The landscape for instant messaging involves cross-platform instant messaging clients that can handle one or multiple protocols. Clients that use the same protocol can typically federate and talk to one another. The following table compares general and technical information for cross-platform instant messaging clients in active development, each of which have their own article that provide further information.
End-to-end encryption (E2EE) is a private communication system in which only communicating users can participate. As such, no one else, including the communication system provider, telecom providers, Internet providers or malicious actors, can access the cryptographic keys needed to converse. End-to-end encryption is intended to prevent data being read or secretly modified, other than by the true sender and recipient(s). The messages are encrypted by the sender but the third party does not have a means to decrypt them, and stores them encrypted. The recipients retrieve the encrypted data and decrypt it themselves. Because no third parties can decipher the data being communicated or stored, for example, companies that provide end-to-end encryption are unable to hand over texts of their customers' messages to the authorities.
The following is a comparison of instant messaging protocols. It contains basic general information about the protocols.
This is a comparison of voice over IP (VoIP) software used to conduct telephone-like voice conversations across Internet Protocol (IP) based networks. For residential markets, voice over IP phone service is often cheaper than traditional public switched telephone network (PSTN) service and can remove geographic restrictions to telephone numbers, e.g., have a PSTN phone number in a New York area code ring in Tokyo.
Matthew Rosenfeld, better known by the pseudonym Moxie Marlinspike, is an American entrepreneur, cryptographer, and computer security researcher. Marlinspike is the creator of Signal, co-founder of the Signal Technology Foundation, and served as the first CEO of Signal Messenger LLC. He is also a co-author of the Signal Protocol encryption used by Signal, WhatsApp, Google Messages, Facebook Messenger, and Skype.
WhatsApp is an instant messaging (IM) and voice-over-IP (VoIP) service owned by technology conglomerate Meta. It allows users to send text, voice messages and video messages, make voice and video calls, and share images, documents, user locations, and other content. WhatsApp's client application runs on mobile devices, and can be accessed from computers. The service requires a cellular mobile telephone number to sign up. In January 2018, WhatsApp released a standalone business app called WhatsApp Business which can communicate with the standard WhatsApp client.
Whisper Systems was an American enterprise mobile security company that was co-founded by security researcher Moxie Marlinspike and roboticist Stuart Anderson in 2010. The company was acquired by Twitter in November 2011. Some of the company's software products were released under open-source licenses after the acquisition. An independent group called Open Whisper Systems later picked up the development of this open-source software, which led to the creation of the Signal Technology Foundation.
Wickr is an American software company based in New York City. It is known for its instant messaging application of the same name. The Wickr instant messaging apps allow users to exchange end-to-end encrypted and content-expiring messages, and are designed for iOS, Android, Mac, Windows, and Linux operating systems. Wickr was acquired by Amazon Web Services (AWS) in mid-2021. The free version of the app was discontinued in December 2023.
Whisper is a proprietary mobile app available without charge. It is a form of anonymous social media, allowing users to post and share photo and video messages anonymously, although this claim has been challenged with privacy concerns over Whisper's handling of user data. The postings, called "whispers", consist of text superimposed over an image, and the background imagery is either automatically retrieved from Whisper's search engine or uploaded by the user. The app, launched in March 2012, is the main product of the media company WhisperText LLC, which was co-founded by CEO Michael Heyward, the son of the entertainment executive Andy Heyward, and Brad Brooks, who is the CEO of mobile messaging service TigerText. Since 2015, the service has sought to become more of a brand advertising platform, with promotional partnerships with Netflix, NBCUniversal, Disney, HBO, and MTV. According to TechCrunch, as of March 2017, Whisper has a total of 17 billion monthly pageviews on its mobile and desktop websites, social channels and publisher network, with 250 million monthly users across 187 countries. It is owned by MediaLab. In October 2022, Whisper was removed from the Apple App Store, and was added to the App Store again but was removed in 2023 again temporarily, but was recently restored to iOS in March of 2024. In September 2024 the app was removed from the Google Play Store and no longer works on Android devices. Whisper never made a statement about the removal of support for Android.
