Hi,

RFC5705 section 4 "Exporter Definition" [1] states..

   The exporter takes three input values:

   o a disambiguating label string,

   o a per-association context value provided by the application using
     the exporter, and

   o a length value.

   If no context is provided, it then computes:

           PRF(...
              )[length]

   If context is provided, it computes:

           PRF(...
              )[length]


..i.e., RFC5705 directly utilizes the TLS PRF (pseudo-random function)
from TLS {1.0, 1.1, 1.3}.  Since the PRF() is no longer defined in TLS
1.3, RFC5705 is incompatible with TLS 1.3, yes?

Also, draft-ietf-tls-tls13-11 seems to contain a built-in keying material
exporter (KME) in S 7.1 step 8 [2]..

   7.1.  Key Schedule

      [...]

      8. exporter_secret = HKDF-Expand-Label(master_secret,
                                          "exporter master secret",
                                          handshake_hash, L)
      [...]


..i.e., does the above step "8." effectively define the TLS 1.3 keying
material exporter?


thanks,

=JeffH


[1] https://tools.ietf.org/html/rfc5705#section-4

[2] https://tools.ietf.org/html/draft-ietf-tls-tls13-11#section-7.1

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