// Copyright (C) 2009,2010,2011,2012 GlavSoft LLC.
// All rights reserved.
//
//-------------------------------------------------------------------------
// This file is part of the TightVNC software.  Please visit our Web site:
//
//                       http://www.tightvnc.com/
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of 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.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//-------------------------------------------------------------------------
//

#include "DesCrypt.h"
#include "util/CommonHeader.h"

/* The following array is reversed for VNC compatibility,
   by Constantin Kaplinsky */

const static unsigned short bytebit[8]	= {
/**	0200, 0100, 040, 020, 010, 04, 02, 01 };	**/
	01, 02, 04, 010, 020, 040, 0100, 0200 };

const static unsigned long bigbyte[24] = {
	0x800000L,	0x400000L,	0x200000L,	0x100000L,
	0x80000L,	0x40000L,	0x20000L,	0x10000L,
	0x8000L,	0x4000L,	0x2000L,	0x1000L,
	0x800L, 	0x400L, 	0x200L, 	0x100L,
	0x80L,		0x40L,		0x20L,		0x10L,
	0x8L,		0x4L,		0x2L,		0x1L	};

/* Use the key schedule specified in the Standard (ANSI X3.92-1981). */

const static unsigned char pc1[56] = {
	56, 48, 40, 32, 24, 16,  8,	 0, 57, 49, 41, 33, 25, 17,
	 9,  1, 58, 50, 42, 34, 26,	18, 10,  2, 59, 51, 43, 35,
	62, 54, 46, 38, 30, 22, 14,	 6, 61, 53, 45, 37, 29, 21,
	13,  5, 60, 52, 44, 36, 28,	20, 12,  4, 27, 19, 11,  3 };

const static unsigned char totrot[16] = {
	1,2,4,6,8,10,12,14,15,17,19,21,23,25,27,28 };

const static unsigned char pc2[48] = {
	13, 16, 10, 23,  0,  4,  2, 27, 14,  5, 20,  9,
	22, 18, 11,  3, 25,  7, 15,  6, 26, 19, 12,  1,
	40, 51, 30, 36, 46, 54, 29, 39, 50, 44, 32, 47,
	43, 48, 38, 55, 33, 52, 45, 41, 49, 35, 28, 31 };

DesCrypt::DesCrypt()
{
  clearKey();
}

DesCrypt::~DesCrypt()
{
}

void DesCrypt::encrypt(UINT8 *dst, const UINT8 *src, size_t dataLen,
                       const UINT8 *key)
{
  deskey(key, ENCRYPT);
  for (size_t i = 0; i < dataLen; i += 8) {
    des(&src[i], &dst[i]);
  }
  clearKey();
}

void DesCrypt::decrypt(UINT8 *dst, const UINT8 *src, size_t dataLen,
                       const UINT8 *key)
{
  deskey(key, DECRYPT);
  for (size_t i = 0; i < dataLen; i += 8) {
    des(&src[i], &dst[i]);
  }
  clearKey();
}

void DesCrypt::clearKey()
{
  memset(m_knL, 0, sizeof(m_knL));
}

void DesCrypt::deskey(const UINT8 hexKey[8], OperationMode mode)
{
  int i, j, l, m, n;
  UINT8 pc1m[56], pcr[56];
  unsigned long kn[32];

  for (j = 0; j < 56; j++) {
    l = pc1[j];
    m = l & 07;
    pc1m[j] = (hexKey[l >> 3] & bytebit[m]) ? 1 : 0;
  }
  for (i = 0; i < 16; i++) {
    if (mode == DECRYPT) m = (15 - i) << 1;
    else m = i << 1;
    n = m + 1;
    kn[m] = kn[n] = 0L;
    for (j = 0; j < 28; j++) {
      l = j + totrot[i];
      if (l < 28) pcr[j] = pc1m[l];
      else pcr[j] = pc1m[l - 28];
    }
    for (j = 28; j < 56; j++) {
      l = j + totrot[i];
      if (l < 56) pcr[j] = pc1m[l];
      else pcr[j] = pc1m[l - 28];
    }
    for (j = 0; j < 24; j++) {
      if (pcr[pc2[j]]) kn[m] |= bigbyte[j];
      if (pcr[pc2[j+24]]) kn[n] |= bigbyte[j];
    }
  }
  cookey(kn);
  return;
}

