Mercurial > dropbear
diff rng_make_prng.c @ 0:d7da3b1e1540 libtomcrypt
put back the 0.95 makefile which was inadvertently merged over
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Mon, 31 May 2004 18:21:40 +0000 |
parents | |
children |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/rng_make_prng.c Mon May 31 18:21:40 2004 +0000 @@ -0,0 +1,53 @@ +/* LibTomCrypt, modular cryptographic library -- Tom St Denis + * + * LibTomCrypt is a library that provides various cryptographic + * algorithms in a highly modular and flexible manner. + * + * The library is free for all purposes without any express + * guarantee it works. + * + * Tom St Denis, [email protected], http://libtomcrypt.org + */ +/* portable way to get secure random bits to feed a PRNG */ +#include "mycrypt.h" + +int rng_make_prng(int bits, int wprng, prng_state *prng, + void (*callback)(void)) +{ + unsigned char buf[256]; + int err; + + _ARGCHK(prng != NULL); + + /* check parameter */ + if ((err = prng_is_valid(wprng)) != CRYPT_OK) { + return err; + } + + if (bits < 64 || bits > 1024) { + return CRYPT_INVALID_PRNGSIZE; + } + + if ((err = prng_descriptor[wprng].start(prng)) != CRYPT_OK) { + return err; + } + + bits = ((bits/8)+((bits&7)!=0?1:0)) * 2; + if (rng_get_bytes(buf, (unsigned long)bits, callback) != (unsigned long)bits) { + return CRYPT_ERROR_READPRNG; + } + + if ((err = prng_descriptor[wprng].add_entropy(buf, (unsigned long)bits, prng)) != CRYPT_OK) { + return err; + } + + if ((err = prng_descriptor[wprng].ready(prng)) != CRYPT_OK) { + return err; + } + + #ifdef CLEAN_STACK + zeromem(buf, sizeof(buf)); + #endif + return CRYPT_OK; +} +