cm/pub/mceliece6960119-x25519

    [cm/pub/] with Classic McEliece 6960-119 + X25519.
    => Classic McEliece
    => X25519

    Combined Classic McEliece 6960-119 and X25519 public keys are used
    for KEM purposes, so should have "kem" key usage set.

    Its algorithm identifier is "mceliece6960119-x25519".
    Its public key value is a concatenation of 1047319-byte
    mceliece6960119 public key and 32-byte X25519 one.

    Public key's fingerprint should be calculated using SHAKE128.
    => SHAKE XOF function

    Optional "/data/prehash" field can contain the SHAKE256 hash
    of the concatenated public keys in "/data/pub/0", that could
    save resources during [cm/kem/mceliece6960119-x25519-hkdf-shake256]
    KDF calculations.