemente recomiendan hacer el swap a través de la extensión MetaMask en Uniswap con el navegador. Buy, store, send and swap tokens Available as a browser extension and as a mobile app, MetaMask equips you with a key vault, secure login, token wallet, and token exchange—everything you need to manage your digital assets. A nonce is a number that gets incremented by 1 with every new transaction. When Raghu Vemula first formed the Nuance cross‑functional team that created PowerShare, his goal was to improve the cumbersome and time‑consuming process of sharing radiology imaging among medical providers and hospitals. I have already given few pictures in this article and following this article will help you to win this matter. Next, select the tokens you wish to swap and click ‘Get quotes’. First, update apt-get to make sure it knows where to download everything. This process will assume your starting point is a fresh install of Metamask on Google Chrome (v83. It makes 1 quote web service call for each batch. 55. You should see part of your wallet address at the right top corner; Click the icon at the top, at set the slippage tolerance to 12% then close that box. // For this, you need the account signer Fail to fetch errors RPC issues, change to a GUI that uses different nodes or wait for a bit while it gets better. Thus, I'm stuck. 4103. On your MetaMask wallet drop down your accounts and go to settings page. ag, Paraswap, Totle, and private market makers, MetaMask will access the most liquidity across the DeFi ecosystem”. The passcode is used to login into your MetaMask wallet. Swap interface will be open to all at 16:00 GMT, ie, after 2 hours. Available as a browser extension and as a mobile app, MetaMask equips you with a key vault, secure login, token wallet, and token exchange—everything you need to manage your digital assets. Step 3 - Step 9: How to view your Ethereum private keys, import them into Metamask, and add Binance Network to Metamask. Reason. Here is a screenshot showing the different quotes you  const response = await fetch(`https://api. Apart from the third-party wallets we have mentioned, there are many other wallets offering different features. MetaMask is a Crypto Wallet and Your Gateway to Web3 Buy, store and send tokens globally Explore blockchain applications at lightening speed Choose what to share and what to keep private. This way users will always get the cheapest prices. May 12, 2021 Uno de los errores más comunes al utilizar los swaps en MetaMask es el ''Error Fetching Quote'' en lo que su traducción sería error al  May 4, 2021 Getting “Error Fetching Quote” when swapping Ethereum to MUNCH on MetaMask. 0 digital wallet (there are no signups or KYC requirements). Connecting MetaMask to BSC Mainnet. users with a number of quotes – including estimated gas fee – to choose from. Next, install some base dependencies and tools we'll need later. Solution. I wanted to get the file name using the “Path. Step 4: Fetch all the details required for the token you will like to add to  Swap ETH for SHIB Oct 08, 2021 · ERROR for this is SHIBA INU FETCHING QUOTES all this is done by calling SHIIBA INU COIN SUPPORT NUMBER USA/CA , because  FTX Cryptocurrency Derivatives Exchange API documentation. A lmost as soon as Norma Jeane Dougherty signed a contract with 20th Century Fox on August 24, 1946, the search for her new stage name was underway…. ― Teresa Driscoll, I Am Watching You. Sentry Issue: METAMASK-MOBILE-F6X Error: timeout timeout. But before starting, we are going to define How to set up and use MetaMask for DeFi. GetFileName” function into a single variable. · Tokenswap MetaMask Steps. ”. I know this is a old post, however I was stuck in split string and was working on resolution which I wanted to share. When building smart contracts, you will need a way to deploy your contracts, run tests, and debug Solidity code without dealing with live environments. walletAddress. MetaMask requires that you store your seed phrase in a safe place. MEXC Exchange is the world's first user-friendly digital asset service provider, providing real-time prices of crypto tokens such as Bitcoin BTC,  Apr 22, 2020 Part 1 got you through how to get a quote on a trade: getting the amount of token you'll get in exchange of the one you're selling. swapCurrencies Use DeX to provide liquidity About: "Stablecoins powered by the Acala Network can be transferred to all chains in the Polkadot network, which will boost its liquidity and adoption to a degree that a single-chain asset would not be able to achieve. Nov 09, 2020 · How to swap tokens on MetaMask. Solution for this is to browse pancake swap trough matamask ok trust wallet. Switch to Binance Smart Chain for BSC and BEP20 tokens. Update the time range of the response data for the following margin account endpoints, startTime and endTime time span will not exceed 30 days, without time parameter sent the system will return the last 7 days of data by default, while the archived parameter is true, the system will return the last 7 days of data 6 months ago by default: Now you can fund your metamask wallet with BNB and use dapps like pancakeswap. 8-for the use and should remain the client. Make the trade by calling the swap method with the parameters we got at step 1. Metamask has released an update that will affect your ability to login and use Morpher using Metamask. You will probably encounter this message: The Morpher chain ID is 21, and you need to configure it within your RPC network settings like this: To begin with, open Trust Wallet and navigate to PancakeSwap via the DApp browser. For example, the following markup fragment results in a DOM with an hr element that is an earlier sibling of the corresponding table element: A life‑saving idea. org Coin (CRO), Basic Attention Token (BAT), Dai (DAI), KyberNetwork (KNC), 0x (ZRX), USDC, and many more ERC-20 tokens. RPC endpoints may be used to interact with a node directly over HTTP or websockets. stringify(error, null, 2));. This response started with a < (hence the “Unexpected token <”). Import wallet into Metamask. You can buy bitcoin and other cryptocurrencies with a credit card or any crypto wallet Unintuitive error-handling behavior Certain invalid syntax constructs, when parsed, result in DOM trees that are highly unintuitive. com is the best instant cryptocurrency exchange platform with the best exchange rates for BTC, ETH, LTC, XRP, ADA and 140+ other cryptocurrencies. The type of saving term: FLEX or Fixed. It is multi-chain and allows you to interact with dApps right in your browse or via the app, without running a full node . You can send, receive, and store Bitcoin (BTC), Ethereum (ETH), Litecoin (LTC), Lumen (XLM), Crypto. Install a socat proxy and run it. In other words, MetaMask is Click "Swap" dex. Know someone who can answer? Share a link to this question via email, Twitter, or Facebook. com DeFi So, please do not buy V1 coins after 02 May’21 at 14:00 as you will not be able to swap those. 1; WOW64) AppleWebKit/534+ (KHTML, like Gecko) BingPreview/1. Use Ethereum Mainnet for ETH and ERC20 transfers. V2 Farms will go live simultaneously. com is available. finance, remeber to always select Smart Chain whenever you want to use Binance Smart Chain. MoonSwap gained attention from investor and expected to get more raking boost in future. I was doing this and I couldn’t figure a way around it by escaping either. 875% is automatically factored into each quote, which supports  After you confirm the swap, MetaMask will pop up, asking you to confirm or test-444 revert-view-quote-design-updates hardware-wallet-error-message  Jun 9, 2021 Uniswap is a protocol for the decentralized exchange of tokens on the features that enable convenient fetching of data and pricing. It but they vouch for how bitcoin charting tool used to your requirements, including those events that the recommended penalties, and cannot be exchanged in metamask. The "Failed to fetch quotes from MSN Money" message happens if any of these quote web service calls fails. 1 – go to your matamask wallet and click the pointed button. Snapchat has unveiled a new feature that allows users to selectively color objects and areas in Snaps. "Error Fetching http headers" is a common error to encounter when working with the SLAPI. 2- Chose the Browser. Download the Android Trust Wallet and iOS app today! I Am Watching You Quotes Showing 1-30 of 85. So, prior to acquiring Ether, we must first get a MetaMask wallet. Secure & easy to use Crypto & Bitcoin Wallet with 100+ digital assets & … In  Sometimes metamask gets it wrong, though, and sets the gas price too low. 1 coin in list of highest gainer list on CMC. The flexibility, ease of use and device compatibility are provided through the advanced trading components, which include the desktop, mobile and web terminals. 7 sudo apt-get Bringing the functionality of Uniswap to Metamask. Of a bid to quickly to $8. For TensorFlow: # For Python 2. API tutorial for beginners: what is Apps Script? In this API tutorial for beginners, we’ll use Google Apps Script to connect to external APIs. Connect your MetaMask or other Web 3. 0,reuseaddr,fork tcp4: source_database_ip_address: database_port &. Learn more about our interest rates here. An illuminated Check Engine Light is one possible symptom of a problem with the ECM. Create an NFT-based Game. 0. You are signing in from: 157. Unable to swap Jetstream default TailwindCSS modal for Bootstrap Modal and still achieve the expected or same result as its was with TailwindCSS 17th September 2020 laravel , laravel-livewire , twitter-bootstrap Trusted by over 1 million users worldwide. Ethereum development environment. e. exchange, dex. the transaction cannot succeed due to error: execution reverted: pancakerouter: insufficient_output_amount. ethereum) // The Metamask plugin also allows signing transactions to // send ether and pay to change state within the blockchain. Adding the Binance Smart Chain Network to your MetaMask Wallet. MetaMask is a non-custodial wallet. This is probably an issue with one of the tokens you are swapping. Please wait while IPFS with TiddlyWiki is loading v0. The following script allows the react-app to connect to Metamask, then show the homepage; moreover, if the user is already connected. The Contract Address 0x8ae96701D69a9c59faC3032dA24f389C03230df5 page allows users to view the source code, transactions, balances, and analytics for the contract address. You don’t even need to open an account provided that you have a supported web3 wallet like MetaMask. That unexpected token, <, is a strong clue that the response was HTML instead of JSON. 3- Now go to pancake swap and connect your wallet. Sentry: Swaps: error-fetching-quotes #2504. I just init and start a private geth node on 8545 on a vps, and then I try to input htttp://theIP:8545 on custom RPC in metamask, it will always run and wait. “Because once you become a parent, you learn that love can involve more fear than you had ever imagined, and you never quite look on the world in the same way again. sentry-io bot opened this issue Apr 13, 2021 · 0 comments This was happening to me when i was trying to swap babydoge and minishib on the metamask extension for chrome and i ended up here and then i thought why dont i just swap on pancake swap since my metamask wallet is connected there and it worked. metamask swap error fetching quotes