void DesCrypt::cookey(unsigned long *raw1)
{
  unsigned long *cook, *raw0;
  unsigned long dough[32];
  int i;

  cook = dough;
  for (i = 0; i < 16; i++, raw1++) {
    raw0 = raw1++;
    *cook	 = (*raw0 & 0x00fc0000L) << 6;
    *cook	|= (*raw0 & 0x00000fc0L) << 10;
    *cook	|= (*raw1 & 0x00fc0000L) >> 10;
    *cook++ |= (*raw1 & 0x00000fc0L) >> 6;
    *cook	 = (*raw0 & 0x0003f000L) << 12;
    *cook	|= (*raw0 & 0x0000003fL) << 16;
    *cook	|= (*raw1 & 0x0003f000L) >> 4;
    *cook++ |= (*raw1 & 0x0000003fL);
  }
  usekey(dough);
  return;
}

/*
void cpkey(into)
unsigned long *into;
{
	unsigned long *from, *endp;

	from = m_knL, endp = &m_knL[32];
	while(from < endp) *into++ = *from++;
	return;
	}
*/

void DesCrypt::usekey(unsigned long *from)
{
  unsigned long *to, *endp;

  to = m_knL, endp = &m_knL[32];
  while (to < endp) *to++ = *from++;
  return;
}

void DesCrypt::des(const unsigned char from[8], unsigned char to[8])
{
  unsigned long work[2];

  scrunch(from, work);
  desfunc(work, m_knL);
  unscrun(work, to);
  return;
}

void DesCrypt::scrunch(const unsigned char *outof, unsigned long *into)
{
  *into    = (*outof++ & 0xffL) << 24;
  *into   |= (*outof++ & 0xffL) << 16;
  *into   |= (*outof++ & 0xffL) << 8;
  *into++ |= (*outof++ & 0xffL);
  *into    = (*outof++ & 0xffL) << 24;
  *into   |= (*outof++ & 0xffL) << 16;
  *into   |= (*outof++ & 0xffL) << 8;
  *into   |= (*outof   & 0xffL);
  return;
}

void DesCrypt::unscrun(const unsigned long *outof, unsigned char *into)
{
  *into++ = (*outof >> 24) & 0xffL;
  *into++ = (*outof >> 16) & 0xffL;
  *into++ = (*outof >>  8) & 0xffL;
  *into++ =  *outof++      & 0xffL;
  *into++ = (*outof >> 24) & 0xffL;
  *into++ = (*outof >> 16) & 0xffL;
  *into++ = (*outof >>  8) & 0xffL;
  *into   =  *outof        & 0xffL;
  return;
}

static unsigned long SP1[64] = {
  0x01010400L, 0x00000000L, 0x00010000L, 0x01010404L,
  0x01010004L, 0x00010404L, 0x00000004L, 0x00010000L,
  0x00000400L, 0x01010400L, 0x01010404L, 0x00000400L,
  0x01000404L, 0x01010004L, 0x01000000L, 0x00000004L,
  0x00000404L, 0x01000400L, 0x01000400L, 0x00010400L,
  0x00010400L, 0x01010000L, 0x01010000L, 0x01000404L,
  0x00010004L, 0x01000004L, 0x01000004L, 0x00010004L,
  0x00000000L, 0x00000404L, 0x00010404L, 0x01000000L,
  0x00010000L, 0x01010404L, 0x00000004L, 0x01010000L,
  0x01010400L, 0x01000000L, 0x01000000L, 0x00000400L,
  0x01010004L, 0x00010000L, 0x00010400L, 0x01000004L,
  0x00000400L, 0x00000004L, 0x01000404L, 0x00010404L,
  0x01010404L, 0x00010004L, 0x01010000L, 0x01000404L,
  0x01000004L, 0x00000404L, 0x00010404L, 0x01010400L,
  0x00000404L, 0x01000400L, 0x01000400L, 0x00000000L,
  0x00010004L, 0x00010400L, 0x00000000L, 0x01010004L
};

