Session (software)

{{Infobox software

| name = Session (software)

| logo = Session App Logo.svg

| logo size = 150px

| logo alt =

| title = Session

| collapsible =

| screenshot = Session App Screenshot.png

| screenshot_size = 220px

| screenshot alt = Screenshot of Session

| caption = Screenshot of Session version 1.17.4 on Android (December 2023)

| developer = The Session Technology Foundation

| released = {{Start date and age|2020|02}}

| ver layout = Stacked

| latest release version = {{multiple releases

| branch1 = Android

| version1 = 1.17.5

| date1 = {{Start date and age|2024|1|12}}{{cite web |title=Private Messenger APKs for Android |website=APKMirror |date=April 8, 2021 |url=https://www.apkmirror.com/apk/oxen-project/session-private-messenger/ |access-date=December 7, 2023 |archive-date=October 19, 2023 |archive-url=https://web.archive.org/web/20231019232405/https://www.apkmirror.com/apk/oxen-project/session-private-messenger/ |url-status=live }}

| branch2 = iOS

| version2 = 2.4.4

| date2 = {{Start date and age|2023|12|19}}{{cite web |title=Private Messenger |website=Softonic |date=October 31, 2023 |url=https://session-private-messenger.en.softonic.com/iphone |access-date=December 7, 2023}}

}}

| operating system = {{Plain list|

Android 6 or above
iOS 12 or above
Windows
MacOS
Linux

}}

| genre = Instant messaging

| license = BSD-3-Clause
MIT
GPL-3.0

| repo = {{URL|https://github.com/session-foundation/}}

| website = {{URL|https://getsession.org/}}

}}

Session is a cross-platform end-to-end encrypted instant messaging application emphasizing user confidentiality and anonymity. Developed and maintained by the non-profit The Session Technology Foundation,{{Cite news |last=Taylor |first=Josh |date=2024-11-04 |title=Encrypted messaging app developer moves out of Australia after police visit employee’s home |url=https://www.theguardian.com/australia-news/2024/nov/05/session-encrypted-messaging-app-developer-moves-out-of-australia-police-visit-switzerland |access-date=2025-05-14 |work=The Guardian |language=en-GB |issn=0261-3077}} it employs a blockchain-based decentralized network for transmission. Users can send one-to-one and group messages, including various media types such as files, voice notes, images, and videos.{{cite news |last1=Bhattacharjee |first1=Shomik Sen |title=Session Is a Blockchain-Based Private Messenger That Uses Decentralised Server Nodes To Ensure Anonymity |url=https://www.gadgets360.com/cryptocurrency/news/session-private-blockchain-messenger-decentralised-nodes-2568208 |access-date=June 18, 2023 |work=Gadgets 360 |date=October 8, 2021 |language=en |archive-date=June 18, 2023 |archive-url=https://web.archive.org/web/20230618215132/https://www.gadgets360.com/cryptocurrency/news/session-private-blockchain-messenger-decentralised-nodes-2568208 |url-status=live }}

Session provides applications for various platforms, such as macOS, Windows, and Linux, along with mobile clients available on both iOS and Android.

Features

Session does not require a telephone number or email address for account creation. Instead, it utilizes a randomly generated 66-digit alphanumeric number for user identification. Communication between users, including messages, voice clips, photos, and files, is end-to-end encrypted using the Session protocol. Session uses the Loki blockchain network for transmissions. In 2021, an independent review by the third-party Quarkslab verified these claims.{{Cite web |last=Ankush |first=Das |date=February 10, 2022 |title=8 Reasons to Try Session as a Private Messaging App |url=https://www.makeuseof.com/why-try-session-private-messenger/ |access-date=December 8, 2022 |website=MakeUseOf |language=en-US |archive-date=October 31, 2022 |archive-url=https://web.archive.org/web/20221031065025/https://www.makeuseof.com/why-try-session-private-messenger/ |url-status=live }}{{Cite web |date=March 9, 2020 |title=New WhatsApp Alternative "Session" Works Without Your Phone Number |url=https://fossbytes.com/open-source-messenger-session-doesnt-even-need-your-phone-number/ |url-status=dead |archive-url=https://web.archive.org/web/20230531001331/https://fossbytes.com/open-source-messenger-session-doesnt-even-need-your-phone-number/ |archive-date=May 31, 2023 |access-date=July 31, 2023 |website=Fossbytes |language=en-US}}{{Cite web |title=Session Messenger Review – Best Secure Messaging App? |url=https://restoreprivacy.com/secure-encrypted-messaging-apps/session/ |access-date=October 11, 2021 |website=RestorePrivacy |language=en-US |archive-date=October 10, 2021 |archive-url=https://web.archive.org/web/20211010194219/https://restoreprivacy.com/secure-encrypted-messaging-apps/session/ |url-status=live }}{{Cite book |title=Oxen Session Audit Technical Report |publisher=Quarkslab SAS |year=2021 |url=https://blog.quarkslab.com/resources/2021-05-04_audit-of-session-secure-messaging-application/20-08-Oxen-REP-v1.4.pdf |access-date=October 11, 2021 |archive-date=October 23, 2021 |archive-url=https://web.archive.org/web/20211023112824/https://blog.quarkslab.com/resources/2021-05-04_audit-of-session-secure-messaging-application/20-08-Oxen-REP-v1.4.pdf |url-status=live }}

Development

Session started as a fork of another messenger, Signal, aiming to build upon its foundation. However, concerns about the centralized structure of Signal Protocol and potential metadata collection led the team to deviate and create their own protocol, called "Session Protocol". This approach prioritized increased anonymity and decentralization. During development, the team encountered various challenges, leading to the necessity of abandoning or modifying many features.{{Cite web |last=Florence |first=Eric |date=January 6, 2022 |title=Session Messenger Review |url=https://securitytech.org/secure-encrypted-messaging-app/session/ |access-date=August 3, 2023 |website=SecurityTech |language=en-US |archive-date=August 1, 2023 |archive-url=https://web.archive.org/web/20230801125502/https://securitytech.org/secure-encrypted-messaging-app/session/ |url-status=live }}

Limitations

Session lacks support for two-factor authentication, and its underlying protocols are still in a developmental phase. Following the migration from the Signal Protocol to its internally developed protocol, forward secrecy and deniable authentication were not implemented.{{Cite web |date=December 16, 2020 |title=The Session Protocol: What's changing — and why - Session Private Messenger |url=https://getsession.org/session-protocol-explained |access-date=August 10, 2023 |website=Session |language=en |archive-date=June 4, 2023 |archive-url=https://web.archive.org/web/20230604175329/https://getsession.org/session-protocol-explained |url-status=live }}