ffmpeg/libavformat/rtmpdh.h

   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 "avformat.h"
  26 #include "config.h"
  27
  28 #if CONFIG_NETTLE || CONFIG_GCRYPT
  29 #if CONFIG_NETTLE
  30 #include <gmp.h>
  31 #include <nettle/bignum.h>
  32
  33 typedef mpz_ptr FFBigNum;
  34 #elif CONFIG_GCRYPT
  35 #include <gcrypt.h>
  36
  37 typedef gcry_mpi_t 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 #elif CONFIG_OPENSSL
  49 #include <openssl/bn.h>
  50 #include <openssl/dh.h>
  51
  52 typedef BIGNUM *FFBigNum;
  53 typedef DH FF_DH;
  54 #endif
  55
  56 /**
  57  * Initialize a Diffie-Hellmann context.
  58  *
  59  * @param key_len length of the key
  60  * @return a new Diffie-Hellmann context on success, NULL otherwise
  61  */
  62 FF_DH *ff_dh_init(int key_len);
  63
  64 /**
  65  * Free a Diffie-Hellmann context.
  66  *
  67  * @param dh a Diffie-Hellmann context to free
  68  */
  69 void ff_dh_free(FF_DH *dh);
  70
  71 /**
  72  * Generate a public key.
  73  *
  74  * @param dh a Diffie-Hellmann context
  75  * @return zero on success, negative value otherwise
  76  */
  77 int ff_dh_generate_public_key(FF_DH *dh);
  78
  79 /**
  80  * Write the public key into the given buffer.
  81  *
  82  * @param dh            a Diffie-Hellmann context, containing the public key to write
  83  * @param pub_key       the buffer where the public key is written
  84  * @param pub_key_len   the length of the buffer
  85  * @return zero on success, negative value otherwise
  86  */
  87 int ff_dh_write_public_key(FF_DH *dh, uint8_t *pub_key, int pub_key_len);
  88
  89 /**
  90  * Compute the shared secret key from the private FF_DH value and the
  91  * other party's public value.
  92  *
  93  * @param dh            a Diffie-Hellmann context, containing the private key
  94  * @param pub_key       the buffer containing the public key
  95  * @param pub_key_len   the length of the buffer
  96  * @param secret_key    the buffer where the secret key is written
  97  * @return length of the shared secret key on success, negative value otherwise
  98  */
  99 int ff_dh_compute_shared_secret_key(FF_DH *dh, const uint8_t *pub_key,
 100                                     int pub_key_len, uint8_t *secret_key);
 101
 102 #endif /* AVFORMAT_RTMPDH_H */