{
static const EC_METHOD ret = {
ec_GFp_simple_group_init,
- ec_GFp_simple_group_set_curve_GFp,
ec_GFp_simple_group_finish,
ec_GFp_simple_group_clear_finish,
ec_GFp_simple_group_copy,
+ ec_GFp_simple_group_set_curve_GFp,
+ ec_GFp_simple_group_get_curve_GFp,
ec_GFp_simple_group_set_generator,
- /* TODO: 'set' and 'get' functions for EC_GROUPs */
+ ec_GFp_simple_group_get0_generator,
+ ec_GFp_simple_group_get_order,
+ ec_GFp_simple_group_get_cofactor,
ec_GFp_simple_point_init,
ec_GFp_simple_point_finish,
ec_GFp_simple_point_clear_finish,
ec_GFp_simple_point_copy,
ec_GFp_simple_point_set_to_infinity,
+ ec_GFp_simple_set_Jprojective_coordinates_GFp,
+ ec_GFp_simple_get_Jprojective_coordinates_GFp,
ec_GFp_simple_point_set_affine_coordinates_GFp,
ec_GFp_simple_point_get_affine_coordinates_GFp,
- /* TODO: other 'set' and 'get' functions for EC_POINTs */
+ ec_GFp_simple_set_compressed_coordinates_GFp,
ec_GFp_simple_point2oct,
ec_GFp_simple_oct2point,
ec_GFp_simple_add,
ec_GFp_simple_dbl,
+ ec_GFp_simple_invert,
ec_GFp_simple_is_at_infinity,
ec_GFp_simple_is_on_curve,
+ ec_GFp_simple_cmp,
ec_GFp_simple_make_affine,
ec_GFp_simple_field_mul,
ec_GFp_simple_field_sqr,
}
-int ec_GFp_simple_group_set_curve_GFp(EC_GROUP *group,
- const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
- {
- int ret = 0;
- BN_CTX *new_ctx = NULL;
- BIGNUM *tmp_a;
-
- if (ctx == NULL)
- {
- ctx = new_ctx = BN_CTX_new();
- if (ctx == NULL)
- return 0;
- }
-
- BN_CTX_start(ctx);
- tmp_a = BN_CTX_get(ctx);
- if (tmp_a == NULL) goto err;
-
- /* group->field */
- if (!BN_copy(&group->field, p)) goto err;
- group->field.neg = 0;
-
- /* group->a */
- if (!BN_nnmod(tmp_a, a, p, ctx)) goto err;
- if (group->meth->field_encode)
- { if (!group->meth->field_encode(group, &group->a, tmp_a, ctx)) goto err; }
- else
- if (!BN_copy(&group->a, tmp_a)) goto err;
-
- /* group->b */
- if (!BN_nnmod(&group->b, b, p, ctx)) goto err;
- if (group->meth->field_encode)
- if (!group->meth->field_encode(group, &group->b, &group->b, ctx)) goto err;
-
- /* group->a_is_minus3 */
- if (!BN_add_word(tmp_a, 3)) goto err;
- group->a_is_minus3 = (0 == BN_cmp(tmp_a, &group->field));
-
- ret = 1;
-
- err:
- BN_CTX_end(ctx);
- if (new_ctx != NULL)
- BN_CTX_free(new_ctx);
- return ret;
- }
-
-
void ec_GFp_simple_group_finish(EC_GROUP *group)
{
BN_free(&group->field);
}
+int ec_GFp_simple_group_set_curve_GFp(EC_GROUP *group,
+ const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
+ {
+ int ret = 0;
+ BN_CTX *new_ctx = NULL;
+ BIGNUM *tmp_a;
+
+ /* p must be a prime > 3 */
+ if (BN_num_bits(p) <= 2 || !BN_is_odd(p))
+ {
+ ECerr(EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE_GFP, EC_R_INVALID_FIELD);
+ return 0;
+ }
+
+ if (ctx == NULL)
+ {
+ ctx = new_ctx = BN_CTX_new();
+ if (ctx == NULL)
+ return 0;
+ }
+
+ BN_CTX_start(ctx);
+ tmp_a = BN_CTX_get(ctx);
+ if (tmp_a == NULL) goto err;
+
+ /* group->field */
+ if (!BN_copy(&group->field, p)) goto err;
+ group->field.neg = 0;
+
+ /* group->a */
+ if (!BN_nnmod(tmp_a, a, p, ctx)) goto err;
+ if (group->meth->field_encode)
+ { if (!group->meth->field_encode(group, &group->a, tmp_a, ctx)) goto err; }
+ else
