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Merge pull request #6065 from SparkiDev/ec_point_cmp_jacobian 

wolfSSL_EC_POINT_cmp: handle Jacobian ordinates
pull/6067/head
David Garske 2023-02-07 10:04:37 -08:00 committed by GitHub
parent 2448adf68b 92065b61b3
commit 3ae8bac3b2
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 137 additions and 9 deletions
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src/pk.c
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@ -9176,6 +9176,7 @@ int wolfSSL_EC_GROUP_cmp(const WOLFSSL_EC_GROUP *a, const WOLFSSL_EC_GROUP *b,
{
int ret;
/* No BN operations performed. */
(void)ctx;
WOLFSSL_ENTER("wolfSSL_EC_GROUP_cmp");
@ -10967,15 +10968,131 @@ int wolfSSL_EC_POINT_invert(const WOLFSSL_EC_GROUP *group,
return ret;
}
#ifdef WOLFSSL_EC_POINT_CMP_JACOBIAN
/* Compare two points on a the same curve.
*
* (Ax, Ay, Az) => (Ax / (Az ^ 2), Ay / (Az ^ 3))
* (Bx, By, Bz) => (Bx / (Bz ^ 2), By / (Bz ^ 3))
* When equal:
* (Ax / (Az ^ 2), Ay / (Az ^ 3)) = (Bx / (Bz ^ 2), By / (Bz ^ 3))
* => (Ax * (Bz ^ 2), Ay * (Bz ^ 3)) = (Bx * (Az ^ 2), By * (Az ^ 3))
*
* @param [in] group EC group.
* @param [in] a EC point to compare.
* @param [in] b EC point to compare.
* @return 0 when equal.
* @return 1 when different.
* @return -1 on error.
*/
static int ec_point_cmp_jacobian(const WOLFSSL_EC_GROUP* group,
const WOLFSSL_EC_POINT *a, const WOLFSSL_EC_POINT *b, WOLFSSL_BN_CTX *ctx)
{
int ret = 0;
BIGNUM* at = BN_new();
BIGNUM* bt = BN_new();
BIGNUM* az = BN_new();
BIGNUM* bz = BN_new();
BIGNUM* mod = BN_new();
/* Check that the big numbers were allocated. */
if ((at == NULL) || (bt == NULL) || (az == NULL) || (bz == NULL) ||
(mod == NULL)) {
ret = -1;
}
/* Get the modulus for the curve. */
if ((ret == 0) &&
(BN_hex2bn(&mod, ecc_sets[group->curve_idx].prime) != 1)) {
ret = -1;
}
if (ret == 0) {
/* bt = Bx * (Az ^ 2). When Az is one then just copy. */
if (BN_is_one(a->Z)) {
if (BN_copy(bt, b->X) == NULL) {
ret = -1;
}
}
/* az = Az ^ 2 */
else if ((BN_mod_mul(az, a->Z, a->Z, mod, ctx) != 1)) {
ret = -1;
}
/* bt = Bx * az = Bx * (Az ^ 2) */
else if (BN_mod_mul(bt, b->X, az, mod, ctx) != 1) {
ret = -1;
}
}
if (ret == 0) {
/* at = Ax * (Bz ^ 2). When Bz is one then just copy. */
if (BN_is_one(b->Z)) {
if (BN_copy(at, a->X) == NULL) {
ret = -1;
}
}
/* bz = Bz ^ 2 */
else if (BN_mod_mul(bz, b->Z, b->Z, mod, ctx) != 1) {
ret = -1;
}
/* at = Ax * bz = Ax * (Bz ^ 2) */
else if (BN_mod_mul(at, a->X, bz, mod, ctx) != 1) {
ret = -1;
}
}
/* Compare x-ordinates. */
if ((ret == 0) && (BN_cmp(at, bt) != 0)) {
ret = 1;
}
if (ret == 0) {
/* bt = By * (Az ^ 3). When Az is one then just copy. */
if (BN_is_one(a->Z)) {
if (BN_copy(bt, b->Y) == NULL) {
ret = -1;
}
}
/* az = az * Az = Az ^ 3 */
else if ((BN_mod_mul(az, az, a->Z, mod, ctx) != 1)) {
ret = -1;
}
/* bt = By * az = By * (Az ^ 3) */
else if (BN_mod_mul(bt, b->Y, az, mod, ctx) != 1) {
ret = -1;
}
}
if (ret == 0) {
/* at = Ay * (Bz ^ 3). When Bz is one then just copy. */
if (BN_is_one(b->Z)) {
if (BN_copy(at, a->Y) == NULL) {
ret = -1;
}
}
/* bz = bz * Bz = Bz ^ 3 */
else if (BN_mod_mul(bz, bz, b->Z, mod, ctx) != 1) {
ret = -1;
}
/* at = Ay * bz = Ay * (Bz ^ 3) */
else if (BN_mod_mul(at, a->Y, bz, mod, ctx) != 1) {
ret = -1;
}
}
/* Compare y-ordinates. */
if ((ret == 0) && (BN_cmp(at, bt) != 0)) {
ret = 1;
}
BN_free(mod);
BN_free(bz);
BN_free(az);
BN_free(bt);
BN_free(at);
return ret;
}
#endif
/* Compare two points on a the same curve.
*
* Return code compliant with OpenSSL.
*
* TODO: Compare affine co-ordinate like OpenSSL?
*
* @param [in] group EC group.
* @param [in] a EC point to invert.
* @param [in] b EC point to invert.
* @param [in] a EC point to compare.
* @param [in] b EC point to compare.
* @param [in] ctx Context to use for BN operations. Unused.
* @return 0 when equal.
* @return 1 when different.
@ -10984,10 +11101,7 @@ int wolfSSL_EC_POINT_invert(const WOLFSSL_EC_GROUP *group,
int wolfSSL_EC_POINT_cmp(const WOLFSSL_EC_GROUP *group,
const WOLFSSL_EC_POINT *a, const WOLFSSL_EC_POINT *b, WOLFSSL_BN_CTX *ctx)
{
int ret;
/* No BN operations performed. */
(void)ctx;
int ret = 0;
WOLFSSL_ENTER("wolfSSL_EC_POINT_cmp");
@ -10997,9 +11111,23 @@ int wolfSSL_EC_POINT_cmp(const WOLFSSL_EC_GROUP *group,
WOLFSSL_MSG("wolfSSL_EC_POINT_cmp Bad arguments");
ret = -1;
}
else {
if (ret != -1) {
#ifdef WOLFSSL_EC_POINT_CMP_JACOBIAN
/* If same Z ordinate then no need to convert to affine. */
if (BN_cmp(a->Z, b->Z) == 0) {
/* Compare */
ret = ((BN_cmp(a->X, b->X) != 0) || (BN_cmp(a->Y, b->Y) != 0));
}
else {
ret = ec_point_cmp_jacobian(group, a, b, ctx);
}
#else
/* No BN operations performed. */
(void)ctx;
ret = (wc_ecc_cmp_point((ecc_point*)a->internal,
(ecc_point*)b->internal) != MP_EQ);
#endif
}
return ret;