84b08eee4b
Move compression, point2oct and oct2point functions into separate files. Add a flags field to EC_METHOD. Add a flag EC_FLAGS_DEFAULT_OCT to use the default compession and oct functions (all existing methods do this). This removes dependencies from EC_METHOD while keeping original functionality.
433 lines
11 KiB
C
433 lines
11 KiB
C
/* crypto/ec/ecp_oct.c */
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/* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
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* for the OpenSSL project.
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* Includes code written by Bodo Moeller for the OpenSSL project.
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*/
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/* ====================================================================
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* Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* openssl-core@openssl.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*
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* This product includes cryptographic software written by Eric Young
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* (eay@cryptsoft.com). This product includes software written by Tim
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* Hudson (tjh@cryptsoft.com).
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*
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*/
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/* ====================================================================
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* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
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* Portions of this software developed by SUN MICROSYSTEMS, INC.,
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* and contributed to the OpenSSL project.
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*/
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#include <openssl/err.h>
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#include <openssl/symhacks.h>
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#include "ec_lcl.h"
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int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point,
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const BIGNUM *x_, int y_bit, BN_CTX *ctx)
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{
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BN_CTX *new_ctx = NULL;
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BIGNUM *tmp1, *tmp2, *x, *y;
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int ret = 0;
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/* clear error queue*/
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ERR_clear_error();
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if (ctx == NULL)
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{
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ctx = new_ctx = BN_CTX_new();
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if (ctx == NULL)
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return 0;
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}
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y_bit = (y_bit != 0);
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BN_CTX_start(ctx);
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tmp1 = BN_CTX_get(ctx);
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tmp2 = BN_CTX_get(ctx);
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x = BN_CTX_get(ctx);
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y = BN_CTX_get(ctx);
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if (y == NULL) goto err;
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/* Recover y. We have a Weierstrass equation
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* y^2 = x^3 + a*x + b,
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* so y is one of the square roots of x^3 + a*x + b.
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*/
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/* tmp1 := x^3 */
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if (!BN_nnmod(x, x_, &group->field,ctx)) goto err;
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if (group->meth->field_decode == 0)
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{
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/* field_{sqr,mul} work on standard representation */
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if (!group->meth->field_sqr(group, tmp2, x_, ctx)) goto err;
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if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx)) goto err;
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}
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else
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{
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if (!BN_mod_sqr(tmp2, x_, &group->field, ctx)) goto err;
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if (!BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx)) goto err;
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}
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/* tmp1 := tmp1 + a*x */
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if (group->a_is_minus3)
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{
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if (!BN_mod_lshift1_quick(tmp2, x, &group->field)) goto err;
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if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field)) goto err;
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if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
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}
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else
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{
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if (group->meth->field_decode)
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{
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if (!group->meth->field_decode(group, tmp2, &group->a, ctx)) goto err;
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if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx)) goto err;
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}
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else
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{
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/* field_mul works on standard representation */
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if (!group->meth->field_mul(group, tmp2, &group->a, x, ctx)) goto err;
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}
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if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
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}
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/* tmp1 := tmp1 + b */
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if (group->meth->field_decode)
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{
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if (!group->meth->field_decode(group, tmp2, &group->b, ctx)) goto err;
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if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
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}
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else
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{
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if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field)) goto err;
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}
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if (!BN_mod_sqrt(y, tmp1, &group->field, ctx))
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{
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unsigned long err = ERR_peek_last_error();
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if (ERR_GET_LIB(err) == ERR_LIB_BN && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE)
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{
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ERR_clear_error();
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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
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}
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else
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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB);
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goto err;
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}
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if (y_bit != BN_is_odd(y))
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{
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if (BN_is_zero(y))
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{
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int kron;
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kron = BN_kronecker(x, &group->field, ctx);
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if (kron == -2) goto err;
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if (kron == 1)
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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSION_BIT);
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else
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/* BN_mod_sqrt() should have cought this error (not a square) */
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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
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goto err;
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}
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if (!BN_usub(y, &group->field, y)) goto err;
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}
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if (y_bit != BN_is_odd(y))
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{
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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_INTERNAL_ERROR);
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goto err;
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}
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if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
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ret = 1;
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err:
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BN_CTX_end(ctx);
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if (new_ctx != NULL)
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BN_CTX_free(new_ctx);
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return ret;
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}
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size_t ec_GFp_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, point_conversion_form_t form,
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unsigned char *buf, size_t len, BN_CTX *ctx)
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{
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size_t ret;
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BN_CTX *new_ctx = NULL;
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int used_ctx = 0;
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BIGNUM *x, *y;
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size_t field_len, i, skip;
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if ((form != POINT_CONVERSION_COMPRESSED)
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&& (form != POINT_CONVERSION_UNCOMPRESSED)
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&& (form != POINT_CONVERSION_HYBRID))
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{
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ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
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goto err;
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}
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if (EC_POINT_is_at_infinity(group, point))
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{
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/* encodes to a single 0 octet */
