summaryrefslogtreecommitdiff
path: root/core/lib/libtomcrypt/src/pk/ecc/ecc_verify_hash.c
diff options
context:
space:
mode:
Diffstat (limited to 'core/lib/libtomcrypt/src/pk/ecc/ecc_verify_hash.c')
-rw-r--r--core/lib/libtomcrypt/src/pk/ecc/ecc_verify_hash.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/pk/ecc/ecc_verify_hash.c b/core/lib/libtomcrypt/src/pk/ecc/ecc_verify_hash.c
new file mode 100644
index 0000000..2ee3609
--- /dev/null
+++ b/core/lib/libtomcrypt/src/pk/ecc/ecc_verify_hash.c
@@ -0,0 +1,228 @@
+/*
+ * Copyright (c) 2001-2007, Tom St Denis
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* 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, tomstdenis@gmail.com, http://libtom.org
+ */
+
+/* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b
+ *
+ * All curves taken from NIST recommendation paper of July 1999
+ * Available at http://csrc.nist.gov/cryptval/dss.htm
+ */
+#include "tomcrypt.h"
+
+/**
+ @file ecc_verify_hash.c
+ ECC Crypto, Tom St Denis
+*/
+
+#ifdef LTC_MECC
+
+/* verify
+ *
+ * w = s^-1 mod n
+ * u1 = xw
+ * u2 = rw
+ * X = u1*G + u2*Q
+ * v = X_x1 mod n
+ * accept if v == r
+ */
+
+/**
+ Verify a ECC signature
+ @param r ECC "r" parameter
+ @param s ECC "s" parameter
+ @param hash The hash that was signed
+ @param hashlen The length of the hash that was signed
+ @param stat [out] The result of the signature verification, 1==valid, 0==invalid
+ @param key The corresponding public DH key
+ @return CRYPT_OK if successful (even if the signature is invalid)
+*/
+int ecc_verify_hash_raw( void *r, void *s,
+ const unsigned char *hash, unsigned long hashlen,
+ int *stat, ecc_key *key)
+{
+ ecc_point *mG, *mQ;
+ void *v, *w, *u1, *u2, *e, *p, *m;
+ void *mp = NULL;
+ int err;
+
+ LTC_ARGCHK(r != NULL);
+ LTC_ARGCHK(s != NULL);
+ LTC_ARGCHK(hash != NULL);
+ LTC_ARGCHK(stat != NULL);
+ LTC_ARGCHK(key != NULL);
+
+ /* default to invalid signature */
+ *stat = 0;
+ mp = NULL;
+
+ /* is the IDX valid ? */
+ if (ltc_ecc_is_valid_idx(key->idx) != 1) {
+ return CRYPT_PK_INVALID_TYPE;
+ }
+
+ /* allocate ints */
+ if ((err = mp_init_multi(&v, &w, &u1, &u2, &p, &e, &m, NULL)) != CRYPT_OK) {
+ return CRYPT_MEM;
+ }
+
+ /* allocate points */
+ mG = ltc_ecc_new_point();
+ mQ = ltc_ecc_new_point();
+ if (mQ == NULL || mG == NULL) {
+ err = CRYPT_MEM;
+ goto error;
+ }
+
+ /* get the order */
+ if ((err = mp_read_radix(p, (char *)key->dp->order, 16)) != CRYPT_OK) { goto error; }
+
+ /* get the modulus */
+ if ((err = mp_read_radix(m, (char *)key->dp->prime, 16)) != CRYPT_OK) { goto error; }
+
+ /* check for zero */
+ if (mp_iszero(r) || mp_iszero(s) || mp_cmp(r, p) != LTC_MP_LT || mp_cmp(s, p) != LTC_MP_LT) {
+ err = CRYPT_INVALID_PACKET;
+ goto error;
+ }
+
+ /* read hash */
+ if ((err = mp_read_unsigned_bin(e, (unsigned char *)hash, (int)hashlen)) != CRYPT_OK) { goto error; }
+
+ /* w = s^-1 mod n */
+ if ((err = mp_invmod(s, p, w)) != CRYPT_OK) { goto error; }
+
+ /* u1 = ew */
+ if ((err = mp_mulmod(e, w, p, u1)) != CRYPT_OK) { goto error; }
