1/*
2 * Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
3 *
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
8 */
9
10#include <openssl/dh.h>
11#include "internal/refcount.h"
12#include "internal/ffc.h"
13
14#define DH_MIN_MODULUS_BITS     512
15
16struct dh_st {
17    /*
18     * This first argument is used to pick up errors when a DH is passed
19     * instead of a EVP_PKEY
20     */
21    int pad;
22    int version;
23    FFC_PARAMS params;
24    /* max generated private key length (can be less than len(q)) */
25    int32_t length;
26    BIGNUM *pub_key;            /* g^x % p */
27    BIGNUM *priv_key;           /* x */
28    int flags;
29    BN_MONT_CTX *method_mont_p;
30    CRYPTO_REF_COUNT references;
31#ifndef FIPS_MODULE
32    CRYPTO_EX_DATA ex_data;
33    ENGINE *engine;
34#endif
35    OSSL_LIB_CTX *libctx;
36    const DH_METHOD *meth;
37    CRYPTO_RWLOCK *lock;
38
39    /* Provider data */
40    size_t dirty_cnt; /* If any key material changes, increment this */
41};
42
43struct dh_method {
44    char *name;
45    /* Methods here */
46    int (*generate_key) (DH *dh);
47    int (*compute_key) (unsigned char *key, const BIGNUM *pub_key, DH *dh);
48
49    /* Can be null */
50    int (*bn_mod_exp) (const DH *dh, BIGNUM *r, const BIGNUM *a,
51                       const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx,
52                       BN_MONT_CTX *m_ctx);
53    int (*init) (DH *dh);
54    int (*finish) (DH *dh);
55    int flags;
56    char *app_data;
57    /* If this is non-NULL, it will be used to generate parameters */
58    int (*generate_params) (DH *dh, int prime_len, int generator,
59                            BN_GENCB *cb);
60};
61