RustCrypto: Signatures has timing side-channel in ML-DSA decomposition

A timing side-channel vulnerability was found in RustCrypto's ML-DSA signature generation. An attacker could potentially extract secret key information by measuring how long the signing operation takes, compromising the security of digital signatures.

The Decompose algorithm in ML-DSA signing exhibits timing variations dependent on secret data, enabling cache/timing-based side-channel attacks to recover private key material. This requires physical proximity or network access to measure execution time during signature generation. The vulnerability has been mitigated in version 0.1.0-rc.2 through constant-time implementation.