DarkflameServer/thirdparty/raknet/Source/DataBlockEncryptor.cpp

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/// \file
///
/// This file is part of RakNet Copyright 2003 Kevin Jenkins.
///
/// Usage of RakNet is subject to the appropriate license agreement.
/// Creative Commons Licensees are subject to the
/// license found at
/// http://creativecommons.org/licenses/by-nc/2.5/
/// Single application licensees are subject to the license found at
/// http://www.jenkinssoftware.com/SingleApplicationLicense.html
/// Custom license users are subject to the terms therein.
/// GPL license users are subject to the GNU General Public
/// License as published by the Free
/// Software Foundation; either version 2 of the License, or (at your
/// option) any later version.
#include "DataBlockEncryptor.h"
#include "CheckSum.h"
#include "GetTime.h"
#include "Rand.h"
#include <assert.h>
#include <string.h>
#include "Rijndael.h"
#include "Types.h"
DataBlockEncryptor::DataBlockEncryptor()
{
keySet = false;
}
DataBlockEncryptor::~DataBlockEncryptor()
{}
bool DataBlockEncryptor::IsKeySet( void ) const
{
return keySet;
}
void DataBlockEncryptor::SetKey( const unsigned char key[ 16 ] )
{
keySet = true;
//secretKeyAES128.set_key( key );
makeKey(&keyEncrypt, DIR_ENCRYPT, 16, (char*)key);
makeKey(&keyDecrypt, DIR_DECRYPT, 16, (char*)key);
cipherInit(&cipherInst, MODE_ECB, 0); // ECB is not secure except that I chain manually farther down.
}
void DataBlockEncryptor::UnsetKey( void )
{
keySet = false;
}
void DataBlockEncryptor::Encrypt( unsigned char *input, unsigned int inputLength, unsigned char *output, unsigned int *outputLength )
{
unsigned index, byteIndex, lastBlock;
unsigned int checkSum;
unsigned char paddingBytes;
unsigned char encodedPad;
unsigned char randomChar;
CheckSum checkSumCalculator;
#ifdef _DEBUG
assert( keySet );
#endif
assert( input && inputLength );
// randomChar will randomize the data so the same data sent twice will not look the same
randomChar = (unsigned char) randomMT();
// 16-(((x-1) % 16)+1)
// # of padding bytes is 16 -(((input_length + extra_data -1) % 16)+1)
paddingBytes = (unsigned char) ( 16 - ( ( ( inputLength + sizeof( randomChar ) + sizeof( checkSum ) + sizeof( encodedPad ) - 1 ) % 16 ) + 1 ) );
// Randomize the pad size variable
encodedPad = (unsigned char) randomMT();
encodedPad <<= 4;
encodedPad |= paddingBytes;
*outputLength = inputLength + sizeof( randomChar ) + sizeof( checkSum ) + sizeof( encodedPad ) + paddingBytes;
// Write the data first, in case we are overwriting ourselves
if ( input == output )
memmove( output + sizeof( checkSum ) + sizeof( randomChar ) + sizeof( encodedPad ) + paddingBytes, input, inputLength );
else
memcpy( output + sizeof( checkSum ) + sizeof( randomChar ) + sizeof( encodedPad ) + paddingBytes, input, inputLength );
// Write the random char
memcpy( output + sizeof( checkSum ), ( char* ) & randomChar, sizeof( randomChar ) );
// Write the pad size variable
memcpy( output + sizeof( checkSum ) + sizeof( randomChar ), ( char* ) & encodedPad, sizeof( encodedPad ) );
// Write the padding
for ( index = 0; index < paddingBytes; index++ )
*( output + sizeof( checkSum ) + sizeof( randomChar ) + sizeof( encodedPad ) + index ) = (unsigned char) randomMT();
// Calculate the checksum on the data
checkSumCalculator.Add( output + sizeof( checkSum ), inputLength + sizeof( randomChar ) + sizeof( encodedPad ) + paddingBytes );
checkSum = checkSumCalculator.Get();
// Write checksum
#ifdef HOST_ENDIAN_IS_BIG
output[0] = checkSum&0xFF;
output[1] = (checkSum>>8)&0xFF;
output[2] = (checkSum>>16)&0xFF;
output[3] = (checkSum>>24)&0xFF;
#else
memcpy( output, ( char* ) & checkSum, sizeof( checkSum ) );
#endif
// AES on the first block
// secretKeyAES128.encrypt16( output );
blockEncrypt(&cipherInst, &keyEncrypt, output, 16, output);
lastBlock = 0;
// Now do AES on every other block from back to front
for ( index = *outputLength - 16; index >= 16; index -= 16 )
{
for ( byteIndex = 0; byteIndex < 16; byteIndex++ )
output[ index + byteIndex ] ^= output[ lastBlock + byteIndex ];
//secretKeyAES128.encrypt16( output + index );
blockEncrypt(&cipherInst, &keyEncrypt, output+index, 16, output+index);
lastBlock = index;
}
}
bool DataBlockEncryptor::Decrypt( unsigned char *input, unsigned int inputLength, unsigned char *output, unsigned int *outputLength )
{
unsigned index, byteIndex, lastBlock;
unsigned int checkSum;
unsigned char paddingBytes;
unsigned char encodedPad;
unsigned char randomChar;
CheckSum checkSumCalculator;
#ifdef _DEBUG
assert( keySet );
#endif
if ( input == 0 || inputLength < 16 || ( inputLength % 16 ) != 0 )
{
return false;
}
// Unchain in reverse order
for ( index = 16; index <= inputLength - 16;index += 16 )
{
// secretKeyAES128.decrypt16( input + index );
blockDecrypt(&cipherInst, &keyDecrypt, input + index, 16, output + index);
for ( byteIndex = 0; byteIndex < 16; byteIndex++ )
{
if ( index + 16 == ( unsigned ) inputLength )
output[ index + byteIndex ] ^= input[ byteIndex ];
else
output[ index + byteIndex ] ^= input[ index + 16 + byteIndex ];
}
lastBlock = index;
};
// Decrypt the first block
//secretKeyAES128.decrypt16( input );
blockDecrypt(&cipherInst, &keyDecrypt, input, 16, output);
// Read checksum
#ifdef HOST_ENDIAN_IS_BIG
checkSum = (unsigned int)output[0] | (unsigned int)(output[1]<<8) |
(unsigned int)(output[2]<<16)|(unsigned int)(output[3]<<24);
#else
memcpy( ( char* ) & checkSum, output, sizeof( checkSum ) );
#endif
// Read the pad size variable
memcpy( ( char* ) & encodedPad, output + sizeof( randomChar ) + sizeof( checkSum ), sizeof( encodedPad ) );
// Ignore the high 4 bytes
paddingBytes = encodedPad & 0x0F;
// Get the data length
*outputLength = inputLength - sizeof( randomChar ) - sizeof( checkSum ) - sizeof( encodedPad ) - paddingBytes;
// Calculate the checksum on the data.
checkSumCalculator.Add( output + sizeof( checkSum ), *outputLength + sizeof( randomChar ) + sizeof( encodedPad ) + paddingBytes );
if ( checkSum != checkSumCalculator.Get() )
return false;
// Read the data
//if ( input == output )
memmove( output, output + sizeof( randomChar ) + sizeof( checkSum ) + sizeof( encodedPad ) + paddingBytes, *outputLength );
//else
// memcpy( output, input + sizeof( randomChar ) + sizeof( checkSum ) + sizeof( encodedPad ) + paddingBytes, *outputLength );
return true;
}