/*
** Checks the signature on the given digest using the key provided.
*/
SECStatus
ECDSA_VerifyDigest(ECPublicKey *key, const SECItem *signature,
const SECItem *digest)
{
SECStatus rv = SECFailure;
#ifndef NSS_DISABLE_ECC
mp_int r_, s_; /* tuple (r', s') is received signature) */
mp_int c, u1, u2, v; /* intermediate values used in verification */
mp_int x1;
mp_int n;
mp_err err = MP_OKAY;
ECParams *ecParams = NULL;
SECItem pointC = { siBuffer, NULL, 0 };
int slen; /* length in bytes of a half signature (r or s) */
int flen; /* length in bytes of the field size */
unsigned olen; /* length in bytes of the base point order */
unsigned obits; /* length in bits of the base point order */
#if EC_DEBUG
char mpstr[256];
printf("ECDSA verification called\n");
#endif
/* Initialize MPI integers. */
/* must happen before the first potential call to cleanup */
MP_DIGITS(&r_) = 0;
MP_DIGITS(&s_) = 0;
MP_DIGITS(&c) = 0;
MP_DIGITS(&u1) = 0;
MP_DIGITS(&u2) = 0;
MP_DIGITS(&x1) = 0;
MP_DIGITS(&v) = 0;
MP_DIGITS(&n) = 0;
/* Check args */
if (!key || !signature || !digest) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
goto cleanup;
}
ecParams = &(key->ecParams);
flen = (ecParams->fieldID.size + 7) >> 3;
olen = ecParams->order.len;
if (signature->len == 0 || signature->len%2 != 0 ||
signature->len > 2*olen) {
PORT_SetError(SEC_ERROR_INPUT_LEN);
goto cleanup;
}
slen = signature->len/2;
SECITEM_AllocItem(NULL, &pointC, 2*flen + 1);
if (pointC.data == NULL)
goto cleanup;
CHECK_MPI_OK( mp_init(&r_) );
CHECK_MPI_OK( mp_init(&s_) );
CHECK_MPI_OK( mp_init(&c) );
CHECK_MPI_OK( mp_init(&u1) );
CHECK_MPI_OK( mp_init(&u2) );
CHECK_MPI_OK( mp_init(&x1) );
CHECK_MPI_OK( mp_init(&v) );
CHECK_MPI_OK( mp_init(&n) );
/*
** Convert received signature (r', s') into MPI integers.
*/
CHECK_MPI_OK( mp_read_unsigned_octets(&r_, signature->data, slen) );
CHECK_MPI_OK( mp_read_unsigned_octets(&s_, signature->data + slen, slen) );
/*
** ANSI X9.62, Section 5.4.2, Steps 1 and 2
**
** Verify that 0 < r' < n and 0 < s' < n
*/
SECITEM_TO_MPINT(ecParams->order, &n);
if (mp_cmp_z(&r_) <= 0 || mp_cmp_z(&s_) <= 0 ||
mp_cmp(&r_, &n) >= 0 || mp_cmp(&s_, &n) >= 0) {
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
goto cleanup; /* will return rv == SECFailure */
}
/*
** ANSI X9.62, Section 5.4.2, Step 3
**
** c = (s')**-1 mod n
*/
CHECK_MPI_OK( mp_invmod(&s_, &n, &c) ); /* c = (s')**-1 mod n */
/*
** ANSI X9.62, Section 5.4.2, Step 4
**
** u1 = ((HASH(M')) * c) mod n
*/
SECITEM_TO_MPINT(*digest, &u1); /* u1 = HASH(M) */
/* In the definition of EC signing, digests are truncated
* to the length of n in bits.
