diff options
Diffstat (limited to 'src/ltc/prngs/rng_make_prng.c')
-rw-r--r-- | src/ltc/prngs/rng_make_prng.c | 44 |
1 files changed, 33 insertions, 11 deletions
diff --git a/src/ltc/prngs/rng_make_prng.c b/src/ltc/prngs/rng_make_prng.c index 2bde291f..19ac1ee3 100644 --- a/src/ltc/prngs/rng_make_prng.c +++ b/src/ltc/prngs/rng_make_prng.c @@ -16,7 +16,12 @@ /** Create a PRNG from a RNG - @param bits Number of bits of entropy desired (64 ... 1024) + + In case you pass bits as '-1' the PRNG will be setup + as if the export/import functionality has been used, + but the imported data comes directly from the RNG. + + @param bits Number of bits of entropy desired (-1 or 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 @@ -25,7 +30,8 @@ int rng_make_prng(int bits, int wprng, prng_state *prng, void (*callback)(void)) { - unsigned char buf[256]; + unsigned char* buf; + unsigned long bytes; int err; LTC_ARGCHK(prng != NULL); @@ -35,31 +41,47 @@ int rng_make_prng(int bits, int wprng, prng_state *prng, return err; } - if (bits < 64 || bits > 1024) { + if (bits == -1) { + bytes = prng_descriptor[wprng].export_size; + } else if (bits < 64 || bits > 1024) { return CRYPT_INVALID_PRNGSIZE; + } else { + bytes = (unsigned long)((bits+7)/8) * 2; } if ((err = prng_descriptor[wprng].start(prng)) != CRYPT_OK) { return err; } - bits = ((bits+7)/8) * 2; - if (rng_get_bytes(buf, (unsigned long)bits, callback) != (unsigned long)bits) { - return CRYPT_ERROR_READPRNG; + buf = XMALLOC(bytes); + if (buf == NULL) { + return CRYPT_MEM; } - if ((err = prng_descriptor[wprng].add_entropy(buf, (unsigned long)bits, prng)) != CRYPT_OK) { - return err; + if (rng_get_bytes(buf, bytes, callback) != bytes) { + err = CRYPT_ERROR_READPRNG; + goto LBL_ERR; } + if (bits == -1) { + if ((err = prng_descriptor[wprng].pimport(buf, bytes, prng)) != CRYPT_OK) { + goto LBL_ERR; + } + } else { + if ((err = prng_descriptor[wprng].add_entropy(buf, bytes, prng)) != CRYPT_OK) { + goto LBL_ERR; + } + } if ((err = prng_descriptor[wprng].ready(prng)) != CRYPT_OK) { - return err; + goto LBL_ERR; } +LBL_ERR: #ifdef LTC_CLEAN_STACK - zeromem(buf, sizeof(buf)); + zeromem(buf, bytes); #endif - return CRYPT_OK; + XFREE(buf); + return err; } #endif /* #ifdef LTC_RNG_MAKE_PRNG */ |