Источник: http://mcspal.pl/06adf/metamask-swap-error-fetching-quotes.html

: M facebook com login device based update nonce

M facebook com login device based update nonce
M facebook com login device based update nonce
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metamask swap error fetching quotes To trade on Balancer: Balancer. MetaMask is a Google Chrome, Vivaldi, Opera and Firefox extension for the browser which makes it easy for web applications to communicate with the Ethereum blockchain. Enter all the details below Network Name: Binance I am following these instructions. 2021-10-14. Set the amount you wish to buy in the "From" box, and press the "Swap" button; Confirm transaction and HODL. Therefore my program must fetch quotes in batches of 50 symbols (if there are more than 50 to get quotes for). You're trying to swap tokens, but your slippage tolerance is too low or liquidity is too low. It should be noted that some wallets charge higher transaction fees, compared to actual network fees, to cover their development cost. And i replace 0x to ronin. 3. A bad or failing ECM may produce any of the following 5 symptoms to alert the driver of a potential problem. MetaMask users can now swap tokens directly from their wallet. It eliminates trusted intermediaries and unnecessary forms of rent extraction, allowing for fast, efficient trading. Prior in selecting “Get Quotes” button, it says “MUNCH is only  Mar 6, 2021 I have been trying to swap my HOGE to ETH since yesterday on Metamask however its giving an error "No quotes available. The Spend Limit permission is the total amount of tokens that are able to move when using MetaMask Swap. 0 (Windows NT 6. Using RPC, you may perform low-level operations like executing ABCI queries, viewing network/consensus state or broadcasting a transaction. If you'r using MetaMask Swap, you'r getting this on-top of the existing 0. Simplemente recomiendan hacer el swap a través de la extensión MetaMask en Uniswap con el navegador. Buy, store, send and swap tokens Available as a browser extension and as a mobile app, MetaMask equips you with a key vault, secure login, token wallet, and token exchange—everything you need to manage your digital assets. A nonce is a number that gets incremented by 1 with every new transaction. When Raghu Vemula first formed the Nuance cross‑functional m facebook com login device based update nonce that created PowerShare, his goal was to improve the cumbersome and time‑consuming process of sharing radiology imaging among medical providers and hospitals. I have already given few pictures in this article and following this article will help you to win this matter. Next, select the tokens you wish to swap and click ‘Get quotes’. First, update apt-get to make sure it knows where to download everything. This process will assume your starting point is a fresh install of Metamask on Google Chrome (v83. It makes 1 quote web service call for each batch. 55. You should see part of your wallet address at the right top corner; Click the icon at the top, at set the slippage tolerance to 12% then close that box. // For this, you need the account signer Fail to fetch errors RPC issues, change to a GUI that uses different nodes or wait for a bit while it gets better. Thus, I'm stuck. 4103. On your MetaMask wallet drop down your accounts and go to settings page. ag, Paraswap, Totle, and private market makers, MetaMask will access the most liquidity across the DeFi ecosystem”. The passcode is used to login into your MetaMask wallet. Swap interface will be open to all at 16:00 GMT, ie, after 2 hours. Available as a browser extension and as a mobile app, MetaMask equips you with a key vault, secure login, token wallet, and token exchange—everything you need to manage your digital assets. Step 3 - Step 9: How to view your Ethereum private keys, import them into Metamask, and add Binance Network to Metamask. Reason. Here is a screenshot showing the different quotes you  const response = await fetch(`https://api. Apart from the third-party wallets we have mentioned, there are many other wallets offering different features. MetaMask is a Crypto Wallet and Your Gateway to Web3 Buy, store and send tokens globally Explore blockchain applications at lightening speed Choose what to share and what to keep private. This way users will always get the cheapest prices. May 12, 2021 Uno de los errores más comunes al utilizar los swaps en MetaMask es el ''Error Fetching Quote'' en lo que su traducción sería error al  May 4, 2021 Getting “Error Fetching Quote” when swapping Ethereum to MUNCH on MetaMask. 0 digital wallet (there are no signups or KYC requirements). Connecting MetaMask to BSC Mainnet. users with a number of quotes – including estimated gas fee – to choose from. Next, install some base dependencies and tools we'll need later. Solution. I wanted to get the file name using the “Path. Step credit union st louis mo Fetch all the details required for the token you will like to add to  Swap ETH for SHIB Oct 08, 2021 · ERROR for this is SHIBA M facebook com login device based update nonce How much does paypal charge for a business account QUOTES all this is done by calling SHIIBA INU COIN SUPPORT NUMBER USA/CAbecause  FTX Cryptocurrency Derivatives Exchange API documentation. A lmost as soon as Norma Jeane Dougherty signed a contract with 20th Century Fox on August 24, 1946, the search for her m facebook com login device based update nonce stage name was underway…. ― Teresa Driscoll, I Am Watching You. Sentry Issue: METAMASK-MOBILE-F6X Error: timeout timeout. But before starting, we are going to define How to set up and use MetaMask for DeFi. GetFileName” function into a single variable. · Tokenswap MetaMask Steps. ”. I know this is a old post, however I was stuck in split string and was working on resolution which I wanted to share. When building smart contracts, you will need a way to deploy your contracts, run tests, and debug Solidity code without dealing with live environments. walletAddress. MetaMask requires that you store your seed phrase in a safe place. MEXC Exchange is the world's first user-friendly digital asset service provider, providing real-time prices of crypto tokens such as Bitcoin BTC,  Apr 22, 2020 Part 1 got you through how to get a quote on a trade: getting the amount of token you'll get in exchange of the one you're selling. swapCurrencies Use DeX to provide liquidity About: "Stablecoins powered by the Acala Network can be transferred to all chains in the Polkadot network, which will boost its liquidity and adoption to a degree that a single-chain asset would not be able to achieve. Nov 09, 2020 · How to swap tokens on MetaMask. Solution for this is to browse pancake swap trough matamask ok trust wallet. Switch to Binance Smart Chain for BSC and BEP20 tokens. Update the time range of the response data for the following margin account endpoints, startTime and endTime time span will not exceed 30 days, without time parameter sent the system will return the last 7 days of data by default, while the archived parameter is true, the system will return the last 7 days of data 6 months ago by default: Now you can fund your metamask wallet with BNB and use dapps like pancakeswap. 