* (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
CHECK_MPI_OK( (obits = mpl_significant_bits(&n)) );
if (digest->len*8 > obits) { /* u1 = HASH(M') */
mpl_rsh(&u1,&u1,digest->len*8 - obits);
}
#if EC_DEBUG
mp_todecimal(&r_, mpstr);
printf("r_: %s (dec)\n", mpstr);
mp_todecimal(&s_, mpstr);
printf("s_: %s (dec)\n", mpstr);
mp_todecimal(&c, mpstr);
printf("c : %s (dec)\n", mpstr);
mp_todecimal(&u1, mpstr);
printf("digest: %s (dec)\n", mpstr);
#endif
CHECK_MPI_OK( mp_mulmod(&u1, &c, &n, &u1) ); /* u1 = u1 * c mod n */
/*
** ANSI X9.62, Section 5.4.2, Step 4
**
** u2 = ((r') * c) mod n
*/
CHECK_MPI_OK( mp_mulmod(&r_, &c, &n, &u2) );
/*
** ANSI X9.62, Section 5.4.3, Step 1
**
** Compute u1*G + u2*Q
** Here, A = u1.G B = u2.Q and C = A + B
** If the result, C, is the point at infinity, reject the signature
*/
if (ec_points_mul(ecParams, &u1, &u2, &key->publicValue, &pointC)
!= SECSuccess) {
rv = SECFailure;
goto cleanup;
}
if (ec_point_at_infinity(&pointC)) {
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
rv = SECFailure;
goto cleanup;
}
CHECK_MPI_OK( mp_read_unsigned_octets(&x1, pointC.data + 1, flen) );
/*
** ANSI X9.62, Section 5.4.4, Step 2
**
** v = x1 mod n
*/
CHECK_MPI_OK( mp_mod(&x1, &n, &v) );
#if EC_DEBUG
mp_todecimal(&r_, mpstr);
printf("r_: %s (dec)\n", mpstr);
mp_todecimal(&v, mpstr);
printf("v : %s (dec)\n", mpstr);
#endif
/*
** ANSI X9.62, Section 5.4.4, Step 3
**
** Verification: v == r'
*/
if (mp_cmp(&v, &r_)) {
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
rv = SECFailure; /* Signature failed to verify. */
} else {
rv = SECSuccess; /* Signature verified. */
}
#if EC_DEBUG
mp_todecimal(&u1, mpstr);
printf("u1: %s (dec)\n", mpstr);
mp_todecimal(&u2, mpstr);
printf("u2: %s (dec)\n", mpstr);
mp_tohex(&x1, mpstr);
printf("x1: %s\n", mpstr);
mp_todecimal(&v, mpstr);
printf("v : %s (dec)\n", mpstr);
#endif
cleanup:
mp_clear(&r_);
mp_clear(&s_);
mp_clear(&c);
mp_clear(&u1);
mp_clear(&u2);
mp_clear(&x1);
mp_clear(&v);
mp_clear(&n);
if (pointC.data) SECITEM_FreeItem(&pointC, PR_FALSE);
if (err) {
MP_TO_SEC_ERROR(err);
rv = SECFailure;
}
#if EC_DEBUG
printf("ECDSA verification %s\n",
(rv == SECSuccess) ? "succeeded" : "failed");
#endif
#else
PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
#endif /* NSS_DISABLE_ECC */
return rv;
}
int main(int argc, char *argv[])
{
mp_int a, b, c;
int pco;
mp_err res;
printf("Test 9: Logical functions\n\n");
if(argc < 3) {
fprintf(stderr, "Usage: %s <a> <b>\n", argv[0]);
return 1;
}
mp_init(&a); mp_init(&b); mp_init(&c);
mp_read_radix(&a, argv[1], 16);
mp_read_radix(&b, argv[2], 16);
printf("a = "); mp_print(&a, stdout); fputc('\n', stdout);
printf("b = "); mp_print(&b, stdout); fputc('\n', stdout);
mpl_not(&a, &c);
printf("~a = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_and(&a, &b, &c);
printf("a & b = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_or(&a, &b, &c);
printf("a | b = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_xor(&a, &b, &c);
printf("a ^ b = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_rsh(&a, &c, 1);
printf("a >> 1 = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_rsh(&a, &c, 5);
printf("a >> 5 = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_rsh(&a, &c, 16);
printf("a >> 16 = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_lsh(&a, &c, 1);
printf("a << 1 = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_lsh(&a, &c, 5);
printf("a << 5 = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_lsh(&a, &c, 16);
printf("a << 16 = "); mp_print(&c, stdout); fputc('\n', stdout);
mpl_num_set(&a, &pco);
printf("population(a) = %d\n", pco);
mpl_num_set(&b, &pco);
printf("population(b) = %d\n", pco);
res = mpl_parity(&a);
if(res == MP_EVEN)
printf("a has even parity\n");
else
printf("a has odd parity\n");
mp_clear(&c);
mp_clear(&b);
mp_clear(&a);
return 0;
}
/* Computes the ECDSA signature (a concatenation of two values r and s)
* on the digest using the given key and the random value kb (used in
* computing s).
