1 /* crypto/ec/ec2_smpl.c */
2 /* ====================================================================
3 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
5 * The Elliptic Curve Public-Key Crypto Library (ECC Code) included
6 * herein is developed by SUN MICROSYSTEMS, INC., and is contributed
7 * to the OpenSSL project.
9 * The ECC Code is licensed pursuant to the OpenSSL open source
10 * license provided below.
12 * In addition, Sun covenants to all licensees who provide a reciprocal
13 * covenant with respect to their own patents if any, not to sue under
14 * current and future patent claims necessarily infringed by the making,
15 * using, practicing, selling, offering for sale and/or otherwise
16 * disposing of the ECC Code as delivered hereunder (or portions thereof),
17 * provided that such covenant shall not apply:
18 * 1) for code that a licensee deletes from the ECC Code;
19 * 2) separates from the ECC Code; or
20 * 3) for infringements caused by:
21 * i) the modification of the ECC Code or
22 * ii) the combination of the ECC Code with other software or
23 * devices where such combination causes the infringement.
25 * The software is originally written by Sheueling Chang Shantz and
26 * Douglas Stebila of Sun Microsystems Laboratories.
29 /* ====================================================================
30 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
32 * Redistribution and use in source and binary forms, with or without
33 * modification, are permitted provided that the following conditions
36 * 1. Redistributions of source code must retain the above copyright
37 * notice, this list of conditions and the following disclaimer.
39 * 2. Redistributions in binary form must reproduce the above copyright
40 * notice, this list of conditions and the following disclaimer in
41 * the documentation and/or other materials provided with the
44 * 3. All advertising materials mentioning features or use of this
45 * software must display the following acknowledgment:
46 * "This product includes software developed by the OpenSSL Project
47 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
49 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
50 * endorse or promote products derived from this software without
51 * prior written permission. For written permission, please contact
52 * openssl-core@openssl.org.
54 * 5. Products derived from this software may not be called "OpenSSL"
55 * nor may "OpenSSL" appear in their names without prior written
56 * permission of the OpenSSL Project.
58 * 6. Redistributions of any form whatsoever must retain the following
60 * "This product includes software developed by the OpenSSL Project
61 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
63 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
64 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
65 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
66 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
67 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
68 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
69 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
70 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
71 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
72 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
73 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
74 * OF THE POSSIBILITY OF SUCH DAMAGE.
75 * ====================================================================
77 * This product includes cryptographic software written by Eric Young
78 * (eay@cryptsoft.com). This product includes software written by Tim
79 * Hudson (tjh@cryptsoft.com).
83 #include <openssl/err.h>
88 const EC_METHOD *EC_GF2m_simple_method(void)
90 static const EC_METHOD ret = {
91 NID_X9_62_characteristic_two_field,
92 ec_GF2m_simple_group_init,
93 ec_GF2m_simple_group_finish,
94 ec_GF2m_simple_group_clear_finish,
95 ec_GF2m_simple_group_copy,
96 ec_GF2m_simple_group_set_curve,
97 ec_GF2m_simple_group_get_curve,
98 ec_GF2m_simple_group_get_degree,
99 ec_GF2m_simple_group_check_discriminant,
100 ec_GF2m_simple_point_init,
101 ec_GF2m_simple_point_finish,
102 ec_GF2m_simple_point_clear_finish,
103 ec_GF2m_simple_point_copy,
104 ec_GF2m_simple_point_set_to_infinity,
105 0 /* set_Jprojective_coordinates_GFp */,
106 0 /* get_Jprojective_coordinates_GFp */,
107 ec_GF2m_simple_point_set_affine_coordinates,
108 ec_GF2m_simple_point_get_affine_coordinates,
109 ec_GF2m_simple_set_compressed_coordinates,
110 ec_GF2m_simple_point2oct,
111 ec_GF2m_simple_oct2point,
114 ec_GF2m_simple_invert,
116 ec_GF2m_mont_precompute_mult,
117 ec_GF2m_simple_is_at_infinity,
118 ec_GF2m_simple_is_on_curve,
120 ec_GF2m_simple_make_affine,
121 ec_GF2m_simple_points_make_affine,
122 ec_GF2m_simple_field_mul,
123 ec_GF2m_simple_field_sqr,
124 ec_GF2m_simple_field_div,
125 0 /* field_encode */,
126 0 /* field_decode */,
127 0 /* field_set_to_one */ };
133 /* Initialize a GF(2^m)-based EC_GROUP structure.
