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rtmpdh.h
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1 /*
2  * RTMP Diffie-Hellmann utilities
3  * Copyright (c) 2012 Samuel Pitoiset
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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_GCRYPT
34 #include <gcrypt.h>
35 
36 typedef gcry_mpi_t FFBigNum;
37 
38 #elif CONFIG_OPENSSL
39 #include <openssl/bn.h>
40 #include <openssl/dh.h>
41 
42 typedef BIGNUM *FFBigNum;
43 #endif
44 
45 typedef struct FF_DH {
46  FFBigNum p;
47  FFBigNum g;
48  FFBigNum pub_key;
49  FFBigNum priv_key;
50  long length;
51 } FF_DH;
52 
53 
54 /**
55  * Initialize a Diffie-Hellmann context.
56  *
57  * @param key_len length of the key
58  * @return a new Diffie-Hellmann context on success, NULL otherwise
59  */
60 FF_DH *ff_dh_init(int key_len);
61 
62 /**
63  * Free a Diffie-Hellmann context.
64  *
65  * @param dh a Diffie-Hellmann context to free
66  */
67 void ff_dh_free(FF_DH *dh);
68 
69 /**
70  * Generate a public key.
71  *
72  * @param dh a Diffie-Hellmann context
73  * @return zero on success, negative value otherwise
74  */
76 
77 /**
78  * Write the public key into the given buffer.
79  *
80  * @param dh a Diffie-Hellmann context, containing the public key to write
81  * @param pub_key the buffer where the public key is written
82  * @param pub_key_len the length of the buffer
83  * @return zero on success, negative value otherwise
84  */
85 int ff_dh_write_public_key(FF_DH *dh, uint8_t *pub_key, int pub_key_len);
86 
87 /**
88  * Compute the shared secret key from the private FF_DH value and the
89  * other party's public value.
90  *
91  * @param dh a Diffie-Hellmann context, containing the private key
92  * @param pub_key the buffer containing the public key
93  * @param pub_key_len the length of the public key buffer
94  * @param secret_key the buffer where the secret key is written
95  * @param secret_key_len the length of the secret key buffer
96  * @return length of the shared secret key on success, negative value otherwise
97  */
98 int ff_dh_compute_shared_secret_key(FF_DH *dh, const uint8_t *pub_key,
99  int pub_key_len, uint8_t *secret_key,
100  int secret_key_len);
101 
102 #endif /* AVFORMAT_RTMPDH_H */
Definition: rtmpdh.h:45
FFBigNum priv_key
Definition: rtmpdh.h:49
uint8_t
FFBigNum p
Definition: rtmpdh.h:46
int ff_dh_compute_shared_secret_key(FF_DH *dh, const uint8_t *pub_key, int pub_key_len, uint8_t *secret_key, int secret_key_len)
Compute the shared secret key from the private FF_DH value and the other party's public value...
Definition: rtmpdh.c:335
void ff_dh_free(FF_DH *dh)
Free a Diffie-Hellmann context.
Definition: rtmpdh.c:214
FFBigNum g
Definition: rtmpdh.h:47
FF_DH * ff_dh_init(int key_len)
Initialize a Diffie-Hellmann context.
Definition: rtmpdh.c:266
long length
Definition: rtmpdh.h:50
int ff_dh_write_public_key(FF_DH *dh, uint8_t *pub_key, int pub_key_len)
Write the public key into the given buffer.
Definition: rtmpdh.c:319
int ff_dh_generate_public_key(FF_DH *dh)
Generate a public key.
Definition: rtmpdh.c:293
FFBigNum pub_key
Definition: rtmpdh.h:48