anchor.diff:  prf_algorithm(Algo, _) ->
       hash_algorithm(Algo).
   
  +mac_algorithm(aead) ->
  +    aead;
  +mac_algorithm(Algo) ->
  +    hash_algorithm(Algo).
  +
   hash_algorithm(null)   -> ?NULL;
   hash_algorithm(md5)    -> ?MD5;
   hash_algorithm(sha)   -> ?SHA; %% Only sha always refers to "SHA-1"
  
positive.code: 
  hash_size(null) ->
      0;
  hash_size(md5) ->
      16;
  hash_size(sha) ->
  
negative.code:       expanded_key_material_length = expanded_key_material(Cipher),
        key_material_length = key_material(Cipher),
        iv_size = iv_size(Cipher),
        mac_algorithm = mac_algorithm(Hash),
        prf_algorithm = prf_algorithm(PrfHashAlg, Version),
        hash_size = hash_size(Hash)}.
  
  