diff options
Diffstat (limited to 'src/crypto/ec/oct.c')
| -rw-r--r-- | src/crypto/ec/oct.c | 476 |
1 files changed, 476 insertions, 0 deletions
diff --git a/src/crypto/ec/oct.c b/src/crypto/ec/oct.c new file mode 100644 index 0000000..c4729ef --- /dev/null +++ b/src/crypto/ec/oct.c @@ -0,0 +1,476 @@ +/* Originally written by Bodo Moeller for the OpenSSL project. + * ==================================================================== + * 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). + * + */ +/* ==================================================================== + * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED. + * + * Portions of the attached software ("Contribution") are developed by + * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project. + * + * The Contribution is licensed pursuant to the OpenSSL open source + * license provided above. + * + * The elliptic curve binary polynomial software is originally written by + * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems + * Laboratories. */ + +#include <openssl/ec.h> + +#include <openssl/bn.h> +#include <openssl/err.h> + +#include "internal.h" + + +static size_t ec_GFp_simple_point2oct(const EC_GROUP *group, + const EC_POINT *point, + point_conversion_form_t form, + uint8_t *buf, size_t len, BN_CTX *ctx) { + size_t ret; + BN_CTX *new_ctx = NULL; + int used_ctx = 0; + BIGNUM *x, *y; + size_t field_len, i; + + if ((form != POINT_CONVERSION_COMPRESSED) && + (form != POINT_CONVERSION_UNCOMPRESSED)) { + OPENSSL_PUT_ERROR(EC, ec_GFp_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) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_point2oct, EC_R_BUFFER_TOO_SMALL); + return 0; + } + buf[0] = 0; + } + return 1; + } + + + /* ret := required output buffer length */ + field_len = BN_num_bytes(&group->field); + 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) { + OPENSSL_PUT_ERROR(EC, ec_GFp_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); + if (y == NULL) { + goto err; + } + + if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) { + goto err; + } + + if ((form == POINT_CONVERSION_COMPRESSED) && + BN_is_odd(y)) { + buf[0] = form + 1; + } else { + buf[0] = form; + } + i = 1; + + if (!BN_bn2bin_padded(buf + i, field_len, x)) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_point2oct, ERR_R_INTERNAL_ERROR); + goto err; + } + i += field_len; + + if (form == POINT_CONVERSION_UNCOMPRESSED) { + if (!BN_bn2bin_padded(buf + i, field_len, y)) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_point2oct, ERR_R_INTERNAL_ERROR); + goto err; + } + i += field_len; + } + + if (i != ret) { + OPENSSL_PUT_ERROR(EC, ec_GFp_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; +} + + +static int ec_GFp_simple_oct2point(const EC_GROUP *group, EC_POINT *point, + const uint8_t *buf, size_t len, + BN_CTX *ctx) { + point_conversion_form_t form; + int y_bit; + BN_CTX *new_ctx = NULL; + BIGNUM *x, *y; + size_t field_len, enc_len; + int ret = 0; + + if (len == 0) { + OPENSSL_PUT_ERROR(EC, ec_GFp_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)) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_oct2point, EC_R_INVALID_ENCODING); + return 0; + } + if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_oct2point, EC_R_INVALID_ENCODING); + return 0; + } + + if (form == 0) { + if (len != 1) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_oct2point, EC_R_INVALID_ENCODING); + return 0; + } + + return EC_POINT_set_to_infinity(group, point); + } + + field_len = BN_num_bytes(&group->field); + enc_len = + (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len; + + if (len != enc_len) { + OPENSSL_PUT_ERROR(EC, ec_GFp_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); + if (y == NULL) + goto err; + + if (!BN_bin2bn(buf + 1, field_len, x)) + goto err; + if (BN_ucmp(x, &group->field) >= 0) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_oct2point, EC_R_INVALID_ENCODING); + goto err; + } + + if (form == POINT_CONVERSION_COMPRESSED) { + if (!EC_POINT_set_compressed_coordinates_GFp(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) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_oct2point, EC_R_INVALID_ENCODING); + goto err; + } + + if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) + goto err; + } + + if (!EC_POINT_is_on_curve(group, point, ctx)) /* test required by X9.62 */ + { + OPENSSL_PUT_ERROR(EC, ec_GFp_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; +} + +int EC_POINT_oct2point(const EC_GROUP *group, EC_POINT *point, + const uint8_t *buf, size_t len, BN_CTX *ctx) { + if (group->meth->oct2point == 0 && + !