FFmpeg
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 #elif CONFIG_MBEDTLS
44 #include <mbedtls/bignum.h>
45 
46 typedef mbedtls_mpi *FFBigNum;
47 
48 #endif
49 
50 typedef struct FF_DH {
51  FFBigNum p;
52  FFBigNum g;
53  FFBigNum pub_key;
54  FFBigNum priv_key;
55  long length;
56 } FF_DH;
57 
58 
59 /**
60  * Initialize a Diffie-Hellmann context.
61  *
62  * @param key_len length of the key
63  * @return a new Diffie-Hellmann context on success, NULL otherwise
64  */
65 FF_DH *ff_dh_init(int key_len);
66 
67 /**
68  * Free a Diffie-Hellmann context.
69  *
70  * @param dh a Diffie-Hellmann context to free
71  */
72 void ff_dh_free(FF_DH *dh);
73 
74 /**
75  * Generate a public key.
76  *
77  * @param dh a Diffie-Hellmann context
78  * @return zero on success, negative value otherwise
79  */
81 
82 /**
83  * Write the public key into the given buffer.
84  *
85  * @param dh a Diffie-Hellmann context, containing the public key to write
86  * @param pub_key the buffer where the public key is written
87  * @param pub_key_len the length of the buffer
88  * @return zero on success, negative value otherwise
89  */
90 int ff_dh_write_public_key(FF_DH *dh, uint8_t *pub_key, int pub_key_len);
91 
92 /**
93  * Compute the shared secret key from the private FF_DH value and the
94  * other party's public value.
95  *
96  * @param dh a Diffie-Hellmann context, containing the private key
97  * @param pub_key the buffer containing the public key
98  * @param pub_key_len the length of the public key buffer
99  * @param secret_key the buffer where the secret key is written
100  * @param secret_key_len the length of the secret key buffer
101  * @return length of the shared secret key on success, negative value otherwise
102  */
104  int pub_key_len, uint8_t *secret_key,
105  int secret_key_len);
106 
107 #endif /* AVFORMAT_RTMPDH_H */
Definition: rtmpdh.h:50
FFBigNum priv_key
Definition: rtmpdh.h:54
uint8_t
FFBigNum p
Definition: rtmpdh.h:51
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&#39;s public value...
Definition: rtmpdh.c:390
void ff_dh_free(FF_DH *dh)
Free a Diffie-Hellmann context.
Definition: rtmpdh.c:269
FFBigNum g
Definition: rtmpdh.h:52
FF_DH * ff_dh_init(int key_len)
Initialize a Diffie-Hellmann context.
Definition: rtmpdh.c:321
long length
Definition: rtmpdh.h:55
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:374
int ff_dh_generate_public_key(FF_DH *dh)
Generate a public key.
Definition: rtmpdh.c:348
FFBigNum pub_key
Definition: rtmpdh.h:53