+ if (!BN_copy(&group->a, tmp_a)) goto err;
+
+ /* group->b */
+ if (!BN_nnmod(&group->b, b, p, ctx)) goto err;
+ if (group->meth->field_encode)
+ if (!group->meth->field_encode(group, &group->b, &group->b, ctx)) goto err;
+
+ /* group->a_is_minus3 */
+ if (!BN_add_word(tmp_a, 3)) goto err;
+ group->a_is_minus3 = (0 == BN_cmp(tmp_a, &group->field));
+
+ ret = 1;
+
+ err:
+ BN_CTX_end(ctx);
+ if (new_ctx != NULL)
+ BN_CTX_free(new_ctx);
+ return ret;
+ }
+
+
+int ec_GFp_simple_group_get_curve_GFp(EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b, BN_CTX *ctx)
+ {
+ int ret = 0;
+ BN_CTX *new_ctx = NULL;
+
+ if (p != NULL)
+ {
+ if (!BN_copy(p, &group->field)) return 0;
+ }
+
+ if (a != NULL || b != NULL)
+ {
+ if (group->meth->field_decode)
+ {
+ if (ctx == NULL)
+ {
+ ctx = new_ctx = BN_CTX_new();
+ if (ctx == NULL)
+ return 0;
+ }
+ if (a != NULL)
+ {
+ if (!group->meth->field_decode(group, a, &group->a, ctx)) goto err;
+ }
+ if (b != NULL)
+ {
+ if (!group->meth->field_decode(group, b, &group->b, ctx)) goto err;
+ }
+ }
+ else
+ {
+ if (a != NULL)
+ {
+ if (!BN_copy(a, &group->a)) goto err;
+ }
+ if (b != NULL)
+ {
+ if (!BN_copy(b, &group->b)) goto err;
+ }
+ }
+ }
+
+ ret = 1;
+
+ err:
+ if (new_ctx)
+ BN_CTX_free(new_ctx);
+ return ret;
+ }
+
+
+
int ec_GFp_simple_group_set_generator(EC_GROUP *group, const EC_POINT *generator,
const BIGNUM *order, const BIGNUM *cofactor)
{
}
-/* TODO: 'set' and 'get' functions for EC_GROUPs */
+EC_POINT *ec_GFp_simple_group_get0_generator(EC_GROUP *group)
+ {
+ return group->generator;
+ }
+
+
+int ec_GFp_simple_group_get_order(EC_GROUP *group, BIGNUM *order, BN_CTX *ctx)
+ {
+ if (!BN_copy(order, &group->order))
+ return 0;
+
+ return !BN_is_zero(&group->order);
+ }
+
+
+int ec_GFp_simple_group_get_cofactor(EC_GROUP *group, BIGNUM *cofactor, BN_CTX *ctx)
+ {
+ if (!BN_copy(cofactor, &group->cofactor))
+ return 0;
+
+ return !BN_is_zero(&group->cofactor);
+ }
int ec_GFp_simple_point_init(EC_POINT *point)
}
-int ec_GFp_simple_point_set_affine_coordinates_GFp(const EC_GROUP *group, EC_POINT *point,
- const BIGNUM *x, const BIGNUM *y, BN_CTX *ctx)
+int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP *group, EC_POINT *point,
+ const BIGNUM *x, const BIGNUM *y, const BIGNUM *z, BN_CTX *ctx)
{
BN_CTX *new_ctx = NULL;
int ret = 0;
+
+ if (ctx == NULL)
+ {
+ ctx = new_ctx = BN_CTX_new();
+ if (ctx == NULL)
+ return 0;
+ }
- if (!BN_copy(&point->X, x)) goto err;
- if (!BN_copy(&point->Y, y)) goto err;
- if (!BN_one(&point->Z)) goto err;
+ if (x != NULL)
+ {
+ if (!BN_nnmod(&point->X, x, &group->field, ctx)) goto err;
+ if (group->meth->field_encode)
+ {
+ if (!group->meth->field_encode(group, &point->X, &point->X, ctx)) goto err;
+ }
+ }
+
+ if (y != NULL)
+ {
+ if (!BN_nnmod(&point->Y, y, &group->field, ctx)) goto err;
+ if (group->meth->field_encode)
+ {
+ if (!group->meth->field_encode(group, &point->Y, &point->Y, ctx)) goto err;
+ }
+ }
+
+ if (z != NULL)
+ {
+ int Z_is_one;
- if (group->meth->field_encode)
+ if (!BN_nnmod(&point->Z, z, &group->field, ctx)) goto err;
+ Z_is_one = BN_is_one(&point->Z);
+ if (group->meth->field_encode)
+ {