*/
SECStatus
ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature,
const SECItem *digest, const unsigned char *kb, const int kblen)
{
SECStatus rv = SECFailure;
#ifndef NSS_DISABLE_ECC
mp_int x1;
mp_int d, k; /* private key, random integer */
mp_int r, s; /* tuple (r, s) is the signature */
mp_int n;
mp_err err = MP_OKAY;
ECParams *ecParams = NULL;
SECItem kGpoint = { siBuffer, NULL, 0};
int flen = 0; /* length in bytes of the field size */
unsigned olen; /* length in bytes of the base point order */
unsigned obits; /* length in bits of the base point order */
#if EC_DEBUG
char mpstr[256];
#endif
/* Initialize MPI integers. */
/* must happen before the first potential call to cleanup */
MP_DIGITS(&x1) = 0;
MP_DIGITS(&d) = 0;
MP_DIGITS(&k) = 0;
MP_DIGITS(&r) = 0;
MP_DIGITS(&s) = 0;
MP_DIGITS(&n) = 0;
/* Check args */
if (!key || !signature || !digest || !kb || (kblen < 0)) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
goto cleanup;
}
ecParams = &(key->ecParams);
flen = (ecParams->fieldID.size + 7) >> 3;
olen = ecParams->order.len;
if (signature->data == NULL) {
/* a call to get the signature length only */
goto finish;
}
if (signature->len < 2*olen) {
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
goto cleanup;
}
CHECK_MPI_OK( mp_init(&x1) );
CHECK_MPI_OK( mp_init(&d) );
CHECK_MPI_OK( mp_init(&k) );
CHECK_MPI_OK( mp_init(&r) );
CHECK_MPI_OK( mp_init(&s) );
CHECK_MPI_OK( mp_init(&n) );
SECITEM_TO_MPINT( ecParams->order, &n );
SECITEM_TO_MPINT( key->privateValue, &d );
CHECK_MPI_OK( mp_read_unsigned_octets(&k, kb, kblen) );
/* Make sure k is in the interval [1, n-1] */
if ((mp_cmp_z(&k) <= 0) || (mp_cmp(&k, &n) >= 0)) {
#if EC_DEBUG
printf("k is outside [1, n-1]\n");
mp_tohex(&k, mpstr);
printf("k : %s \n", mpstr);
mp_tohex(&n, mpstr);
printf("n : %s \n", mpstr);
#endif
PORT_SetError(SEC_ERROR_NEED_RANDOM);
goto cleanup;