134 * Note that all other members are handled by EC_GROUP_new.
136 int ec_GF2m_simple_group_init(EC_GROUP *group)
138 BN_init(&group->field);
145 /* Free a GF(2^m)-based EC_GROUP structure.
146 * Note that all other members are handled by EC_GROUP_free.
148 void ec_GF2m_simple_group_finish(EC_GROUP *group)
150 BN_free(&group->field);
156 /* Clear and free a GF(2^m)-based EC_GROUP structure.
157 * Note that all other members are handled by EC_GROUP_clear_free.
159 void ec_GF2m_simple_group_clear_finish(EC_GROUP *group)
161 BN_clear_free(&group->field);
162 BN_clear_free(&group->a);
163 BN_clear_free(&group->b);
172 /* Copy a GF(2^m)-based EC_GROUP structure.
173 * Note that all other members are handled by EC_GROUP_copy.
175 int ec_GF2m_simple_group_copy(EC_GROUP *dest, const EC_GROUP *src)
178 if (!BN_copy(&dest->field, &src->field)) return 0;
179 if (!BN_copy(&dest->a, &src->a)) return 0;
180 if (!BN_copy(&dest->b, &src->b)) return 0;
181 dest->poly[0] = src->poly[0];
182 dest->poly[1] = src->poly[1];
183 dest->poly[2] = src->poly[2];
184 dest->poly[3] = src->poly[3];
185 dest->poly[4] = src->poly[4];
186 bn_wexpand(&dest->a, (dest->poly[0] + BN_BITS2 - 1) / BN_BITS2);
187 bn_wexpand(&dest->b, (dest->poly[0] + BN_BITS2 - 1) / BN_BITS2);
188 for (i = dest->a.top; i < dest->a.dmax; i++) dest->a.d[i] = 0;
189 for (i = dest->b.top; i < dest->b.dmax; i++) dest->b.d[i] = 0;
194 /* Set the curve parameters of an EC_GROUP structure. */
195 int ec_GF2m_simple_group_set_curve(EC_GROUP *group,
196 const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
201 if (!BN_copy(&group->field, p)) goto err;
202 i = BN_GF2m_poly2arr(&group->field, group->poly, 5);
203 if ((i != 5) && (i != 3))
205 ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE, EC_R_UNSUPPORTED_FIELD);
210 if (!BN_GF2m_mod_arr(&group->a, a, group->poly)) goto err;
211 bn_wexpand(&group->a, (group->poly[0] + BN_BITS2 - 1) / BN_BITS2);
212 for (i = group->a.top; i < group->a.dmax; i++) group->a.d[i] = 0;
215 if (!BN_GF2m_mod_arr(&group->b, b, group->poly)) goto err;
216 bn_wexpand(&group->b, (group->poly[0] + BN_BITS2 - 1) / BN_BITS2);
217 for (i = group->b.top; i < group->b.dmax; i++) group->b.d[i] = 0;
225 /* Get the curve parameters of an EC_GROUP structure.
226 * If p, a, or b are NULL then there values will not be set but the method will return with success.
228 int ec_GF2m_simple_group_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b, BN_CTX *ctx)
234 if (!BN_copy(p, &group->field)) return 0;
237 if (a != NULL || b != NULL)
241 if (!BN_copy(a, &group->a)) goto err;
245 if (!BN_copy(b, &group->b)) goto err;
256 /* Gets the degree of the field. For a curve over GF(2^m) this is the value m. */
257 int ec_GF2m_simple_group_get_degree(const EC_GROUP *group)
259 return BN_num_bits(&group->field)-1;
263 /* Checks the discriminant of the curve.