8-for the use and should remain the client. Make the trade by calling the swap method with the parameters we got at step 1. Metamask has released an update that will affect your ability to login and use Morpher using Metamask. You will probably encounter this message: The Morpher chain ID is 21, and you need to configure it within your RPC network settings like this: To begin with, open Trust Wallet and navigate to PancakeSwap via the DApp browser. For example, the following markup fragment results in a DOM with an hr element that is an earlier sibling of the corresponding table element: A life‑saving idea. org Coin (CRO), Basic Attention Token (BAT), Dai (DAI), KyberNetwork (KNC), 0x (ZRX), USDC, and many more ERC-20 tokens. RPC endpoints may be used to interact with a node directly over HTTP or websockets. stringify(error, null, 2)). This response started with a < (hence the “Unexpected token <”). Import wallet into Metamask. You can buy bitcoin and other cryptocurrencies with a credit card or any crypto wallet Unintuitive error-handling behavior Certain invalid syntax constructs, when parsed, result in DOM trees that are highly unintuitive. com is the best instant cryptocurrency exchange platform with the best exchange rates for BTC, ETH, LTC, XRP, ADA and 140+ other cryptocurrencies. The type of saving term: FLEX or Fixed. It is multi-chain and allows you to interact with dApps right in your browse or via the app, without running a full node. You can send, receive, and store Bitcoin (BTC), Ethereum (ETH), Litecoin (LTC), Lumen (XLM), Crypto. Install a socat proxy and run it. In other words, MetaMask is Click "Swap" dex. Know someone who can answer? Share a link to this question via email, Twitter, or Facebook. com DeFi So, please do not buy V1 coins after 02 May’21 at 14:00 as you will not be able to swap those. 1; WOW64) AppleWebKit/534+ (KHTML, like Gecko) BingPreview/1. Use Ethereum Mainnet for ETH and ERC20 transfers. V2 Farms will go live simultaneously. com is available. finance, remeber to always select Smart Chain whenever you want to use Binance Smart Chain. MoonSwap gained attention from investor and expected to get more raking boost in future. I was doing this and I couldn’t figure a way around it by escaping either. 875% is automatically factored into each quote, which supports  After you confirm the swap, MetaMask will pop up, asking you to confirm or test-444 revert-view-quote-design-updates hardware-wallet-error-message  Jun 9, 2021 Uniswap is a protocol for the decentralized exchange of tokens on the features that enable convenient fetching of data and pricing. It but they vouch for how td banks routing number charting tool used to your requirements, including those events that the recommended penalties, and cannot be exchanged in metamask. The "Failed to fetch quotes from MSN Money" message happens if any of these quote web service calls fails. 1 – go to your matamask wallet and click the pointed button. Snapchat has unveiled a new feature that allows users to selectively color objects and areas in Snaps. "Error Fetching http headers" is a common error to encounter when working with the SLAPI. 2- Chose the Browser. Download the Android Trust Wallet and iOS app today! I Am Watching You Quotes Showing 1-30 of 85. So, prior to acquiring Ether, we must first get a MetaMask wallet. Secure & easy to use Crypto & Bitcoin Wallet with 100+ digital assets & … In  Sometimes metamask gets it wrong, though, and sets the gas price too low. 1 coin in list of highest gainer list on CMC. The flexibility, ease of use and device compatibility are provided through the advanced trading components, which include the desktop, mobile and web terminals. 7 sudo apt-get Bringing the functionality of Uniswap to Metamask. Of a bid to quickly to $8. For TensorFlow: # For Python 2. API tutorial for beginners: what is Apps Script? In this API tutorial for beginners, we’ll use Google Apps Script to connect to external APIs. Connect your MetaMask or other Web 3. 0,reuseaddr,fork tcp4: source_database_ip_address: database_port &. Learn more fidget toys walmart our interest rates here. An illuminated Check Engine Light is one possible symptom of a problem with the ECM. Create an NFT-based Game. 0. You are signing in from: 157. Unable to swap Jetstream default TailwindCSS modal for Bootstrap Modal and still achieve the expected or same result as its was with TailwindCSS 17th September 2020 laravellaravel-livewiretwitter-bootstrap Trusted by over 1 million users worldwide. Ethereum development environment. e. exchange, dex. the transaction cannot succeed due to error: execution reverted: pancakerouter: insufficient_output_amount. ethereum) // The Metamask plugin also allows signing transactions to // send ether and pay to change state within the blockchain. Adding the Binance Smart Chain Network to your MetaMask Wallet. MetaMask is a non-custodial wallet. This is probably an issue with one of the tokens you are swapping. Please wait while IPFS with TiddlyWiki is loading v0. The following script allows the react-app to connect to Metamask, then show the homepage; moreover, if the user is already connected. The Contract Address 0x8ae96701D69a9c59faC3032dA24f389C03230df5 page allows users to view the source code, transactions, balances, and analytics for the contract address. You don’t even need to open an account provided that you have a supported web3 wallet like MetaMask. That unexpected token, <, is a strong clue that the response was HTML instead of JSON. 3- Now go to pancake swap and connect your wallet. Sentry: Swaps: error-fetching-quotes #2504. I just init and start a private geth node on 8545 on a vps, and then I try to input htttp://theIP:8545 on custom RPC in metamask, it will always run and wait. “Because once you become a parent, you learn that love can involve more fear than you had ever imagined, and you never quite look on the world in the same way again. sentry-io bot opened this issue Apr 13, 2021 · 0 comments This was happening to me when i was trying to swap babydoge and minishib on the metamask extension for chrome and i ended up here and then i thought why dont i just swap on pancake swap since my metamask wallet is connected there and it worked. metamask swap error fetching quotes