}
/*
** We do not want timing information to leak the length of k,
** so we compute k*G using an equivalent scalar of fixed
** bit-length.
** Fix based on patch for ECDSA timing attack in the paper
** by Billy Bob Brumley and Nicola Tuveri at
** http://eprint.iacr.org/2011/232
**
** How do we convert k to a value of a fixed bit-length?
** k starts off as an integer satisfying 0 <= k < n. Hence,
** n <= k+n < 2n, which means k+n has either the same number
** of bits as n or one more bit than n. If k+n has the same
** number of bits as n, the second addition ensures that the
** final value has exactly one more bit than n. Thus, we
** always end up with a value that exactly one more bit than n.
*/
CHECK_MPI_OK( mp_add(&k, &n, &k) );
if (mpl_significant_bits(&k) <= mpl_significant_bits(&n)) {
CHECK_MPI_OK( mp_add(&k, &n, &k) );
}
/*
** ANSI X9.62, Section 5.3.2, Step 2
**
** Compute kG
*/
kGpoint.len = 2*flen + 1;
kGpoint.data = PORT_Alloc(2*flen + 1);
if ((kGpoint.data == NULL) ||
(ec_points_mul(ecParams, &k, NULL, NULL, &kGpoint)
!= SECSuccess))
goto cleanup;
/*
** ANSI X9.62, Section 5.3.3, Step 1
**
** Extract the x co-ordinate of kG into x1
*/
CHECK_MPI_OK( mp_read_unsigned_octets(&x1, kGpoint.data + 1,
(mp_size) flen) );
/*
** ANSI X9.62, Section 5.3.3, Step 2
**
** r = x1 mod n NOTE: n is the order of the curve
*/
CHECK_MPI_OK( mp_mod(&x1, &n, &r) );
/*
** ANSI X9.62, Section 5.3.3, Step 3
**
** verify r != 0
*/
if (mp_cmp_z(&r) == 0) {
PORT_SetError(SEC_ERROR_NEED_RANDOM);
goto cleanup;
}
/*
** ANSI X9.62, Section 5.3.3, Step 4
**
** s = (k**-1 * (HASH(M) + d*r)) mod n
*/
SECITEM_TO_MPINT(*digest, &s); /* s = HASH(M) */
/* In the definition of EC signing, digests are truncated
* to the length of n in bits.
* (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
CHECK_MPI_OK( (obits = mpl_significant_bits(&n)) );
if (digest->len*8 > obits) {
mpl_rsh(&s,&s,digest->len*8 - obits);
}
#if EC_DEBUG
mp_todecimal(&n, mpstr);
printf("n : %s (dec)\n", mpstr);
mp_todecimal(&d, mpstr);
printf("d : %s (dec)\n", mpstr);
mp_tohex(&x1, mpstr);
printf("x1: %s\n", mpstr);
mp_todecimal(&s, mpstr);
printf("digest: %s (decimal)\n", mpstr);
mp_todecimal(&r, mpstr);
printf("r : %s (dec)\n", mpstr);
mp_tohex(&r, mpstr);
printf("r : %s\n", mpstr);
#endif
CHECK_MPI_OK( mp_invmod(&k, &n, &k) ); /* k = k**-1 mod n */
CHECK_MPI_OK( mp_mulmod(&d, &r, &n, &d) ); /* d = d * r mod n */
CHECK_MPI_OK( mp_addmod(&s, &d, &n, &s) ); /* s = s + d mod n */
CHECK_MPI_OK( mp_mulmod(&s, &k, &n, &s) ); /* s = s * k mod n */
#if EC_DEBUG
mp_todecimal(&s, mpstr);
printf("s : %s (dec)\n", mpstr);
mp_tohex(&s, mpstr);
printf("s : %s\n", mpstr);
#endif
/*
** ANSI X9.62, Section 5.3.3, Step 5
**
** verify s != 0
*/
if (mp_cmp_z(&s) == 0) {
PORT_SetError(SEC_ERROR_NEED_RANDOM);
goto cleanup;
}
/*
**
** Signature is tuple (r, s)
*/
CHECK_MPI_OK( mp_to_fixlen_octets(&r, signature->data, olen) );
CHECK_MPI_OK( mp_to_fixlen_octets(&s, signature->data + olen, olen) );
finish:
signature->len = 2*olen;
rv = SECSuccess;
err = MP_OKAY;
cleanup:
mp_clear(&x1);
mp_clear(&d);
mp_clear(&k);
mp_clear(&r);
mp_clear(&s);
mp_clear(&n);
if (kGpoint.data) {
PORT_ZFree(kGpoint.data, 2*flen + 1);
}
if (err) {
MP_TO_SEC_ERROR(err);
rv = SECFailure;
}
#if EC_DEBUG
printf("ECDSA signing with seed %s\n",
(rv == SECSuccess) ? "succeeded" : "failed");
#endif
#else
PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
#endif /* NSS_DISABLE_ECC */
return rv;
}
/* Computes the ECDSA signature (a concatenation of two values r and s)
* on the digest using the given key and the random value kb (used in
* computing s).
