blob: 188aad7a45cef2450bff944bfe19539c11541c72
| 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 | */ |
| 75 | int ff_dh_generate_public_key(FF_DH *dh); |
| 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 */ |
| 103 |