seeking a info for clearing a confusion

[Sadik Sikder <sadiksikder () gmail com>]

Hello all
I am developing for myself own Decryption system for my own packet
analyzer. During developing stage i have some confusion following
i hava confusion regarding pre_master_secret. according to IETF

8.1 <https://tools.ietf.org/html/rfc5246#section-8.1>.  Computing the
Master Secret

For all key exchange methods, the same algorithm is used to convert
   the pre_master_secret into the master_secret.  The pre_master_secret
   should be deleted from memory once the master_secret has been
   computed.

      master_secret = PRF(pre_master_secret, "master secret",
                          ClientHello.random + ServerHello.random)
                          [0..47];

   The master secret is always exactly 48 bytes in length.  The length
   of the premaster secret will vary depending on key exchange method.


-----------------------------------------------------------------------

my question is about pre_master_secret, is this pre_master_secret
generated by encrypting client.rando[32][]

by server public exponent?


6.3 <https://tools.ietf.org/html/rfc5246#section-6.3>.  Key Calculation

   The Record Protocol requires an algorithm to generate keys required
   by the current connection state (see Appendix A.6
<https://tools.ietf.org/html/rfc5246#appendix-A.6>) from the security
   parameters provided by the handshake protocol.


The master secret is expanded into a sequence of secure bytes, which
   is then split to a client write MAC key, a server write MAC key, a
   client write encryption key, and a server write encryption key.  Each
   of these is generated from the byte sequence in that order.  Unused
   values are empty.  Some AEAD ciphers may additionally require a
   client write IV and a server write IV (see Section 6.2.3.3
<https://tools.ietf.org/html/rfc5246#section-6.2.3.3>).

   When keys and MAC keys are generated, the master secret is used as an
   entropy source.

   To generate the key material, compute

      key_block = PRF(SecurityParameters.master_secret,
                      "key expansion",
                      SecurityParameters.server_random +
                      SecurityParameters.client_random);


Q: my question is here about "SecurityParameters.master_secret" , what is
this master_secret?
is this same value (if i am not wrong )of master.secret generated by
CLIENT_RANDOM <space> <64 bytes of hex encoded client_random> <space> <96
bytes of hex encoded *master secret*>?


Thanks in advance...






*Kind Regards,*

Samsuddin Sikder
Masters Student
M.Sc. in Communication Systems Engineering
Cologne University of Applied Sciences (FH-Köln),Germany

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