diff options
Diffstat (limited to 'openssl-1.1.0h/crypto/ec/ec2_oct.c')
| -rw-r--r-- | openssl-1.1.0h/crypto/ec/ec2_oct.c | 352 |
1 files changed, 352 insertions, 0 deletions
diff --git a/openssl-1.1.0h/crypto/ec/ec2_oct.c b/openssl-1.1.0h/crypto/ec/ec2_oct.c new file mode 100644 index 0000000..ea88ce8 --- /dev/null +++ b/openssl-1.1.0h/crypto/ec/ec2_oct.c @@ -0,0 +1,352 @@ +/* + * Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the OpenSSL license (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +/* ==================================================================== + * 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. + * + */ + +#include <openssl/err.h> + +#include "ec_lcl.h" + +#ifndef OPENSSL_NO_EC2M + +/*- + * 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); + 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); + BN_CTX_free(new_ctx); + return ret; + + err: + if (used_ctx) + BN_CTX_end(ctx); + 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; + } + } + + /* + * EC_POINT_set_affine_coordinates_GF2m is responsible for checking that + * the point is on the curve. + */ + if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx)) + goto err; + } + + ret = 1; + + err: + BN_CTX_end(ctx); + BN_CTX_free(new_ctx); + return ret; +} +#endif |