Messaging Layer Security

Messaging Layer Security (MLS) is a security layer for end-to-end encrypting messages in arbitrarily sized groups. It is maintained by the MLS working group of the Internet Engineering Task Force to provide an efficient and practical security mechanism.[1][2][3]

Messaging Layer Security
AbbreviationMLS
First publishedJuly 2023 (2023-07)
OrganizationIETF
Authors
  • R. Barnes
  • B. Beurdouche
  • R. Robert
  • J. Millican
  • E. Omara
  • K. Cohn-Gordon
DomainSecurity
Websitewww.rfc-editor.org/rfc/rfc9420.html

Security properties

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Security properties of MLS include message confidentiality, message integrity and authentication, membership authentication, asynchronicity, forward secrecy, post-compromise security, and scalability.[4]

History

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The idea was born in 2016 and first discussed in an unofficial meeting during IETF 96 in Berlin with attendees from Wire, Mozilla and Cisco.[5]

Initial ideas were based on pairwise encryption for secure 1:1 and group communication. In 2017, an academic paper introducing Asynchronous Ratcheting Trees was published by the University of Oxford and Facebook setting the focus on more efficient encryption schemes.[6]

The first BoF took place in February 2018 at IETF 101 in London. The founding members are Mozilla, Facebook, Wire, Google, Twitter, University of Oxford, and INRIA.[7]

As of March 29, 2023, the IETF has approved publication of Messaging Layer Security (MLS) as a new standard.[8] It was officially published on July 19, 2023.[9][10]

Matrix is one of the protocols declaring migration to MLS.[11]

Research by PQShield suggests post-quantum cryptography (PQC) could be added to MLS-like messaging, but MLS does not currently support PQC.[12][13]

Implementations

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  • OpenMLS: language: Rust, license: MIT
  • MLS++: language: C++, license: BSD-2
  • mls-rs: language: Rust, license: MIT, Apache 2.0
  • MLS-TS: language: TypeScript, license: Apache 2.0

References

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  1. ^ "Inside MLS, the New Protocol for Secure Enterprise Messaging". Dark Reading. 27 June 2019. Retrieved 2019-11-15.
  2. ^ at 10:29, Richard Chirgwin 22 Aug 2018. "Elders of internet hash out standards to grant encrypted message security for world+dog". www.theregister.co.uk. Retrieved 2019-11-15.{{cite web}}: CS1 maint: numeric names: authors list (link)
  3. ^ "Messaging Layer Security". GitHub.
  4. ^ "Messaging Layer Security (mls) -". datatracker.ietf.org. Retrieved 2019-03-05.
  5. ^ "Das sind die sieben Entwickler-Trends 2019: Vom Java-Comeback über MLS bis KI/ML-zentrierte Technologien". IT Finanzmagazin. 2 January 2019. Retrieved 7 January 2019.
  6. ^ Cohn-Gordon, Katriel; Cremers, Cas; Garratt, Luke; Millican, Jon; Milner, Kevin (2017). "On Ends-to-Ends Encryption: Asynchronous Group Messaging with Strong Security Guarantees". Cryptology ePrint Archive.
  7. ^ Chirgwin, Richard (22 August 2018). "Elders of internet hash out standards to grant encrypted message security for world+dog". Retrieved 30 November 2018.
  8. ^ Sullivan, Nick; Turner, Sean (2023-03-29). "Messaging Layer Security: Secure and Usable End-to-End Encryption". IETF. Retrieved 2023-07-28.
  9. ^ "New MLS protocol provides groups better and more efficient security at Internet scale". 2023-07-19. Retrieved 2023-07-28.
  10. ^ Beurdouche, Benjamin; Vasquez, Sarah (2023-07-20). "Messaging Layer Security is now an internet standard". Mozilla. Retrieved 2023-07-28.
  11. ^ "Are We MLS Yet?". Are We MLS Yet?. Retrieved 2024-09-23.
  12. ^ Hashimoto, Keitaro; Katsumata, Shuichi; Prest, Thomas (2022-11-07). "How to Hide MetaData in MLS-Like Secure Group Messaging: Simple, Modular, and Post-Quantum" (PDF). Cryptology ePrint Archive. Retrieved 2024-12-09.
  13. ^ "Post-quantum messaging: examining Apple's new PQ3 protocol". PQShield. 2024-02-22. Retrieved 2024-12-09.
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