diff options
Diffstat (limited to 'release/src/router/cyassl/ctaocrypt/src/dsa.c')
| -rw-r--r-- | release/src/router/cyassl/ctaocrypt/src/dsa.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/release/src/router/cyassl/ctaocrypt/src/dsa.c b/release/src/router/cyassl/ctaocrypt/src/dsa.c new file mode 100644 index 00000000..28e328ad --- /dev/null +++ b/release/src/router/cyassl/ctaocrypt/src/dsa.c @@ -0,0 +1,216 @@ +/* dsa.c + * + * Copyright (C) 2006-2011 Sawtooth Consulting Ltd. + * + * This file is part of CyaSSL. + * + * CyaSSL is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * CyaSSL is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +#ifndef NO_DSA + +#include "ctc_dsa.h" +#include "ctc_sha.h" +#include "random.h" +#include "error.h" + + +enum { + DSA_HALF_SIZE = 20, /* r and s size */ + DSA_SIG_SIZE = 40 /* signaure size */ +}; + + +#ifndef min + + static INLINE word32 min(word32 a, word32 b) + { + return a > b ? b : a; + } + +#endif /* min */ + + +void InitDsaKey(DsaKey* key) +{ + key->type = -1; /* haven't decdied yet */ + +/* TomsFastMath doesn't use memory allocation */ +#ifndef USE_FAST_MATH + key->p.dp = 0; /* public alloc parts */ + key->q.dp = 0; + key->g.dp = 0; + key->y.dp = 0; + + key->x.dp = 0; /* private alloc parts */ +#endif +} + + +void FreeDsaKey(DsaKey* key) +{ +/* TomsFastMath doesn't use memory allocation */ +#ifndef USE_FAST_MATH + if (key->type == DSA_PRIVATE) + mp_clear(&key->x); + mp_clear(&key->y); + mp_clear(&key->g); + mp_clear(&key->q); + mp_clear(&key->p); +#endif +} + + +int DsaSign(const byte* digest, byte* out, DsaKey* key, RNG* rng) +{ + mp_int k, kInv, r, s, H; + int ret = 0, sz; + byte buffer[DSA_HALF_SIZE]; + + if (mp_init_multi(&k, &kInv, &r, &s, &H, 0) != MP_OKAY) + return MP_INIT_E; + + sz = min(sizeof(buffer), mp_unsigned_bin_size(&key->q)); + + /* generate k */ + RNG_GenerateBlock(rng, buffer, sz); + buffer[0] |= 0x0C; + + if (mp_read_unsigned_bin(&k, buffer, sz) != MP_OKAY) + ret = MP_READ_E; + + if (mp_cmp_d(&k, 1) != MP_GT) + ret = MP_CMP_E; + + /* inverse k mod q */ + if (ret == 0 && mp_invmod(&k, &key->q, &kInv) != MP_OKAY) + ret = MP_INVMOD_E; + + /* generate r, r = (g exp k mod p) mod q */ + if (ret == 0 && mp_exptmod(&key->g, &k, &key->p, &r) != MP_OKAY) + ret = MP_EXPTMOD_E; + + if (ret == 0 && mp_mod(&r, &key->q, &r) != MP_OKAY) + ret = MP_MOD_E; + + /* generate H from sha digest */ + if (ret == 0 && mp_read_unsigned_bin(&H, digest,SHA_DIGEST_SIZE) != MP_OKAY) + ret = MP_READ_E; + + /* generate s, s = (kInv * (H + x*r)) % q */ + if (ret == 0 && mp_mul(&key->x, &r, &s) != MP_OKAY) + ret = MP_MUL_E; + + if (ret == 0 && mp_add(&s, &H, &s) != MP_OKAY) + ret = MP_ADD_E; + + if (ret == 0 && mp_mulmod(&s, &kInv, &key->q, &s) != MP_OKAY) + ret = MP_MULMOD_E; + + /* write out */ + if (ret == 0) { + int rSz = mp_unsigned_bin_size(&r); + int sSz = mp_unsigned_bin_size(&s); + + if (rSz == DSA_HALF_SIZE - 1) { + out[0] = 0; + out++; + } + + if (mp_to_unsigned_bin(&r, out) != MP_OKAY) + ret = MP_TO_E; + else { + if (sSz == DSA_HALF_SIZE - 1) { + out[rSz] = 0; + out++; + } + ret = mp_to_unsigned_bin(&s, out + rSz); + } + } + + mp_clear(&H); + mp_clear(&s); + mp_clear(&r); + mp_clear(&kInv); + mp_clear(&k); + + return ret; +} + + +int DsaVerify(const byte* digest, const byte* sig, DsaKey* key, int* answer) +{ + mp_int w, u1, u2, v, r, s; + int ret = 0; + + if (mp_init_multi(&w, &u1, &u2, &v, &r, &s) != MP_OKAY) + return MP_INIT_E; + + /* set r and s from signature */ + if (mp_read_unsigned_bin(&r, sig, DSA_HALF_SIZE) != MP_OKAY || + mp_read_unsigned_bin(&s, sig + DSA_HALF_SIZE, DSA_HALF_SIZE) != MP_OKAY) + ret = MP_READ_E; + + /* sanity checks */ + + + /* put H into u1 from sha digest */ + if (ret == 0 && mp_read_unsigned_bin(&u1,digest,SHA_DIGEST_SIZE) != MP_OKAY) + ret = MP_READ_E; + + /* w = s invmod q */ + if (ret == 0 && mp_invmod(&s, &key->q, &w) != MP_OKAY) + ret = MP_INVMOD_E; + + /* u1 = (H * w) % q */ + if (ret == 0 && mp_mulmod(&u1, &w, &key->q, &u1) != MP_OKAY) + ret = MP_MULMOD_E; + + /* u2 = (r * w) % q */ + if (ret == 0 && mp_mulmod(&r, &w, &key->q, &u2) != MP_OKAY) + ret = MP_MULMOD_E; + + /* verify v = ((g^u1 * y^u2) mod p) mod q */ + if (ret == 0 && mp_exptmod(&key->g, &u1, &key->p, &u1) != MP_OKAY) + ret = MP_EXPTMOD_E; + + if (ret == 0 && mp_exptmod(&key->y, &u2, &key->p, &u2) != MP_OKAY) + ret = MP_EXPTMOD_E; + + if (ret == 0 && mp_mulmod(&u1, &u2, &key->p, &v) != MP_OKAY) + ret = MP_MULMOD_E; + + if (ret == 0 && mp_mod(&v, &key->q, &v) != MP_OKAY) + ret = MP_MULMOD_E; + + /* do they match */ + if (ret == 0 && mp_cmp(&r, &v) == MP_EQ) + *answer = 1; + else + *answer = 0; + + mp_clear(&s); + mp_clear(&r); + mp_clear(&u1); + mp_clear(&u2); + mp_clear(&w); + mp_clear(&v); + + return ret; +} + + +#endif /* NO_DSA */ + |