anchor.diff:       ?TLS_RSA_WITH_3DES_EDE_CBC_SHA,
        ?TLS_RSA_WITH_AES_128_CBC_SHA256,
        ?TLS_RSA_WITH_AES_128_CBC_SHA,
  -     %%?TLS_RSA_WITH_IDEA_CBC_SHA,
        ?TLS_RSA_WITH_RC4_128_SHA,
        ?TLS_RSA_WITH_RC4_128_MD5,
        ?TLS_RSA_WITH_DES_CBC_SHA].
  
positive.code: iv_size(Cipher) ->
      block_size(Cipher).
  
  block_size(Cipher) when Cipher == idea_cbc;
  			Cipher == des_cbc;
  			Cipher == '3des_ede_cbc' -> 
      8;
  
  
negative.code: 
  expanded_key_material(null) ->
      0;
  expanded_key_material(rc4_128) ->
      16;
  expanded_key_material(Cipher) when Cipher == des_cbc ->
      8;
  