1 /* crypto/ec/ecp_smpl.c */
2 /* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
3 * for the OpenSSL project.
4 * Includes code written by Bodo Moeller for the OpenSSL project.
6 /* ====================================================================
7 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
21 * 3. All advertising materials mentioning features or use of this
22 * software must display the following acknowledgment:
23 * "This product includes software developed by the OpenSSL Project
24 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27 * endorse or promote products derived from this software without
28 * prior written permission. For written permission, please contact
29 * openssl-core@openssl.org.
31 * 5. Products derived from this software may not be called "OpenSSL"
32 * nor may "OpenSSL" appear in their names without prior written
33 * permission of the OpenSSL Project.
35 * 6. Redistributions of any form whatsoever must retain the following
37 * "This product includes software developed by the OpenSSL Project
38 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51 * OF THE POSSIBILITY OF SUCH DAMAGE.
52 * ====================================================================
54 * This product includes cryptographic software written by Eric Young
55 * (eay@cryptsoft.com). This product includes software written by Tim
56 * Hudson (tjh@cryptsoft.com).
59 /* ====================================================================
60 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
61 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
62 * and contributed to the OpenSSL project.
65 #include <openssl/err.h>
66 #include <openssl/symhacks.h>
69 #include <openssl/fips.h>
74 const EC_METHOD
*EC_GFp_simple_method(void)
77 return fips_ec_gfp_simple_method();
79 static const EC_METHOD ret
= {
81 NID_X9_62_prime_field
,
82 ec_GFp_simple_group_init
,
83 ec_GFp_simple_group_finish
,
84 ec_GFp_simple_group_clear_finish
,
85 ec_GFp_simple_group_copy
,
86 ec_GFp_simple_group_set_curve
,
87 ec_GFp_simple_group_get_curve
,
88 ec_GFp_simple_group_get_degree
,
89 ec_GFp_simple_group_check_discriminant
,
90 ec_GFp_simple_point_init
,
91 ec_GFp_simple_point_finish
,
92 ec_GFp_simple_point_clear_finish
,
93 ec_GFp_simple_point_copy
,
94 ec_GFp_simple_point_set_to_infinity
,
95 ec_GFp_simple_set_Jprojective_coordinates_GFp
,
96 ec_GFp_simple_get_Jprojective_coordinates_GFp
,
97 ec_GFp_simple_point_set_affine_coordinates
,
98 ec_GFp_simple_point_get_affine_coordinates
,
102 ec_GFp_simple_invert
,
103 ec_GFp_simple_is_at_infinity
,
104 ec_GFp_simple_is_on_curve
,
106 ec_GFp_simple_make_affine
,
107 ec_GFp_simple_points_make_affine
,
109 0 /* precompute_mult */,
110 0 /* have_precompute_mult */,
111 ec_GFp_simple_field_mul
,
112 ec_GFp_simple_field_sqr
,
114 0 /* field_encode */,
115 0 /* field_decode */,
116 0 /* field_set_to_one */ };
123 /* Most method functions in this file are designed to work with
124 * non-trivial representations of field elements if necessary
125 * (see ecp_mont.c): while standard modular addition and subtraction
126 * are used, the field_mul and field_sqr methods will be used for
127 * multiplication, and field_encode and field_decode (if defined)
128 * will be used for converting between representations.
130 * Functions ec_GFp_simple_points_make_affine() and
131 * ec_GFp_simple_point_get_affine_coordinates() specifically assume
132 * that if a non-trivial representation is used, it is a Montgomery
