#define LUA_LIB

#include <lua.h>
#include <lauxlib.h>

#include <time.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#define PADDING_MODE_ISO7816_4 0
#define PADDING_MODE_PKCS7 1
#define PADDING_MODE_COUNT 2

#define SMALL_CHUNK 256

/* the eight DES S-boxes */

static uint32_t SB1[64] = {
	0x01010400, 0x00000000, 0x00010000, 0x01010404,
	0x01010004, 0x00010404, 0x00000004, 0x00010000,
	0x00000400, 0x01010400, 0x01010404, 0x00000400,
	0x01000404, 0x01010004, 0x01000000, 0x00000004,
	0x00000404, 0x01000400, 0x01000400, 0x00010400,
	0x00010400, 0x01010000, 0x01010000, 0x01000404,
	0x00010004, 0x01000004, 0x01000004, 0x00010004,
	0x00000000, 0x00000404, 0x00010404, 0x01000000,
	0x00010000, 0x01010404, 0x00000004, 0x01010000,
	0x01010400, 0x01000000, 0x01000000, 0x00000400,
	0x01010004, 0x00010000, 0x00010400, 0x01000004,
	0x00000400, 0x00000004, 0x01000404, 0x00010404,
	0x01010404, 0x00010004, 0x01010000, 0x01000404,
	0x01000004, 0x00000404, 0x00010404, 0x01010400,
	0x00000404, 0x01000400, 0x01000400, 0x00000000,
	0x00010004, 0x00010400, 0x00000000, 0x01010004
};

static uint32_t SB2[64] = {
	0x80108020, 0x80008000, 0x00008000, 0x00108020,
	0x00100000, 0x00000020, 0x80100020, 0x80008020,
	0x80000020, 0x80108020, 0x80108000, 0x80000000,
	0x80008000, 0x00100000, 0x00000020, 0x80100020,
	0x00108000, 0x00100020, 0x80008020, 0x00000000,
	0x80000000, 0x00008000, 0x00108020, 0x80100000,
	0x00100020, 0x80000020, 0x00000000, 0x00108000,
	0x00008020, 0x80108000, 0x80100000, 0x00008020,
	0x00000000, 0x00108020, 0x80100020, 0x00100000,
	0x80008020, 0x80100000, 0x80108000, 0x00008000,
	0x80100000, 0x80008000, 0x00000020, 0x80108020,
	0x00108020, 0x00000020, 0x00008000, 0x80000000,
	0x00008020, 0x80108000, 0x00100000, 0x80000020,
	0x00100020, 0x80008020, 0x80000020, 0x00100020,
	0x00108000, 0x00000000, 0x80008000, 0x00008020,
	0x80000000, 0x80100020, 0x80108020, 0x00108000
};

static uint32_t SB3[64] = {
	0x00000208, 0x08020200, 0x00000000, 0x08020008,
	0x08000200, 0x00000000, 0x00020208, 0x08000200,
	0x00020008, 0x08000008, 0x08000008, 0x00020000,
	0x08020208, 0x00020008, 0x08020000, 0x00000208,
	0x08000000, 0x00000008, 0x08020200, 0x00000200,
	0x00020200, 0x08020000, 0x08020008, 0x00020208,
	0x08000208, 0x00020200, 0x00020000, 0x08000208,
	0x00000008, 0x08020208, 0x00000200, 0x08000000,
	0x08020200, 0x08000000, 0x00020008, 0x00000208,
	0x00020000, 0x08020200, 0x08000200, 0x00000000,
	0x00000200, 0x00020008, 0x08020208, 0x08000200,
	0x08000008, 0x00000200, 0x00000000, 0x08020008,
	0x08000208, 0x00020000, 0x08000000, 0x08020208,
	0x00000008, 0x00020208, 0x00020200, 0x08000008,
	0x08020000, 0x08000208, 0x00000208, 0x08020000,
	0x00020208, 0x00000008, 0x08020008, 0x00020200
};

static uint32_t SB4[64] = {
	0x00802001, 0x00002081, 0x00002081, 0x00000080,
	0x00802080, 0x00800081, 0x00800001, 0x00002001,
	0x00000000, 0x00802000, 0x00802000, 0x00802081,
	0x00000081, 0x00000000, 0x00800080, 0x00800001,
	0x00000001, 0x00002000, 0x00800000, 0x00802001,
	0x00000080, 0x00800000, 0x00002001, 0x00002080,
	0x00800081, 0x00000001, 0x00002080, 0x00800080,
	0x00002000, 0x00802080, 0x00802081, 0x00000081,
	0x00800080, 0x00800001, 0x00802000, 0x00802081,
	0x00000081, 0x00000000, 0x00000000, 0x00802000,
	0x00002080, 0x00800080, 0x00800081, 0x00000001,
	0x00802001, 0x00002081, 0x00002081, 0x00000080,
	0x00802081, 0x00000081, 0x00000001, 0x00002000,
	0x00800001, 0x00002001, 0x00802080, 0x00800081,
	0x00002001, 0x00002080, 0x00800000, 0x00802001,
	0x00000080, 0x00800000, 0x00002000, 0x00802080
};

