February 5, 2002
Practical Aspects of Modern Cryptography
14
TLS’s PRF
nPRF(secret, label, seed) =
P_MD5(S1, label + seed) XOR
P_SHA-1(S2, label + seed);
where S1, S2 are the two halves of the secret nP_hash(secret, seed) =
HMAC_hash(secret, A(1) + seed) + HMAC_hash(secret, A(2) + seed) + HMAC_hash(secret, A(3) + seed) + ... nA(0) = seed
A(i) = HMAC_hash(secret, A(i-1))