/*$*********************************************************
$*
$* This code has been taken from DDJ 11/93, from an 
$* article by Pawel Szczerbina. Please read the file
$* README for my questions about the legal status of
$* this code.
$*
$* Password encryption routines follow.
$* Converted to C from Barry Nance's Pascal
$* prog published in the March -93 issue of Byte.
$*
$* Adapted to be useable for ncpfs by 
$* Volker Lendecke <lendecke@namu01.gwdg.de> in 
$* October 1995. 
$*
$**********************************************************/

/******************* Data types ***************************/
typedef unsigned char buf32[32];
typedef unsigned char buf16[16];
typedef unsigned char buf8[8];
typedef unsigned char buf4[4];
typedef unsigned char u8;

static u8 encrypttable[256] =
{0x7,0x8,0x0,0x8,0x6,0x4,0xE,0x4,0x5,0xC,0x1,0x7,0xB,0xF,0xA,0x8,
 0xF,0x8,0xC,0xC,0x9,0x4,0x1,0xE,0x4,0x6,0x2,0x4,0x0,0xA,0xB,0x9,
 0x2,0xF,0xB,0x1,0xD,0x2,0x1,0x9,0x5,0xE,0x7,0x0,0x0,0x2,0x6,0x6,
 0x0,0x7,0x3,0x8,0x2,0x9,0x3,0xF,0x7,0xF,0xC,0xF,0x6,0x4,0xA,0x0,
 0x2,0x3,0xA,0xB,0xD,0x8,0x3,0xA,0x1,0x7,0xC,0xF,0x1,0x8,0x9,0xD,
 0x9,0x1,0x9,0x4,0xE,0x4,0xC,0x5,0x5,0xC,0x8,0xB,0x2,0x3,0x9,0xE,
 0x7,0x7,0x6,0x9,0xE,0xF,0xC,0x8,0xD,0x1,0xA,0x6,0xE,0xD,0x0,0x7,
 0x7,0xA,0x0,0x1,0xF,0x5,0x4,0xB,0x7,0xB,0xE,0xC,0x9,0x5,0xD,0x1,
 0xB,0xD,0x1,0x3,0x5,0xD,0xE,0x6,0x3,0x0,0xB,0xB,0xF,0x3,0x6,0x4,
 0x9,0xD,0xA,0x3,0x1,0x4,0x9,0x4,0x8,0x3,0xB,0xE,0x5,0x0,0x5,0x2,
 0xC,0xB,0xD,0x5,0xD,0x5,0xD,0x2,0xD,0x9,0xA,0xC,0xA,0x0,0xB,0x3,
 0x5,0x3,0x6,0x9,0x5,0x1,0xE,0xE,0x0,0xE,0x8,0x2,0xD,0x2,0x2,0x0,
 0x4,0xF,0x8,0x5,0x9,0x6,0x8,0x6,0xB,0xA,0xB,0xF,0x0,0x7,0x2,0x8,
 0xC,0x7,0x3,0xA,0x1,0x4,0x2,0x5,0xF,0x7,0xA,0xC,0xE,0x5,0x9,0x3,
 0xE,0x7,0x1,0x2,0xE,0x1,0xF,0x4,0xA,0x6,0xC,0x6,0xF,0x4,0x3,0x0,
 0xC,0x0,0x3,0x6,0xF,0x8,0x7,0xB,0x2,0xD,0xC,0x6,0xA,0xA,0x8,0xD};

static buf32 encryptkeys  =
{0x48,0x93,0x46,0x67,0x98,0x3D,0xE6,0x8D,
 0xB7,0x10,0x7A,0x26,0x5A,0xB9,0xB1,0x35,
 0x6B,0x0F,0xD5,0x70,0xAE,0xFB,0xAD,0x11,
 0xF4,0x47,0xDC,0xA7,0xEC,0xCF,0x50,0xC0};


static void
shuffle1(buf32 temp, unsigned char *target)
{
	short b4;
	unsigned char b3;
	int s, b2, i;

	b4 = 0;

	for (b2 = 0; b2 <= 1; ++b2)
	{
		for (s = 0; s <= 31; ++s)
		{
			b3 = (temp[s]+b4) ^ (temp[(s+b4)&31] - encryptkeys[s]);
			b4 = b4 + b3;
			temp[s] = b3;
		}
	}

	for (i = 0; i <= 15; ++i) {
		target[i] =    encrypttable[temp[ 2*i    ]]
			    | (encrypttable[temp[ 2*i + 1]] << 4);
	}
}


void
shuffle(unsigned char *lon, const unsigned char *buf, int buflen,
	unsigned char *target)
{
	int b2, d, s;
	buf32 temp;

	while (   (buflen > 0)
	       && (buf[buflen - 1] == 0)) {
		buflen = buflen - 1;
	}

	for (s = 0; s < 32; s++) {
		temp[s] = 0;
	}

	d = 0;
	while (buflen >= 32)
	{
		for (s = 0; s <= 31; ++s)
		{
			temp[s] = temp[s] ^ buf[d];
			d = d + 1;
		}
		buflen = buflen - 32;
	}
	b2 = d;
	if (buflen > 0)
	{
		for (s = 0; s <= 31; ++s)
		{
			if (d + buflen == b2)
			{
				b2 = d;
				temp[s] = temp[s] ^ encryptkeys[s];
			} else {
				temp[s] = temp[s] ^ buf[b2];
				b2 = b2 + 1;
			}
		}
	}

	for (s = 0; s <= 31; ++s)
		temp[s] = temp[s] ^ lon[s & 3];

	shuffle1(temp,target);
}


void
nw_encrypt(unsigned char *fra,unsigned char *buf,unsigned char *til)
{
	buf32 k;
	int s;

	shuffle(&(fra[0]), buf, 16, &(k[ 0]));
	shuffle(&(fra[4]), buf, 16, &(k[16]));

	for (s = 0; s <= 15; ++s)
		k[s] = k[s] ^ k[31 - s];

	for (s = 0; s <= 7; ++s)
		til[s] = k[s] ^ k[15 - s];
}