Ursa is a cryptographic library for use with blockchains. The revocation scheme that is part of the Ursa CL-Signatures implementations has a flaw that could impact the privacy guarantees defined by the AnonCreds verifiable credential model. Notably, a malicious verifier may be able to generate a unique identifier for a holder providing a verifiable presentation that includes a Non-Revocation proof. The impact of the flaw is that a malicious verifier may be able to determine a unique identifier for a holder presenting a Non-Revocation proof. Ursa has moved to end-of-life status and no fix is expected.
| Package (Ecosystem) | Introduced | Fixed | Limit |
|---|---|---|---|
| ursa(crates.io) | 0 | N/A | N/A |
| anoncreds-clsignatures(crates.io) | 0 | 0.1.0 | N/A |
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