264 * y^2 + x*y = x^3 + a*x^2 + b is an elliptic curve <=> b != 0 (mod p)
266 int ec_GF2m_simple_group_check_discriminant(const EC_GROUP *group, BN_CTX *ctx)
270 BN_CTX *new_ctx = NULL;
274 ctx = new_ctx = BN_CTX_new();
277 ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT, ERR_R_MALLOC_FAILURE);
283 if (b == NULL) goto err;
285 if (!BN_GF2m_mod_arr(b, &group->b, group->poly)) goto err;
287 /* check the discriminant:
288 * y^2 + x*y = x^3 + a*x^2 + b is an elliptic curve <=> b != 0 (mod p)
290 if (BN_is_zero(b)) goto err;
297 BN_CTX_free(new_ctx);
302 /* Initializes an EC_POINT. */
303 int ec_GF2m_simple_point_init(EC_POINT *point)
312 /* Frees an EC_POINT. */
313 void ec_GF2m_simple_point_finish(EC_POINT *point)
321 /* Clears and frees an EC_POINT. */
322 void ec_GF2m_simple_point_clear_finish(EC_POINT *point)
324 BN_clear_free(&point->X);
325 BN_clear_free(&point->Y);
326 BN_clear_free(&point->Z);
331 /* Copy the contents of one EC_POINT into another. Assumes dest is initialized. */
332 int ec_GF2m_simple_point_copy(EC_POINT *dest, const EC_POINT *src)
334 if (!BN_copy(&dest->X, &src->X)) return 0;
335 if (!BN_copy(&dest->Y, &src->Y)) return 0;
336 if (!BN_copy(&dest->Z, &src->Z)) return 0;
337 dest->Z_is_one = src->Z_is_one;
343 /* Set an EC_POINT to the point at infinity.
344 * A point at infinity is represented by having Z=0.
346 int ec_GF2m_simple_point_set_to_infinity(const EC_GROUP *group, EC_POINT *point)
349 return (BN_zero(&point->Z));
353 /* Set the coordinates of an EC_POINT using affine coordinates.
354 * Note that the simple implementation only uses affine coordinates.
356 int ec_GF2m_simple_point_set_affine_coordinates(const EC_GROUP *group, EC_POINT *point,
357 const BIGNUM *x, const BIGNUM *y, BN_CTX *ctx)
360 if (x == NULL || y == NULL)
362 ECerr(EC_F_EC_GF2M_SIMPLE_POINT_SET_AFFINE_COORDINATES, ERR_R_PASSED_NULL_PARAMETER);
366 if (!BN_copy(&point->X, x)) goto err;
368 if (!BN_copy(&point->Y, y)) goto err;
370 if (!BN_copy(&point->Z, BN_value_one())) goto err;
380 /* Gets the affine coordinates of an EC_POINT.
381 * Note that the simple implementation only uses affine coordinates.
383 int ec_GF2m_simple_point_get_affine_coordinates(const EC_GROUP *group, const EC_POINT *point,
384 BIGNUM *x, BIGNUM *y, BN_CTX *ctx)
388 if (EC_POINT_is_at_infinity(group, point))
390 ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES, EC_R_POINT_AT_INFINITY);
394 if (BN_cmp(&point->Z, BN_value_one()))
396 ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
401 if (!BN_copy(x, &point->X)) goto err;
406 if (!BN_copy(y, &point->Y)) goto err;
416 /* Include patented algorithms. */
417 #include "ec2_smpt.c"
420 /* Converts an EC_POINT to an octet string.
421 * If buf is NULL, the encoded length will be returned.
422 * If the length len of buf is smaller than required an error will be returned.
424 * The point compression section of this function is patented by Certicom Corp.