static uint32_t SB5[64] = {
	0x00000100, 0x02080100, 0x02080000, 0x42000100,
	0x00080000, 0x00000100, 0x40000000, 0x02080000,
	0x40080100, 0x00080000, 0x02000100, 0x40080100,
	0x42000100, 0x42080000, 0x00080100, 0x40000000,
	0x02000000, 0x40080000, 0x40080000, 0x00000000,
	0x40000100, 0x42080100, 0x42080100, 0x02000100,
	0x42080000, 0x40000100, 0x00000000, 0x42000000,
	0x02080100, 0x02000000, 0x42000000, 0x00080100,
	0x00080000, 0x42000100, 0x00000100, 0x02000000,
	0x40000000, 0x02080000, 0x42000100, 0x40080100,
	0x02000100, 0x40000000, 0x42080000, 0x02080100,
	0x40080100, 0x00000100, 0x02000000, 0x42080000,
	0x42080100, 0x00080100, 0x42000000, 0x42080100,
	0x02080000, 0x00000000, 0x40080000, 0x42000000,
	0x00080100, 0x02000100, 0x40000100, 0x00080000,
	0x00000000, 0x40080000, 0x02080100, 0x40000100
};

static uint32_t SB6[64] = {
	0x20000010, 0x20400000, 0x00004000, 0x20404010,
	0x20400000, 0x00000010, 0x20404010, 0x00400000,
	0x20004000, 0x00404010, 0x00400000, 0x20000010,
	0x00400010, 0x20004000, 0x20000000, 0x00004010,
	0x00000000, 0x00400010, 0x20004010, 0x00004000,
	0x00404000, 0x20004010, 0x00000010, 0x20400010,
	0x20400010, 0x00000000, 0x00404010, 0x20404000,
	0x00004010, 0x00404000, 0x20404000, 0x20000000,
	0x20004000, 0x00000010, 0x20400010, 0x00404000,
	0x20404010, 0x00400000, 0x00004010, 0x20000010,
	0x00400000, 0x20004000, 0x20000000, 0x00004010,
	0x20000010, 0x20404010, 0x00404000, 0x20400000,
	0x00404010, 0x20404000, 0x00000000, 0x20400010,
	0x00000010, 0x00004000, 0x20400000, 0x00404010,
	0x00004000, 0x00400010, 0x20004010, 0x00000000,
	0x20404000, 0x20000000, 0x00400010, 0x20004010
};

static uint32_t SB7[64] = {
	0x00200000, 0x04200002, 0x04000802, 0x00000000,
	0x00000800, 0x04000802, 0x00200802, 0x04200800,
	0x04200802, 0x00200000, 0x00000000, 0x04000002,
	0x00000002, 0x04000000, 0x04200002, 0x00000802,
	0x04000800, 0x00200802, 0x00200002, 0x04000800,
	0x04000002, 0x04200000, 0x04200800, 0x00200002,
	0x04200000, 0x00000800, 0x00000802, 0x04200802,
	0x00200800, 0x00000002, 0x04000000, 0x00200800,
	0x04000000, 0x00200800, 0x00200000, 0x04000802,
	0x04000802, 0x04200002, 0x04200002, 0x00000002,
	0x00200002, 0x04000000, 0x04000800, 0x00200000,
	0x04200800, 0x00000802, 0x00200802, 0x04200800,
	0x00000802, 0x04000002, 0x04200802, 0x04200000,
	0x00200800, 0x00000000, 0x00000002, 0x04200802,
	0x00000000, 0x00200802, 0x04200000, 0x00000800,
	0x04000002, 0x04000800, 0x00000800, 0x00200002
};

static uint32_t SB8[64] = {
	0x10001040, 0x00001000, 0x00040000, 0x10041040,
	0x10000000, 0x10001040, 0x00000040, 0x10000000,
	0x00040040, 0x10040000, 0x10041040, 0x00041000,
	0x10041000, 0x00041040, 0x00001000, 0x00000040,
	0x10040000, 0x10000040, 0x10001000, 0x00001040,
	0x00041000, 0x00040040, 0x10040040, 0x10041000,
	0x00001040, 0x00000000, 0x00000000, 0x10040040,
	0x10000040, 0x10001000, 0x00041040, 0x00040000,
	0x00041040, 0x00040000, 0x10041000, 0x00001000,
	0x00000040, 0x10040040, 0x00001000, 0x00041040,
	0x10001000, 0x00000040, 0x10000040, 0x10040000,
	0x10040040, 0x10000000, 0x00040000, 0x10001040,
	0x00000000, 0x10041040, 0x00040040, 0x10000040,
	0x10040000, 0x10001000, 0x10001040, 0x00000000,
	0x10041040, 0x00041000, 0x00041000, 0x00001040,
	0x00001040, 0x00040040, 0x10000000, 0x10041000
};

/* PC1: left and right halves bit-swap */

static uint32_t LHs[16] = {
	0x00000000, 0x00000001, 0x00000100, 0x00000101,
	0x00010000, 0x00010001, 0x00010100, 0x00010101,
	0x01000000, 0x01000001, 0x01000100, 0x01000101,
	0x01010000, 0x01010001, 0x01010100, 0x01010101
};

static uint32_t RHs[16] = {
	0x00000000, 0x01000000, 0x00010000, 0x01010000,
	0x00000100, 0x01000100, 0x00010100, 0x01010100,
	0x00000001, 0x01000001, 0x00010001, 0x01010001,
	0x00000101, 0x01000101, 0x00010101, 0x01010101,
};