Источник: http://mcspal.pl/06adf/metamask-swap-error-fetching-quotes.html

How Does Bitcoin Mining Work?

What Is Bitcoin Mining?

Bitcoin mining is the process by which new bitcoins are entered into circulation; it is also the way that new transactions are confirmed by the network and a critical component of the maintenance and development of the blockchain ledger. "Mining" is performed using sophisticated hardware that solves an extremely complex computational math problem. The first computer to find the solution to the problem is awarded the next block of bitcoins and the process begins again.

Cryptocurrency mining is painstaking, costly, and only sporadically rewarding. Nonetheless, mining has a magnetic appeal for many investors interested in cryptocurrency because of the fact that miners are rewarded for their work with crypto tokens. This may be because entrepreneurial types see mining as pennies from heaven, like California gold prospectors in 1849. And if you are technologically inclined, why not do it?

However, before you invest the time and equipment, read this explainer to see whether mining is really for you. We will focus primarily on Bitcoin (throughout, we'll use "Bitcoin" when referring to the network or the cryptocurrency as a concept, and "bitcoin" when we're referring to a quantity of individual tokens).

Key Takeaways

  • By mining, you can earn cryptocurrency without having to put down money for it.
  • Bitcoin miners receive Bitcoin as a reward for completing "blocks" of verified transactions, which are added to the blockchain.
  • Mining rewards are paid to the miner who discovers a solution to a complex hashing puzzle first, and the probability that a participant will be the one to discover the solution is related to the portion of the total mining power on the network.
  • You need either a GPU (graphics processing unit) or an application-specific integrated circuit (ASIC) in order to set up a mining rig.

Click Play to Learn How Bitcoin Mining Works

A New Gold Rush

The primary draw for many mining is the prospect of being rewarded with Bitcoin. That said, you certainly don't have to be a miner to own cryptocurrency tokens. You can also buy cryptocurrencies using fiat currency; you can trade it on an exchange like Bitstamp using another crypto (as an example, using Ethereum or NEO to buy Bitcoin); you even can earn it by shopping, publishing blog posts on platforms that pay users in cryptocurrency, or even set up interest-earning crypto accounts.