+ if (!group->meth->field_encode(group, &point->Z, &point->Z, ctx)) goto err;
+ }
+ point->Z_is_one = Z_is_one;
+ }
+
+ ret = 1;
+
+ err:
+ if (new_ctx != NULL)
+ BN_CTX_free(new_ctx);
+ return ret;
+ }
+
+
+int ec_GFp_simple_get_Jprojective_coordinates_GFp(const EC_GROUP *group, const EC_POINT *point,
+ BIGNUM *x, BIGNUM *y, BIGNUM *z, BN_CTX *ctx)
+ {
+ BN_CTX *new_ctx = NULL;
+ int ret = 0;
+
+ if (group->meth->field_decode != 0)
{
if (ctx == NULL)
{
if (ctx == NULL)
return 0;
}
-
- if (!group->meth->field_encode(group, &point->X, &point->X, ctx)) goto err;
- if (!group->meth->field_encode(group, &point->Y, &point->Y, ctx)) goto err;
- if (!group->meth->field_encode(group, &point->Z, &point->Z, ctx)) goto err;
- }
- point->Z_is_one = 1;
+ if (x != NULL)
+ {
+ if (!group->meth->field_decode(group, x, &point->X, ctx)) goto err;
+ }
+ if (y != NULL)
+ {
+ if (!group->meth->field_decode(group, y, &point->Y, ctx)) goto err;
+ }
+ if (z != NULL)
+ {
+ if (!group->meth->field_decode(group, z, &point->Z, ctx)) goto err;
+ }
+ }
+ else
+ {
+ if (x != NULL)
+ {
+ if (!BN_copy(x, &point->X)) goto err;
+ }
+ if (y != NULL)
+ {
+ if (!BN_copy(y, &point->Y)) goto err;
+ }
+ if (z != NULL)
+ {
+ if (!BN_copy(z, &point->Z)) goto err;
+ }
+ }
+ ret = 1;
+
err:
if (new_ctx != NULL)
BN_CTX_free(new_ctx);
}
+int ec_GFp_simple_point_set_affine_coordinates_GFp(const EC_GROUP *group, EC_POINT *point,
+ const BIGNUM *x, const BIGNUM *y, BN_CTX *ctx)
+ {
+ if (x == NULL || y == NULL)
+ {
+ /* unlike for projective coordinates, we do not tolerate this */
+ ECerr(EC_F_EC_GFP_SIMPLE_POINT_SET_AFFINE_COORDINATES_GFP, ERR_R_PASSED_NULL_PARAMETER);
+ return 0;
+ }
+
+ return EC_POINT_set_Jprojective_coordinates_GFp(group, point, x, y, BN_value_one(), ctx);
+ }
+
+
int ec_GFp_simple_point_get_affine_coordinates_GFp(const EC_GROUP *group, const EC_POINT *point,
BIGNUM *x, BIGNUM *y, BN_CTX *ctx)
{
if (BN_is_one(Z_))
{
- if (!BN_copy(x, X_)) goto err;
- if (!BN_copy(y, Y_)) goto err;
+ if (x != NULL)
+ {
+ if (!BN_copy(x, X_)) goto err;
+ }
+ if (y != NULL)
+ {
+ if (!BN_copy(y, Y_)) goto err;
+ }
}
else
{
goto err;
}
if (!BN_mod_sqr(Z_2, Z_1, &group->field, ctx)) goto err;
- if (!BN_mod_mul(Z_3, Z_2, Z_1, &group->field, ctx)) goto err;
- if (!BN_mod_mul(x, X_, Z_2, &group->field, ctx)) goto err;
- if (!BN_mod_mul(y, Y_, Z_3, &group->field, ctx)) goto err;
+ if (x != NULL)
+ {
+ if (!BN_mod_mul(x, X_, Z_2, &group->field, ctx)) goto err;
+ }
+
+ if (y != NULL)
+ {
+ if (!BN_mod_mul(Z_3, Z_2, Z_1, &group->field, ctx)) goto err;
+ if (!BN_mod_mul(y, Y_, Z_3, &group->field, ctx)) goto err;
+ }
}
ret = 1;
}
-/* TODO: other 'set' and 'get' functions for EC_POINTs */
+int ec_GFp_simple_set_compressed_coordinates_GFp(const EC_GROUP *group, EC_POINT *point,
+ const BIGNUM *x, int y_bit, BN_CTX *ctx)
+ {
+ BN_CTX *new_ctx = NULL;
+ BIGNUM *tmp1, *tmp2, *y;
+ int ret = 0;
+
+ if (ctx == NULL)
+ {
+ ctx = new_ctx = BN_CTX_new();
+ if (ctx == NULL)
+ return 0;
+ }
+
+ y_bit = (y_bit != 0);
+
+ BN_CTX_start(ctx);
+ tmp1 = BN_CTX_get(ctx);
+ tmp2 = BN_CTX_get(ctx);
+ y = BN_CTX_get(ctx);
+ if (y == NULL) goto err;
+
+ /* Recover y. We have a Weierstrass equation
+ * y^2 = x^3 + a*x + b,
