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Security Advisories: GSA_kwCzR0hTQS13NXZyLTZxaHItMzZjY84AA1SR

`ed25519-dalek` Double Public Key Signing Function Oracle Attack

Versions of ed25519-dalek prior to v2.0 model private and public keys as separate types which can be assembled into a Keypair, and also provide APIs for serializing and deserializing 64-byte private/public keypairs.

Such APIs and serializations are inherently unsafe as the public key is one of the inputs used in the deterministic computation of the S part of the signature, but not in the R value. An adversary could somehow use the signing function as an oracle that allows arbitrary public keys as input can obtain two signatures for the same message sharing the same R and only differ on the S part.

Unfortunately, when this happens, one can easily extract the private key.

Revised public APIs in v2.0 of ed25519-dalek do NOT allow a decoupled private/public keypair as signing input, except as part of specially labeled "hazmat" APIs which are clearly labeled as being dangerous if misused.

Permalink: https://github.com/advisories/GHSA-w5vr-6qhr-36cc
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS13NXZyLTZxaHItMzZjY84AA1SR
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: 9 months ago
Updated: 9 months ago

Identifiers: GHSA-w5vr-6qhr-36cc
References:

• https://github.com/MystenLabs/ed25519-unsafe-libs
• https://rustsec.org/advisories/RUSTSEC-2022-0093.html
• https://github.com/advisories/GHSA-w5vr-6qhr-36cc

Repository: https://github.com/MystenLabs/ed25519-unsafe-libs
Blast Radius: 0.0

Affected Packages