133 * representation (i.e. 'encoding' means multiplying by some factor R).
137 int ec_GFp_simple_group_init(EC_GROUP
*group
)
139 BN_init(&group
->field
);
142 group
->a_is_minus3
= 0;
147 void ec_GFp_simple_group_finish(EC_GROUP
*group
)
149 BN_free(&group
->field
);
155 void ec_GFp_simple_group_clear_finish(EC_GROUP
*group
)
157 BN_clear_free(&group
->field
);
158 BN_clear_free(&group
->a
);
159 BN_clear_free(&group
->b
);
163 int ec_GFp_simple_group_copy(EC_GROUP
*dest
, const EC_GROUP
*src
)
165 if (!BN_copy(&dest
->field
, &src
->field
)) return 0;
166 if (!BN_copy(&dest
->a
, &src
->a
)) return 0;
167 if (!BN_copy(&dest
->b
, &src
->b
)) return 0;
169 dest
->a_is_minus3
= src
->a_is_minus3
;
175 int ec_GFp_simple_group_set_curve(EC_GROUP
*group
,
176 const BIGNUM
*p
, const BIGNUM
*a
, const BIGNUM
*b
, BN_CTX
*ctx
)
179 BN_CTX
*new_ctx
= NULL
;
182 /* p must be a prime > 3 */
183 if (BN_num_bits(p
) <= 2 || !BN_is_odd(p
))
185 ECerr(EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE
, EC_R_INVALID_FIELD
);
191 ctx
= new_ctx
= BN_CTX_new();
197 tmp_a
= BN_CTX_get(ctx
);
198 if (tmp_a
== NULL
) goto err
;
201 if (!BN_copy(&group
->field
, p
)) goto err
;
202 BN_set_negative(&group
->field
, 0);
205 if (!BN_nnmod(tmp_a
, a
, p
, ctx
)) goto err
;
206 if (group
->meth
->field_encode
)
207 { if (!group
->meth
->field_encode(group
, &group
->a
, tmp_a
, ctx
)) goto err
; }
209 if (!BN_copy(&group
->a
, tmp_a
)) goto err
;
212 if (!BN_nnmod(&group
->b
, b
, p
, ctx
)) goto err
;
213 if (group
->meth
->field_encode
)
214 if (!group
->meth
->field_encode(group
, &group
->b
, &group
->b
, ctx
)) goto err
;
216 /* group->a_is_minus3 */
217 if (!BN_add_word(tmp_a
, 3)) goto err
;
218 group
->a_is_minus3
= (0 == BN_cmp(tmp_a
, &group
->field
));
225 BN_CTX_free(new_ctx
);
230 int ec_GFp_simple_group_get_curve(const EC_GROUP
*group
, BIGNUM
*p
, BIGNUM
*a
, BIGNUM
*b
, BN_CTX
*ctx
)
233 BN_CTX
*new_ctx
= NULL
;
237 if (!BN_copy(p
, &group
->field
)) return 0;
240 if (a
!= NULL
|| b
!= NULL
)
242 if (group
->meth
->field_decode
)
246 ctx
= new_ctx
= BN_CTX_new();
252 if (!group
->meth
->field_decode(group
, a
, &group
->a
, ctx
)) goto err
;
256 if (!group
->meth
->field_decode(group
, b
, &group
->b
, ctx
)) goto err
;
263 if (!BN_copy(a
, &group
->a
)) goto err
;
267 if (!BN_copy(b
, &group
->b
)) goto err
;
276 BN_CTX_free(new_ctx
);
281 int ec_GFp_simple_group_get_degree(const EC_GROUP
*group
)
283 return BN_num_bits(&group
->field
);
287 int ec_GFp_simple_group_check_discriminant(const EC_GROUP
*group
, BN_CTX
*ctx
)
290 BIGNUM
*a
,*b
,*order
,*tmp_1
,*tmp_2
;
291 const BIGNUM
*p
= &group
->field
;
292 BN_CTX
*new_ctx
= NULL
;
296 ctx
= new_ctx
= BN_CTX_new();
299 ECerr(EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT
, ERR_R_MALLOC_FAILURE
);
306 tmp_1
= BN_CTX_get(ctx
);
307 tmp_2
= BN_CTX_get(ctx
);
308 order
= BN_CTX_get(ctx
);
309 if (order
== NULL
) goto err
;
311 if (group
->meth
->field_decode
)
313 if (!group
->meth
->field_decode(group
, a
, &group
->a
, ctx
)) goto err
;
314 if (!group
->meth
->field_decode(group
, b
, &group
->b
, ctx
)) goto err
;
318 if (!BN_copy(a
, &group
->a
)) goto err
;
319 if (!BN_copy(b
, &group
->b
)) goto err
;
322 /* check the discriminant:
323 * y^2 = x^3 + a*x + b is an elliptic curve <=> 4*a^3 + 27*b^2 != 0 (mod p)
327 if (BN_is_zero(b
)) goto err
;
329 else if (!BN_is_zero(b
))
331 if (!BN_mod_sqr(tmp_1
, a
, p
, ctx
)) goto err
;
332 if (!BN_mod_mul(tmp_2
, tmp_1
, a
, p
, ctx
)) goto err
;