/* platform-independant 32-bit integer manipulation macros */

#define GET_UINT32(n,b,i)					   \
{											   \
	(n) = ( (uint32_t) (b)[(i)	] << 24 )	   \
		| ( (uint32_t) (b)[(i) + 1] << 16 )	   \
		| ( (uint32_t) (b)[(i) + 2] <<  8 )	   \
		| ( (uint32_t) (b)[(i) + 3]	   );	  \
}

#define PUT_UINT32(n,b,i)					   \
{											   \
	(b)[(i)	] = (uint8_t) ( (n) >> 24 );	   \
	(b)[(i) + 1] = (uint8_t) ( (n) >> 16 );	   \
	(b)[(i) + 2] = (uint8_t) ( (n) >>  8 );	   \
	(b)[(i) + 3] = (uint8_t) ( (n)	   );	   \
}

/* Initial Permutation macro */

#define DES_IP(X,Y)											 \
{															   \
	T = ((X >>  4) ^ Y) & 0x0F0F0F0F; Y ^= T; X ^= (T <<  4);   \
	T = ((X >> 16) ^ Y) & 0x0000FFFF; Y ^= T; X ^= (T << 16);   \
	T = ((Y >>  2) ^ X) & 0x33333333; X ^= T; Y ^= (T <<  2);   \
	T = ((Y >>  8) ^ X) & 0x00FF00FF; X ^= T; Y ^= (T <<  8);   \
	Y = ((Y << 1) | (Y >> 31)) & 0xFFFFFFFF;					\
	T = (X ^ Y) & 0xAAAAAAAA; Y ^= T; X ^= T;				   \
	X = ((X << 1) | (X >> 31)) & 0xFFFFFFFF;					\
}

/* Final Permutation macro */

#define DES_FP(X,Y)											 \
{															   \
	X = ((X << 31) | (X >> 1)) & 0xFFFFFFFF;					\
	T = (X ^ Y) & 0xAAAAAAAA; X ^= T; Y ^= T;				   \
	Y = ((Y << 31) | (Y >> 1)) & 0xFFFFFFFF;					\
	T = ((Y >>  8) ^ X) & 0x00FF00FF; X ^= T; Y ^= (T <<  8);   \
	T = ((Y >>  2) ^ X) & 0x33333333; X ^= T; Y ^= (T <<  2);   \
	T = ((X >> 16) ^ Y) & 0x0000FFFF; Y ^= T; X ^= (T << 16);   \
	T = ((X >>  4) ^ Y) & 0x0F0F0F0F; Y ^= T; X ^= (T <<  4);   \
}

/* DES round macro */

#define DES_ROUND(X,Y)						  \
{											   \
	T = *SK++ ^ X;							  \
	Y ^= SB8[ (T	  ) & 0x3F ] ^			  \
		 SB6[ (T >>  8) & 0x3F ] ^			  \
		 SB4[ (T >> 16) & 0x3F ] ^			  \
		 SB2[ (T >> 24) & 0x3F ];			   \
												\
	T = *SK++ ^ ((X << 28) | (X >> 4));		 \
	Y ^= SB7[ (T	  ) & 0x3F ] ^			  \
		 SB5[ (T >>  8) & 0x3F ] ^			  \
		 SB3[ (T >> 16) & 0x3F ] ^			  \
		 SB1[ (T >> 24) & 0x3F ];			   \
}

/* DES key schedule */

static void 
des_main_ks( uint32_t SK[32], const uint8_t key[8] ) {
	int i;
	uint32_t X, Y, T;

	GET_UINT32( X, key, 0 );
	GET_UINT32( Y, key, 4 );

	/* Permuted Choice 1 */

	T =  ((Y >>  4) ^ X) & 0x0F0F0F0F;  X ^= T; Y ^= (T <<  4);
	T =  ((Y	  ) ^ X) & 0x10101010;  X ^= T; Y ^= (T	  );

	X =   (LHs[ (X	  ) & 0xF] << 3) | (LHs[ (X >>  8) & 0xF ] << 2)
		| (LHs[ (X >> 16) & 0xF] << 1) | (LHs[ (X >> 24) & 0xF ]	 )
		| (LHs[ (X >>  5) & 0xF] << 7) | (LHs[ (X >> 13) & 0xF ] << 6)
		| (LHs[ (X >> 21) & 0xF] << 5) | (LHs[ (X >> 29) & 0xF ] << 4);

	Y =   (RHs[ (Y >>  1) & 0xF] << 3) | (RHs[ (Y >>  9) & 0xF ] << 2)
		| (RHs[ (Y >> 17) & 0xF] << 1) | (RHs[ (Y >> 25) & 0xF ]	 )
		| (RHs[ (Y >>  4) & 0xF] << 7) | (RHs[ (Y >> 12) & 0xF ] << 6)
		| (RHs[ (Y >> 20) & 0xF] << 5) | (RHs[ (Y >> 28) & 0xF ] << 4);

	X &= 0x0FFFFFFF;
	Y &= 0x0FFFFFFF;

	/* calculate subkeys */

	for( i = 0; i < 16; i++ )
	{
		if( i < 2 || i == 8 || i == 15 )
		{
			X = ((X <<  1) | (X >> 27)) & 0x0FFFFFFF;
			Y = ((Y <<  1) | (Y >> 27)) & 0x0FFFFFFF;
		}
		else
		{
			X = ((X <<  2) | (X >> 26)) & 0x0FFFFFFF;
			Y = ((Y <<  2) | (Y >> 26)) & 0x0FFFFFFF;
		}

