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428 lines
13 KiB
428 lines
13 KiB
/* crypto/ec/ecp_oct.c */ |
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/* |
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* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de> |
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* for the OpenSSL project. Includes code written by Bodo Moeller for the |
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* 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, |
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EC_POINT *point, |
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const BIGNUM *x_, int y_bit, |
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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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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) |
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goto err; |
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|
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/*- |
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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)) |
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goto err; |
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if (group->meth->field_decode == 0) { |
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/* field_{sqr,mul} work on standard representation */ |
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if (!group->meth->field_sqr(group, tmp2, x_, ctx)) |
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goto err; |
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if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx)) |
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goto err; |
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} else { |
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if (!BN_mod_sqr(tmp2, x_, &group->field, ctx)) |
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goto err; |
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if (!BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx)) |
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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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if (!BN_mod_lshift1_quick(tmp2, x, &group->field)) |
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goto err; |
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if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field)) |
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goto err; |
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if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) |
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goto err; |
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} else { |
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if (group->meth->field_decode) { |
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if (!group->meth->field_decode(group, tmp2, &group->a, ctx)) |
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goto err; |
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if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx)) |
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goto err; |
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} else { |
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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)) |
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goto err; |
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} |
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if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) |
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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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if (!group->meth->field_decode(group, tmp2, &group->b, ctx)) |
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goto err; |
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if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) |
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goto err; |
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} else { |
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if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field)) |
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goto err; |
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} |
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if (!BN_mod_sqrt(y, tmp1, &group->field, ctx)) { |
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unsigned long err = ERR_peek_last_error(); |
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if (ERR_GET_LIB(err) == ERR_LIB_BN |
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&& ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) { |
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ERR_clear_error(); |
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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, |
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EC_R_INVALID_COMPRESSED_POINT); |
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} else |
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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, |
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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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if (BN_is_zero(y)) { |
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int kron; |
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kron = BN_kronecker(x, &group->field, ctx); |
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if (kron == -2) |
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goto err; |
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if (kron == 1) |
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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, |
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EC_R_INVALID_COMPRESSION_BIT); |
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else |
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/* |
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* BN_mod_sqrt() should have cought this error (not a square) |
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*/ |
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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, |
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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)) |
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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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ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, |
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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)) |
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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, |
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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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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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/* encodes to a single 0 octet */ |
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if (buf != NULL) { |
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if (len < 1) { |
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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 = |
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(form == |
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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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if (len < ret) { |
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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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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) |
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goto err; |
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if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) |
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goto err; |
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if ((form == POINT_CONVERSION_COMPRESSED |
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|| 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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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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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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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 |
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|| form == POINT_CONVERSION_HYBRID) { |
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skip = field_len - BN_num_bytes(y); |
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if (skip > field_len) { |
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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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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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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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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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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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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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if (len != 1) { |
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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 = |
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(form == |
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POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len; |
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if (len != enc_len) { |
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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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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) |
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goto err; |
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if (!BN_bin2bn(buf + 1, field_len, x)) |
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goto err; |
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if (BN_ucmp(x, &group->field) >= 0) { |
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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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if (!EC_POINT_set_compressed_coordinates_GFp |
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(group, point, x, y_bit, ctx)) |
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goto err; |
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} else { |
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if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) |
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goto err; |
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if (BN_ucmp(y, &group->field) >= 0) { |
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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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if (y_bit != BN_is_odd(y)) { |
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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)) |
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goto err; |
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} |
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/* test required by X9.62 */ |
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if (EC_POINT_is_on_curve(group, point, ctx) <= 0) { |
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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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