Session (software)

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,^[3] 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.^[4]

Session

Screenshot of Session version 1.17.4 on Android (December 2023)
Developer(s)	The Session Technology Foundation
Initial release	February 2020; 5 years ago (2020-02)
Stable release(s)
Android 1.17.5 / January 12, 2024; 16 months ago (2024-01-12)[1] iOS 2.4.4 / December 19, 2023; 17 months ago (2023-12-19)[2]
Repository	github.com/session-foundation/
Operating system	Android 6 or above iOS 12 or above Windows MacOS Linux
Type	Instant messaging
License	BSD-3-Clause MIT GPL-3.0
Website	getsession.org

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.^[5][6][7][8]

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.^[7][9]

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.^[10]