333 if (!BN_lshift(tmp_1
, tmp_2
, 2)) goto err
;
336 if (!BN_mod_sqr(tmp_2
, b
, p
, ctx
)) goto err
;
337 if (!BN_mul_word(tmp_2
, 27)) goto err
;
340 if (!BN_mod_add(a
, tmp_1
, tmp_2
, p
, ctx
)) goto err
;
341 if (BN_is_zero(a
)) goto err
;
349 BN_CTX_free(new_ctx
);
354 int ec_GFp_simple_point_init(EC_POINT
*point
)
365 void ec_GFp_simple_point_finish(EC_POINT
*point
)
373 void ec_GFp_simple_point_clear_finish(EC_POINT
*point
)
375 BN_clear_free(&point
->X
);
376 BN_clear_free(&point
->Y
);
377 BN_clear_free(&point
->Z
);
382 int ec_GFp_simple_point_copy(EC_POINT
*dest
, const EC_POINT
*src
)
384 if (!BN_copy(&dest
->X
, &src
->X
)) return 0;
385 if (!BN_copy(&dest
->Y
, &src
->Y
)) return 0;
386 if (!BN_copy(&dest
->Z
, &src
->Z
)) return 0;
387 dest
->Z_is_one
= src
->Z_is_one
;
393 int ec_GFp_simple_point_set_to_infinity(const EC_GROUP
*group
, EC_POINT
*point
)
401 int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP
*group
, EC_POINT
*point
,
402 const BIGNUM
*x
, const BIGNUM
*y
, const BIGNUM
*z
, BN_CTX
*ctx
)
404 BN_CTX
*new_ctx
= NULL
;
409 ctx
= new_ctx
= BN_CTX_new();
416 if (!BN_nnmod(&point
->X
, x
, &group
->field
, ctx
)) goto err
;
417 if (group
->meth
->field_encode
)
419 if (!group
->meth
->field_encode(group
, &point
->X
, &point
->X
, ctx
)) goto err
;
425 if (!BN_nnmod(&point
->Y
, y
, &group
->field
, ctx
)) goto err
;
426 if (group
->meth
->field_encode
)
428 if (!group
->meth
->field_encode(group
, &point
->Y
, &point
->Y
, ctx
)) goto err
;
436 if (!BN_nnmod(&point
->Z
, z
, &group
->field
, ctx
)) goto err
;
437 Z_is_one
= BN_is_one(&point
->Z
);
438 if (group
->meth
->field_encode
)
440 if (Z_is_one
&& (group
->meth
->field_set_to_one
!= 0))
442 if (!group
->meth
->field_set_to_one(group
, &point
->Z
, ctx
)) goto err
;
446 if (!group
->meth
->field_encode(group
, &point
->Z
, &point
->Z
, ctx
)) goto err
;
449 point
->Z_is_one
= Z_is_one
;
456 BN_CTX_free(new_ctx
);
461 int ec_GFp_simple_get_Jprojective_coordinates_GFp(const EC_GROUP
*group
, const EC_POINT
*point
,
462 BIGNUM
*x
, BIGNUM
*y
, BIGNUM
*z
, BN_CTX
*ctx
)
464 BN_CTX
*new_ctx
= NULL
;
467 if (group
->meth
->field_decode
!= 0)
471 ctx
= new_ctx
= BN_CTX_new();
478 if (!group
->meth
->field_decode(group
, x
, &point
->X
, ctx
)) goto err
;
482 if (!group
->meth
->field_decode(group
, y
, &point
->Y
, ctx
)) goto err
;
486 if (!group
->meth
->field_decode(group
, z
, &point
->Z
, ctx
)) goto err
;
493 if (!BN_copy(x
, &point
->X
)) goto err
;
497 if (!BN_copy(y
, &point
->Y
)) goto err
;
501 if (!BN_copy(z
, &point
->Z
)) goto err
;
509 BN_CTX_free(new_ctx
);
514 int ec_GFp_simple_point_set_affine_coordinates(const EC_GROUP
*group
, EC_POINT
*point
,
515 const BIGNUM
*x
, const BIGNUM
*y
, BN_CTX
*ctx
)
517 if (x
== NULL
|| y
== NULL
)
519 /* unlike for projective coordinates, we do not tolerate this */
520 ECerr(EC_F_EC_GFP_SIMPLE_POINT_SET_AFFINE_COORDINATES
, ERR_R_PASSED_NULL_PARAMETER
);
524 return EC_POINT_set_Jprojective_coordinates_GFp(group
, point
, x
, y
, BN_value_one(), ctx
);
528 int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP
*group
, const EC_POINT
*point
,
529 BIGNUM
*x
, BIGNUM
*y
, BN_CTX
*ctx
)
531 BN_CTX
*new_ctx
= NULL
;
532 BIGNUM
*Z
, *Z_1
, *Z_2
, *Z_3
;
536 if (EC_POINT_is_at_infinity(group
, point
))
538 ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES
, EC_R_POINT_AT_INFINITY
);
544 ctx
= new_ctx
= BN_CTX_new();
551 Z_1
= BN_CTX_get(ctx
);
552 Z_2
= BN_CTX_get(ctx
);
553 Z_3
= BN_CTX_get(ctx
);
554 if (Z_3
== NULL