		*SK++ =   ((X <<  4) & 0x24000000) | ((X << 28) & 0x10000000)
				| ((X << 14) & 0x08000000) | ((X << 18) & 0x02080000)
				| ((X <<  6) & 0x01000000) | ((X <<  9) & 0x00200000)
				| ((X >>  1) & 0x00100000) | ((X << 10) & 0x00040000)
				| ((X <<  2) & 0x00020000) | ((X >> 10) & 0x00010000)
				| ((Y >> 13) & 0x00002000) | ((Y >>  4) & 0x00001000)
				| ((Y <<  6) & 0x00000800) | ((Y >>  1) & 0x00000400)
				| ((Y >> 14) & 0x00000200) | ((Y	  ) & 0x00000100)
				| ((Y >>  5) & 0x00000020) | ((Y >> 10) & 0x00000010)
				| ((Y >>  3) & 0x00000008) | ((Y >> 18) & 0x00000004)
				| ((Y >> 26) & 0x00000002) | ((Y >> 24) & 0x00000001);

		*SK++ =   ((X << 15) & 0x20000000) | ((X << 17) & 0x10000000)
				| ((X << 10) & 0x08000000) | ((X << 22) & 0x04000000)
				| ((X >>  2) & 0x02000000) | ((X <<  1) & 0x01000000)
				| ((X << 16) & 0x00200000) | ((X << 11) & 0x00100000)
				| ((X <<  3) & 0x00080000) | ((X >>  6) & 0x00040000)
				| ((X << 15) & 0x00020000) | ((X >>  4) & 0x00010000)
				| ((Y >>  2) & 0x00002000) | ((Y <<  8) & 0x00001000)
				| ((Y >> 14) & 0x00000808) | ((Y >>  9) & 0x00000400)
				| ((Y	  ) & 0x00000200) | ((Y <<  7) & 0x00000100)
				| ((Y >>  7) & 0x00000020) | ((Y >>  3) & 0x00000011)
				| ((Y <<  2) & 0x00000004) | ((Y >> 21) & 0x00000002);
	}
}

/* DES 64-bit block encryption/decryption */

static void 
des_crypt( const uint32_t SK[32], const uint8_t input[8], uint8_t output[8] ) {
	uint32_t X, Y, T;

	GET_UINT32( X, input, 0 );
	GET_UINT32( Y, input, 4 );

	DES_IP( X, Y );

	DES_ROUND( Y, X );  DES_ROUND( X, Y );
	DES_ROUND( Y, X );  DES_ROUND( X, Y );
	DES_ROUND( Y, X );  DES_ROUND( X, Y );
	DES_ROUND( Y, X );  DES_ROUND( X, Y );
	DES_ROUND( Y, X );  DES_ROUND( X, Y );
	DES_ROUND( Y, X );  DES_ROUND( X, Y );
	DES_ROUND( Y, X );  DES_ROUND( X, Y );
	DES_ROUND( Y, X );  DES_ROUND( X, Y );

	DES_FP( Y, X );

	PUT_UINT32( Y, output, 0 );
	PUT_UINT32( X, output, 4 );
}

static int
lrandomkey(lua_State *L) {
	char tmp[8];
	int i;
	char x = 0;
	for (i=0;i<8;i++) {
		tmp[i] = random() & 0xff;
		x ^= tmp[i];
	}
	if (x==0) {
		tmp[0] |= 1;	// avoid 0
	}
	lua_pushlstring(L, tmp, 8);
	return 1;
}

static void
padding_mode_table(lua_State *L) {
	// see macros PADDING_MODE_ISO7816_4, etc.
	const char * mode[] = {
		"iso7816_4",
		"pkcs7",
	};
	int n = sizeof(mode) / sizeof(mode[0]);
	int i;
	lua_createtable(L,0,n);
	for (i=0;i<n;i++) {
		lua_pushinteger(L, i);
		lua_setfield(L, -2, mode[i]);
	}
}

typedef void (*padding_add)(uint8_t buf[8], int offset);
typedef int (*padding_remove)(const uint8_t *last);

static void
padding_add_iso7816_4(uint8_t buf[8], int offset) {
	buf[offset] = 0x80;
	memset(buf+offset+1, 0, 7-offset);
}

static int
padding_remove_iso7816_4(const uint8_t *last) {
	int padding = 1;
	int i;
	for (i=0;i<8;i++,last--) {
		if (*last == 0) {
			padding++;
		} else if (*last == 0x80) {
			return padding;
		} else {
			break;
		}
	}
	// invalid
	return 0;
}

static void
padding_add_pkcs7(uint8_t buf[8], int offset) {
	uint8_t x = 8-offset;
	memset(buf+offset, x, 8-offset);
}

static int
padding_remove_pkcs7(const uint8_t *last) {
	int padding = *last;
	int i;
	for (i=1;i<padding;i++) {
		--last;
		if (*last != padding)
			return 0;	// invalid
	}
	return padding;
}

static padding_add padding_add_func[] = {
	padding_add_iso7816_4,
	padding_add_pkcs7,
};

static padding_remove padding_remove_func[] = {
	padding_remove_iso7816_4,
	padding_remove_pkcs7,
};

