1 /* crypto/ec/ecp_oct.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>
70 int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point,
71 const BIGNUM *x_, int y_bit, BN_CTX *ctx)
73 BN_CTX *new_ctx = NULL;
74 BIGNUM *tmp1, *tmp2, *x, *y;
77 /* clear error queue*/
82 ctx = new_ctx = BN_CTX_new();
90 tmp1 = BN_CTX_get(ctx);
91 tmp2 = BN_CTX_get(ctx);
94 if (y == NULL) goto err;
96 /* Recover y. We have a Weierstrass equation
97 * y^2 = x^3 + a*x + b,
98 * so y is one of the square roots of x^3 + a*x + b.
102 if (!BN_nnmod(x, x_, &group->field,ctx)) goto err;
103 if (group->meth->field_decode == 0)
105 /* field_{sqr,mul} work on standard representation */
106 if (!group->meth->field_sqr(group, tmp2, x_, ctx)) goto err;
107 if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx)) goto err;
111 if (!BN_mod_sqr(tmp2, x_, &group->field, ctx)) goto err;
112 if (!BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx)) goto err;
115 /* tmp1 := tmp1 + a*x */
116 if (group->a_is_minus3)
118 if (!BN_mod_lshift1_quick(tmp2, x, &group->field)) goto err;
119 if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field)) goto err;
120 if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
124 if (group->meth->field_decode)
126 if (!group->meth->field_decode(group, tmp2, &group->a, ctx)) goto err;
127 if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx)) goto err;
131 /* field_mul works on standard representation */
132 if (!group->meth->field_mul(group, tmp2, &group->a, x, ctx)) goto err;
135 if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
138 /* tmp1 := tmp1 + b */
139 if (group->meth->field_decode)
141 if (!group->meth->field_decode(group, tmp2, &group->b, ctx)) goto err;
142 if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
146 if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field)) goto err;
149 if (!BN_mod_sqrt(y, tmp1, &group->field, ctx))
151 unsigned long err = ERR_peek_last_error();
153 if (ERR_GET_LIB(err) == ERR_LIB_BN && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE)
156 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
159 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB);
163 if (y_bit != BN_is_odd(y))
169 kron = BN_kronecker(x, &group->field, ctx);
170 if (kron == -2) goto err;
173 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSION_BIT);
175 /* BN_mod_sqrt() should have cought this error (not a square) */
176 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
179 if (!BN_usub(y, &group->field, y)) goto err;
181 if (y_bit != BN_is_odd(y))
183 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_INTERNAL_ERROR);
187 if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
194 BN_CTX_free(new_ctx);
199 size_t ec_GFp_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, point_conversion_form_t form,
200 unsigned char *buf, size_t len, BN_CTX *ctx)
203 BN_CTX *new_ctx = NULL;
206 size_t field_len, i, skip;
208 if ((form != POINT_CONVERSION_COMPRESSED)
209 && (form != POINT_CONVERSION_UNCOMPRESSED)
210 && (form != POINT_CONVERSION_HYBRID))
212 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
216 if (EC_POINT_is_at_infinity(group, point))
218 /* encodes to a single 0 octet */
223 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
232 /* ret := required output buffer length */
233 field_len = BN_num_bytes(&group->field);
234 ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
236 /* if 'buf' is NULL, just return required length */
241 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
247 ctx = new_ctx = BN_CTX_new();
256 if (y == NULL) goto err;
258 if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
260 if ((form == POINT_CONVERSION_COMPRESSED || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
267 skip = field_len - BN_num_bytes(x);
268 if (skip > field_len)
270 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
278 skip = BN_bn2bin(x, buf + i);
280 if (i != 1 + field_len)
282 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
286 if (form == POINT_CONVERSION_UNCOMPRESSED || form == POINT_CONVERSION_HYBRID)
288 skip = field_len - BN_num_bytes(y);
289 if (skip > field_len)
291 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
299 skip = BN_bn2bin(y, buf + i);
305 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
313 BN_CTX_free(new_ctx);
320 BN_CTX_free(new_ctx);
325 int ec_GFp_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
326 const unsigned char *buf, size_t len, BN_CTX *ctx)
328 point_conversion_form_t form;
330 BN_CTX *new_ctx = NULL;
332 size_t field_len, enc_len;
337 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
343 if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
344 && (form != POINT_CONVERSION_UNCOMPRESSED)
345 && (form != POINT_CONVERSION_HYBRID))
347 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
350 if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit)
352 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
360 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
364 return EC_POINT_set_to_infinity(group, point);
367 field_len = BN_num_bytes(&group->field);
368 enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
372 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
378 ctx = new_ctx = BN_CTX_new();
386 if (y == NULL) goto err;
388 if (!BN_bin2bn(buf + 1, field_len, x)) goto err;
389 if (BN_ucmp(x, &group->field) >= 0)
391 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
395 if (form == POINT_CONVERSION_COMPRESSED)
397 if (!EC_POINT_set_compressed_coordinates_GFp(group, point, x, y_bit, ctx)) goto err;
401 if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) goto err;
402 if (BN_ucmp(y, &group->field) >= 0)
404 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
407 if (form == POINT_CONVERSION_HYBRID)
409 if (y_bit != BN_is_odd(y))
411 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
416 if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
419 if (!EC_POINT_is_on_curve(group, point, ctx)) /* test required by X9.62 */
421 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
430 BN_CTX_free(new_ctx);