BLAKE2b is the 64-bit-word variant of BLAKE2 and the successor of BLAKE-512. BLAKE2b and BLAKE2s are specified in RFC 7693.
VeraCrypt uses BLAKE2b with its maximum output size of 64 bytes (512 bits) internally in Argon2id. For non-system volume header key derivation, BLAKE2b-512 is reached by selecting the Argon2 key derivation algorithm in VeraCrypt; this corresponds to Argon2id internally. In hash-oriented contexts such as random pool mixing and keyfile generation, the same underlying hash may be displayed as BLAKE2b-512.
BLAKE2b-512 is not offered as a separate PBKDF2-HMAC hash algorithm. To use BLAKE2b-512 in VeraCrypt non-system volume header key derivation, select Argon2id; no separate hash algorithm selection is available for Argon2id.