425 * under US Patent 6,141,420. Point compression is disabled by default and can
426 * be enabled by defining the preprocessor macro OPENSSL_EC_BIN_PT_COMP at
429 size_t ec_GF2m_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, point_conversion_form_t form,
430 unsigned char *buf, size_t len, BN_CTX *ctx)
433 BN_CTX *new_ctx = NULL;
436 size_t field_len, i, skip;
438 #ifndef OPENSSL_EC_BIN_PT_COMP
439 if ((form == POINT_CONVERSION_COMPRESSED) || (form == POINT_CONVERSION_HYBRID))
441 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_DISABLED);
446 if ((form != POINT_CONVERSION_COMPRESSED)
447 && (form != POINT_CONVERSION_UNCOMPRESSED)
448 && (form != POINT_CONVERSION_HYBRID))
450 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
454 if (EC_POINT_is_at_infinity(group, point))
456 /* encodes to a single 0 octet */
461 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
470 /* ret := required output buffer length */
471 field_len = (EC_GROUP_get_degree(group) + 7) / 8;
472 ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
474 /* if 'buf' is NULL, just return required length */
479 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
485 ctx = new_ctx = BN_CTX_new();
494 yxi = BN_CTX_get(ctx);
495 if (yxi == NULL) goto err;
497 if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err;
500 #ifdef OPENSSL_EC_BIN_PT_COMP
501 if ((form != POINT_CONVERSION_UNCOMPRESSED) && !BN_is_zero(x))
503 if (!group->meth->field_div(group, yxi, y, x, ctx)) goto err;
504 if (BN_is_odd(yxi)) buf[0]++;
510 skip = field_len - BN_num_bytes(x);
511 if (skip > field_len)
513 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
521 skip = BN_bn2bin(x, buf + i);
523 if (i != 1 + field_len)
525 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
529 if (form == POINT_CONVERSION_UNCOMPRESSED || form == POINT_CONVERSION_HYBRID)
531 skip = field_len - BN_num_bytes(y);
532 if (skip > field_len)
534 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
542 skip = BN_bn2bin(y, buf + i);
548 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
556 BN_CTX_free(new_ctx);
563 BN_CTX_free(new_ctx);
568 /* Converts an octet string representation to an EC_POINT.
569 * Note that the simple implementation only uses affine coordinates.
571 int ec_GF2m_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
572 const unsigned char *buf, size_t len, BN_CTX *ctx)
574 point_conversion_form_t form;
576 BN_CTX *new_ctx = NULL;
578 size_t field_len, enc_len;
583 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
589 if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
590 && (form != POINT_CONVERSION_UNCOMPRESSED)
591 && (form != POINT_CONVERSION_HYBRID))
593 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
596 if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit)
598 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
606 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
610 return EC_POINT_set_to_infinity(group, point);
613 field_len = (EC_GROUP_get_degree(group) + 7) / 8;
614 enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
618 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
624 ctx = new_ctx = BN_CTX_new();
632 yxi = BN_CTX_get(ctx);
633 if (yxi == NULL) goto err;
635 if (!BN_bin2bn(buf + 1, field_len, x)) goto err;
636 if (BN_ucmp(x, &group->field) >= 0)
638 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
642 if (form == POINT_CONVERSION_COMPRESSED)
644 if (!EC_POINT_set_compressed_coordinates_GF2m(group, point, x, y_bit, ctx)) goto err;
648 if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) goto err;
649 if (BN_ucmp(y, &group->field) >= 0)
651 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
654 if (form == POINT_CONVERSION_HYBRID)
656 if (!group->meth->field_div(group, yxi, y, x, ctx)) goto err;
657 if (y_bit != BN_is_odd(yxi))
659 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
664 if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err;
667 if (!EC_POINT_is_on_curve(group, point, ctx)) /* test required by X9.62 */
669 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
678 BN_CTX_free(new_ctx);
683 /* Computes a + b and stores the result in r. r could be a or b, a could be b.
684 * Uses algorithm A.10.2 of IEEE P1363.
