pub const ENVELOPE_VERSION: u8 = 0x02;Expand description
Envelope wire-version. Bumped when the byte layout OR the
cryptographic scheme (KDF / AAD construction) changes; readers refuse
unknown versions with a typed error so a bump doesn’t silently
mis-parse or mis-decrypt legacy rows. 0x02 introduced the H3
HKDF-SHA256 key derivation + AAD header binding (the 0x01 MVP used
the raw X25519 output directly with empty AAD).