) goto err
;
556 /* transform (X, Y, Z) into (x, y) := (X/Z^2, Y/Z^3) */
558 if (group
->meth
->field_decode
)
560 if (!group
->meth
->field_decode(group
, Z
, &point
->Z
, ctx
)) goto err
;
570 if (group
->meth
->field_decode
)
574 if (!group
->meth
->field_decode(group
, x
, &point
->X
, ctx
)) goto err
;
578 if (!group
->meth
->field_decode(group
, y
, &point
->Y
, ctx
)) goto err
;
585 if (!BN_copy(x
, &point
->X
)) goto err
;
589 if (!BN_copy(y
, &point
->Y
)) goto err
;
595 if (!BN_mod_inverse(Z_1
, Z_
, &group
->field
, ctx
))
597 ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES
, ERR_R_BN_LIB
);
601 if (group
->meth
->field_encode
== 0)
603 /* field_sqr works on standard representation */
604 if (!group
->meth
->field_sqr(group
, Z_2
, Z_1
, ctx
)) goto err
;
608 if (!BN_mod_sqr(Z_2
, Z_1
, &group
->field
, ctx
)) goto err
;
613 /* in the Montgomery case, field_mul will cancel out Montgomery factor in X: */
614 if (!group
->meth
->field_mul(group
, x
, &point
->X
, Z_2
, ctx
)) goto err
;
619 if (group
->meth
->field_encode
== 0)
621 /* field_mul works on standard representation */
622 if (!group
->meth
->field_mul(group
, Z_3
, Z_2
, Z_1
, ctx
)) goto err
;
626 if (!BN_mod_mul(Z_3
, Z_2
, Z_1
, &group
->field
, ctx
)) goto err
;
629 /* in the Montgomery case, field_mul will cancel out Montgomery factor in Y: */
630 if (!group
->meth
->field_mul(group
, y
, &point
->Y
, Z_3
, ctx
)) goto err
;
639 BN_CTX_free(new_ctx
);
643 int ec_GFp_simple_add(const EC_GROUP
*group
, EC_POINT
*r
, const EC_POINT
*a
, const EC_POINT
*b
, BN_CTX
*ctx
)
645 int (*field_mul
)(const EC_GROUP
*, BIGNUM
*, const BIGNUM
*, const BIGNUM
*, BN_CTX
*);
646 int (*field_sqr
)(const EC_GROUP
*, BIGNUM
*, const BIGNUM
*, BN_CTX
*);
648 BN_CTX
*new_ctx
= NULL
;
649 BIGNUM
*n0
, *n1
, *n2
, *n3
, *n4
, *n5
, *n6
;
653 return EC_POINT_dbl(group
, r
, a
, ctx
);
654 if (EC_POINT_is_at_infinity(group
, a
))
655 return EC_POINT_copy(r
, b
);
656 if (EC_POINT_is_at_infinity(group
, b
))
657 return EC_POINT_copy(r
, a
);
659 field_mul
= group
->meth
->field_mul
;
660 field_sqr
= group
->meth
->field_sqr
;
665 ctx
= new_ctx
= BN_CTX_new();
671 n0
= BN_CTX_get(ctx
);
672 n1
= BN_CTX_get(ctx
);
673 n2
= BN_CTX_get(ctx
);
674 n3
= BN_CTX_get(ctx
);
675 n4
= BN_CTX_get(ctx
);
676 n5
= BN_CTX_get(ctx
);
677 n6
= BN_CTX_get(ctx
);
678 if (n6
== NULL
) goto end
;
680 /* Note that in this function we must not read components of 'a' or 'b'
681 * once we have written the corresponding components of 'r'.
682 * ('r' might be one of 'a' or 'b'.)
688 if (!BN_copy(n1
, &a
->X
)) goto end
;
689 if (!BN_copy(n2
, &a
->Y
)) goto end
;
695 if (!field_sqr(group
, n0
, &b
->Z
, ctx
)) goto end
;
696 if (!field_mul(group
, n1
, &a
->X
, n0
, ctx
)) goto end
;
697 /* n1 = X_a * Z_b^2 */
699 if (!field_mul(group
, n0
, n0
, &b
->Z
, ctx
)) goto end
;
700 if (!field_mul(group
, n2
, &a
->Y
, n0
, ctx
)) goto end
;
701 /* n2 = Y_a * Z_b^3 */
707 if (!BN_copy(n3
, &b
->X
)) goto end
;
708 if (!BN_copy(n4
, &b
->Y
)) goto end
;
714 if (!field_sqr(group
, n0
, &a
->Z
, ctx
)) goto end
;
715 if (!field_mul(group
, n3
, &b
->X
, n0
, ctx
)) goto end
;
716 /* n3 = X_b * Z_a^2 */
718 if (!field_mul(group
, n0
, n0
, &a
->Z
, ctx
)) goto end
;
719 if (!field_mul(group
, n4
, &b
->Y
, n0
, ctx
)) goto end
;
720 /* n4 = Y_b * Z_a^3 */
724 if (!BN_mod_sub_quick(n5
, n1
, n3
, p
)) goto end
;
725 if (!BN_mod_sub_quick(n6
, n2
, n4
, p
)) goto end
;
733 /* a is the same point as b */
735 ret
