[cm/signed/] with SPHINCS+-SHAKE256-256f.
255-bit security level, fast variant,
simple parameters and deterministic signatures.
=> https://sphincs.org/ SPHINCS+
=> https://keccak.team/ SHAKE256
"sphincs+-shake-256f" algorithm identifier
must be used for the signature in pure signing mode.
"sphincs+-shake-256f-ph" is used in prehash mode.