static inline void
check_padding_mode(lua_State *L, int mode) {
	if (mode < 0 || mode >= PADDING_MODE_COUNT)
		luaL_error(L, "Invalid padding mode %d", mode);
}

static void
add_padding(lua_State *L, uint8_t buf[8], const uint8_t *src, int offset, int mode) {
	check_padding_mode(L, mode);
	if (offset >= 8)
		luaL_error(L, "Invalid padding");
	memcpy(buf, src, offset);
	padding_add_func[mode](buf, offset);
}

static int
remove_padding(lua_State *L, const uint8_t *last, int mode) {
	check_padding_mode(L, mode);
	return padding_remove_func[mode](last);
}

static void
des_key(lua_State *L, uint32_t SK[32]) {
	size_t keysz = 0;
	const void * key = luaL_checklstring(L, 1, &keysz);
	if (keysz != 8) {
		luaL_error(L, "Invalid key size %d, need 8 bytes", (int)keysz);
	}
	des_main_ks(SK, (const uint8_t*)key);
}

static int
ldesencode(lua_State *L) {
	uint32_t SK[32];
	des_key(L, SK);

	size_t textsz = 0;
	const uint8_t * text = (const uint8_t *)luaL_checklstring(L, 2, &textsz);
	size_t chunksz = (textsz + 8) & ~7;
	int padding_mode = luaL_optinteger(L, 3, PADDING_MODE_ISO7816_4);
	uint8_t tmp[SMALL_CHUNK];
	uint8_t *buffer = tmp;
	if (chunksz > SMALL_CHUNK) {
		buffer = (uint8_t*)lua_newuserdatauv(L, chunksz, 0);
	}
	int i;
	for (i=0;i<(int)textsz-7;i+=8) {
		des_crypt(SK, text+i, buffer+i);
	}
	uint8_t tail[8];
	add_padding(L, tail, text+i, textsz - i, padding_mode);
	des_crypt(SK, tail, buffer+i);
	lua_pushlstring(L, (const char *)buffer, chunksz);

	return 1;
}

static int
ldesdecode(lua_State *L) {
	uint32_t ESK[32];
	des_key(L, ESK);
	uint32_t SK[32];
	int i;
	for( i = 0; i < 32; i += 2 ) {
		SK[i] = ESK[30 - i];
		SK[i + 1] = ESK[31 - i];
	}
	size_t textsz = 0;
	const uint8_t *text = (const uint8_t *)luaL_checklstring(L, 2, &textsz);
	if ((textsz & 7) || textsz == 0) {
		return luaL_error(L, "Invalid des crypt text length %d", (int)textsz);
	}
	int padding_mode = luaL_optinteger(L, 3, PADDING_MODE_ISO7816_4);
	uint8_t tmp[SMALL_CHUNK];
	uint8_t *buffer = tmp;
	if (textsz > SMALL_CHUNK) {
		buffer = (uint8_t*)lua_newuserdatauv(L, textsz, 0);
	}
	for (i=0;i<textsz;i+=8) {
		des_crypt(SK, text+i, buffer+i);
	}
	int padding = remove_padding(L, buffer + textsz - 1, padding_mode);
	if (padding <= 0 || padding > 8) {
		return luaL_error(L, "Invalid des crypt text");
	}
	lua_pushlstring(L, (const char *)buffer, textsz - padding);
	return 1;
}


static void
Hash(const char * str, int sz, uint8_t key[8]) {
	uint32_t djb_hash = 5381L;
	uint32_t js_hash = 1315423911L;

	int i;
	for (i=0;i<sz;i++) {
		uint8_t c = (uint8_t)str[i];
		djb_hash += (djb_hash << 5) + c;
		js_hash ^= ((js_hash << 5) + c + (js_hash >> 2));
	}

	key[0] = djb_hash & 0xff;
	key[1] = (djb_hash >> 8) & 0xff;
	key[2] = (djb_hash >> 16) & 0xff;
	key[3] = (djb_hash >> 24) & 0xff;

	key[4] = js_hash & 0xff;
	key[5] = (js_hash >> 8) & 0xff;
	key[6] = (js_hash >> 16) & 0xff;
	key[7] = (js_hash >> 24) & 0xff;
}

static int
lhashkey(lua_State *L) {
	size_t sz = 0;
	const char * key = luaL_checklstring(L, 1, &sz);
	uint8_t realkey[8];
	Hash(key,(int)sz,realkey);
	lua_pushlstring(L, (const char *)realkey, 8);
	return 1;
}

static int
ltohex(lua_State *L) {
	static char hex[] = "0123456789abcdef";
	size_t sz = 0;
	const uint8_t * text = (const uint8_t *)luaL_checklstring(L, 1, &sz);
	char tmp[SMALL_CHUNK];
	char *buffer = tmp;
	if (sz > SMALL_CHUNK/2) {
		buffer = (char*)lua_newuserdatauv(L, sz * 2, 0);
	}
	int i;
	for (i=0;i<sz;i++) {
		buffer[i*2] = hex[text[i] >> 4];
		buffer[i*2+1] = hex[text[i] & 0xf];
	}
	lua_pushlstring(L, buffer, sz * 2);
	return 1;
}

