diff options
Diffstat (limited to 'main/openssl/crypto/ec/ec2_smpl.c')
| -rw-r--r-- | main/openssl/crypto/ec/ec2_smpl.c | 1042 |
1 files changed, 1042 insertions, 0 deletions
diff --git a/main/openssl/crypto/ec/ec2_smpl.c b/main/openssl/crypto/ec/ec2_smpl.c new file mode 100644 index 00000000..af94458c --- /dev/null +++ b/main/openssl/crypto/ec/ec2_smpl.c @@ -0,0 +1,1042 @@ +/* crypto/ec/ec2_smpl.c */ +/* ==================================================================== + * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED. + * + * The Elliptic Curve Public-Key Crypto Library (ECC Code) included + * herein is developed by SUN MICROSYSTEMS, INC., and is contributed + * to the OpenSSL project. + * + * The ECC Code is licensed pursuant to the OpenSSL open source + * license provided below. + * + * The software is originally written by Sheueling Chang Shantz and + * Douglas Stebila of Sun Microsystems Laboratories. + * + */ +/* ==================================================================== + * Copyright (c) 1998-2005 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). + * + */ + +#include <openssl/err.h> + +#include "ec_lcl.h" + + +const EC_METHOD *EC_GF2m_simple_method(void) + { + static const EC_METHOD ret = { + NID_X9_62_characteristic_two_field, + ec_GF2m_simple_group_init, + ec_GF2m_simple_group_finish, + ec_GF2m_simple_group_clear_finish, + ec_GF2m_simple_group_copy, + ec_GF2m_simple_group_set_curve, + ec_GF2m_simple_group_get_curve, + ec_GF2m_simple_group_get_degree, + ec_GF2m_simple_group_check_discriminant, + ec_GF2m_simple_point_init, + ec_GF2m_simple_point_finish, + ec_GF2m_simple_point_clear_finish, + ec_GF2m_simple_point_copy, + ec_GF2m_simple_point_set_to_infinity, + 0 /* set_Jprojective_coordinates_GFp */, + 0 /* get_Jprojective_coordinates_GFp */, + ec_GF2m_simple_point_set_affine_coordinates, + ec_GF2m_simple_point_get_affine_coordinates, + ec_GF2m_simple_set_compressed_coordinates, + ec_GF2m_simple_point2oct, + ec_GF2m_simple_oct2point, + ec_GF2m_simple_add, + ec_GF2m_simple_dbl, + ec_GF2m_simple_invert, + ec_GF2m_simple_is_at_infinity, + ec_GF2m_simple_is_on_curve, + ec_GF2m_simple_cmp, + ec_GF2m_simple_make_affine, + ec_GF2m_simple_points_make_affine, + + /* the following three method functions are defined in ec2_mult.c */ + ec_GF2m_simple_mul, + ec_GF2m_precompute_mult, + ec_GF2m_have_precompute_mult, + + ec_GF2m_simple_field_mul, + ec_GF2m_simple_field_sqr, + ec_GF2m_simple_field_div, + 0 /* field_encode */, + 0 /* field_decode */, + 0 /* field_set_to_one */ }; + + return &ret; + } + + +/* Initialize a GF(2^m)-based EC_GROUP structure. + * Note that all other members are handled by EC_GROUP_new. + */ +int ec_GF2m_simple_group_init(EC_GROUP *group) + { + BN_init(&group->field); + BN_init(&group->a); + BN_init(&group->b); + return 1; + } + + +/* Free a GF(2^m)-based EC_GROUP structure. + * Note that all other members are handled by EC_GROUP_free. + */ +void ec_GF2m_simple_group_finish(EC_GROUP *group) + { + BN_free(&group->field); + BN_free(&group->a); + BN_free(&group->b); + } + + +/* Clear and free a GF(2^m)-based EC_GROUP structure. + * Note that all other members are handled by EC_GROUP_clear_free. + */ +void ec_GF2m_simple_group_clear_finish(EC_GROUP *group) + { + BN_clear_free(&group->field); + BN_clear_free(&group->a); + BN_clear_free(&group->b); + group->poly[0] = 0; + group->poly[1] = 0; + group->poly[2] = 0; + group->poly[3] = 0; + group->poly[4] = 0; + group->poly[5] = -1; + } + + +/* Copy a GF(2^m)-based EC_GROUP structure. + * Note that all other members are handled by EC_GROUP_copy. + */ +int ec_GF2m_simple_group_copy(EC_GROUP *dest, const EC_GROUP *src) + { + int i; + if (!BN_copy(&dest->field, &src->field)) return 0; + if (!BN_copy(&dest->a, &src->a)) return 0; + if (!BN_copy(&dest->b, &src->b)) return 0; + dest->poly[0] = src->poly[0]; + dest->poly[1] = src->poly[1]; + dest->poly[2] = src->poly[2]; + dest->poly[3] = src->poly[3]; + dest->poly[4] = src->poly[4]; + dest->poly[5] = src->poly[5]; + if (bn_wexpand(&dest->a, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2) == NULL) return 0; + if (bn_wexpand(&dest->b, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2) == NULL) return 0; + for (i = dest->a.top; i < dest->a.dmax; i++) dest->a.d[i] = 0; + for (i = dest->b.top; i < dest->b.dmax; i++) dest->b.d[i] = 0; + return 1; + } + + +/* Set the curve parameters of an EC_GROUP structure. */ +int ec_GF2m_simple_group_set_curve(EC_GROUP *group, + const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) + { + int ret = 0, i; + + /* group->field */ + if (!BN_copy(&group->field, p)) goto err; + i = BN_GF2m_poly2arr(&group->field, group->poly, 6) - 1; + if ((i != 5) && (i != 3)) + { + ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE, EC_R_UNSUPPORTED_FIELD); + goto err; + } + + /* group->a */ + if (!BN_GF2m_mod_arr(&group->a, a, group->poly)) goto err; + if(bn_wexpand(&group->a, (int)(group->poly[0] + BN_BITS2 - 1) / BN_BITS2) == NULL) goto err; + for (i = group->a.top; i < group->a.dmax; i++) group->a.d[i] = 0; + + /* group->b */ + if (!BN_GF2m_mod_arr(&group->b, b, group->poly)) goto err; + if(bn_wexpand(&group->b, (int)(group->poly[0] + BN_BITS2 - 1) / BN_BITS2) == NULL) goto err; + for (i = group->b.top; i < group->b.dmax; i++) group->b.d[i] = 0; + + ret = 1; + err: + return ret; + } + + +/* Get the curve parameters of an EC_GROUP structure. + * If p, a, or b are NULL then there values will not be set but the method will return with success. + */ +int ec_GF2m_simple_group_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b, BN_CTX *ctx) + { + int ret = 0; + + if (p != NULL) + { + if (!BN_copy(p, &group->field)) return 0; + } + + if (a != NULL) + { + if (!BN_copy(a, &group->a)) goto err; + } + + if (b != NULL) + { + if (!BN_copy(b, &group->b)) goto err; + } + + ret = 1; + + err: + return ret; + } + + +/* Gets the degree of the field. For a curve over GF(2^m) this is the value m. */ +int ec_GF2m_simple_group_get_degree(const EC_GROUP *group) + { + return BN_num_bits(&group->field)-1; + } + + +/* Checks the discriminant of the curve. + * y^2 + x*y = x^3 + a*x^2 + b is an elliptic curve <=> b != 0 (mod p) + */ +int ec_GF2m_simple_group_check_discriminant(const EC_GROUP *group, BN_CTX *ctx) + { + int ret = 0; + BIGNUM *b; + BN_CTX *new_ctx = NULL; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + { + ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT, ERR_R_MALLOC_FAILURE); + goto err; + } + } + BN_CTX_start(ctx); + b = BN_CTX_get(ctx); + if (b == NULL) goto err; + + if (!BN_GF2m_mod_arr(b, &group->b, group->poly)) goto err; + + /* check the discriminant: + * y^2 + x*y = x^3 + a*x^2 + b is an elliptic curve <=> b != 0 (mod p) + */ + if (BN_is_zero(b)) goto err; + + ret = 1; + +err: + if (ctx != NULL) + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +/* Initializes an EC_POINT. */ +int ec_GF2m_simple_point_init(EC_POINT *point) + { + BN_init(&point->X); + BN_init(&point->Y); + BN_init(&point->Z); + return 1; + } + + +/* Frees an EC_POINT. */ +void ec_GF2m_simple_point_finish(EC_POINT *point) + { + BN_free(&point->X); + BN_free(&point->Y); + BN_free(&point->Z); + } + + +/* Clears and frees an EC_POINT. */ +void ec_GF2m_simple_point_clear_finish(EC_POINT *point) + { + BN_clear_free(&point->X); + BN_clear_free(&point->Y); + BN_clear_free(&point->Z); + point->Z_is_one = 0; + } + + +/* Copy the contents of one EC_POINT into another. Assumes dest is initialized. */ +int ec_GF2m_simple_point_copy(EC_POINT *dest, const EC_POINT *src) + { + if (!BN_copy(&dest->X, &src->X)) return 0; + if (!BN_copy(&dest->Y, &src->Y)) return 0; + if (!BN_copy(&dest->Z, &src->Z)) return 0; + dest->Z_is_one = src->Z_is_one; + + return 1; + } + + +/* Set an EC_POINT to the point at infinity. + * A point at infinity is represented by having Z=0. + */ +int ec_GF2m_simple_point_set_to_infinity(const EC_GROUP *group, EC_POINT *point) + { + point->Z_is_one = 0; + BN_zero(&point->Z); + return 1; + } + + +/* Set the coordinates of an EC_POINT using affine coordinates. + * Note that the simple implementation only uses affine coordinates. + */ +int ec_GF2m_simple_point_set_affine_coordinates(const EC_GROUP *group, EC_POINT *point, + const BIGNUM *x, const BIGNUM *y, BN_CTX *ctx) + { + int ret = 0; + if (x == NULL || y == NULL) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT_SET_AFFINE_COORDINATES, ERR_R_PASSED_NULL_PARAMETER); + return 0; + } + + if (!BN_copy(&point->X, x)) goto err; + BN_set_negative(&point->X, 0); + if (!BN_copy(&point->Y, y)) goto err; + BN_set_negative(&point->Y, 0); + if (!BN_copy(&point->Z, BN_value_one())) goto err; + BN_set_negative(&point->Z, 0); + point->Z_is_one = 1; + ret = 1; + + err: + return ret; + } + + +/* Gets the affine coordinates of an EC_POINT. + * Note that the simple implementation only uses affine coordinates. + */ +int ec_GF2m_simple_point_get_affine_coordinates(const EC_GROUP *group, const EC_POINT *point, + BIGNUM *x, BIGNUM *y, BN_CTX *ctx) + { + int ret = 0; + + if (EC_POINT_is_at_infinity(group, point)) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES, EC_R_POINT_AT_INFINITY); + return 0; + } + + if (BN_cmp(&point->Z, BN_value_one())) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); + return 0; + } + if (x != NULL) + { + if (!BN_copy(x, &point->X)) goto err; + BN_set_negative(x, 0); + } + if (y != NULL) + { + if (!BN_copy(y, &point->Y)) goto err; + BN_set_negative(y, 0); + } + ret = 1; + + err: + return ret; + } + + +/* Calculates 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. + * + * The method is from the following publication: + * + * Harper, Menezes, Vanstone: + * "Public-Key Cryptosystems with Very Small Key Lengths", + * EUROCRYPT '92, Springer-Verlag LNCS 658, + * published February 1993 + * + * US Patents 6,141,420 and 6,618,483 (Vanstone, Mullin, Agnew) describe + * the same method, but claim no priority date earlier than July 29, 1994 + * (and additionally fail to cite the EUROCRYPT '92 publication as prior art). + */ +int ec_GF2m_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point, + const BIGNUM *x_, int y_bit, BN_CTX *ctx) + { + 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; + } + + +/* Converts an EC_POINT to an octet string. + * If buf is NULL, the encoded length will be returned. + * If the length len of buf is smaller than required an error will be returned. + */ +size_t ec_GF2m_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, point_conversion_form_t form, + unsigned char *buf, size_t len, BN_CTX *ctx) + { + size_t ret; + BN_CTX *new_ctx = NULL; + int used_ctx = 0; + BIGNUM *x, *y, *yxi; + size_t field_len, i, skip; + + if ((form != POINT_CONVERSION_COMPRESSED) + && (form != POINT_CONVERSION_UNCOMPRESSED) + && (form != POINT_CONVERSION_HYBRID)) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_INVALID_FORM); + goto err; + } + + if (EC_POINT_is_at_infinity(group, point)) + { + /* encodes to a single 0 octet */ + if (buf != NULL) + { + if (len < 1) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL); + return 0; + } + buf[0] = 0; + } + return 1; + } + + + /* ret := required output buffer length */ + field_len = (EC_GROUP_get_degree(group) + 7) / 8; + ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len; + + /* if 