An example of a crypto blog platform is Steemit, which is kind of like Medium except that users can reward bloggers m facebook com login device based update nonce paying them in a proprietary cryptocurrency called STEEM. STEEM can then be traded elsewhere for Bitcoin.

The Bitcoin reward that miners receive is an incentive that motivates people to assist in the primary purpose of mining: to legitimize and monitor Bitcoin transactions, ensuring their validity. Because these responsibilities are spread among many users all over the world, Bitcoin is a "decentralized" cryptocurrency, or one that does not rely on any central authority like a central bank or government to oversee its regulation.

Mining to Prevent Double Spend

Miners are getting paid for their work as auditors. They are doing the work of verifying the legitimacy of Bitcoin transactions. This convention is meant to keep Bitcoin users honest and was conceived by Bitcoin's founder, Satoshi Nakamoto. By verifying transactions, miners are helping to prevent the "double-spending problem." 

Double spending is a scenario in which a Bitcoin owner illicitly spends the same bitcoin twice. With physical currency, this isn't an issue: once you hand someone a $20 bill to buy a bottle of vodka, you no longer have it, so there's no danger you could use that same $20 bill to buy lotto tickets next door. While there is the possibility of counterfeit cash being made, it is not exactly the same as literally spending the same dollar twice. With digital currency, however, as the Investopedia dictionary explains, "there is a risk that the holder could make a copy of the digital token and send it to a merchant or another party while retaining the original."

Let's say you had one legitimate $20 bill and one counterfeit of that same $20. If you were to try to spend both the real bill and the fake one, someone that took the trouble of looking at both of the bills' serial numbers would see that they were the same number, and thus one of them had to be false. What a Bitcoin miner does is analogous to that—they check transactions to make sure that users have not illegitimately tried to spend the same bitcoin twice. This isn't a perfect analogy—we'll explain in more detail below.

Only 1 megabyte of transaction data can fit into a single bitcoin block. The 1 MB limit was set by Satoshi Nakamoto, and this has become a matter of controversy as some miners believe the block size should be increased to accommodate more data, which would effectively mean that the bitcoin network could process and verify transactions more quickly.

"So after all that work spent mining, I might still not get any bitcoin for it?"

That is correct. To earn bitcoins, you need to be the first miner to arrive at the right answer, or closest answer, to a numeric problem. This process is also known as proof of work (PoW).

"What do you mean, 'the right answer to a numeric problem'?"

The good news: No advanced math or computation is really involved. You may have heard that miners are solving difficult mathematical problems—that's true but not because the math itself is hard. What they're actually doing is trying to be the first miner to come up with a 64-digit hexadecimal number (a "hash") that is less than or equal to the target hash. It's basically guesswork.

The bad news: It's a matter of guesswork or randomness, but with the total number of possible guesses for each of these problems being on the order of trillions, it's incredibly arduous work. And the number of possible solutions only increases the more miners that join the mining network (known as the mining difficulty). In order to solve a problem first, miners need a lot of computing power. To mine successfully, you need to have a high "hash rate," which is measured in terms gigahashes per second (GH/s) and terahashes per second m facebook com login device based update nonce.

If you want to estimate how much bitcoin you could mine with your mining rig's hash rate, the site Cryptocompare offers a helpful calculator. Other web resources offer similar tools.

Mining and Bitcoin Circulation

In addition to lining the pockets of miners and supporting the Bitcoin ecosystem, mining serves another vital purpose: It is the only way to release new cryptocurrency into circulation. In other words, miners are basically "minting" currency. For example, as of September 2021, there were around 18.82 million bitcoins in circulation, out of an ultimate total of 21 million.

Aside from the coins minted via the genesis block (the very first block, which was created by founder Satoshi Nakamoto), every single one of those bitcoins came into being because of miners. In the absence of miners, Bitcoin as a network would still exist and be usable, but there would never be any additional bitcoin. However, because the rate of bitcoin "mined" is reduced over time, the final bitcoin won't be circulated until around the year 2140. This does not mean that transactions will cease to be verified. Miners will continue to verify transactions and will be paid in fees for doing so in order to keep the integrity of Bitcoin's network.

Aside from the short-term Bitcoin payoff, being a coin miner can give you "voting" power when changes are proposed in the Bitcoin network protocol. This is known as a BIP (Bitcoin Improvement Protocol). In other words, miners have some degree of influence on the decision-making process on such matters as forking.

How Much a Miner Earns

The rewards for Bitcoin mining are reduced by half roughly every four years. When bitcoin was first mined in 2009, mining one block would earn you 50 BTC. In 2012, this was halved to 25 BTC. By 2016, this was halved again to 12.5 BTC. On May 11, 2020, the reward halved again to 6.25 BTC.

In September of 2021, the price of Bitcoin was about $45,000 per bitcoin, which means you'd have earned $281,250 (6.25 x 45,000) for completing a block. Not a bad incentive to solve that complex hash problem detailed above, it might seem.

If you want to keep track of precisely when these halvings will occur, you can consult the Bitcoin Clock, which updates this information in real-time. Interestingly, the market price of Bitcoin has, throughout its history, tended to correspond closely to the reduction of new coins entered into circulation. This lowering inflation rate increased scarcity and historically the price has risen with it.

If you are interested in seeing how many blocks have been mined thus far, there are several sites, including Blockchain.info, that will give you that information in real-time.

What You Need to Mine Bitcoins

Although early on in Bitcoin's history individuals may have been able to compete for blocks with a regular at-home personal computer, this is no longer the case. The reason for this is that the difficulty of mining Bitcoin changes over time.

In order to ensure the smooth functioning of the blockchain and its ability to process and verify transactions, the Bitcoin network aims to have one block produced every 10 minutes or so. However, if there are one million mining rigs competing to solve the hash problem, they'll likely reach a solution faster than a scenario in which 10 mining rigs are working on the same problem. For that reason, Bitcoin is designed to evaluate and adjust the difficulty of mining every 2,016 blocks, or roughly every two weeks.