686 int ec_GF2m_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx)
688 BN_CTX *new_ctx = NULL;
689 BIGNUM *x0, *y0, *x1, *y1, *x2, *y2, *s, *t;
692 if (EC_POINT_is_at_infinity(group, a))
694 if (!EC_POINT_copy(r, b)) return 0;
698 if (EC_POINT_is_at_infinity(group, b))
700 if (!EC_POINT_copy(r, a)) return 0;
706 ctx = new_ctx = BN_CTX_new();
712 x0 = BN_CTX_get(ctx);
713 y0 = BN_CTX_get(ctx);
714 x1 = BN_CTX_get(ctx);
715 y1 = BN_CTX_get(ctx);
716 x2 = BN_CTX_get(ctx);
717 y2 = BN_CTX_get(ctx);
720 if (t == NULL) goto err;
724 if (!BN_copy(x0, &a->X)) goto err;
725 if (!BN_copy(y0, &a->Y)) goto err;
729 if (!EC_POINT_get_affine_coordinates_GF2m(group, a, x0, y0, ctx)) goto err;
733 if (!BN_copy(x1, &b->X)) goto err;
734 if (!BN_copy(y1, &b->Y)) goto err;
738 if (!EC_POINT_get_affine_coordinates_GF2m(group, b, x1, y1, ctx)) goto err;
742 if (BN_GF2m_cmp(x0, x1))
744 if (!BN_GF2m_add(t, x0, x1)) goto err;
745 if (!BN_GF2m_add(s, y0, y1)) goto err;
746 if (!group->meth->field_div(group, s, s, t, ctx)) goto err;
747 if (!group->meth->field_sqr(group, x2, s, ctx)) goto err;
748 if (!BN_GF2m_add(x2, x2, &group->a)) goto err;
749 if (!BN_GF2m_add(x2, x2, s)) goto err;
750 if (!BN_GF2m_add(x2, x2, t)) goto err;
754 if (BN_GF2m_cmp(y0, y1) || BN_is_zero(x1))
756 if (!EC_POINT_set_to_infinity(group, r)) goto err;
760 if (!group->meth->field_div(group, s, y1, x1, ctx)) goto err;
761 if (!BN_GF2m_add(s, s, x1)) goto err;
763 if (!group->meth->field_sqr(group, x2, s, ctx)) goto err;
764 if (!BN_GF2m_add(x2, x2, s)) goto err;
765 if (!BN_GF2m_add(x2, x2, &group->a)) goto err;
768 if (!BN_GF2m_add(y2, x1, x2)) goto err;
769 if (!group->meth->field_mul(group, y2, y2, s, ctx)) goto err;
770 if (!BN_GF2m_add(y2, y2, x2)) goto err;
771 if (!BN_GF2m_add(y2, y2, y1)) goto err;
773 if (!EC_POINT_set_affine_coordinates_GF2m(group, r, x2, y2, ctx)) goto err;
780 BN_CTX_free(new_ctx);
785 /* Computes 2 * a and stores the result in r. r could be a.
786 * Uses algorithm A.10.2 of IEEE P1363.
788 int ec_GF2m_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, BN_CTX *ctx)
790 return ec_GF2m_simple_add(group, r, a, a, ctx);
794 int ec_GF2m_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
796 if (EC_POINT_is_at_infinity(group, point) || BN_is_zero(&point->Y))
797 /* point is its own inverse */
800 if (!EC_POINT_make_affine(group, point, ctx)) return 0;
801 return BN_GF2m_add(&point->Y, &point->X, &point->Y);
805 /* Indicates whether the given point is the point at infinity. */
806 int ec_GF2m_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
808 return BN_is_zero(&point->Z);
812 /* Determines whether the given EC_POINT is an actual point on the curve defined
813 * in the EC_GROUP. A point is valid if it satisfies the Weierstrass equation:
814 * y^2 + x*y = x^3 + a*x^2 + b.
816 int ec_GF2m_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx)
818 BN_CTX *new_ctx = NULL;
819 BIGNUM *rh, *lh, *tmp1;
822 if (EC_POINT_is_at_infinity(group, point))
825 /* only support affine coordinates */
826 if (!point->Z_is_one) goto err;
830 ctx = new_ctx = BN_CTX_new();
836 rh = BN_CTX_get(ctx);
837 lh = BN_CTX_get(ctx);
838 tmp1 = BN_CTX_get(ctx);
839 if (tmp1 == NULL) goto err;
841 /* We have a curve defined by a Weierstrass equation
842 * y^2 + x*y = x^3 + a*x^2 + b.
