The current implementations of BLAKE2b and BLAKE2s support both variable output lengths and keyed BLAKE2 (blake2b, blake2s), but do not yet enable setting the personalisation and salt sections of the parameter block. Personalisation in particular is becoming more commonplace in BLAKE2's usage within cryptographic protocols. It would be beneficial both inherently and for interoperability if the BLAKE2 implementations provided an interface for instantiating the digest state with a personalisation string and/or a salt.