Шифрование по алгоритму XOR

[GoldFinch]

вот так выглядит алгоритм шифрования абисса:

// код C++

#pragma pack(push,2)
	struct packetbuf
	{
		unsigned short length;
		char data[USHRT_MAX+1-2];
	};
#pragma pack(pop)

class XorcryptManipulator
{
public:
	XorcryptManipulator(){}
	void Initialize(int key_lo,int key_hi);
	opacketstream& operator() ( opacketstream& pout );
	ipacketstream& operator() ( ipacketstream& pin );
private:
	__int64 key_in;  //key for input stream
	__int64 key_out; //key for output stream
};


opacketstream& bot::XorcryptManipulator::operator()( opacketstream& pout )
{
	packetbuf& buf=pout.buffer();	
	union
	{
		__int64 key;
		char bytes[8];
	} k2;
	k2.key=key_out;
	
	char k;
	buf.data[0] ^= k2.bytes[0];
	for (int i=1;i<buf.length;++i,buf.data[i-1]^=k)
		k=k2.bytes[i&7] ^ buf.data[i-1];

	key_out += buf.length;
	return pout;
}

ipacketstream& bot::XorcryptManipulator::operator()( ipacketstream& pin )
{
	packetbuf& buf=pin.buffer();	
	union
	{
		__int64 key;
		char bytes[8];
	} k2;
	k2.key=key_in;

	char k=buf.data[0];
	buf.data[0] ^= k2.bytes[0];
	for(int i=1;i<buf.length;++i)
	{
		char t=buf.data[i];
		buf.data[i]^=k^k2.bytes[i&7];
		k=t;
	}

	key_in += buf.length;
	return pin;
}

void bot::XorcryptManipulator::Initialize( int key_lo,int key_hi )
{
	union
	{
		__int64 key;
		struct
		{
			int lo;
			int hi;
		};
	} k;
	k.lo=key_lo;
	k.hi=key_hi;
	key_in=k.key;
	key_out=k.key;
}