843 * To test this, we add up the right-hand side in 'rh'
844 * and the left-hand side in 'lh'.
848 if (!group->meth->field_sqr(group, tmp1, &point->X, ctx)) goto err;
849 if (!group->meth->field_mul(group, rh, tmp1, &point->X, ctx)) goto err;
851 /* rh := rh + a*X^2 */
852 if (!group->meth->field_mul(group, tmp1, tmp1, &group->a, ctx)) goto err;
853 if (!BN_GF2m_add(rh, rh, tmp1)) goto err;
856 if (!BN_GF2m_add(rh, rh, &group->b)) goto err;
859 if (!group->meth->field_sqr(group, lh, &point->Y, ctx)) goto err;
862 if (!group->meth->field_mul(group, tmp1, &point->X, &point->Y, ctx)) goto err;
863 if (!BN_GF2m_add(lh, lh, tmp1)) goto err;
865 ret = (0 == BN_GF2m_cmp(lh, rh));
868 if (ctx) BN_CTX_end(ctx);
869 if (new_ctx) BN_CTX_free(new_ctx);
874 /* Indicates whether two points are equal.
877 * 0 equal (in affine coordinates)
880 int ec_GF2m_simple_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx)
882 BIGNUM *aX, *aY, *bX, *bY;
883 BN_CTX *new_ctx = NULL;
886 if (EC_POINT_is_at_infinity(group, a))
888 return EC_POINT_is_at_infinity(group, b) ? 0 : 1;
891 if (a->Z_is_one && b->Z_is_one)
893 return ((BN_cmp(&a->X, &b->X) == 0) && BN_cmp(&a->Y, &b->Y) == 0) ? 0 : 1;
898 ctx = new_ctx = BN_CTX_new();
904 aX = BN_CTX_get(ctx);
905 aY = BN_CTX_get(ctx);
906 bX = BN_CTX_get(ctx);
907 bY = BN_CTX_get(ctx);
908 if (bY == NULL) goto err;
910 if (!EC_POINT_get_affine_coordinates_GF2m(group, a, aX, aY, ctx)) goto err;
911 if (!EC_POINT_get_affine_coordinates_GF2m(group, b, bX, bY, ctx)) goto err;
912 ret = ((BN_cmp(aX, bX) == 0) && BN_cmp(aY, bY) == 0) ? 0 : 1;
915 if (ctx) BN_CTX_end(ctx);
916 if (new_ctx) BN_CTX_free(new_ctx);
921 /* Forces the given EC_POINT to internally use affine coordinates. */
922 int ec_GF2m_simple_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
924 BN_CTX *new_ctx = NULL;
928 if (point->Z_is_one || EC_POINT_is_at_infinity(group, point))
933 ctx = new_ctx = BN_CTX_new();
941 if (y == NULL) goto err;
943 if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err;
944 if (!BN_copy(&point->X, x)) goto err;
945 if (!BN_copy(&point->Y, y)) goto err;
946 if (!BN_one(&point->Z)) goto err;
951 if (ctx) BN_CTX_end(ctx);
952 if (new_ctx) BN_CTX_free(new_ctx);
957 /* Forces each of the EC_POINTs in the given array to use affine coordinates. */
958 int ec_GF2m_simple_points_make_affine(const EC_GROUP *group, size_t num, EC_POINT *points[], BN_CTX *ctx)
962 for (i = 0; i < num; i++)
964 if (!group->meth->make_affine(group, points[i], ctx)) return 0;
971 /* Wrapper to simple binary polynomial field multiplication implementation. */
972 int ec_GF2m_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
974 return BN_GF2m_mod_mul_arr(r, a, b, group->poly, ctx);
978 /* Wrapper to simple binary polynomial field squaring implementation. */
979 int ec_GF2m_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)
981 return BN_GF2m_mod_sqr_arr(r, a, group->poly, ctx);
985 /* Wrapper to simple binary polynomial field division implementation. */
986 int ec_GF2m_simple_field_div(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
988 return BN_GF2m_mod_div(r, a, b, &group->field, ctx);