#define HEX(v,c) { char tmp = (char) c; if (tmp >= '0' && tmp <= '9') { v = tmp-'0'; } else { v = tmp - 'a' + 10; } }

static int
lfromhex(lua_State *L) {
	size_t sz = 0;
	const char * text = luaL_checklstring(L, 1, &sz);
	if (sz & 1) {
		return luaL_error(L, "Invalid hex text size %d", (int)sz);
	}
	char tmp[SMALL_CHUNK];
	char *buffer = tmp;
	if (sz > SMALL_CHUNK*2) {
		buffer = (char*)lua_newuserdatauv(L, sz / 2, 0);
	}
	int i;
	for (i=0;i<sz;i+=2) {
		uint8_t hi,low;
		HEX(hi, text[i]);
		HEX(low, text[i+1]);
		if (hi > 16 || low > 16) {
			return luaL_error(L, "Invalid hex text", text);
		}
		buffer[i/2] = hi<<4 | low;
	}
	lua_pushlstring(L, buffer, i/2);
	return 1;
}

// Constants are the integer part of the sines of integers (in radians) * 2^32.
static const uint32_t k[64] = {
0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee ,
0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501 ,
0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be ,
0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821 ,
0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa ,
0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8 ,
0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed ,
0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a ,
0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c ,
0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70 ,
0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05 ,
0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665 ,
0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039 ,
0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1 ,
0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1 ,
0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 };
 
// r specifies the per-round shift amounts
static const uint32_t r[] = {7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22,
					  5,  9, 14, 20, 5,  9, 14, 20, 5,  9, 14, 20, 5,  9, 14, 20,
					  4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23,
					  6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21};
 
// leftrotate function definition
#define LEFTROTATE(x, c) (((x) << (c)) | ((x) >> (32 - (c))))

static void
digest_md5(uint32_t w[16], uint32_t result[4]) {
	uint32_t a, b, c, d, f, g, temp;
	int i;
 
	a = 0x67452301u;
	b = 0xefcdab89u;
	c = 0x98badcfeu;
	d = 0x10325476u;

	for(i = 0; i<64; i++) {
		if (i < 16) {
			f = (b & c) | ((~b) & d);
			g = i;
		} else if (i < 32) {
			f = (d & b) | ((~d) & c);
			g = (5*i + 1) % 16;
		} else if (i < 48) {
			f = b ^ c ^ d;
			g = (3*i + 5) % 16; 
		} else {
			f = c ^ (b | (~d));
			g = (7*i) % 16;
		}

		temp = d;
		d = c;
		c = b;
		b = b + LEFTROTATE((a + f + k[i] + w[g]), r[i]);
		a = temp;
	}

	result[0] = a;
	result[1] = b;
	result[2] = c;
	result[3] = d;
}

// hmac64 use md5 algorithm without padding, and the result is (c^d .. a^b)
static void
hmac(uint32_t x[2], uint32_t y[2], uint32_t result[2]) {
	uint32_t w[16];
	uint32_t r[4];
	int i;
	for (i=0;i<16;i+=4) {
		w[i] = x[1];
		w[i+1] = x[0];
		w[i+2] = y[1];
		w[i+3] = y[0];
	}

	digest_md5(w,r);

	result[0] = r[2]^r[3];
	result[1] = r[0]^r[1];
}

static void
hmac_md5(uint32_t x[2], uint32_t y[2], uint32_t result[2]) {
	uint32_t w[16];
	uint32_t r[4];
	int i;
	for (i=0;i<12;i+=4) {
		w[i] = x[0];
		w[i+1] = x[1];
		w[i+2] = y[0];
		w[i+3] = y[1];
	}

	w[12] = 0x80;
	w[13] = 0;
	w[14] = 384;
	w[15] = 0;

	digest_md5(w,r);

	result[0] = (r[0] + 0x67452301u) ^ (r[2] + 0x98badcfeu);
	result[1] = (r[1] + 0xefcdab89u) ^ (r[3] + 0x10325476u);
}

static void
read64(lua_State *L, uint32_t xx[2], uint32_t yy[2]) {
	size_t sz = 0;
	const uint8_t *x = (const uint8_t *)luaL_checklstring(L, 1, &sz);
	if (sz != 8) {
		luaL_error(L, "Invalid uint64 x");
	}
	const uint8_t *y = (const uint8_t *)luaL_checklstring(L, 2, &sz);
	if (sz != 8) {
		luaL_error(L, "Invalid uint64 y");
	}
	xx[0] = x[0] | x[1]<<8 | x[2]<<16 | x[3]<<24;
	xx[1] = x[4] | x[5]<<8 | x[6]<<16 | x[7]<<24;
	yy[0] = y[0] | y[1]<<8 | y[2]<<16 | y[3]<<24;
	yy[1] = y[4] | y[5]<<8 | y[6]<<16 | y[7]<<24;
}

static int
pushqword(lua_State *L, uint32_t result[2]) {
	uint8_t tmp[8];
	tmp[0] = result[0] & 0xff;
	tmp[1] = (result[0] >> 8 )& 0xff;
	tmp[2] = (result[0] >> 16 )& 0xff;
	tmp[3] = (result[0] >> 24 )& 0xff;
	tmp[4] = result[1] & 0xff;
	tmp[5] = (result[1] >> 8 )& 0xff;
	tmp[6] = (result[1] >> 16 )& 0xff;
	tmp[7] = (result[1] >> 24 )& 0xff;

	lua_pushlstring(L, (const char *)tmp, 8);
	return 1;
}

static int
lhmac64(lua_State *L) {
	uint32_t x[2], y[2];
	read64(L, x, y);
	uint32_t result[2];
	hmac(x,y,result);
	return pushqword(L, result);
}