+ * so y is one of the square roots of x^3 + a*x + b.
+ */
+
+ /* tmp1 := x^3 */
+ if (!BN_mod_sqr(tmp2, x, &group->field, ctx)) goto err;
+ if (!BN_mod_mul(tmp1, tmp2, x, &group->field, ctx)) goto err;
+
+ /* tmp1 := tmp1 + a*x */
+ if (group->a_is_minus3)
+ {
+ if (!BN_mod_lshift1_quick(tmp2, x, &group->field)) goto err;
+ if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field)) goto err;
+ if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
+ }
+ else
+ {
+ if (group->meth->field_decode)
+ {
+ if (!group->meth->field_decode(group, tmp2, &group->a, ctx)) goto err;
+ if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx)) goto err;
+ }
+ else
+ {
+ if (!BN_mod_mul(tmp2, &group->a, x, &group->field, ctx)) goto err;
+ }
+
+ if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
+ }
+
+ /* tmp1 := tmp1 + b */
+ if (group->meth->field_decode)
+ {
+ if (!group->meth->field_decode(group, tmp2, &group->b, ctx)) goto err;
+ if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
+ }
+ else
+ {
+ if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field)) goto err;
+ }
+
+ if (!BN_mod_sqrt(y, tmp1, &group->field, ctx))
+ {
+ ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES_GFP, ERR_R_BN_LIB);
+ goto err;
+ }
+ /* If tmp1 is not a square (i.e. there is no point on the curve with
+ * our x), then y now is a nonsense value too */
+
+ if (y_bit != BN_is_odd(y))
+ {
+ if (BN_is_zero(y))
+ {
+ int kron;
+
+ kron = BN_kronecker(x, &group->field, ctx);
+ if (kron == -2) goto err;
+
+ if (kron == 1)
+ ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES_GFP, EC_R_INVALID_COMPRESSION_BIT);
+ else
+ ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES_GFP, EC_R_INVALID_COMPRESSED_POINT);
+ goto err;
+ }
+ if (!BN_usub(y, &group->field, y)) goto err;
+ }
+ if (y_bit != BN_is_odd(y))
+ {
+ ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES_GFP, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+
+ if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
+
+ ret = 1;
+
+ err:
+ BN_CTX_end(ctx);
+ if (new_ctx != NULL)
+ BN_CTX_free(new_ctx);
+ return ret;
+ }
size_t ec_GFp_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, point_conversion_form_t form,
if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
- if ((form == POINT_CONVERSION_COMPRESSED || form == POINT_CONVERSION_HYBRID) && BN_is_bit_set(y, 0))
+ if ((form == POINT_CONVERSION_COMPRESSED || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
buf[0] = form + 1;
else
buf[0] = form;
goto err;
}
- if (form != POINT_CONVERSION_COMPRESSED)
+ if (form == POINT_CONVERSION_COMPRESSED)
+ {
+ if (!EC_POINT_set_compressed_coordinates_GFp(group, point, x, y_bit, ctx)) goto err;
+ }
+ else
{
if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) goto err;
if (BN_ucmp(y, &group->field) >= 0)
}
if (form == POINT_CONVERSION_HYBRID)
{
- if (y_bit != BN_is_bit_set(y, 0))
+ if (y_bit != BN_is_odd(y))
{
ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
goto err;
}
}
- }
- if (form == POINT_CONVERSION_COMPRESSED)
- {
- /* Recover y. We have a Weierstrass equation
- * y^2 = x^3 + a*x + b,
- * so y is one of the square roots of x^3 + a*x + b.