*/
SECStatus
ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature,
const SECItem *digest, const unsigned char *kb, const int kblen, int kmflag)
{
SECStatus rv = SECFailure;
mp_int x1;
mp_int d, k; /* private key, random integer */
mp_int r, s; /* tuple (r, s) is the signature */
mp_int n;
mp_err err = MP_OKAY;
ECParams *ecParams = NULL;
SECItem kGpoint = { siBuffer, NULL, 0};
int flen = 0; /* length in bytes of the field size */
unsigned olen; /* length in bytes of the base point order */
#if EC_DEBUG
char mpstr[256];
#endif
/* Initialize MPI integers. */
/* must happen before the first potential call to cleanup */
MP_DIGITS(&x1) = 0;
MP_DIGITS(&d) = 0;
MP_DIGITS(&k) = 0;
MP_DIGITS(&r) = 0;
MP_DIGITS(&s) = 0;
MP_DIGITS(&n) = 0;
/* Check args */
if (!key || !signature || !digest || !kb || (kblen < 0)) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
goto cleanup;
}
ecParams = &(key->ecParams);
flen = (ecParams->fieldID.size + 7) >> 3;
olen = ecParams->order.len;
if (signature->data == NULL) {
/* a call to get the signature length only */
goto finish;
}
if (signature->len < 2*olen) {
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
rv = SECBufferTooSmall;
goto cleanup;
}
CHECK_MPI_OK( mp_init(&x1, kmflag) );
CHECK_MPI_OK( mp_init(&d, kmflag) );
CHECK_MPI_OK( mp_init(&k, kmflag) );
CHECK_MPI_OK( mp_init(&r, kmflag) );
CHECK_MPI_OK( mp_init(&s, kmflag) );
CHECK_MPI_OK( mp_init(&n, kmflag) );
SECITEM_TO_MPINT( ecParams->order, &n );
SECITEM_TO_MPINT( key->privateValue, &d );
CHECK_MPI_OK( mp_read_unsigned_octets(&k, kb, kblen) );
/* Make sure k is in the interval [1, n-1] */
if ((mp_cmp_z(&k) <= 0) || (mp_cmp(&k, &n) >= 0)) {
#if EC_DEBUG
printf("k is outside [1, n-1]\n");
mp_tohex(&k, mpstr);
printf("k : %s \n", mpstr);
mp_tohex(&n, mpstr);
printf("n : %s \n", mpstr);
#endif
PORT_SetError(SEC_ERROR_NEED_RANDOM);
goto cleanup;
}
/*
* Using an equivalent exponent of fixed length (same as n or 1 bit less
* than n) to keep the kG timing relatively constant.
*
* Note that this is an extra step on top of the approach defined in
* ANSI X9.62 so as to make a fixed length K.