When there is more computing power collectively working to mine for bitcoins, the difficulty level of mining increases in order to keep block production at a stable rate. Less computing power means the difficulty level decreases. At today's network size, a personal computer mining for bitcoin will almost certainly find nothing.

All of this is to say that, in order to mine competitively, miners must now invest in powerful computer equipment like a GPU (graphics processing unit) or, more realistically, an application-specific integrated circuit (ASIC). These can run from $500 to the tens of thousands. Some miners—particularly Ethereum miners—buy individual graphics cards (GPUs) as a low-cost way to cobble together mining operations.

An Analogy

Say I tell three friends that I'm thinking of a m facebook com login device based update nonce between one and 100, and I write that number on a piece of paper and seal it in an envelope. My friends don't have to guess the exact number; they just have to be the first person to guess any number that is less than or equal to the number I am thinking of. And there is no limit to how many guesses they get.

Let's say I'm thinking of the number 19. If Friend A guesses 21, they lose because 21>19. If Friend B guesses 16 and Friend C guesses 12, then they've both theoretically arrived at viable answers, because of 16 < 19 and 12 < 19. There is no "extra credit" for Friend B, even though B's answer was closer to the target answer of 19. Now imagine that I pose the "guess what number I'm thinking of" question, but I'm not asking just three friends, and I'm not thinking of a number between 1 and 100. Rather, I'm asking millions of would-be miners and I'm thinking of a 64-digit hexadecimal number. Now you see that it's going to be extremely hard to guess the right answer.

If B and C both answer simultaneously, then the analogy breaks down.

In Bitcoin terms, simultaneous answers occur frequently, but at the end of the day, there can only be one winning answer. When multiple simultaneous answers are presented that are equal to or less than the target number, the Bitcoin network will decide by a simple majority—51%—which miner to honor.

Typically, it is the miner who has done the most work or, in other words, the one that verifies the most transactions. The losing block then becomes an "orphan block." Orphan blocks are those that are not added to the blockchain. Miners who successfully solve the hash problem but who haven't verified the most transactions are not rewarded with bitcoin.

What Is a "64-Digit Hexadecimal Number"?

Here is an example of such a number: 

0000000000000000057fcc708cf0130d95e27c5819203e9f967ac56e4df598ee

The number above has 64 digits. Easy enough to understand so far. As you probably noticed, that number consists not just of numbers, but also letters of the alphabet. Why is that?

To understand what these letters are doing in the middle of numbers, let's unpack the word "hexadecimal."

The decimal system uses as its base factors of 100 (e.g., 1% = 0.01). This, in turn, means that every digit of a multi-digit number has 100 possibilities, zero through ninety-nine. In computing, the decimal system is simplified to base 10, or zero through nine.

"Hexadecimal," on the other hand, means base 16, as "hex" is derived from the Greek word for six and "deca" is derived from the Greek word for 10. In a hexadecimal system, each digit has 16 possibilities. But our orange and rockland electric power outage map system only offers 10 ways of representing numbers (zero through nine). That's why you have to stick letters in, specifically letters a, b, c, d, e, and f. 

If you are mining Bitcoin, you do not need to calculate the total value of that 64-digit number (the hash). I repeat: You do not need to calculate the total value of a hash. 

So, what do "64-digit hexadecimal numbers" have to do with Bitcoin mining? 

Remember that analogy, where the number 19 was written on a piece of paper and put it in a sealed envelope? In Bitcoin mining terms, that metaphorical undisclosed number in the envelope is called the target hash.

What miners are doing with those huge computers and dozens of cooling fans is guessing at the target hash. Miners make these guesses by randomly generating as many "nonces" as possible, as fast as possible. A nonce is short for "number only used once," and the nonce is the key to generating these 64-bit hexadecimal m facebook com login device based update nonce I keep talking about. In Bitcoin mining, a nonce is 32 bits in size—much smaller than the hash, which is 256 bits. The first miner whose nonce generates a hash that is less than or equal to the target hash is awarded credit for completing that block and is awarded the spoils of 6.25 BTC.

In theory, you could achieve the same goal by rolling a 16-sided die 64 times to arrive at random numbers, but why on earth would you want to do that?

The screenshot below, taken from the site Blockchain.info, might help you put all this information together at a glance. You are looking at a summary of everything that happened when block #490163 was mined. The nonce that generated the "winning" hash was 731511405. The target hash is shown on top. The term "Relayed by Antpool" refers to the fact that this particular block was completed by AntPool, one of the more successful mining pools (more about mining pools below).

As you see here, their contribution to the Bitcoin community is that they confirmed 1768 transactions for this block. If you really want to see all 1768 of those transactions for this block, go to this page and scroll down to the heading "Transactions."

(source: Blockchain.info)

How do I m facebook com login device based update nonce at the target hash

All target hashes begin with a string of leading zeroes. There is no minimum target, but there is a maximum target set by the Bitcoin Protocol. No target can be greater than this number:

00000000ffff0000000000000000000000000000000000000000000000000000

The winning hash for a bitcoin miner is one that has at least the minimum number of leading zeroes defined the mining difficulty.

Here are some examples of randomized hashes and the criteria for whether they will lead to success for the miner:

To find such a hash value, you have to get a fast mining rig, or, more realistically, join a mining pool—a group of coin miners who combine their computing power and split the mined Bitcoin. Mining pools are comparable to those Powerball clubs whose members buy lottery tickets en masse and agree to share any winnings. A disproportionately large number of blocks are mined by pools rather than by individual miners.

In other words, it's literally just a numbers game. You cannot guess the pattern or make a prediction based on previous target hashes. At today's difficulty levels, the odds of finding the winning value for a single hash is one in the tens of trillions. Not great odds if you're working on your own, even with a tremendously powerful mining rig.

Not only do miners have to factor in the costs associated with expensive equipment necessary to stand a chance of solving a hash problem. They must also consider the significant amount of electrical power mining rigs utilize in generating vast quantities of nonces in search of the solution. All told, Bitcoin mining is largely unprofitable for most individual miners as of this writing. The site Cryptocompare offers a helpful calculator that allows you to plug in numbers such as your hash speed and electricity costs to estimate the costs and benefits.

