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 33typedef mpz_ptr FFBigNum; 34#elif CONFIG_GCRYPT 35#include <gcrypt.h> 36 37typedef gcry_mpi_t FFBigNum; 38#endif 39 40typedef 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 52typedef BIGNUM *FFBigNum; 53typedef 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 */ 62FF_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 */ 69void 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 */ 77int 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 */ 87int 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 */ 99int 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 */ 103