anchor.diff:  
   hash_size(null) ->
       0;
  +%% The AEAD MAC hash size is not used in the context 
  +%% of calculating the master secret. See RFC 5246 Section 6.2.3.3.
  +hash_size(aead) ->
  +    0;
   hash_size(md5) ->
       16;
   hash_size(sha) ->
  
positive.code: prf_algorithm(Algo, _) ->
      hash_algorithm(Algo).
  
  hash_algorithm(null)   -> ?NULL;
  hash_algorithm(md5)    -> ?MD5;
  hash_algorithm(sha)   -> ?SHA; %% Only sha always refers to "SHA-1"
  
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)}.
  
  