b4d6121d85292df531db39142e3a3c9c69b84b40
[libav.git] / libavformat / rtmpdh.h
1 /*
2 * RTMP Diffie-Hellmann utilities
3 * Copyright (c) 2012 Samuel Pitoiset
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #ifndef AVFORMAT_RTMPDH_H
23 #define AVFORMAT_RTMPDH_H
24
25 #include <stdint.h>
26
27 #include "config.h"
28
29 #if CONFIG_GMP
30 #include <gmp.h>
31
32 typedef mpz_ptr FFBigNum;
33 #elif CONFIG_OPENSSL
34 #include <openssl/bn.h>
35 #include <openssl/dh.h>
36
37 typedef BIGNUM *FFBigNum;
38 #endif
39
40 typedef struct FF_DH {
41 FFBigNum p;
42 FFBigNum g;
43 FFBigNum pub_key;
44 FFBigNum priv_key;
45 long length;
46 } FF_DH;
47
48
49 /**
50 * Initialize a Diffie-Hellmann context.
51 *
52 * @param key_len length of the key
53 * @return a new Diffie-Hellmann context on success, NULL otherwise
54 */
55 FF_DH *ff_dh_init(int key_len);
56
57 /**
58 * Free a Diffie-Hellmann context.
59 *
60 * @param dh a Diffie-Hellmann context to free
61 */
62 void ff_dh_free(FF_DH *dh);
63
64 /**
65 * Generate a public key.
66 *
67 * @param dh a Diffie-Hellmann context
68 * @return zero on success, negative value otherwise
69 */
70 int ff_dh_generate_public_key(FF_DH *dh);
71
72 /**
73 * Write the public key into the given buffer.
74 *
75 * @param dh a Diffie-Hellmann context, containing the public key to write
76 * @param pub_key the buffer where the public key is written
77 * @param pub_key_len the length of the buffer
78 * @return zero on success, negative value otherwise
79 */
80 int ff_dh_write_public_key(FF_DH *dh, uint8_t *pub_key, int pub_key_len);
81
82 /**
83 * Compute the shared secret key from the private FF_DH value and the
84 * other party's public value.
85 *
86 * @param dh a Diffie-Hellmann context, containing the private key
87 * @param pub_key the buffer containing the public key
88 * @param pub_key_len the length of the public key buffer
89 * @param secret_key the buffer where the secret key is written
90 * @param secret_key_len the length of the secret key buffer
91 * @return length of the shared secret key on success, negative value otherwise
92 */
93 int ff_dh_compute_shared_secret_key(FF_DH *dh, const uint8_t *pub_key,
94 int pub_key_len, uint8_t *secret_key,
95 int secret_key_len);
96
97 #endif /* AVFORMAT_RTMPDH_H */