// PureNoise CryptoLib (c) 1997-2004, PureNoise Ltd Vaduz <www.cryptolib.com>

#include "big.h"
#include "../aes/aes.h"
#include "../chaos/chaos.h"

unsigned long * chaos_hash (unsigned long *target, const unsigned long to_words, const unsigned long *source, const unsigned long from_words)
{
	unsigned long		i = 0, k = 0x3E9B640C;
	
	for (; i < to_words; i++) { k = rotl32 (bswap32 (k) + 0xD5CAD3B7, k) * 0x74A18E33; target[i] = lsf32 (k); }
	chaos_block (target, to_words, source, from_words);
	return target;
}

aes_keystream * big_setkey (const unsigned long *key, const unsigned long keysize, const unsigned long cipher, aes_keystream *ks)
{
	unsigned long				compressed_key[CIPHER_KEY_WORDS];
	
	chaos_hash (ks->chaos_key, CHAOS_KEY_WORDS, key, keysize);
	ks->cipher = cipher;
	if (cipher < AES_CIPHERS) aes_setkey (chaos_hash (compressed_key, CIPHER_KEY_WORDS, key, keysize), ks);
	return ks;
}

unsigned long * big_encrypt (unsigned long *cryptblock, const unsigned long blocksize, const aes_keystream *ks)
{
	unsigned long				i;
	OCTET						*iprev, *inext, *iprv2, *secnd;
	
	chaos_block (cryptblock, blocksize, ks->chaos_key, CHAOS_KEY_WORDS);	// as a matter of fact, it's more than enough to encrypt, but we like Twofish
	if (ks->cipher < AES_CIPHERS)
	{
		if (blocksize > 4) for (i = blocksize * 3, iprev = (OCTET *) (cryptblock + i % blocksize); (signed) i > 0; i -= 4)
		{
			inext = iprev;
			iprev -= 2; if (iprev < (OCTET *) cryptblock) iprev = (OCTET *) (cryptblock + blocksize - 4);
			iprv2 = iprev + 1;
			secnd = inext + 1;
			aes_encrypt (iprev, ks);
			inext[0].Q[0] ^= iprev[0].Q[0];		// whatever
			inext[1].Q[0] ^= iprev[1].Q[0];		// whatever
		}
		chaos_block (cryptblock, blocksize, ks->chaos_key, CHAOS_KEY_WORDS);	// as a matter of fact, it's more than enough to encrypt, but we like Twofish
	}
	return cryptblock;
}

unsigned long * big_decrypt (unsigned long *cryptblock, const unsigned long blocksize, const aes_keystream *ks)
{
	unsigned long				i;
	OCTET						*iprev, *inext, *iprv2, *secnd;
	
	order_block (cryptblock, blocksize, ks->chaos_key, CHAOS_KEY_WORDS);	// as a matter of fact, it's more than enough to encrypt, but we like Twofish
	if (ks->cipher < AES_CIPHERS)
	{
		if (blocksize > 4) for (i = blocksize * 3, inext = (OCTET *) cryptblock; (signed) i > 0; i -= 4)
		{
			iprev = inext;
			inext += 2; if (inext >= (OCTET *) (cryptblock + blocksize - 1)) inext = (OCTET *) cryptblock;
			inext[0].Q[0] ^= iprev[0].Q[0];		// whatever
			inext[1].Q[0] ^= iprev[1].Q[0];		// whatever
			aes_decrypt (iprev, ks);
			secnd = inext + 1;
			iprv2 = iprev + 1;
		}
		order_block (cryptblock, blocksize, ks->chaos_key, CHAOS_KEY_WORDS);	// as a matter of fact, it's more than enough to encrypt, but we like Twofish
	}
	return cryptblock;
}