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if (buf != NULL)
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{
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if (len < 1)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
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return 0;
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}
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buf[0] = 0;
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}
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return 1;
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}
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/* ret := required output buffer length */
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field_len = BN_num_bytes(&group->field);
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ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
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/* if 'buf' is NULL, just return required length */
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if (buf != NULL)
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{
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if (len < ret)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
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goto err;
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}
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if (ctx == NULL)
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{
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ctx = new_ctx = BN_CTX_new();
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if (ctx == NULL)
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return 0;
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}
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BN_CTX_start(ctx);
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used_ctx = 1;
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x = BN_CTX_get(ctx);
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y = BN_CTX_get(ctx);
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if (y == NULL) goto err;
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if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
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if ((form == POINT_CONVERSION_COMPRESSED || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
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buf[0] = form + 1;
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else
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buf[0] = form;
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i = 1;
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skip = field_len - BN_num_bytes(x);
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if (skip > field_len)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
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goto err;
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}
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while (skip > 0)
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{
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buf[i++] = 0;
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skip--;
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}
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skip = BN_bn2bin(x, buf + i);
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i += skip;
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if (i != 1 + field_len)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
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goto err;
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}
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if (form == POINT_CONVERSION_UNCOMPRESSED || form == POINT_CONVERSION_HYBRID)
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{
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skip = field_len - BN_num_bytes(y);
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if (skip > field_len)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
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goto err;
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}
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while (skip > 0)
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{
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buf[i++] = 0;
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skip--;
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}
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skip = BN_bn2bin(y, buf + i);
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i += skip;
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}
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if (i != ret)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
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goto err;
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}
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}
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if (used_ctx)
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BN_CTX_end(ctx);
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if (new_ctx != NULL)
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BN_CTX_free(new_ctx);
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return ret;
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err:
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if (used_ctx)
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BN_CTX_end(ctx);
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if (new_ctx != NULL)
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BN_CTX_free(new_ctx);
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return 0;
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}
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int ec_GFp_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
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const unsigned char *buf, size_t len, BN_CTX *ctx)
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{
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point_conversion_form_t form;
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int y_bit;
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BN_CTX *new_ctx = NULL;
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BIGNUM *x, *y;
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size_t field_len, enc_len;
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int ret = 0;
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if (len == 0)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
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return 0;
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}
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form = buf[0];
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y_bit = form & 1;
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form = form & ~1U;
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if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
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&& (form != POINT_CONVERSION_UNCOMPRESSED)
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&& (form != POINT_CONVERSION_HYBRID))
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{
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ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
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return 0;
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}
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if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
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return 0;
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}
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if (form == 0)
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{
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if (len != 1)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
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return 0;
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}
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return EC_POINT_set_to_infinity(group, point);
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}
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field_len = BN_num_bytes(&group->field);
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enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
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if (len != enc_len)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
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return 0;
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}
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if (ctx == NULL)
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{
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ctx = new_ctx = BN_CTX_new();
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if (ctx == NULL)
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return 0;
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}
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BN_CTX_start(ctx);
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x = BN_CTX_get(ctx);
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y = BN_CTX_get(ctx);
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if (y == NULL) goto err;
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if (!BN_bin2bn(buf + 1, field_len, x)) goto err;
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if (BN_ucmp(x, &group->field) >= 0)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
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goto err;
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}
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if (form == POINT_CONVERSION_COMPRESSED)
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{
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if (!EC_POINT_set_compressed_coordinates_GFp(group, point, x, y_bit, ctx)) goto err;
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}
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else
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{
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if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) goto err;
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if (BN_ucmp(y, &group->field) >= 0)
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{
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ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
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goto err;
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}
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if (form == POINT_CONVERSION_HYBRID)
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{
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if (y_bit != BN_is_odd(y))
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{
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ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
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goto err;
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}
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}
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if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
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}
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if (!EC_POINT_is_on_curve(group, point, ctx)) /* test required by X9.62 */
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{
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ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
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goto err;
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}
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ret = 1;
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err:
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BN_CTX_end(ctx);
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if (new_ctx != NULL)
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BN_CTX_free(new_ctx);
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return ret;
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}
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