/* * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved. * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved * * Licensed under the Apache License 2.0 (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 */ #include #include "ec_lcl.h" const EC_METHOD *EC_GFp_mont_method(void) { static const EC_METHOD ret = { EC_FLAGS_DEFAULT_OCT, NID_X9_62_prime_field, ec_GFp_mont_group_init, ec_GFp_mont_group_finish, ec_GFp_mont_group_clear_finish, ec_GFp_mont_group_copy, ec_GFp_mont_group_set_curve, ec_GFp_simple_group_get_curve, ec_GFp_simple_group_get_degree, ec_group_simple_order_bits, ec_GFp_simple_group_check_discriminant, ec_GFp_simple_point_init, ec_GFp_simple_point_finish, ec_GFp_simple_point_clear_finish, ec_GFp_simple_point_copy, ec_GFp_simple_point_set_to_infinity, ec_GFp_simple_set_Jprojective_coordinates_GFp, ec_GFp_simple_get_Jprojective_coordinates_GFp, ec_GFp_simple_point_set_affine_coordinates, ec_GFp_simple_point_get_affine_coordinates, 0, 0, 0, ec_GFp_simple_add, ec_GFp_simple_dbl, ec_GFp_simple_invert, ec_GFp_simple_is_at_infinity, ec_GFp_simple_is_on_curve, ec_GFp_simple_cmp, ec_GFp_simple_make_affine, ec_GFp_simple_points_make_affine, 0 /* mul */ , 0 /* precompute_mult */ , 0 /* have_precompute_mult */ , ec_GFp_mont_field_mul, ec_GFp_mont_field_sqr, 0 /* field_div */ , ec_GFp_mont_field_inv, ec_GFp_mont_field_encode, ec_GFp_mont_field_decode, ec_GFp_mont_field_set_to_one, ec_key_simple_priv2oct, ec_key_simple_oct2priv, 0, /* set private */ ec_key_simple_generate_key, ec_key_simple_check_key, ec_key_simple_generate_public_key, 0, /* keycopy */ 0, /* keyfinish */ ecdh_simple_compute_key, 0, /* field_inverse_mod_ord */ ec_GFp_simple_blind_coordinates, ec_GFp_simple_ladder_pre, ec_GFp_simple_ladder_step, ec_GFp_simple_ladder_post }; return &ret; } int ec_GFp_mont_group_init(EC_GROUP *group) { int ok; ok = ec_GFp_simple_group_init(group); group->field_data1 = NULL; group->field_data2 = NULL; return ok; } void ec_GFp_mont_group_finish(EC_GROUP *group) { BN_MONT_CTX_free(group->field_data1); group->field_data1 = NULL; BN_free(group->field_data2); group->field_data2 = NULL; ec_GFp_simple_group_finish(group); } void ec_GFp_mont_group_clear_finish(EC_GROUP *group) { BN_MONT_CTX_free(group->field_data1); group->field_data1 = NULL; BN_clear_free(group->field_data2); group->field_data2 = NULL; ec_GFp_simple_group_clear_finish(group); } int ec_GFp_mont_group_copy(EC_GROUP *dest, const EC_GROUP *src) { BN_MONT_CTX_free(dest->field_data1); dest->field_data1 = NULL; BN_clear_free(dest->field_data2); dest->field_data2 = NULL; if (!ec_GFp_simple_group_copy(dest, src)) return 0; if (src->field_data1 != NULL) { dest->field_data1 = BN_MONT_CTX_new(); if (dest->field_data1 == NULL) return 0; if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1)) goto err; } if (src->field_data2 != NULL) { dest->field_data2 = BN_dup(src->field_data2); if (dest->field_data2 == NULL) goto err; } return 1; err: BN_MONT_CTX_free(dest->field_data1); dest->field_data1 = NULL; return 0; } int ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) { BN_CTX *new_ctx = NULL; BN_MONT_CTX *mont = NULL; BIGNUM *one = NULL; int ret = 0; BN_MONT_CTX_free(group->field_data1); group->field_data1 = NULL; BN_free(group->field_data2); group->field_data2 = NULL; if (ctx == NULL) { ctx = new_ctx = BN_CTX_new(); if (ctx == NULL) return 0; } mont = BN_MONT_CTX_new(); if (mont == NULL) goto err; if (!BN_MONT_CTX_set(mont, p, ctx)) { ECerr(EC_F_EC_GFP_MONT_GROUP_SET_CURVE, ERR_R_BN_LIB); goto err; } one = BN_new(); if (one == NULL) goto err; if (!BN_to_montgomery(one, BN_value_one(), mont, ctx)) goto err; group->field_data1 = mont; mont = NULL; group->field_data2 = one; one = NULL; ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx); if (!ret) { BN_MONT_CTX_free(group->field_data1); group->field_data1 = NULL; BN_free(group->field_data2); group->field_data2 = NULL; } err: BN_free(one); BN_CTX_free(new_ctx); BN_MONT_CTX_free(mont); return ret; } int ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) { if (group->field_data1 == NULL) { ECerr(EC_F_EC_GFP_MONT_FIELD_MUL, EC_R_NOT_INITIALIZED); return 0; } return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx); } int ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) { if (group->field_data1 == NULL) { ECerr(EC_F_EC_GFP_MONT_FIELD_SQR, EC_R_NOT_INITIALIZED); return 0; } return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx); } /*- * Computes the multiplicative inverse of a in GF(p), storing the result in r. * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error. * We have a Mont structure, so SCA hardening is FLT inversion. */ int ec_GFp_mont_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) { BIGNUM *e = NULL; BN_CTX *new_ctx = NULL; int ret = 0; if (group->field_data1 == NULL) return 0; if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL) return 0; BN_CTX_start(ctx); if ((e = BN_CTX_get(ctx)) == NULL) goto err; /* Inverse in constant time with Fermats Little Theorem */ if (!BN_set_word(e, 2)) goto err; if (!BN_sub(e, group->field, e)) goto err; /*- * Exponent e is public. * No need for scatter-gather or BN_FLG_CONSTTIME. */ if (!BN_mod_exp_mont(r, a, e, group->field, ctx, group->field_data1)) goto err; /* throw an error on zero */ if (BN_is_zero(r)) { ECerr(EC_F_EC_GFP_MONT_FIELD_INV, EC_R_CANNOT_INVERT); goto err; } ret = 1; err: BN_CTX_end(ctx); BN_CTX_free(new_ctx); return ret; } int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) { if (group->field_data1 == NULL) { ECerr(EC_F_EC_GFP_MONT_FIELD_ENCODE, EC_R_NOT_INITIALIZED); return 0; } return BN_to_montgomery(r, a, (BN_MONT_CTX *)group->field_data1, ctx); } int ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) { if (group->field_data1 == NULL) { ECerr(EC_F_EC_GFP_MONT_FIELD_DECODE, EC_R_NOT_INITIALIZED); return 0; } return BN_from_montgomery(r, a, group->field_data1, ctx); } int ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r, BN_CTX *ctx) { if (group->field_data2 == NULL) { ECerr(EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE, EC_R_NOT_INITIALIZED); return 0; } if (!BN_copy(r, group->field_data2)) return 0; return 1; }