(group->meth->flags & EC_FLAGS_DEFAULT_OCT)) { + OPENSSL_PUT_ERROR(EC, EC_POINT_oct2point, + ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); + return 0; + } + if (group->meth != point->meth) { + OPENSSL_PUT_ERROR(EC, EC_POINT_oct2point, EC_R_INCOMPATIBLE_OBJECTS); + return 0; + } + if (group->meth->flags & EC_FLAGS_DEFAULT_OCT) { + return ec_GFp_simple_oct2point(group, point, buf, len, ctx); + } + + return group->meth->oct2point(group, point, buf, len, ctx); +} + +size_t EC_POINT_point2oct(const EC_GROUP *group, const EC_POINT *point, + point_conversion_form_t form, uint8_t *buf, + size_t len, BN_CTX *ctx) { + if (group->meth->point2oct == 0 && + !(group->meth->flags & EC_FLAGS_DEFAULT_OCT)) { + OPENSSL_PUT_ERROR(EC, EC_POINT_point2oct, + ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); + return 0; + } + if (group->meth != point->meth) { + OPENSSL_PUT_ERROR(EC, EC_POINT_point2oct, EC_R_INCOMPATIBLE_OBJECTS); + return 0; + } + if (group->meth->flags & EC_FLAGS_DEFAULT_OCT) { + return ec_GFp_simple_point2oct(group, point, form, buf, len, ctx); + } + + return group->meth->point2oct(group, point, form, buf, len, ctx); +} + +int ec_GFp_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 *tmp1, *tmp2, *x, *y; + int ret = 0; + + ERR_clear_error(); + + if (ctx == NULL) { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) { + return 0; + } + } + + y_bit = (y_bit != 0); + + BN_CTX_start(ctx); + tmp1 = BN_CTX_get(ctx); + tmp2 = BN_CTX_get(ctx); + x = BN_CTX_get(ctx); + y = BN_CTX_get(ctx); + if (y == NULL) { + goto err; + } + + /* Recover y. We have a Weierstrass equation + * y^2 = x^3 + a*x + b, + * so y is one of the square roots of x^3 + a*x + b. */ + + /* tmp1 := x^3 */ + if (!BN_nnmod(x, x_, &group->field, ctx)) { + goto err; + } + + if (group->meth->field_decode == 0) { + /* field_{sqr,mul} work on standard representation */ + if (!group->meth->field_sqr(group, tmp2, x_, ctx) || + !group->meth->field_mul(group, tmp1, tmp2, x_, ctx)) { + goto err; + } + } else { + if (!BN_mod_sqr(tmp2, x_, &group->field, ctx) || + !BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx)) { + goto err; + } + } + + /* tmp1 := tmp1 + a*x */ + if (group->a_is_minus3) { + if (!BN_mod_lshift1_quick(tmp2, x, &group->field) || + !BN_mod_add_quick(tmp2, tmp2, x, &group->field) || + !BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) { + goto err; + } + } else { + if (group->meth->field_decode) { + if (!group->meth->field_decode(group, tmp2, &group->a, ctx) || + !BN_mod_mul(tmp2, tmp2, x, &group->field, ctx)) { + goto err; + } + } else { + /* field_mul works on standard representation */ + if (!group->meth->field_mul(group, tmp2, &group->a, x, ctx)) { + goto err; + } + } + + if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) { + goto err; + } + } + + /* tmp1 := tmp1 + b */ + if (group->meth->field_decode) { + if (!group->meth->field_decode(group, tmp2, &group->b, ctx) || + !BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) { + goto err; + } + } else { + if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field)) { + goto err; + } + } + + if (!BN_mod_sqrt(y, tmp1, &group->field, ctx)) { + unsigned long err = ERR_peek_last_error(); + + if (ERR_GET_LIB(err) == ERR_LIB_BN && + ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) { + ERR_clear_error(); + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_set_compressed_coordinates, EC_R_INVALID_COMPRESSED_POINT); + } else { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_set_compressed_coordinates, ERR_R_BN_LIB); + } + goto err; + } + + if (y_bit != BN_is_odd(y)) { + if (BN_is_zero(y)) { + int kron; + + kron = BN_kronecker(x, &group->field, ctx); + if (kron == -2) { + goto err; + } + + if (kron == 1) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_set_compressed_coordinates, + EC_R_INVALID_COMPRESSION_BIT); + } else { + /* BN_mod_sqrt() should have cought this error (not a square) */ + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_set_compressed_coordinates, + EC_R_INVALID_COMPRESSED_POINT); + } + goto err; + } + if (!BN_usub(y, &group->field, y)) { + goto err; + } + } + if (y_bit != BN_is_odd(y)) { + OPENSSL_PUT_ERROR(EC, ec_GFp_simple_set_compressed_coordinates, + ERR_R_INTERNAL_ERROR); + goto err; + } + + if (!EC_POINT_set_affine_coordinates_GFp(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; +} + +int EC_POINT_set_compressed_coordinates_GFp(const EC_GROUP *group, + EC_POINT *point, const BIGNUM *x, + int y_bit, BN_CTX *ctx) { + if (group->meth->point_set_compressed_coordinates == 0 && + !(group->meth->flags & EC_FLAGS_DEFAULT_OCT)) { + OPENSSL_PUT_ERROR(EC, EC_POINT_set_compressed_coordinates_GFp, + ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); + return 0; + } + if (group->meth != point->meth) { + OPENSSL_PUT_ERROR(EC, EC_POINT_set_compressed_coordinates_GFp, + EC_R_INCOMPATIBLE_OBJECTS); + return 0; + } + if (group->meth->flags & EC_FLAGS_DEFAULT_OCT) { + return ec_GFp_simple_set_compressed_coordinates(group, point, x, y_bit, + ctx); + } + return group->meth->point_set_compressed_coordinates(group, point, x, y_bit, + ctx); +} |