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Overview of Privacy and Unlinkability (eid-privacy, 2025)

URL: https://eid-privacy.github.io/wp4/2025/10/20/overview.html

Summary

Examines data leakage risks and cryptographic mitigations for Switzerland's Swiyu e-ID system. Catalogues attack vectors including verifier abuse, revocation detection, profiling, and government tracking. Reviews mitigations: ZKPs, BBS signatures, threshold decryption, blind signatures, service-specific pseudonyms, Private Information Retrieval (Spiral), and Tor anonymisation. Concludes with Crescent and Longfellow as the two leading ZKP candidates.

Related resources

• Anonymous Credentials from ECDSA (Frigo & shelat 2024) (paper, 2024)
• Crescent: Stronger Privacy for Existing Credentials (Paquin, Policharla, Zaverucha 2024) (paper, 2024)
• Short Group Signatures (Boneh, Boyen, Shacham 2004) (paper, 2004)