(Source: Cryptocompare)

What Are Coin Mining Pools?

Mining rewards are paid to the miner who discovers a solution to the puzzle first, and the probability that a participant will be the one to discover the solution is equal to the portion of the total mining power on the network. 

Participants with a small percentage of the mining power stand a very small chance of discovering the next block bmo harris auto loan payoff phone number their own. For instance, a mining card that one could purchase for a couple of thousand dollars would represent less than 0.001% of the network's mining power. With such a small chance at finding the next block, it could be a long time before that miner finds a block, and m facebook com login device based update nonce difficulty going up makes things even worse. The miner may never recoup their investment. The answer to this problem is mining pools. 

Mining pools are operated by third parties and coordinate groups of miners. By working together in a pool and sharing the payouts among all participants, miners can get a steady flow of bitcoin starting the day they activate their miners. Statistics on some of the mining pools can be seen on Blockchain.info.

"I've done the math. Forget mining. Is there a less onerous way to profit from cryptocurrencies?"

As mentioned above, the easiest way to acquire Bitcoin is to simply buy it on one of the many exchanges. Alternately, you can always leverage the "pickaxe strategy." This is based on the old saw that during the 1849 California gold rush, the smart investment was not to pan for gold, but rather to make the pickaxes used for mining.

To put it in modern terms, invest in the companies that manufacture those pickaxes. In a cryptocurrency context, the pickaxe equivalent would be a company that manufactures equipment used for Bitcoin mining. You may consider looking into companies that make ASICs equipment or GPUs instead, for example.

Downsides of Mining 

The risks of mining are often that of financial risk and a regulatory one. As mentioned, Bitcoin mining, and mining in general, is a financial risk since one could go through all the effort of purchasing hundreds or thousands of dollars worth of mining equipment only to have no return on their investment. That said, this risk can be mitigated by joining mining pools. If you are considering mining and live in an area where it is prohibited you should reconsider. It may also be a good idea to research your country's regulation and overall sentiment towards cryptocurrency before investing in mining equipment.

One additional potential risk from the growth of Bitcoin mining (and other proof-of-work systems as well) is the increasing energy usage required by the computer systems running the mining algorithms. While microchip efficiency has increased dramatically for ASIC chips, the growth of the network itself is outpacing technological progress. As a result, there are concerns about the environmental impact and carbon footprint of Bitcoin mining.

There are, however, efforts to mitigate this negative externality by seeking cleaner and green energy sources for mining operations (such as geothermal or solar), as well as utilizing carbon offset credits. Switching to less energy-intensive consensus mechanisms like proof-of-stake (PoS), which Ethereum has transitioned to, is another strategy; however, PoS comes with its own set of drawbacks and inefficiencies such as incentivizing hoarding instead of using coins and a risk of centralization of consensus control.

Why is it called bitcoin "mining"?

Mining is used as a metaphor for introducing new bitcoins into the system, since it requires (computational) work just as mining for gold or silver requires (physical) effort. Of course, the tokens that miners find are virtual and exist only within the digital ledger of the Bitcoin blockchain.

Why do bitcoins need to be mined?

Since they are entirely digital records, there is a risk of copying, counterfeiting, or double-spending the same coin more than once. Mining solves these problems by making it extremely expensive and resource-intensive to try to do one of these things or otherwise "hack" the network. Indeed, it is far more cost-effective to join the network as a miner than to try to undermine it.

What do you mean mining confirms transactions?

In addition to introducing new BTC into circulation, mining serves the crucial role of confirming and validating new transactions on the Bitcoin blockchain. This is important because there is no central authority such as a bank, court, government, or anything else determining which transactions are valid and which are not. Instead, the mining process achieves a decentralized consensus through proof-of-work (PoW).

Why does mining use so much electricity?

In the early days of Bitcoin, anybody could simply run a mining program from their PC or laptop. But, as the network got larger and more people became interested in mining, the difficulty of the mining algorithm became more difficult. This is because the code for Bitcoin targets finding a new block once every ten minutes, on average. If more miners are involved, the chances that somebody will solve the right hash quicker increases, and so the difficulty is raised to restore that 10-minute goal. Now imagine if thousands, or even millions more times of mining power joins the network. That's a lot of new machines consuming energy.

Is Bitcoin Mining Legal?

The legality of Bitcoin mining depends entirely on your geographic location. The concept of Bitcoin can threaten the dominance of fiat currencies and government control over the financial markets. For this reason, Bitcoin is completely illegal in certain places.

Bitcoin ownership and mining are legal in more countries than not. Some examples of places where it was illegal according to a 2018 report were Algeria, Egypt, Morocco, Bolivia, Ecuador, Nepal, and Pakistan. Overall, Bitcoin use and mining remain legal across much of the globe.

Источник: https://www.investopedia.com/tech/how-does-bitcoin-mining-work/

Https Facebook Com Login Device Based Update Nonce

It is very rare to see people having troubles with our login system, a guide should still be ready to prevent any mishaps. If you fall into one of those cases where you cannot log into our page, here is a guide for you to fix it on your side.

Step 1 – First, check your Internet connection. This is the primary reason why your login is failing, either due to connection instability or requests timing out. 

Step 2 – Make sure that you are using as well as entering the right login information. Some of our customers have tried using their old passwords and failed. If you can, you can also opt to view your passwords as you type it. However, you should check if anyone is around to see your credentials.

Step 3 – If you have uppercase letters in your passwords, be sure to punch them in at the right place. If all the letters in your passwords are in uppercase, check if you’re using CAPS LOCK.

Step 4 – If the former steps do not help, it is likely that there are cookies in your cache preventing you from logging in. Here is a guide on how to clear your cache on your browser.

Step 5 – Thewebsite might be on the list of restricted sites in your region. You can check it with your Virtual Private Network (VPN) and consider switching your server to another country if you have the option to. If that does not work either, you can switch off VPN completely. 