= EC_POINT_dbl(group
, r
, a
, ctx
);
741 /* a is the inverse of b */
750 if (!BN_mod_add_quick(n1
, n1
, n3
, p
)) goto end
;
751 if (!BN_mod_add_quick(n2
, n2
, n4
, p
)) goto end
;
756 if (a
->Z_is_one
&& b
->Z_is_one
)
758 if (!BN_copy(&r
->Z
, n5
)) goto end
;
763 { if (!BN_copy(n0
, &b
->Z
)) goto end
; }
764 else if (b
->Z_is_one
)
765 { if (!BN_copy(n0
, &a
->Z
)) goto end
; }
767 { if (!field_mul(group
, n0
, &a
->Z
, &b
->Z
, ctx
)) goto end
; }
768 if (!field_mul(group
, &r
->Z
, n0
, n5
, ctx
)) goto end
;
771 /* Z_r = Z_a * Z_b * n5 */
774 if (!field_sqr(group
, n0
, n6
, ctx
)) goto end
;
775 if (!field_sqr(group
, n4
, n5
, ctx
)) goto end
;
776 if (!field_mul(group
, n3
, n1
, n4
, ctx
)) goto end
;
777 if (!BN_mod_sub_quick(&r
->X
, n0
, n3
, p
)) goto end
;
778 /* X_r = n6^2 - n5^2 * 'n7' */
781 if (!BN_mod_lshift1_quick(n0
, &r
->X
, p
)) goto end
;
782 if (!BN_mod_sub_quick(n0
, n3
, n0
, p
)) goto end
;
783 /* n9 = n5^2 * 'n7' - 2 * X_r */
786 if (!field_mul(group
, n0
, n0
, n6
, ctx
)) goto end
;
787 if (!field_mul(group
, n5
, n4
, n5
, ctx
)) goto end
; /* now n5 is n5^3 */
788 if (!field_mul(group
, n1
, n2
, n5
, ctx
)) goto end
;
789 if (!BN_mod_sub_quick(n0
, n0
, n1
, p
)) goto end
;
791 if (!BN_add(n0
, n0
, p
)) goto end
;
792 /* now 0 <= n0 < 2*p, and n0 is even */
793 if (!BN_rshift1(&r
->Y
, n0
)) goto end
;
794 /* Y_r = (n6 * 'n9' - 'n8' * 'n5^3') / 2 */
799 if (ctx
) /* otherwise we already called BN_CTX_end */
802 BN_CTX_free(new_ctx
);
807 int ec_GFp_simple_dbl(const EC_GROUP
*group
, EC_POINT
*r
, const EC_POINT
*a
, BN_CTX
*ctx
)
809 int (*field_mul
)(const EC_GROUP
*, BIGNUM
*, const BIGNUM
*, const BIGNUM
*, BN_CTX
*);
810 int (*field_sqr
)(const EC_GROUP
*, BIGNUM
*, const BIGNUM
*, BN_CTX
*);
812 BN_CTX
*new_ctx
= NULL
;
813 BIGNUM
*n0
, *n1
, *n2
, *n3
;
816 if (EC_POINT_is_at_infinity(group
, a
))
823 field_mul
= group
->meth
->field_mul
;
824 field_sqr
= group
->meth
->field_sqr
;
829 ctx
= new_ctx
= BN_CTX_new();
835 n0
= BN_CTX_get(ctx
);
836 n1
= BN_CTX_get(ctx
);
837 n2
= BN_CTX_get(ctx
);
838 n3
= BN_CTX_get(ctx
);
839 if (n3
== NULL
) goto err
;
841 /* Note that in this function we must not read components of 'a'
842 * once we have written the corresponding components of 'r'.
843 * ('r' might the same as 'a'.)
849 if (!field_sqr(group
, n0
, &a
->X
, ctx
)) goto err
;
850 if (!BN_mod_lshift1_quick(n1
, n0
, p
)) goto err
;
851 if (!BN_mod_add_quick(n0
, n0
, n1
, p
)) goto err
;
852 if (!BN_mod_add_quick(n1
, n0
, &group
->a
, p
)) goto err
;
853 /* n1 = 3 * X_a^2 + a_curve */
855 else if (group
->a_is_minus3
)
857 if (!field_sqr(group
, n1
, &a
->Z
, ctx
)) goto err
;
858 if (!BN_mod_add_quick(n0
, &a
->X
, n1
, p
)) goto err
;
859 if (!BN_mod_sub_quick(n2
, &a
->X
, n1
, p
)) goto err
;
860 if (!field_mul(group
, n1
, n0
, n2
, ctx
)) goto err
;
861 if (!BN_mod_lshift1_quick(n0
, n1
, p
)) goto err
;
862 if (!BN_mod_add_quick(n1
, n0
, n1
, p
)) goto err
;
863 /* n1 = 3 * (X_a + Z_a^2) * (X_a - Z_a^2)
864 * = 3 * X_a^2 - 3 * Z_a^4 */
868 if (!field_sqr(group
, n0
, &a
->X
, ctx
)) goto err
;
869 if (!BN_mod_lshift1_quick(n1
, n0
, p
)) goto err
;
870 if (!BN_mod_add_quick(n0
, n0
, n1
, p
)) goto err
;
871 if (!field_sqr(group
, n1
, &a
->Z
, ctx
)) goto err
;
872 if (!field_sqr(group
, n1
, n1
, ctx
)) goto err
;
873 if (!field_mul(group
, n1
, n1
, &group
->a
, ctx
)) goto err
;
874 if (!BN_mod_add_quick(n1
, n1
, n0
, p
)) goto err
;
875 /* n1 = 3 * X_a^2 + a_curve * Z_a^4 */
881 if (!BN_copy(n0