+
+ /* u2 = rw */
+ if ((err = mp_mulmod(r, w, p, u2)) != CRYPT_OK) { goto error; }
+
+ /* find mG and mQ */
+ if ((err = mp_read_radix(mG->x, (char *)key->dp->Gx, 16)) != CRYPT_OK) { goto error; }
+ if ((err = mp_read_radix(mG->y, (char *)key->dp->Gy, 16)) != CRYPT_OK) { goto error; }
+ if ((err = mp_set(mG->z, 1)) != CRYPT_OK) { goto error; }
+
+ if ((err = mp_copy(key->pubkey.x, mQ->x)) != CRYPT_OK) { goto error; }
+ if ((err = mp_copy(key->pubkey.y, mQ->y)) != CRYPT_OK) { goto error; }
+ if ((err = mp_copy(key->pubkey.z, mQ->z)) != CRYPT_OK) { goto error; }
+
+ /* compute u1*mG + u2*mQ = mG */
+ if (ltc_mp.ecc_mul2add == NULL) {
+ if ((err = ltc_mp.ecc_ptmul(u1, mG, mG, m, 0)) != CRYPT_OK) { goto error; }
+ if ((err = ltc_mp.ecc_ptmul(u2, mQ, mQ, m, 0)) != CRYPT_OK) { goto error; }
+
+ /* find the montgomery mp */
+ if ((err = mp_montgomery_setup(m, &mp)) != CRYPT_OK) { goto error; }
+
+ /* add them */
+ if ((err = ltc_mp.ecc_ptadd(mQ, mG, mG, m, mp)) != CRYPT_OK) { goto error; }
+
+ /* reduce */
+ if ((err = ltc_mp.ecc_map(mG, m, mp)) != CRYPT_OK) { goto error; }
+ } else {
+ /* use Shamir's trick to compute u1*mG + u2*mQ using half of the doubles */
+ if ((err = ltc_mp.ecc_mul2add(mG, u1, mQ, u2, mG, m)) != CRYPT_OK) { goto error; }
+ }
+
+ /* v = X_x1 mod n */
+ if ((err = mp_mod(mG->x, p, v)) != CRYPT_OK) { goto error; }
+
+ /* does v == r */
+ if (mp_cmp(v, r) == LTC_MP_EQ) {
+ *stat = 1;
+ }
+
+ /* clear up and return */
+ err = CRYPT_OK;
+error:
+ ltc_ecc_del_point(mG);
+ ltc_ecc_del_point(mQ);
+ mp_clear_multi(v, w, u1, u2, p, e, m, NULL);
+ if (mp != NULL) {
+ mp_montgomery_free(mp);
+ }
+ return err;
+}
+
+/**
+ Verify an ECC signature
+ @param sig The signature to verify
+ @param siglen The length of the signature (octets)
+ @param hash The hash (message digest) that was signed
+ @param hashlen The length of the hash (octets)
+ @param stat Result of signature, 1==valid, 0==invalid
+ @param key The corresponding public ECC key
+ @return CRYPT_OK if successful (even if the signature is not valid)
+*/
+
+int ecc_verify_hash(const unsigned char *sig, unsigned long siglen,
+ const unsigned char *hash, unsigned long hashlen,
+ int *stat, ecc_key *key)
+{
+ void *r, *s;
+ int err;
+
+ LTC_ARGCHK(sig != NULL);
+ LTC_ARGCHK(hash != NULL);
+ LTC_ARGCHK(stat != NULL);
+ LTC_ARGCHK(key != NULL);
+
+ /* allocate ints */
+ if ((err = mp_init_multi(&r, &s, NULL)) != CRYPT_OK) {
+ return CRYPT_MEM;
+ }
+
+ /* parse header */
+ if ((err = der_decode_sequence_multi(sig, siglen,
+ LTC_ASN1_INTEGER, 1UL, r,
+ LTC_ASN1_INTEGER, 1UL, s,
+ LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
+ goto error;
+ }
+
+ /* do the op */
+ err = ecc_verify_hash_raw(r, s, hash, hashlen, stat, key);
+
+error:
+ mp_clear_multi(r, s, NULL);
+ return err;
+}
+
+#endif
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc_verify_hash.c,v $ */
+/* $Revision: 1.14 $ */
+/* $Date: 2007/05/12 14:32:35 $ */
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-16 06:48:23 +0000