Advisories for Cargo/Vodozemac package

Versions before 0.7.0 of vodozemac use a non-constant time base64 implementation for importing key material for Megolm group sessions and PkDecryption Ed25519 secret keys. This flaw might allow an attacker to infer some information about the secret key material through a side-channel attack.

Versions 0.5.0 and 0.5.1 of vodozemac have degraded secret zeroization capabilities, due to changes in third-party cryptographic dependencies (the Dalek crates), which moved secret zeroization capabilities behind a feature flag while vodozemac disabled the default feature set.