/*
  h1 = crypt.hmac64_md5(a,b)
  m = md5.sum((a..b):rep(3))
  h2 = crypt.xor_str(m:sub(1,8), m:sub(9,16))
  assert(h1 == h2)
 */
static int
lhmac64_md5(lua_State *L) {
	uint32_t x[2], y[2];
	read64(L, x, y);
	uint32_t result[2];
	hmac_md5(x,y,result);
	return pushqword(L, result);
}

/*
	8bytes key
	string text
 */
static int
lhmac_hash(lua_State *L) {
	uint32_t key[2];
	size_t sz = 0;
	const uint8_t *x = (const uint8_t *)luaL_checklstring(L, 1, &sz);
	if (sz != 8) {
		luaL_error(L, "Invalid uint64 key");
	}
	key[0] = x[0] | x[1]<<8 | x[2]<<16 | x[3]<<24;
	key[1] = x[4] | x[5]<<8 | x[6]<<16 | x[7]<<24;
	const char * text = luaL_checklstring(L, 2, &sz);
	uint8_t h[8];
	Hash(text,(int)sz,h);
	uint32_t htext[2];
	htext[0] = h[0] | h[1]<<8 | h[2]<<16 | h[3]<<24;
	htext[1] = h[4] | h[5]<<8 | h[6]<<16 | h[7]<<24;
	uint32_t result[2];
	hmac(htext,key,result);
	return pushqword(L, result);
}

// powmodp64 for DH-key exchange

// The biggest 64bit prime
#define P 0xffffffffffffffc5ull

static inline uint64_t
mul_mod_p(uint64_t a, uint64_t b) {
	uint64_t m = 0;
	while(b) {
		if(b&1) {
			uint64_t t = P-a;
			if ( m >= t) {
				m -= t;
			} else {
				m += a;
			}
		}
		if (a >= P - a) {
			a = a * 2 - P;
		} else {
			a = a * 2;
		}
		b>>=1;
	}
	return m;
}

static inline uint64_t
pow_mod_p(uint64_t a, uint64_t b) {
	if (b==1) {
		return a;
	}
	uint64_t t = pow_mod_p(a, b>>1);
	t = mul_mod_p(t,t);
	if (b % 2) {
		t = mul_mod_p(t, a);
	}
	return t;
}

// calc a^b % p
static uint64_t
powmodp(uint64_t a, uint64_t b) {
	if (a > P)
		a%=P;
	return pow_mod_p(a,b);
}

static void
push64(lua_State *L, uint64_t r) {
	uint8_t tmp[8];
	tmp[0] = r & 0xff;
	tmp[1] = (r >> 8 )& 0xff;
	tmp[2] = (r >> 16 )& 0xff;
	tmp[3] = (r >> 24 )& 0xff;
	tmp[4] = (r >> 32 )& 0xff;
	tmp[5] = (r >> 40 )& 0xff;
	tmp[6] = (r >> 48 )& 0xff;
	tmp[7] = (r >> 56 )& 0xff;

	lua_pushlstring(L, (const char *)tmp, 8);
}

static int
ldhsecret(lua_State *L) {
	uint32_t x[2], y[2];
	read64(L, x, y);
	uint64_t xx = (uint64_t)x[0] | (uint64_t)x[1]<<32;
	uint64_t yy = (uint64_t)y[0] | (uint64_t)y[1]<<32;
	if (xx == 0 || yy == 0)
		return luaL_error(L, "Can't be 0");
	uint64_t r = powmodp(xx, yy);

	push64(L, r);

	return 1;
}

#define G 5

static int
ldhexchange(lua_State *L) {
	size_t sz = 0;
	const uint8_t *x = (const uint8_t *)luaL_checklstring(L, 1, &sz);
	if (sz != 8) {
		luaL_error(L, "Invalid dh uint64 key");
	}
	uint32_t xx[2];
	xx[0] = x[0] | x[1]<<8 | x[2]<<16 | x[3]<<24;
	xx[1] = x[4] | x[5]<<8 | x[6]<<16 | x[7]<<24;

	uint64_t x64 = (uint64_t)xx[0] | (uint64_t)xx[1]<<32;
	if (x64 == 0)
		return luaL_error(L, "Can't be 0");

