Mercurial > dropbear
view libtomcrypt/src/math/rand_prime.c @ 1446:b8764eee6bdb
add --enable-static configure argument. disable conflicting harden flags
author | Matt Johnston <matt@ucc.asn.au> |
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date | Tue, 27 Jun 2017 22:37:46 +0800 |
parents | f849a5ca2efc |
children | 6dba84798cd5 |
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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://libtom.org */ #include "tomcrypt.h" /** @file rand_prime.c Generate a random prime, Tom St Denis */ #define USE_BBS 1 int rand_prime(void *N, long len, prng_state *prng, int wprng) { int err, res, type; unsigned char *buf; LTC_ARGCHK(N != NULL); /* get type */ if (len < 0) { type = USE_BBS; len = -len; } else { type = 0; } /* allow sizes between 2 and 512 bytes for a prime size */ if (len < 2 || len > 512) { return CRYPT_INVALID_PRIME_SIZE; } /* valid PRNG? Better be! */ if ((err = prng_is_valid(wprng)) != CRYPT_OK) { return err; } /* allocate buffer to work with */ buf = XCALLOC(1, len); if (buf == NULL) { return CRYPT_MEM; } do { /* generate value */ if (prng_descriptor[wprng].read(buf, len, prng) != (unsigned long)len) { XFREE(buf); return CRYPT_ERROR_READPRNG; } /* munge bits */ buf[0] |= 0x80 | 0x40; buf[len-1] |= 0x01 | ((type & USE_BBS) ? 0x02 : 0x00); /* load value */ if ((err = mp_read_unsigned_bin(N, buf, len)) != CRYPT_OK) { XFREE(buf); return err; } /* test */ if ((err = mp_prime_is_prime(N, 8, &res)) != CRYPT_OK) { XFREE(buf); return err; } } while (res == LTC_MP_NO); #ifdef LTC_CLEAN_STACK zeromem(buf, len); #endif XFREE(buf); return CRYPT_OK; } /* $Source$ */ /* $Revision$ */ /* $Date$ */