, &a
->Y
)) goto err
;
885 if (!field_mul(group
, n0
, &a
->Y
, &a
->Z
, ctx
)) goto err
;
887 if (!BN_mod_lshift1_quick(&r
->Z
, n0
, p
)) goto err
;
889 /* Z_r = 2 * Y_a * Z_a */
892 if (!field_sqr(group
, n3
, &a
->Y
, ctx
)) goto err
;
893 if (!field_mul(group
, n2
, &a
->X
, n3
, ctx
)) goto err
;
894 if (!BN_mod_lshift_quick(n2
, n2
, 2, p
)) goto err
;
895 /* n2 = 4 * X_a * Y_a^2 */
898 if (!BN_mod_lshift1_quick(n0
, n2
, p
)) goto err
;
899 if (!field_sqr(group
, &r
->X
, n1
, ctx
)) goto err
;
900 if (!BN_mod_sub_quick(&r
->X
, &r
->X
, n0
, p
)) goto err
;
901 /* X_r = n1^2 - 2 * n2 */
904 if (!field_sqr(group
, n0
, n3
, ctx
)) goto err
;
905 if (!BN_mod_lshift_quick(n3
, n0
, 3, p
)) goto err
;
909 if (!BN_mod_sub_quick(n0
, n2
, &r
->X
, p
)) goto err
;
910 if (!field_mul(group
, n0
, n1
, n0
, ctx
)) goto err
;
911 if (!BN_mod_sub_quick(&r
->Y
, n0
, n3
, p
)) goto err
;
912 /* Y_r = n1 * (n2 - X_r) - n3 */
919 BN_CTX_free(new_ctx
);
924 int ec_GFp_simple_invert(const EC_GROUP
*group
, EC_POINT
*point
, BN_CTX
*ctx
)
926 if (EC_POINT_is_at_infinity(group
, point
) || BN_is_zero(&point
->Y
))
927 /* point is its own inverse */
930 return BN_usub(&point
->Y
, &group
->field
, &point
->Y
);
934 int ec_GFp_simple_is_at_infinity(const EC_GROUP
*group
, const EC_POINT
*point
)
936 return BN_is_zero(&point
->Z
);
940 int ec_GFp_simple_is_on_curve(const EC_GROUP
*group
, const EC_POINT
*point
, BN_CTX
*ctx
)
942 int (*field_mul
)(const EC_GROUP
*, BIGNUM
*, const BIGNUM
*, const BIGNUM
*, BN_CTX
*);
943 int (*field_sqr
)(const EC_GROUP
*, BIGNUM
*, const BIGNUM
*, BN_CTX
*);
945 BN_CTX
*new_ctx
= NULL
;
946 BIGNUM
*rh
, *tmp
, *Z4
, *Z6
;
949 if (EC_POINT_is_at_infinity(group
, point
))
952 field_mul
= group
->meth
->field_mul
;
953 field_sqr
= group
->meth
->field_sqr
;
958 ctx
= new_ctx
= BN_CTX_new();
964 rh
= BN_CTX_get(ctx
);
965 tmp
= BN_CTX_get(ctx
);
966 Z4
= BN_CTX_get(ctx
);
967 Z6
= BN_CTX_get(ctx
);
968 if (Z6
== NULL
) goto err
;
970 /* We have a curve defined by a Weierstrass equation
971 * y^2 = x^3 + a*x + b.
972 * The point to consider is given in Jacobian projective coordinates
973 * where (X, Y, Z) represents (x, y) = (X/Z^2, Y/Z^3).
974 * Substituting this and multiplying by Z^6 transforms the above equation into
975 * Y^2 = X^3 + a*X*Z^4 + b*Z^6.
976 * To test this, we add up the right-hand side in 'rh'.
980 if (!field_sqr(group
, rh
, &point
->X
, ctx
)) goto err
;
982 if (!point
->Z_is_one
)
984 if (!field_sqr(group
, tmp
, &point
->Z
, ctx
)) goto err
;
985 if (!field_sqr(group
, Z4
, tmp
, ctx
)) goto err
;
986 if (!field_mul(group
, Z6
, Z4
, tmp
, ctx
)) goto err
;
988 /* rh := (rh + a*Z^4)*X */
989 if (group
->a_is_minus3
)
991 if (!BN_mod_lshift1_quick(tmp
, Z4
, p
)) goto err
;
992 if (!BN_mod_add_quick(tmp
, tmp
, Z4
, p
)) goto err
;
993 if (!BN_mod_sub_quick(rh
, rh
, tmp
, p
)) goto err
;
994 if (!field_mul(group
, rh
, rh
, &point
->X
, ctx
)) goto err
;
998 if (!field_mul(group
, tmp
, Z4
, &group
->a
, ctx
)) goto err
;
999 if (!BN_mod_add_quick(rh
, rh
, tmp
, p
)) goto err
;
1000 if (!field_mul(group
, rh
, rh
, &point
->X
, ctx
)) goto err
;
1003 /* rh := rh + b*Z^6 */
1004 if (!field_mul(group
, tmp
, &group
->b
, Z6
, ctx
)) goto err
;
1005 if (!BN_mod_add_quick(rh
, rh
, tmp
, p
)) goto err
;
1009 /* point->Z_is_one */
1011 /* rh := (rh + a)*X */
1012 if (!BN_mod_add_quick(rh
, rh
, &group
->a
, p
)) goto err
;
1013 if (!field_mul(group
, rh
, rh
, &point
->X
, ctx
)) goto err
;
1015 if (!BN_mod_add_quick(rh