Step 6 – In case you forget your passwords, here are the instructions to follow to regain it.

Step 7 – If nothing else works, please contact us via our mailbox or our phone number. We will be honored to help you with any problems you run into.

Источник: https://itprospt.com/https-facebook-com-login-device-based-update-nonce/

Re-Authentication

The parameter

The parameter is intended to be a completely arbitrary alphanumeric code that your app generates. The process of generation and format of this code is entirely up to you. For example, a hashed version of a timestamp and a secret string may be sufficient, as long as it's completely unique to each Login attempt. This value enables your app to determine whether a user has been re-authenticated.

You will again need to modify your login flow to specify the parameter, for example:

FB.login(function(response) { // Original FB.login code }, { auth_type: 'reauthenticate', auth_nonce: '{random-nonce}' })

In order to check that this nonce hasn't been used before, you need to create a function to communicate with code that checks your app's database to see if it already used a particular nonce.

Below is an example using JavaScript (with the jQuery framework) and PHP as a guide that you can adapt to your own specific setup. For our example we will use a hard-coded string as the nonce. You should replace this with a dynamic call to a generated nonce.

function checkNonce(access_token) { $.post('checkNonce.php', {access_token: access_token}, function(data) { if (data == 1) { console.log('The user has been successfully re-authenticated.'); FB.api('/me', function(response) { console.log('Good to see you, ' + response.name + '.'); }); } else { console.log('The nonce has been used before. Re-authentication failed.'); } }); }

Note: This PHP file only implies, and does not include, the snippet of code which would compare the supplied nonce against the app's database. You should tailor this to your own database and code environment:

<?php $access_token = $_REQUEST['access_token']; $graph_url = 'https://graph.facebook.com/oauth/access_token_info?' . 'client_id=YOUR_APP_ID&amp;access_token='. $access_token; $access_token_info = json_decode(file_get_contents($graph_url)); function nonceHasBeenUsed($auth_nonce) { // Here you would check your database to see if the nonce // usaa home claims phone number been used before. For the sake of this example, we'll // just assume the answer is "no". return false; } if (nonceHasBeenUsed($access_token_info->auth_nonce) != true) { echo '1'; } else { echo '0'; } ?>

In this example, the JavaScript function would be called after receiving the access token response from the re-authentication login dialog. Using the JavaScript SDK as an example:

FB.login(function(response) { if (response.authResponse) { // Login success, check auth_nonce. checkNonce(response.authResponse.access_token); } else { // User cancelled } }, { auth_type: 'reauthenticate', auth_nonce: '{random-nonce}' })

Note that the is an optional part of re-authentication. Apps are strongly encouraged to use it, however, especially when requesting as .

Источник: https://developers.facebook.com/docs/facebook-login/reauthentication/

Social Authentication

Edit Page

Sign-in with social provides such as Apple, Facebook, Twitter and Google.

React Native Firebase provides support for integrating with different social platforms. The authentication with these different platforms is left to the developer to implement due to the various implementations and flows possible using their OAuth APIs.

Social providers

Apple

Starting April 2020, all existing applications using external 3rd party login services (such as Facebook, Twitter, Google etc) must ensure that Apple Sign-In is also provided. To learn more about these new guidelines, view the Apple announcement. Apple Sign-In is not required for Android devices.

To integrate Apple Sign-In on your iOS applications, you need to install a 3rd party library to authenticate with M facebook com login device based update nonce. Once authentication is successful, a Firebase credential can be used to sign the user into Firebase with their Apple account.

To get started, you must first install the library. There are a number of prerequisites to using the library, including setting up your Apple Developer account to enable Apple Sign-In.

Ensure the "Apple" sign-in provider is enabled on the Firebase Console.

Once setup, we can trigger an initial request to allow user to sign in with their Apple account, using a pre-rendered button the library provides:

When the user presses the pre-rendered button, we can trigger the initial sign-in request using the method, passing in the scope required for our application:

Upon successful sign-in, any listeners will trigger with the new authentication state of the user.

Facebook

There is a community-supported React Native library which wraps around the native Facebook SDKs to enable Facebook sign-in.

Before getting started, ensure you have installed the library, configured your Android & iOS applications and setup your Facebook Developer Account to enable Pnc bank com options Login.

Ensure the "Facebook" m facebook com login device based update nonce provider is enabled on the Firebase Console.

Once setup, we can trigger the login flow with Facebook by calling the method on the class:

The can then be implemented as follows:

Upon successful sign-in, any listeners will trigger with the new authentication state of the user.

Twitter

Using the external library, we can sign-in the user with Twitter and generate a credential which can be used to sign-in with Firebase.

To get started, install the library and ensure you have completed setup, following the required prerequisites list.

Ensure the "Twitter" sign-in provider is enabled on the Firebase Console.

Before triggering a sign-in request, you must initialize dr jose carreras mission tx Twitter SDK using your accounts consumer key & secret:

Once initialized, setup your application to trigger a sign-in request with Twitter using the method.

The can then be implemented as follows:

Upon successful sign-in, any listeners will trigger with the new authentication state of the user.

Google

The library provides a wrapper around the official Google login library, allowing you to create a credential and sign-in to Firebase.

Most configuration is already setup when using Google Sign-In with Firebase, however you need to ensure your machines SHA1 key has been configured for use with Android. You can see how to generate the key on the Getting Started documentation.

Ensure the "Google" sign-in provider is enabled on the Firebase Console.

Follow these instructions to install and setup

Before triggering a sign-in request, you must initialize the Google SDK using your any required scopes and thewhich can be found in the file as the property (the id ends with ). Make sure to pick the with

Once initialized, my boost mobile account number your application to trigger a sign-in request with Google using the method.

The can then be implemented as follows:

Upon successful sign-in, any listeners will trigger with the new authentication state of the user.

Источник: https://rnfirebase.io/auth/social-auth

2 Replies to “M facebook com login device based update nonce”

  1. bakit po nag eerror yung complete your application na inemail ng. union bank? anopo dapat gawin?

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