static unsigned long SP2[64] = {
  0x80108020L, 0x80008000L, 0x00008000L, 0x00108020L,
  0x00100000L, 0x00000020L, 0x80100020L, 0x80008020L,
  0x80000020L, 0x80108020L, 0x80108000L, 0x80000000L,
  0x80008000L, 0x00100000L, 0x00000020L, 0x80100020L,
  0x00108000L, 0x00100020L, 0x80008020L, 0x00000000L,
  0x80000000L, 0x00008000L, 0x00108020L, 0x80100000L,
  0x00100020L, 0x80000020L, 0x00000000L, 0x00108000L,
  0x00008020L, 0x80108000L, 0x80100000L, 0x00008020L,
  0x00000000L, 0x00108020L, 0x80100020L, 0x00100000L,
  0x80008020L, 0x80100000L, 0x80108000L, 0x00008000L,
  0x80100000L, 0x80008000L, 0x00000020L, 0x80108020L,
  0x00108020L, 0x00000020L, 0x00008000L, 0x80000000L,
  0x00008020L, 0x80108000L, 0x00100000L, 0x80000020L,
  0x00100020L, 0x80008020L, 0x80000020L, 0x00100020L,
  0x00108000L, 0x00000000L, 0x80008000L, 0x00008020L,
  0x80000000L, 0x80100020L, 0x80108020L, 0x00108000L
};

static unsigned long SP3[64] = {
  0x00000208L, 0x08020200L, 0x00000000L, 0x08020008L,
  0x08000200L, 0x00000000L, 0x00020208L, 0x08000200L,
  0x00020008L, 0x08000008L, 0x08000008L, 0x00020000L,
  0x08020208L, 0x00020008L, 0x08020000L, 0x00000208L,
  0x08000000L, 0x00000008L, 0x08020200L, 0x00000200L,
  0x00020200L, 0x08020000L, 0x08020008L, 0x00020208L,
  0x08000208L, 0x00020200L, 0x00020000L, 0x08000208L,
  0x00000008L, 0x08020208L, 0x00000200L, 0x08000000L,
  0x08020200L, 0x08000000L, 0x00020008L, 0x00000208L,
  0x00020000L, 0x08020200L, 0x08000200L, 0x00000000L,
  0x00000200L, 0x00020008L, 0x08020208L, 0x08000200L,
  0x08000008L, 0x00000200L, 0x00000000L, 0x08020008L,
  0x08000208L, 0x00020000L, 0x08000000L, 0x08020208L,
  0x00000008L, 0x00020208L, 0x00020200L, 0x08000008L,
  0x08020000L, 0x08000208L, 0x00000208L, 0x08020000L,
  0x00020208L, 0x00000008L, 0x08020008L, 0x00020200L
};

static unsigned long SP4[64] = {
  0x00802001L, 0x00002081L, 0x00002081L, 0x00000080L,
  0x00802080L, 0x00800081L, 0x00800001L, 0x00002001L,
  0x00000000L, 0x00802000L, 0x00802000L, 0x00802081L,
  0x00000081L, 0x00000000L, 0x00800080L, 0x00800001L,
  0x00000001L, 0x00002000L, 0x00800000L, 0x00802001L,
  0x00000080L, 0x00800000L, 0x00002001L, 0x00002080L,
  0x00800081L, 0x00000001L, 0x00002080L, 0x00800080L,
  0x00002000L, 0x00802080L, 0x00802081L, 0x00000081L,
  0x00800080L, 0x00800001L, 0x00802000L, 0x00802081L,
  0x00000081L, 0x00000000L, 0x00000000L, 0x00802000L,
  0x00002080L, 0x00800080L, 0x00800081L, 0x00000001L,
  0x00802001L, 0x00002081L, 0x00002081L, 0x00000080L,
  0x00802081L, 0x00000081L, 0x00000001L, 0x00002000L,
  0x00800001L, 0x00002001L, 0x00802080L, 0x00800081L,
  0x00002001L, 0x00002080L, 0x00800000L, 0x00802001L,
  0x00000080L, 0x00800000L, 0x00002000L, 0x00802080L
};