- */
-
- BIGNUM *tmp1, *tmp2;
-
- tmp1 = BN_CTX_get(ctx);
- tmp2 = BN_CTX_get(ctx);
- if (tmp2 == NULL) goto err;
-
- /* tmp1 := x^3 */
- if (!BN_mod_sqr(tmp2, x, &group->field, ctx)) goto err;
- if (!BN_mod_mul(tmp1, tmp2, x, &group->field, ctx)) goto err;
-
- /* tmp1 := tmp1 + a*x */
- if (group->a_is_minus3)
- {
- if (!BN_mod_lshift1_quick(tmp2, x, &group->field)) goto err;
- if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field)) goto err;
- if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
- }
- else
- {
- if (!BN_mod_mul(tmp2, &group->a, x, &group->field, ctx)) goto err;
- if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
- }
-
- /* tmp1 := tmp1 + b */
- if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field)) goto err;
-
- if (!BN_mod_sqrt(y, tmp1, &group->field, ctx))
- {
- ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, ERR_R_BN_LIB);
- goto err;
- }
-
- if (y_bit != BN_is_bit_set(y, 0))
- {
- if (!BN_usub(y, &group->field, y)) goto err;
- }
- if (y_bit != BN_is_bit_set(y, 0))
- {
- ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, ERR_R_INTERNAL_ERROR);
- goto err;
- }
+ if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
}
- if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
-
if (!EC_POINT_is_on_curve(group, point, ctx)) /* test required by X9.62 */
{
ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
n6 = BN_CTX_get(ctx);
if (n6 == NULL) goto end;
+ /* Note that in this function we must not read components of 'a' or 'b'
+ * once we have written the corresponding components of 'r'.
+ * ('r' might be one of 'a' or 'b'.)
+ */
+
/* n1, n2 */
if (b->Z_is_one)
{
n3 = BN_CTX_get(ctx);
if (n3 == NULL) goto err;
+ /* Note that in this function we must not read components of 'a'
+ * once we have written the corresponding components of 'r'.
+ * ('r' might the same as 'a'.)
