On Tue, Apr 28, 2020 at 12:58:57PM +0200, Johannes Thumshirn wrote: > > There was interest in also using a HMAC version of Blake2b from the community, > but as none of the crypto libraries used by user-space BTRFS tools as a > backend does currently implement a HMAC version with Blake2b, it is not (yet) > included. Note that BLAKE2b optionally takes a key, so using HMAC with it is unnecessary. And the kernel crypto API's implementation of BLAKE2b already supports this. I.e. you can call crypto_shash_setkey() directly on "blake2b-256". - Eric