Mercurial > dropbear
view libtomcrypt/src/prngs/rng_make_prng.c @ 1343:bbc0a0ee3843
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author | Matt Johnston <matt@ucc.asn.au> |
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date | Thu, 18 May 2017 23:00:12 +0800 |
parents | 0cbe8f6dbf9e |
children | f849a5ca2efc |
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/* 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.com */ #include "tomcrypt.h" /** @file rng_make_prng.c portable way to get secure random bits to feed a PRNG (Tom St Denis) */ /** Create a PRNG from a RNG @param bits Number of bits of entropy desired (64 ... 1024) @param wprng Index of which PRNG to setup @param prng [out] PRNG state to initialize @param callback A pointer to a void function for when the RNG is slow, this can be NULL @return CRYPT_OK if successful */ int rng_make_prng(int bits, int wprng, prng_state *prng, void (*callback)(void)) { unsigned char buf[256]; int err; LTC_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 LTC_CLEAN_STACK zeromem(buf, sizeof(buf)); #endif return CRYPT_OK; } /* $Source: /cvs/libtom/libtomcrypt/src/prngs/rng_make_prng.c,v $ */ /* $Revision: 1.4 $ */ /* $Date: 2006/03/31 14:15:35 $ */