'buf' is NULL, just return required length */ + if (buf != NULL) + { + if (len < ret) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL); + goto err; + } + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + used_ctx = 1; + x = BN_CTX_get(ctx); + y = BN_CTX_get(ctx); + yxi = BN_CTX_get(ctx); + if (yxi == NULL) goto err; + + if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err; + + buf[0] = form; + if ((form != POINT_CONVERSION_UNCOMPRESSED) && !BN_is_zero(x)) + { + if (!group->meth->field_div(group, yxi, y, x, ctx)) goto err; + if (BN_is_odd(yxi)) buf[0]++; + } + + i = 1; + + skip = field_len - BN_num_bytes(x); + if (skip > field_len) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); + goto err; + } + while (skip > 0) + { + buf[i++] = 0; + skip--; + } + skip = BN_bn2bin(x, buf + i); + i += skip; + if (i != 1 + field_len) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); + goto err; + } + + if (form == POINT_CONVERSION_UNCOMPRESSED || form == POINT_CONVERSION_HYBRID) + { + skip = field_len - BN_num_bytes(y); + if (skip > field_len) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); + goto err; + } + while (skip > 0) + { + buf[i++] = 0; + skip--; + } + skip = BN_bn2bin(y, buf + i); + i += skip; + } + + if (i != ret) + { + ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); + goto err; + } + } + + if (used_ctx) + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + + err: + if (used_ctx) + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return 0; + } + + +/* Converts an octet string representation to an EC_POINT. + * Note that the simple implementation only uses affine coordinates. + */ +int ec_GF2m_simple_oct2point(const EC_GROUP *group, EC_POINT *point, + const unsigned char *buf, size_t len, BN_CTX *ctx) + { + point_conversion_form_t form; + int y_bit; + BN_CTX *new_ctx = NULL; + BIGNUM *x, *y, *yxi; + size_t field_len, enc_len; + int ret = 0; + + if (len == 0) + { + ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL); + return 0; + } + form = buf[0]; + y_bit = form & 1; + form = form & ~1U; + if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED) + && (form != POINT_CONVERSION_UNCOMPRESSED) + && (form != POINT_CONVERSION_HYBRID)) + { + ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + return 0; + } + if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) + { + ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + return 0; + } + + if (form == 0) + { + if (len != 1) + { + ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + return 0; + } + + return EC_POINT_set_to_infinity(group, point); + } + + field_len = (EC_GROUP_get_degree(group) + 7) / 8; + enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len; + + if (len != enc_len) + { + ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + return 0; + } + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + x = BN_CTX_get(ctx); + y = BN_CTX_get(ctx); + yxi = BN_CTX_get(ctx); + if (yxi == NULL) goto err; + + if (!BN_bin2bn(buf + 1, field_len, x)) goto err; + if (BN_ucmp(x, &group->field) >= 0) + { + ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + goto err; + } + + if (form == POINT_CONVERSION_COMPRESSED) + { + if (!EC_POINT_set_compressed_coordinates_GF2m(group, point, x, y_bit, ctx)) goto err; + } + else + { + if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) goto err; + if (BN_ucmp(y, &group->field) >= 0) + { + ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + goto err; + } + if (form == POINT_CONVERSION_HYBRID) + { + if (!group->meth->field_div(group, yxi, y, x, ctx)) goto err; + if (y_bit != BN_is_odd(yxi)) + { + ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + goto err; + } + } + + if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err; + } + + if (!EC_POINT_is_on_curve(group, point, ctx)) /* test required by X9.62 */ + { + ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE); + goto err; + } + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +/* Computes a + b and stores the result in r. r could be a or b, a could be b. + * Uses algorithm A.10.2 of IEEE P1363. + */ +int ec_GF2m_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx) + { + BN_CTX *new_ctx = NULL; + BIGNUM *x0, *y0, *x1, *y1, *x2, *y2, *s, *t; + int ret = 0; + + if (EC_POINT_is_at_infinity(group, a)) + { + if (!EC_POINT_copy(r, b)) return 0; + return 1; + } + + if (EC_POINT_is_at_infinity(group, b)) + { + if (!EC_POINT_copy(r, a)) return 0; + return 1; + } + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + x0 = BN_CTX_get(ctx); + y0 = BN_CTX_get(ctx); + x1 = BN_CTX_get(ctx); + y1 = BN_CTX_get(ctx); + x2 = BN_CTX_get(ctx); + y2 = BN_CTX_get(ctx); + s = BN_CTX_get(ctx); + t = BN_CTX_get(ctx); + if (t == NULL) goto err; + + if (a->Z_is_one) + { + if (!BN_copy(x0, &a->X)) goto err; + if (!BN_copy(y0, &a->Y)) goto err; + } + else + { + if (!EC_POINT_get_affine_coordinates_GF2m(group, a, x0, y0, ctx)) goto err; + } + if (b->Z_is_one) + { + if (!BN_copy(x1, &b->X)) goto err; + if (!BN_copy(y1, &b->Y)) goto err; + } + else + { + if (!EC_POINT_get_affine_coordinates_GF2m(group, b, x1, y1, ctx)) goto err; + } + + + if (BN_GF2m_cmp(x0, x1)) + { + if (!BN_GF2m_add(t, x0, x1)) goto err; + if (!BN_GF2m_add(s, y0, y1)) goto err; + if (!group->meth->field_div(group, s, s, t, ctx)) goto err; + if (!group->meth->field_sqr(group, x2, s, ctx)) goto err; + if (!BN_GF2m_add(x2, x2, &group->a)) goto err; + if (!BN_GF2m_add(x2, x2, s)) goto err; + if (!BN_GF2m_add(x2, x2, t)) goto err; + } + else + { + if (BN_GF2m_cmp(y0, y1) || BN_is_zero(x1)) + { + if (!EC_POINT_set_to_infinity(group, r)) goto err; + ret = 1; + goto err; + } + if (!group->meth->field_div(group, s, y1, x1, ctx)) goto err; + if (!BN_GF2m_add(s, s, x1)) goto err; + + if (!group->meth->field_sqr(group, x2, s, ctx)) goto err; + if (!BN_GF2m_add(x2, x2, s)) goto err; + if (!BN_GF2m_add(x2, x2, &group->a)) goto err; + } + + if (!BN_GF2m_add(y2, x1, x2)) goto err; + if (!group->meth->field_mul(group, y2, y2, s, ctx)) goto err; + if (!BN_GF2m_add(y2, y2, x2)) goto err; + if (!BN_GF2m_add(y2, y2, y1)) goto err; + + if (!EC_POINT_set_affine_coordinates_GF2m(group, r, x2, y2, ctx)) goto err; + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +/* Computes 2 * a and stores the result in r. r could be a. + * Uses algorithm A.10.2 of IEEE P1363. + */ +int ec_GF2m_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, BN_CTX *ctx) + { + return ec_GF2m_simple_add(group, r, a, a, ctx); + } + + +int ec_GF2m_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx) + { + if (EC_POINT_is_at_infinity(group, point) || BN_is_zero(&point->Y)) + /* point is its own inverse */ + return 1; + + if (!EC_POINT_make_affine(group, point, ctx)) return 0; + return BN_GF2m_add(&point->Y, &point->X, &point->Y); + } + + +/* Indicates whether the given point is the point at infinity. */ +int ec_GF2m_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point) + { + return BN_is_zero(&point->Z); + } + + +/* Determines whether the given EC_POINT is an actual point on the curve defined + * in the EC_GROUP. A point is valid if it satisfies the Weierstrass equation: + * y^2 + x*y = x^3 + a*x^2 + b. + */ +int ec_GF2m_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx) + { + int ret = -1; + BN_CTX *new_ctx = NULL; + BIGNUM *lh, *y2; + int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *); + int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); + + if (EC_POINT_is_at_infinity(group, point)) + return 1; + + field_mul = group->meth->field_mul; + field_sqr = group->meth->field_sqr; + + /* only support affine coordinates */ + if (!point->Z_is_one) goto err; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return -1; + } + + BN_CTX_start(ctx); + y2 = BN_CTX_get(ctx); + lh = BN_CTX_get(ctx); + if (lh == NULL) goto err; + + /* We have a curve defined by a Weierstrass equation + * y^2 + x*y = x^3 + a*x^2 + b. + * <=> x^3 + a*x^2 + x*y + b + y^2 = 0 + * <=> ((x + a) * x + y ) * x + b + y^2 = 0 + */ + if (!BN_GF2m_add(lh, &point->X, &group->a)) goto err; + if (!field_mul(group, lh, lh, &point->X, ctx)) goto err; + if (!BN_GF2m_add(lh, lh, &point->Y)) goto err; + if (!field_mul(group, lh, lh, &point->X, ctx)) goto err; + if (!BN_GF2m_add(lh, lh, &group->b)) goto err; + if (!field_sqr(group, y2, &point->Y, ctx)) goto err; + if (!BN_GF2m_add(lh, lh, y2)) goto err; + ret = BN_is_zero(lh); + err: + if (ctx) BN_CTX_end(ctx); + if (new_ctx) BN_CTX_free(new_ctx); + return ret; + } + + +/* Indicates whether two points are equal. + * Return values: + * -1 error + * 0 equal (in affine coordinates) + * 1 not equal + */ +int ec_GF2m_simple_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx) + { + BIGNUM *aX, *aY, *bX, *bY; + BN_CTX *new_ctx = NULL; + int ret = -1; + + if (EC_POINT_is_at_infinity(group, a)) + { + return EC_POINT_is_at_infinity(group, b) ? 0 : 1; + } + + if (EC_POINT_is_at_infinity(group, b)) + return 1; + + if (a->Z_is_one && b->Z_is_one) + { + return ((BN_cmp(&a->X, &b->X) == 0) && BN_cmp(&a->Y, &b->Y) == 0) ? 0 : 1; + } + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return -1; + } + + BN_CTX_start(ctx); + aX = BN_CTX_get(ctx); + aY = BN_CTX_get(ctx); + bX = BN_CTX_get(ctx); + bY = BN_CTX_get(ctx); + if (bY == NULL) goto err; + + if (!EC_POINT_get_affine_coordinates_GF2m(group, a, aX, aY, ctx)) goto err; + if (!EC_POINT_get_affine_coordinates_GF2m(group, b, bX, bY, ctx)) goto err; + ret = ((BN_cmp(aX, bX) == 0) && BN_cmp(aY, bY) == 0) ? 0 : 1; + + err: + if (ctx) BN_CTX_end(ctx); + if (new_ctx) BN_CTX_free(new_ctx); + return ret; + } + + +/* Forces the given EC_POINT to internally use affine coordinates. */ +int ec_GF2m_simple_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx) + { + BN_CTX *new_ctx = NULL; + BIGNUM *x, *y; + int ret = 0; + + if (point->Z_is_one || EC_POINT_is_at_infinity(group, point)) + return 1; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + x = BN_CTX_get(ctx); + y = BN_CTX_get(ctx); + if (y == NULL) goto err; + + if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err; + if (!BN_copy(&point->X, x)) goto err; + if (!BN_copy(&point->Y, y)) goto err; + if (!BN_one(&point->Z)) goto err; + + ret = 1; + + err: + if (ctx) BN_CTX_end(ctx); + if (new_ctx) BN_CTX_free(new_ctx); + return ret; + } + + +/* Forces each of the EC_POINTs in the given array to use affine coordinates. */ +int ec_GF2m_simple_points_make_affine(const EC_GROUP *group, size_t num, EC_POINT *points[], BN_CTX *ctx) + { + size_t i; + + for (i = 0; i < num; i++) + { + if (!group->meth->make_affine(group, points[i], ctx)) return 0; + } + + return 1; + } + + +/* Wrapper to simple binary polynomial field multiplication implementation. */ +int ec_GF2m_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) + { + return BN_GF2m_mod_mul_arr(r, a, b, group->poly, ctx); + } + + +/* Wrapper to simple binary polynomial field squaring implementation. */ +int ec_GF2m_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) + { + return BN_GF2m_mod_sqr_arr(r, a, group->poly, ctx); + } + + +/* Wrapper to simple binary polynomial field division implementation. */ +int ec_GF2m_simple_field_div(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) + { + return BN_GF2m_mod_div(r, a, b, &group->field, ctx); + } |