, rh
, &group
->b
, p
)) goto err
;
1019 if (!field_sqr(group
, tmp
, &point
->Y
, ctx
)) goto err
;
1021 ret
= (0 == BN_ucmp(tmp
, rh
));
1025 if (new_ctx
!= NULL
)
1026 BN_CTX_free(new_ctx
);
1031 int ec_GFp_simple_cmp(const EC_GROUP
*group
, const EC_POINT
*a
, const EC_POINT
*b
, BN_CTX
*ctx
)
1035 * 0 equal (in affine coordinates)
1039 int (*field_mul
)(const EC_GROUP
*, BIGNUM
*, const BIGNUM
*, const BIGNUM
*, BN_CTX
*);
1040 int (*field_sqr
)(const EC_GROUP
*, BIGNUM
*, const BIGNUM
*, BN_CTX
*);
1041 BN_CTX
*new_ctx
= NULL
;
1042 BIGNUM
*tmp1
, *tmp2
, *Za23
, *Zb23
;
1043 const BIGNUM
*tmp1_
, *tmp2_
;
1046 if (EC_POINT_is_at_infinity(group
, a
))
1048 return EC_POINT_is_at_infinity(group
, b
) ? 0 : 1;
1051 if (EC_POINT_is_at_infinity(group
, b
))
1054 if (a
->Z_is_one
&& b
->Z_is_one
)
1056 return ((BN_cmp(&a
->X
, &b
->X
) == 0) && BN_cmp(&a
->Y
, &b
->Y
) == 0) ? 0 : 1;
1059 field_mul
= group
->meth
->field_mul
;
1060 field_sqr
= group
->meth
->field_sqr
;
1064 ctx
= new_ctx
= BN_CTX_new();
1070 tmp1
= BN_CTX_get(ctx
);
1071 tmp2
= BN_CTX_get(ctx
);
1072 Za23
= BN_CTX_get(ctx
);
1073 Zb23
= BN_CTX_get(ctx
);
1074 if (Zb23
== NULL
) goto end
;
1076 /* We have to decide whether
1077 * (X_a/Z_a^2, Y_a/Z_a^3) = (X_b/Z_b^2, Y_b/Z_b^3),
1078 * or equivalently, whether
1079 * (X_a*Z_b^2, Y_a*Z_b^3) = (X_b*Z_a^2, Y_b*Z_a^3).
1084 if (!field_sqr(group
, Zb23
, &b
->Z
, ctx
)) goto end
;
1085 if (!field_mul(group
, tmp1
, &a
->X
, Zb23
, ctx
)) goto end
;
1092 if (!field_sqr(group
, Za23
, &a
->Z
, ctx
)) goto end
;
1093 if (!field_mul(group
, tmp2
, &b
->X
, Za23
, ctx
)) goto end
;
1099 /* compare X_a*Z_b^2 with X_b*Z_a^2 */
1100 if (BN_cmp(tmp1_
, tmp2_
) != 0)
1102 ret
= 1; /* points differ */
1109 if (!field_mul(group
, Zb23
, Zb23
, &b
->Z
, ctx
)) goto end
;
1110 if (!field_mul(group
, tmp1
, &a
->Y
, Zb23
, ctx
)) goto end
;
1117 if (!field_mul(group
, Za23
, Za23
, &a
->Z
, ctx
)) goto end
;
1118 if (!field_mul(group
, tmp2
, &b
->Y
, Za23
, ctx
)) goto end
;
1124 /* compare Y_a*Z_b^3 with Y_b*Z_a^3 */
1125 if (BN_cmp(tmp1_
, tmp2_
) != 0)
1127 ret
= 1; /* points differ */
1131 /* points are equal */
1136 if (new_ctx
!= NULL
)
1137 BN_CTX_free(new_ctx
);
1142 int ec_GFp_simple_make_affine(const EC_GROUP
*group
, EC_POINT
*point
, BN_CTX
*ctx
)
1144 BN_CTX
*new_ctx
= NULL
;
1148 if (point
->Z_is_one
|| EC_POINT_is_at_infinity(group
, point
))
1153 ctx
= new_ctx
= BN_CTX_new();
1159 x
= BN_CTX_get(ctx
);
1160 y
= BN_CTX_get(ctx
);
1161 if (y
== NULL
) goto err
;
1163 if (!EC_POINT_get_affine_coordinates_GFp(group
, point
, x
, y
, ctx
)) goto err
;
1164 if (!EC_POINT_set_affine_coordinates_GFp(group
, point
, x
, y
, ctx
)) goto err
;
1165 if (!point
->Z_is_one
)
1167 ECerr(EC_F_EC_GFP_SIMPLE_MAKE_AFFINE
, ERR_R_INTERNAL_ERROR
);
1175 if (new_ctx
!= NULL
)
1176 BN_CTX_free(new_ctx
);
1181 int ec_GFp_simple_points_make_affine(const EC_GROUP
*group
, size_t num
, EC_POINT
*points
[], BN_CTX
*ctx
)
1183 BN_CTX
*new_ctx
= NULL
;
1184 BIGNUM
*tmp0
, *tmp1
;
1186 BIGNUM
**heap
= NULL
;
1195 ctx
= new_ctx
= BN_CTX_new();
1201 tmp0
= BN_CTX_get(ctx
);
1202 tmp1
= BN_CTX_get(ctx
);
1203 if (tmp0
== NULL
|| tmp1
== NULL
) goto err
;
1205 /* Before converting the individual points, compute inverses of all Z values.
1206 * Modular inversion is rather slow, but luckily we can do with a single
1207 * explicit inversion, plus about 3 multiplications per input value.
1213 /* Now pow2 is the smallest power of 2 satifsying pow2 >= num.
