lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [day] [month] [year] [list]
Date: Wed, 9 Apr 2014 13:57:45 +0000
From: Peter Gutmann <>
To: "" <>
Subject: Re: [PHC] Deriving multiple keys (was RE: Mechanical tests)

Thomas Pornin <> writes:

>In TLS (see section 6.3 of RFC 5246), the symmetric keys are derived from the
>"master secret" with a single PRF call:
>   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);

Oops, yeah, I was thinking of the general use of the label in the PRF, e.g.
the MAC/Finished-message "client finished" vs. "server finished", and then for
key expansion "master secret" vs. "key expansion", but you're right, the
keying material is from a single application of the PRF.


Powered by blists - more mailing lists