Jan Borysovych Koum is a Ukrainian-American billionaire businessman and computer programmer. He is the co-founder and former CEO of WhatsApp, a mobile messaging app which was acquired by Facebook in 2014 for US$19.3 billion. According to Forbes, he has an estimated net worth of US$15.2 billion as of October 2023, making him one of the richest people in the world. Koum was ranked 44th on the Forbes' list of richest Americans in 2023 with a net worth of $15.1 billion.
Brian Acton is an American business executive and computer programmer serving as the executive chairperson of Signal Technology Foundation, which he co-founded with Moxie Marlinspike in 2018. Acton also serves as interim chief executive officer (CEO) of Signal Messenger LLC.
TextSecure was an encrypted messaging application for Android that was developed from 2010 to 2015. It was a predecessor to Signal and the first application to use the Signal Protocol, which has since been implemented into WhatsApp and other applications. TextSecure used end-to-end encryption to secure the transmission of text messages, group messages, attachments and media messages to other TextSecure users.
Open Whisper Systems was a software development group that was founded by Moxie Marlinspike in 2013. The group picked up the open source development of TextSecure and RedPhone, and was later responsible for starting the development of the Signal Protocol and the Signal messaging app. In 2018, Signal Messenger was incorporated as an LLC by Moxie Marlinspike and Brian Acton and then rolled under the independent 501c3 non-profit Signal Technology Foundation. Today, the Signal app is developed by Signal Messenger LLC, which is funded by the Signal Technology Foundation.
Signal is an open-source, encrypted messaging service for instant messaging, voice calls, and video calls. The instant messaging function includes sending text, voice notes, images, videos, and other files. Communication may be one-to-one between users or may involve group messaging.
In cryptography, the Double Ratchet Algorithm is a key management algorithm that was developed by Trevor Perrin and Moxie Marlinspike in 2013. It can be used as part of a cryptographic protocol to provide end-to-end encryption for instant messaging. After an initial key exchange it manages the ongoing renewal and maintenance of short-lived session keys. It combines a cryptographic so-called "ratchet" based on the Diffie–Hellman key exchange (DH) and a ratchet based on a key derivation function (KDF), such as a hash function, and is therefore called a double ratchet.
The Open Technology Fund (OTF) is an American nonprofit corporation that aims to support global Internet freedom technologies. Its mission is to "support open technologies and communities that increase free expression, circumvent censorship, and obstruct repressive surveillance as a way to promote human rights and open societies." As of November 2019, the Open Technology Fund became an independent nonprofit corporation and a grantee of the U.S. Agency for Global Media. Until its formation as an independent entity, it had operated as a program of Radio Free Asia.
The Signal Protocol is a non-federated cryptographic protocol that provides end-to-end encryption for voice and instant messaging conversations. The protocol was developed by Open Whisper Systems in 2013 and was introduced in the open-source TextSecure app, which later became Signal. Several closed-source applications have implemented the protocol, such as WhatsApp, which is said to encrypt the conversations of "more than a billion people worldwide" or Google who provides end-to-end encryption by default to all RCS-based conversations between users of their Google Messages app for one-to-one conversations. Facebook Messenger also say they offer the protocol for optional Secret Conversations, as does Skype for its Private Conversations.
Meredith Whittaker is the president of the Signal Foundation and serves on its board of directors. She was formerly the Minderoo Research Professor at New York University (NYU), and the co-founder and faculty director of the AI Now Institute. She also served as a senior advisor on AI to Chair Lina Khan at the Federal Trade Commission. Whittaker was employed at Google for 13 years, where she founded Google's Open Research group and co-founded the M-Lab. In 2018, she was a core organizer of the Google Walkouts and resigned from the company in July 2019.
MobileCoin is a peer-to-peer cryptocurrency developed by MobileCoin Inc., which was founded in 2017 by Josh Goldbard and Shane Glynn.
The UFED is a product series of the Israeli company Cellebrite, which is used for the extraction and analysis of data from mobile devices by law enforcement agencies.