1214 * We need twice that. */
1217 heap
= OPENSSL_malloc(pow2
* sizeof heap
[0]);
1218 if (heap
== NULL
) goto err
;
1220 /* The array is used as a binary tree, exactly as in heapsort:
1224 * heap[4] heap[5] heap[6] heap[7]
1225 * heap[8]heap[9] heap[10]heap[11] heap[12]heap[13] heap[14] heap[15]
1227 * We put the Z's in the last line;
1228 * then we set each other node to the product of its two child-nodes (where
1229 * empty or 0 entries are treated as ones);
1230 * then we invert heap[1];
1231 * then we invert each other node by replacing it by the product of its
1232 * parent (after inversion) and its sibling (before inversion).
1235 for (i
= pow2
/2 - 1; i
> 0; i
--)
1237 for (i
= 0; i
< num
; i
++)
1238 heap
[pow2
/2 + i
] = &points
[i
]->Z
;
1239 for (i
= pow2
/2 + num
; i
< pow2
; i
++)
1242 /* set each node to the product of its children */
1243 for (i
= pow2
/2 - 1; i
> 0; i
--)
1246 if (heap
[i
] == NULL
) goto err
;
1248 if (heap
[2*i
] != NULL
)
1250 if ((heap
[2*i
+ 1] == NULL
) || BN_is_zero(heap
[2*i
+ 1]))
1252 if (!BN_copy(heap
[i
], heap
[2*i
])) goto err
;
1256 if (BN_is_zero(heap
[2*i
]))
1258 if (!BN_copy(heap
[i
], heap
[2*i
+ 1])) goto err
;
1262 if (!group
->meth
->field_mul(group
, heap
[i
],
1263 heap
[2*i
], heap
[2*i
+ 1], ctx
)) goto err
;
1269 /* invert heap[1] */
1270 if (!BN_is_zero(heap
[1]))
1272 if (!BN_mod_inverse(heap
[1], heap
[1], &group
->field
, ctx
))
1274 ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE
, ERR_R_BN_LIB
);
1278 if (group
->meth
->field_encode
!= 0)
1280 /* in the Montgomery case, we just turned R*H (representing H)
1281 * into 1/(R*H), but we need R*(1/H) (representing 1/H);
1282 * i.e. we have need to multiply by the Montgomery factor twice */
1283 if (!group
->meth
->field_encode(group
, heap
[1], heap
[1], ctx
)) goto err
;
1284 if (!group
->meth
->field_encode(group
, heap
[1], heap
[1], ctx
)) goto err
;
1287 /* set other heap[i]'s to their inverses */
1288 for (i
= 2; i
< pow2
/2 + num
; i
+= 2)
1291 if ((heap
[i
+ 1] != NULL
) && !BN_is_zero(heap
[i
+ 1]))
1293 if (!group
->meth
->field_mul(group
, tmp0
, heap
[i
/2], heap
[i
+ 1], ctx
)) goto err
;
1294 if (!group
->meth
->field_mul(group
, tmp1
, heap
[i
/2], heap
[i
], ctx
)) goto err
;
1295 if (!BN_copy(heap
[i
], tmp0
)) goto err
;
1296 if (!BN_copy(heap
[i
+ 1], tmp1
)) goto err
;
1300 if (!BN_copy(heap
[i
], heap
[i
/2])) goto err
;
1304 /* we have replaced all non-zero Z's by their inverses, now fix up all the points */
1305 for (i
= 0; i
< num
; i
++)
1307 EC_POINT
*p
= points
[i
];
1309 if (!BN_is_zero(&p
->Z
))
1311 /* turn (X, Y, 1/Z) into (X/Z^2, Y/Z^3, 1) */
1313 if (!group
->meth
->field_sqr(group
, tmp1
, &p
->Z
, ctx
)) goto err
;
1314 if (!group
->meth
->field_mul(group
, &p
->X
, &p
->X
, tmp1
, ctx
)) goto err
;
1316 if (!group
->meth
->field_mul(group
, tmp1
, tmp1
, &p
->Z
, ctx
)) goto err
;
1317 if (!group
->meth
->field_mul(group
, &p
->Y
, &p
->Y
, tmp1
, ctx
)) goto err
;
1319 if (group
->meth
->field_set_to_one
!= 0)
1321 if (!group
->meth
->field_set_to_one(group
, &p
->Z
, ctx
)) goto err
;
1325 if (!BN_one(&p
->Z
)) goto err
;
1335 if (new_ctx
!= NULL
)
1336 BN_CTX_free(new_ctx
);
1339 /* heap[pow2/2] .. heap[pow2-1] have not been allocated locally! */
1340 for (i
= pow2
/2 - 1; i
> 0; i
--)
1342 if (heap
[i
] != NULL
)
1343 BN_clear_free(heap
[i
]);
1351 int ec_GFp_simple_field_mul(const EC_GROUP
*group
, BIGNUM
*r
, const BIGNUM
*a
, const BIGNUM
*b
, BN_CTX
*ctx
)
1353 return BN_mod_mul(r
, a
, b
, &group
->field
, ctx
);
1357 int ec_GFp_simple_field_sqr(const EC_GROUP
*group
, BIGNUM
*r
, const BIGNUM
*a
, BN_CTX
*ctx
)
1359 return BN_mod_sqr(r
, a
, &group
->field
, ctx
);