*/
CHECK_MPI_OK( mp_add(&k, &n, &k) );
CHECK_MPI_OK( mp_div_2(&k, &k) );
/*
** ANSI X9.62, Section 5.3.2, Step 2
**
** Compute kG
*/
kGpoint.len = 2*flen + 1;
kGpoint.data = PORT_Alloc(2*flen + 1, kmflag);
if ((kGpoint.data == NULL) ||
(ec_points_mul(ecParams, &k, NULL, NULL, &kGpoint, kmflag)
!= SECSuccess))
goto cleanup;
/*
** ANSI X9.62, Section 5.3.3, Step 1
**
** Extract the x co-ordinate of kG into x1
*/
CHECK_MPI_OK( mp_read_unsigned_octets(&x1, kGpoint.data + 1,
(mp_size) flen) );
/*
** ANSI X9.62, Section 5.3.3, Step 2
**
** r = x1 mod n NOTE: n is the order of the curve
*/
CHECK_MPI_OK( mp_mod(&x1, &n, &r) );
/*
** ANSI X9.62, Section 5.3.3, Step 3
**
** verify r != 0
*/
if (mp_cmp_z(&r) == 0) {
PORT_SetError(SEC_ERROR_NEED_RANDOM);
goto cleanup;
}
/*
** ANSI X9.62, Section 5.3.3, Step 4
**
** s = (k**-1 * (HASH(M) + d*r)) mod n
*/
SECITEM_TO_MPINT(*digest, &s); /* s = HASH(M) */
/* In the definition of EC signing, digests are truncated
* to the length of n in bits.
* (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
if (digest->len*8 > (unsigned int)ecParams->fieldID.size) {
mpl_rsh(&s,&s,digest->len*8 - ecParams->fieldID.size);
}
#if EC_DEBUG
mp_todecimal(&n, mpstr);
printf("n : %s (dec)\n", mpstr);
mp_todecimal(&d, mpstr);
printf("d : %s (dec)\n", mpstr);
mp_tohex(&x1, mpstr);
printf("x1: %s\n", mpstr);
mp_todecimal(&s, mpstr);
printf("digest: %s (decimal)\n", mpstr);
mp_todecimal(&r, mpstr);
printf("r : %s (dec)\n", mpstr);
mp_tohex(&r, mpstr);
printf("r : %s\n", mpstr);
#endif
CHECK_MPI_OK( mp_invmod(&k, &n, &k) ); /* k = k**-1 mod n */
CHECK_MPI_OK( mp_mulmod(&d, &r, &n, &d) ); /* d = d * r mod n */
CHECK_MPI_OK( mp_addmod(&s, &d, &n, &s) ); /* s = s + d mod n */
CHECK_MPI_OK( mp_mulmod(&s, &k, &n, &s) ); /* s = s * k mod n */
#if EC_DEBUG
mp_todecimal(&s, mpstr);
printf("s : %s (dec)\n", mpstr);
mp_tohex(&s, mpstr);
printf("s : %s\n", mpstr);
#endif
/*
** ANSI X9.62, Section 5.3.3, Step 5
**
** verify s != 0
*/
if (mp_cmp_z(&s) == 0) {
PORT_SetError(SEC_ERROR_NEED_RANDOM);
goto cleanup;
}
/*
**
** Signature is tuple (r, s)
*/
CHECK_MPI_OK( mp_to_fixlen_octets(&r, signature->data, olen) );
CHECK_MPI_OK( mp_to_fixlen_octets(&s, signature->data + olen, olen) );
finish:
signature->len = 2*olen;
rv = SECSuccess;
err = MP_OKAY;
cleanup:
mp_clear(&x1);
mp_clear(&d);
mp_clear(&k);
mp_clear(&r);
mp_clear(&s);
mp_clear(&n);
if (kGpoint.data) {
PORT_ZFree(kGpoint.data, 2*flen + 1);
}
if (err) {
MP_TO_SEC_ERROR(err);
rv = SECFailure;
}
#if EC_DEBUG
printf("ECDSA signing with seed %s\n",
(rv == SECSuccess) ? "succeeded" : "failed");
#endif
return rv;
}
