2 * Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 #include "internal/ffc.h"
13 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation.
14 * To only be used with ephemeral FFC public keys generated using the approved
15 * safe-prime groups. (Checks that the public key is in the range [2, p - 1]
17 * ret contains 0 on success, or error flags (see FFC_ERROR_PUBKEY_TOO_SMALL)
19 int ffc_validate_public_key_partial(const FFC_PARAMS *params,
20 const BIGNUM *pub_key, int *ret)
27 ctx = BN_CTX_new_ex(NULL);
32 tmp = BN_CTX_get(ctx);
33 /* Step(1): Verify pub_key >= 2 */
35 || !BN_set_word(tmp, 1))
37 if (BN_cmp(pub_key, tmp) <= 0) {
38 *ret |= FFC_ERROR_PUBKEY_TOO_SMALL;
41 /* Step(1): Verify pub_key <= p-2 */
42 if (BN_copy(tmp, params->p) == NULL
43 || !BN_sub_word(tmp, 1))
45 if (BN_cmp(pub_key, tmp) >= 0) {
46 *ret |= FFC_ERROR_PUBKEY_TOO_LARGE;
59 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
61 int ffc_validate_public_key(const FFC_PARAMS *params, const BIGNUM *pub_key,
68 if (!ffc_validate_public_key_partial(params, pub_key, ret))
71 if (params->q != NULL) {
72 ctx = BN_CTX_new_ex(NULL);
76 tmp = BN_CTX_get(ctx);
78 /* Check pub_key^q == 1 mod p */
80 || !BN_mod_exp(tmp, pub_key, params->q, params->p, ctx))
82 if (!BN_is_one(tmp)) {
83 *ret |= FFC_ERROR_PUBKEY_INVALID;
98 * See SP800-56Ar3 Section 5.6.2.1.2: Owner assurance of Private key validity.
99 * Verifies priv_key is in the range [1..upper-1]. The passed in value of upper
100 * is normally params->q but can be 2^N for approved safe prime groups.
101 * Note: This assumes that the domain parameters are valid.
103 int ffc_validate_private_key(const BIGNUM *upper, const BIGNUM *priv, int *ret)
109 if (BN_cmp(priv, BN_value_one()) < 0) {
110 *ret |= FFC_ERROR_PRIVKEY_TOO_SMALL;
113 if (BN_cmp(priv, upper) >= 0) {
114 *ret |= FFC_ERROR_PRIVKEY_TOO_LARGE;