Type Transcriptions

[Shark8 <OneWingedShark@gmail.com>]

I recently started a little project intended to implement TLS 1.2 in Ada 
2012 and SPARK; reading through the RFC and transcribing the types has 
been relatively straightforward.

However there is one hiccup; a certain class of record-type is dependent 
on the values in another record, yet distinctly separate; ex:


       struct {
          opaque nonce_explicit[SecurityParameters.record_iv_length];
          aead-ciphered struct {
              opaque content[TLSCompressed.length];
          };
       } GenericAEADCipher;

where SecurityParameters is

       struct {
           ConnectionEnd          entity;
           PRFAlgorithm           prf_algorithm;
           BulkCipherAlgorithm    bulk_cipher_algorithm;
           CipherType             cipher_type;
           uint8                  enc_key_length;
           uint8                  block_length;
           uint8                  fixed_iv_length;
           uint8                  record_iv_length;
           MACAlgorithm           mac_algorithm;
           uint8                  mac_length;
           uint8                  mac_key_length;
           CompressionMethod      compression_algorithm;
           opaque                 master_secret[48];
           opaque                 client_random[32];
           opaque                 server_random[32];
       } SecurityParameters;

Now I've already transcribed the SecurityParameters parameters record, 
but it seems to me that since these other types are dependent on the 
SecurityParameters, I could change it into a generic package with the 
record's current components being input parameters.

Any advice on which route to take would be greatly appreciated.