First round of my stupid questions about NTS

[Richard Laager]

On 1/18/19 8:05 PM, Gary E. Miller via devel wrote:
> Section 5.1, they come from RFC 5706 using the PRF() function.

Agreed.

> The question is where the master key used by PRF() comes from.

That comes from the TLS session. See RFC 5705's mentions of "TLS master
secret". For more specifics, note that the code in RFC 5705 section 5.1
uses master_secret, client_random, and server_random out of something
called SecurityParameters, and then see RFC 5246, section 6.1,
especially page 16 and 17:
https://tools.ietf.org/html/rfc5246#section-6.1

      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;

-- 
Richard

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