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The Signal Private Group System and Anonymous Credentials Supporting Efficient Verifiable Encryption (Chase, Perrin, Zaverucha 2020)

Last modified: 2026-10-27

DOI: 10.1145/3372297.3417887 · URL: https://doi.org/10.1145/3372297.3417887

Summary

Describes Signal's private group system, in which the server stores encrypted group membership and members authenticate with keyed-verification anonymous credentials. The credentials support efficient verifiable encryption of attributes. One of the largest real-world deployments of anonymous credentials, cited in BL26-SoK-AnonCreds as evidence that pairing-free KVACs are deployable.

Related resources

• Algebraic MACs and Keyed-Verification Anonymous Credentials (Chase, Meiklejohn, Zaverucha 2014) (paper, 2014)
• Revisiting Keyed-Verification Anonymous Credentials (Orrù 2025) (paper, 2025)
• SoK: Anonymous Credentials for Digital Identity Wallets (Bormann, Lehmann 2026) (paper, 2026)