From 65df1745743a2f0f5b6647a223f781bb153e6449 Mon Sep 17 00:00:00 2001 From: Damien Miller Date: Mon, 19 Jul 2004 09:30:38 +1000 Subject: - (djm) [openbsd-compat/bsd-arc4random.c] Discard early keystream, like OpenBSD ok dtucker@ --- openbsd-compat/bsd-arc4random.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'openbsd-compat') diff --git a/openbsd-compat/bsd-arc4random.c b/openbsd-compat/bsd-arc4random.c index 22003ff0a..5284e1af8 100644 --- a/openbsd-compat/bsd-arc4random.c +++ b/openbsd-compat/bsd-arc4random.c @@ -17,7 +17,7 @@ #include "includes.h" #include "log.h" -RCSID("$Id: bsd-arc4random.c,v 1.8 2004/02/17 05:49:55 djm Exp $"); +RCSID("$Id: bsd-arc4random.c,v 1.9 2004/07/18 23:30:40 djm Exp $"); #ifndef HAVE_ARC4RANDOM @@ -56,13 +56,21 @@ unsigned int arc4random(void) void arc4random_stir(void) { unsigned char rand_buf[SEED_SIZE]; + int i; memset(&rc4, 0, sizeof(rc4)); if (RAND_bytes(rand_buf, sizeof(rand_buf)) <= 0) fatal("Couldn't obtain random bytes (error %ld)", ERR_get_error()); RC4_set_key(&rc4, sizeof(rand_buf), rand_buf); - RC4(&rc4, sizeof(rand_buf), rand_buf, rand_buf); + + /* + * Discard early keystream, as per recommendations in: + * http://www.wisdom.weizmann.ac.il/~itsik/RC4/Papers/Rc4_ksa.ps + */ + for(i = 0; i <= 256; i += sizeof(rand_buf)) + RC4(&rc4, sizeof(rand_buf), rand_buf, rand_buf); + memset(rand_buf, 0, sizeof(rand_buf)); rc4_ready = REKEY_BYTES; -- cgit v1.2.3