+ */
+
/* n1 */
if (a->Z_is_one)
{
}
+int ec_GFp_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
+ {
+ if (EC_POINT_is_at_infinity(group, point) || BN_is_zero(&point->Y))
+ /* point is its own inverse */
+ return 1;
+
+ return BN_usub(&point->Y, &group->field, &point->Y);
+ }
+
+
int ec_GFp_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
{
return BN_is_zero(&point->Z);
/* rh := rh + a*X*Z^4 */
if (!field_mul(group, tmp1, &point->X, Z4, ctx)) goto err;
- if (&group->a_is_minus3)
+ if (group->a_is_minus3)
{
if (!BN_mod_lshift1_quick(tmp2, tmp1, p)) goto err;
if (!BN_mod_add_quick(tmp2, tmp2, tmp1, p)) goto err;
/* point->Z_is_one */
/* rh := rh + a*X */
- if (&group->a_is_minus3)
+ if (group->a_is_minus3)
{
if (!BN_mod_lshift1_quick(tmp2, &point->X, p)) goto err;
if (!BN_mod_add_quick(tmp2, tmp2, &point->X, p)) goto err;
}
+int ec_GFp_simple_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx)
+ {
+ /* return values:
+ * -1 error
+ * 0 equal (in affine coordinates)
+ * 1 not equal
+ */
+
+ int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *);
+ int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
+ BN_CTX *new_ctx = NULL;
+ BIGNUM *tmp1, *tmp2, *Za23, *Zb23;
+ const BIGNUM *tmp1_, *tmp2_;
+ int ret = -1;
+
+ if (EC_POINT_is_at_infinity(group, a))
+ {
+ return EC_POINT_is_at_infinity(group, b) ? 0 : 1;
+ }
+
+ if (a->Z_is_one && b->Z_is_one)
+ {
+ return ((BN_cmp(&a->X, &b->X) == 0) && BN_cmp(&a->Y, &b->Y) == 0) ? 0 : 1;
+ }
+
+ field_mul = group->meth->field_mul;
+ field_sqr = group->meth->field_sqr;
+
+ if (ctx == NULL)
+ {
+ ctx = new_ctx = BN_CTX_new();
+ if (ctx == NULL)
+ return -1;
+ }
+
+ BN_CTX_start(ctx);
+ tmp1 = BN_CTX_get(ctx);
+ tmp2 = BN_CTX_get(ctx);
+ Za23 = BN_CTX_get(ctx);
+ Zb23 = BN_CTX_get(ctx);
+ if (Zb23 == NULL) goto end;
+
+ /* We have to decide whether
+ * (X_a/Z_a^2, Y_a/Z_a^3) = (X_b/Z_b^2, Y_b/Z_b^3),
+ * or equivalently, whether
+ * (X_a*Z_b^2, Y_a*Z_b^3) = (X_b*Z_a^2, Y_b*Z_a^3).
+ */
+
+ if (!b->Z_is_one)
+ {
+ if (!field_sqr(group, Zb23, &b->Z, ctx)) goto end;
+ if (!field_mul(group, tmp1, &a->X, Zb23, ctx)) goto end;
+ tmp1_ = tmp1;
+ }
+ else
+ tmp1_ = &a->X;
+ if (!a->Z_is_one)
+ {
+ if (!field_sqr(group, Za23, &a->Z, ctx)) goto end;
+ if (!field_mul(group, tmp2, &b->X, Za23, ctx)) goto end;
+ tmp2_ = tmp2;
+ }
+ else
+ tmp2_ = &b->X;
+
+ /* compare X_a*Z_b^2 with X_b*Z_a^2 */
+ if (BN_cmp(tmp1_, tmp2_) != 0)
+ {
+ ret = 1; /* points differ */
+ goto end;
+ }
+
+
+ if (!b->Z_is_one)
+ {
+ if (!field_mul(group, Zb23, Zb23, &b->Z, ctx)) goto end;
+ if (!field_mul(group, tmp1, &a->Y, Zb23, ctx)) goto end;
+ /* tmp1_ = tmp1 */
+ }
+ else
+ tmp1_ = &a->Y;
+ if (!a->Z_is_one)
+ {
+ if (!field_mul(group, Za23, Za23, &a->Z, ctx)) goto end;
+ if (!field_mul(group, tmp2, &b->Y, Za23, ctx)) goto end;
+ /* tmp2_ = tmp2 */
+ }
+ else
+ tmp2_ = &b->Y;
+
+ /* compare Y_a*Z_b^3 with Y_b*Z_a^3 */
+ if (BN_cmp(tmp1_, tmp2_) != 0)
+ {
+ ret = 1; /* points differ */
+ goto end;
+ }
+
+ /* points are equal */
+ ret = 0;
+
+ end:
+ BN_CTX_end(ctx);
+ if (new_ctx != NULL)
+ BN_CTX_free(new_ctx);
+ return ret;
+ }
+
+
int ec_GFp_simple_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
{
BN_CTX *new_ctx = NULL;
projects / openssl.git / blobdiff