	uint64_t r = powmodp(G,	x64);
	push64(L, r);
	return 1;
}

// base64

static int
lb64encode(lua_State *L) {
	static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
	size_t sz = 0;
	const uint8_t * text = (const uint8_t *)luaL_checklstring(L, 1, &sz);
	int encode_sz = (sz + 2)/3*4;
	char tmp[SMALL_CHUNK];
	char *buffer = tmp;
	if (encode_sz > SMALL_CHUNK) {
		buffer = (char*)lua_newuserdatauv(L, encode_sz, 0);
	}
	int i,j;
	j=0;
	for (i=0;i<(int)sz-2;i+=3) {
		uint32_t v = text[i] << 16 | text[i+1] << 8 | text[i+2];
		buffer[j] = encoding[v >> 18];
		buffer[j+1] = encoding[(v >> 12) & 0x3f];
		buffer[j+2] = encoding[(v >> 6) & 0x3f];
		buffer[j+3] = encoding[(v) & 0x3f];
		j+=4;
	}
	int padding = sz-i;
	uint32_t v;
	switch(padding) {
	case 1 :
		v = text[i];
		buffer[j] = encoding[v >> 2];
		buffer[j+1] = encoding[(v & 3) << 4];
		buffer[j+2] = '=';
		buffer[j+3] = '=';
		break;
	case 2 :
		v = text[i] << 8 | text[i+1];
		buffer[j] = encoding[v >> 10];
		buffer[j+1] = encoding[(v >> 4) & 0x3f];
		buffer[j+2] = encoding[(v & 0xf) << 2];
		buffer[j+3] = '=';
		break;
	}
	lua_pushlstring(L, buffer, encode_sz);
	return 1;
}

static inline int
b64index(uint8_t c) {
	static const int decoding[] = {62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51};
	int decoding_size = sizeof(decoding)/sizeof(decoding[0]);
	if (c<43) {
		return -1;
	}
	c -= 43;
	if (c>=decoding_size)
		return -1;
	return decoding[c];
}

static int
lb64decode(lua_State *L) {
	size_t sz = 0;
	const uint8_t * text = (const uint8_t *)luaL_checklstring(L, 1, &sz);
	int decode_sz = (sz+3)/4*3;
	char tmp[SMALL_CHUNK];
	char *buffer = tmp;
	if (decode_sz > SMALL_CHUNK) {
		buffer = (char*)lua_newuserdatauv(L, decode_sz, 0);
	}
	int i,j;
	int output = 0;
	for (i=0;i<sz;) {
		int padding = 0;
		int c[4];
		for (j=0;j<4;) {
			if (i>=sz && 4>j){
				/*To improve compatibility, there may not be enough equal signs */ 
				c[j] = -2;   
			}else{
				c[j] = b64index(text[i]);
			}
			if (c[j] == -1) {
				++i;
				continue;
			}
			if (c[j] == -2) {
				++padding;
			}
			++i;
			++j;
		}
		uint32_t v;
		switch (padding) {
		case 0:
			v = (unsigned)c[0] << 18 | c[1] << 12 | c[2] << 6 | c[3];
			buffer[output] = v >> 16;
			buffer[output+1] = (v >> 8) & 0xff;
			buffer[output+2] = v & 0xff;
			output += 3;
			break;
		case 1:
			if (c[3] != -2 || (c[2] & 3)!=0) {
				return luaL_error(L, "Invalid base64 text");
			}
			v = (unsigned)c[0] << 10 | c[1] << 4 | c[2] >> 2 ;
			buffer[output] = v >> 8;
			buffer[output+1] = v & 0xff;
			output += 2;
			break;
		case 2:
			if (c[3] != -2 || c[2] != -2 || (c[1] & 0xf) !=0)  {
				return luaL_error(L, "Invalid base64 text");
			}
			v = (unsigned)c[0] << 2 | c[1] >> 4;
			buffer[output] = v;
			++ output;
			break;
		default:
			return luaL_error(L, "Invalid base64 text");
		}
	}
	lua_pushlstring(L, buffer, output);
	return 1;
}

static int
lxor_str(lua_State *L) {
	size_t len1,len2;
	const char *s1 = luaL_checklstring(L,1,&len1);
	const char *s2 = luaL_checklstring(L,2,&len2);
	if (len2 == 0) {
		return luaL_error(L, "Can't xor empty string");
	}
	luaL_Buffer b;
	char * buffer = luaL_buffinitsize(L, &b, len1);
	int i;
	for (i=0;i<len1;i++) {
		buffer[i] = s1[i] ^ s2[i % len2];
	}
	luaL_addsize(&b, len1);
	luaL_pushresult(&b);
	return 1;
}

// defined in lsha1.c
int lsha1(lua_State *L);
int lhmac_sha1(lua_State *L);


LUAMOD_API int
luaopen_skynet_crypt(lua_State *L) {
	luaL_checkversion(L);
	static int init = 0;
	if (!init) {
		// Don't need call srandom more than once.
		init = 1 ;
		srandom((random() << 8) ^ (time(NULL) << 16) ^ getpid());
	}
	luaL_Reg l[] = {
		{ "hashkey", lhashkey },
		{ "randomkey", lrandomkey },
		{ "desencode", ldesencode },
		{ "desdecode", ldesdecode },
		{ "hexencode", ltohex },
		{ "hexdecode", lfromhex },
		{ "hmac64", lhmac64 },
		{ "hmac64_md5", lhmac64_md5 },
		{ "dhexchange", ldhexchange },
		{ "dhsecret", ldhsecret },
		{ "base64encode", lb64encode },
		{ "base64decode", lb64decode },
		{ "sha1", lsha1 },
		{ "hmac_sha1", lhmac_sha1 },
		{ "hmac_hash", lhmac_hash },
		{ "xor_str", lxor_str },
		{ "padding", NULL },
		{ NULL, NULL },
	};
	luaL_newlib(L,l);

	padding_mode_table(L);
	lua_setfield(L, -2, "padding");

	return 1;
}

LUAMOD_API int
luaopen_client_crypt(lua_State *L) {
	return luaopen_skynet_crypt(L);
}