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Viewing changes to include/libtorrent/pe_crypto.hpp

  • Committer: Bazaar Package Importer
  • Author(s): Cristian Greco
  • Date: 2008-07-02 10:46:21 UTC
  • Revision ID: james.westby@ubuntu.com-20080702104621-jzx3pfke9lkcxfxn
Tags: upstream-0.13.1
Import upstream version 0.13.1

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include/libtorrent/pe_crypto.hpp
 
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/*
 
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Copyright (c) 2007, Un Shyam
 
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All rights reserved.
 
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Redistribution and use in source and binary forms, with or without
 
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modification, are permitted provided that the following conditions
 
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are met:
 
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    * Redistributions of source code must retain the above copyright
 
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      notice, this list of conditions and the following disclaimer.
 
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    * Redistributions in binary form must reproduce the above copyright
 
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      notice, this list of conditions and the following disclaimer in
 
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      the documentation and/or other materials provided with the distribution.
 
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    * Neither the name of the author nor the names of its
 
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      contributors may be used to endorse or promote products derived
 
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      from this software without specific prior written permission.
 
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 
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POSSIBILITY OF SUCH DAMAGE.
 
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*/
 
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#ifndef TORRENT_DISABLE_ENCRYPTION
 
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#ifndef TORRENT_PE_CRYPTO_HPP_INCLUDED
 
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#define TORRENT_PE_CRYPTO_HPP_INCLUDED
 
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#include <openssl/dh.h>
 
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#include <openssl/engine.h>
 
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#include <openssl/rc4.h>
 
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#include "libtorrent/peer_id.hpp" // For sha1_hash
 
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#include "libtorrent/assert.hpp"
 
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namespace libtorrent
 
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{
 
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        class DH_key_exchange
 
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        {
 
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        public:
 
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                DH_key_exchange ();
 
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                ~DH_key_exchange ();
 
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                // Get local public key, always 96 bytes
 
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                char const* get_local_key (void) const;
 
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                // read remote_pubkey, generate and store shared secret in
 
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                // m_dh_secret
 
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                void compute_secret (const char* remote_pubkey);
 
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                const char* get_secret (void) const;
 
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        private:
 
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                int get_local_key_size () const
 
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                {
 
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                        TORRENT_ASSERT(m_DH);
 
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                        return BN_num_bytes (m_DH->pub_key);
 
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                }
 
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                DH* m_DH;
 
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                static const unsigned char m_dh_prime[96];
 
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                static const unsigned char m_dh_generator[1];
 
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                char m_dh_local_key[96];
 
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                char m_dh_secret[96];
 
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        };
 
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        class RC4_handler // Non copyable
 
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        {
 
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        public:
 
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                // Input longkeys must be 20 bytes
 
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                RC4_handler (const sha1_hash& rc4_local_longkey,
 
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                                         const sha1_hash& rc4_remote_longkey)
 
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                {
 
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                        RC4_set_key (&m_local_key, 20,
 
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                                                 reinterpret_cast<unsigned char const*>(rc4_local_longkey.begin()));
 
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                        RC4_set_key (&m_remote_key, 20,
 
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                                                 reinterpret_cast<unsigned char const*>(rc4_remote_longkey.begin()));
 
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                        // Discard first 1024 bytes
 
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                        char buf[1024];
 
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                        encrypt (buf, 1024);
 
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                        decrypt (buf, 1024);
 
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                };
 
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                ~RC4_handler () {};
 
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                void encrypt (char* pos, int len)
 
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                {
 
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                        TORRENT_ASSERT(len >= 0);
 
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                        TORRENT_ASSERT(pos);
 
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                        RC4 (&m_local_key, len, reinterpret_cast<unsigned char const*>(pos),
 
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                                 reinterpret_cast<unsigned char*>(pos));
 
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                }
 
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                void decrypt (char* pos, int len)
 
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                {
 
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                        TORRENT_ASSERT(len >= 0);
 
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                        TORRENT_ASSERT(pos);
 
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                        RC4 (&m_remote_key, len, reinterpret_cast<unsigned char const*>(pos),
 
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                                 reinterpret_cast<unsigned char*>(pos));
 
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                }
 
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        private:
 
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                RC4_KEY m_local_key; // Key to encrypt outgoing data
 
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                RC4_KEY m_remote_key; // Key to decrypt incoming data
 
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        };
 
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} // namespace libtorrent
 
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#endif // TORRENT_PE_CRYPTO_HPP_INCLUDED
 
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#endif // TORRENT_DISABLE_ENCRYPTION