Use only one hash algorithm (SHA512) in the PRF.

On some platforms, OpenSSL by default does not support the Whirlpool algorithm.
This commit is contained in:
Guus Sliepen 2012-02-21 23:17:12 +01:00
parent 1f00111e94
commit cb6cbf452f

View file

@ -23,7 +23,7 @@
#include "prf.h"
/* Generate key material from a master secret and a seed, based on RFC 4346 section 5.
We use SHA512 and Whirlpool instead of MD5 and SHA1.
We use SHA512 instead of MD5 and SHA1.
*/
static bool prf_xor(int nid, const char *secret, size_t secretlen, char *seed, size_t seedlen, char *out, ssize_t outlen) {
@ -66,11 +66,8 @@ static bool prf_xor(int nid, const char *secret, size_t secretlen, char *seed, s
}
bool prf(const char *secret, size_t secretlen, char *seed, size_t seedlen, char *out, size_t outlen) {
/* Split secret in half, generate outlen bits with two different hash algorithms,
and XOR the results. */
/* This construction allows us to easily switch back to a scheme where the PRF is calculated using two different digest algorithms. */
memset(out, 0, outlen);
return prf_xor(NID_sha512, secret, (secretlen + 1) / 2, seed, seedlen, out, outlen)
&& prf_xor(NID_whirlpool, secret + secretlen / 2, (secretlen + 1) / 2, seed, seedlen, out, outlen);
return prf_xor(NID_sha512, secret, secretlen, seed, seedlen, out, outlen);
}