| /* crypto/ec/ec2_smpt.c */ |
| /* This code was originally written by Douglas Stebila |
| * <dstebila@student.math.uwaterloo.ca> for the OpenSSL project. |
| */ |
| /* ==================================================================== |
| * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. All advertising materials mentioning features or use of this |
| * software must display the following acknowledgment: |
| * "This product includes software developed by the OpenSSL Project |
| * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" |
| * |
| * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
| * endorse or promote products derived from this software without |
| * prior written permission. For written permission, please contact |
| * openssl-core@openssl.org. |
| * |
| * 5. Products derived from this software may not be called "OpenSSL" |
| * nor may "OpenSSL" appear in their names without prior written |
| * permission of the OpenSSL Project. |
| * |
| * 6. Redistributions of any form whatsoever must retain the following |
| * acknowledgment: |
| * "This product includes software developed by the OpenSSL Project |
| * for use in the OpenSSL Toolkit (http://www.openssl.org/)" |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
| * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| * OF THE POSSIBILITY OF SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This product includes cryptographic software written by Eric Young |
| * (eay@cryptsoft.com). This product includes software written by Tim |
| * Hudson (tjh@cryptsoft.com). |
| * |
| */ |
| |
| |
| /* Calaculates and sets the affine coordinates of an EC_POINT from the given |
| * compressed coordinates. Uses algorithm 2.3.4 of SEC 1. |
| * Note that the simple implementation only uses affine coordinates. |
| * |
| * This algorithm is patented by Certicom Corp. under US Patent 6,141,420 |
| * (for licensing information, contact licensing@certicom.com). |
| * This function is disabled by default and can be enabled by defining the |
| * preprocessor macro OPENSSL_EC_BIN_PT_COMP at Configure-time. |
| */ |
| int ec_GF2m_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point, |
| const BIGNUM *x_, int y_bit, BN_CTX *ctx) |
| { |
| #ifndef OPENSSL_EC_BIN_PT_COMP |
| ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_DISABLED); |
| return 0; |
| #else |
| BN_CTX *new_ctx = NULL; |
| BIGNUM *tmp, *x, *y, *z; |
| int ret = 0, z0; |
| |
| /* clear error queue */ |
| ERR_clear_error(); |
| |
| if (ctx == NULL) |
| { |
| ctx = new_ctx = BN_CTX_new(); |
| if (ctx == NULL) |
| return 0; |
| } |
| |
| y_bit = (y_bit != 0) ? 1 : 0; |
| |
| BN_CTX_start(ctx); |
| tmp = BN_CTX_get(ctx); |
| x = BN_CTX_get(ctx); |
| y = BN_CTX_get(ctx); |
| z = BN_CTX_get(ctx); |
| if (z == NULL) goto err; |
| |
| if (!BN_GF2m_mod_arr(x, x_, group->poly)) goto err; |
| if (BN_is_zero(x)) |
| { |
| if (!BN_GF2m_mod_sqrt_arr(y, &group->b, group->poly, ctx)) goto err; |
| } |
| else |
| { |
| if (!group->meth->field_sqr(group, tmp, x, ctx)) goto err; |
| if (!group->meth->field_div(group, tmp, &group->b, tmp, ctx)) goto err; |
| if (!BN_GF2m_add(tmp, &group->a, tmp)) goto err; |
| if (!BN_GF2m_add(tmp, x, tmp)) goto err; |
| if (!BN_GF2m_mod_solve_quad_arr(z, tmp, group->poly, ctx)) |
| { |
| unsigned long err = ERR_peek_last_error(); |
| |
| if (ERR_GET_LIB(err) == ERR_LIB_BN && ERR_GET_REASON(err) == BN_R_NO_SOLUTION) |
| { |
| ERR_clear_error(); |
| ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT); |
| } |
| else |
| ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB); |
| goto err; |
| } |
| z0 = (BN_is_odd(z)) ? 1 : 0; |
| if (!group->meth->field_mul(group, y, x, z, ctx)) goto err; |
| if (z0 != y_bit) |
| { |
| if (!BN_GF2m_add(y, y, x)) goto err; |
| } |
| } |
| |
| if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err; |
| |
| ret = 1; |
| |
| err: |
| BN_CTX_end(ctx); |
| if (new_ctx != NULL) |
| BN_CTX_free(new_ctx); |
| return ret; |
| #endif |
| } |