static unsigned long SP5[64] = {
  0x00000100L, 0x02080100L, 0x02080000L, 0x42000100L,
  0x00080000L, 0x00000100L, 0x40000000L, 0x02080000L,
  0x40080100L, 0x00080000L, 0x02000100L, 0x40080100L,
  0x42000100L, 0x42080000L, 0x00080100L, 0x40000000L,
  0x02000000L, 0x40080000L, 0x40080000L, 0x00000000L,
  0x40000100L, 0x42080100L, 0x42080100L, 0x02000100L,
  0x42080000L, 0x40000100L, 0x00000000L, 0x42000000L,
  0x02080100L, 0x02000000L, 0x42000000L, 0x00080100L,
  0x00080000L, 0x42000100L, 0x00000100L, 0x02000000L,
  0x40000000L, 0x02080000L, 0x42000100L, 0x40080100L,
  0x02000100L, 0x40000000L, 0x42080000L, 0x02080100L,
  0x40080100L, 0x00000100L, 0x02000000L, 0x42080000L,
  0x42080100L, 0x00080100L, 0x42000000L, 0x42080100L,
  0x02080000L, 0x00000000L, 0x40080000L, 0x42000000L,
  0x00080100L, 0x02000100L, 0x40000100L, 0x00080000L,
  0x00000000L, 0x40080000L, 0x02080100L, 0x40000100L
};

static unsigned long SP6[64] = {
  0x20000010L, 0x20400000L, 0x00004000L, 0x20404010L,
  0x20400000L, 0x00000010L, 0x20404010L, 0x00400000L,
  0x20004000L, 0x00404010L, 0x00400000L, 0x20000010L,
  0x00400010L, 0x20004000L, 0x20000000L, 0x00004010L,
  0x00000000L, 0x00400010L, 0x20004010L, 0x00004000L,
  0x00404000L, 0x20004010L, 0x00000010L, 0x20400010L,
  0x20400010L, 0x00000000L, 0x00404010L, 0x20404000L,
  0x00004010L, 0x00404000L, 0x20404000L, 0x20000000L,
  0x20004000L, 0x00000010L, 0x20400010L, 0x00404000L,
  0x20404010L, 0x00400000L, 0x00004010L, 0x20000010L,
  0x00400000L, 0x20004000L, 0x20000000L, 0x00004010L,
  0x20000010L, 0x20404010L, 0x00404000L, 0x20400000L,
  0x00404010L, 0x20404000L, 0x00000000L, 0x20400010L,
  0x00000010L, 0x00004000L, 0x20400000L, 0x00404010L,
  0x00004000L, 0x00400010L, 0x20004010L, 0x00000000L,
  0x20404000L, 0x20000000L, 0x00400010L, 0x20004010L
};

static unsigned long SP7[64] = {
  0x00200000L, 0x04200002L, 0x04000802L, 0x00000000L,
  0x00000800L, 0x04000802L, 0x00200802L, 0x04200800L,
  0x04200802L, 0x00200000L, 0x00000000L, 0x04000002L,
  0x00000002L, 0x04000000L, 0x04200002L, 0x00000802L,
  0x04000800L, 0x00200802L, 0x00200002L, 0x04000800L,
  0x04000002L, 0x04200000L, 0x04200800L, 0x00200002L,
  0x04200000L, 0x00000800L, 0x00000802L, 0x04200802L,
  0x00200800L, 0x00000002L, 0x04000000L, 0x00200800L,
  0x04000000L, 0x00200800L, 0x00200000L, 0x04000802L,
  0x04000802L, 0x04200002L, 0x04200002L, 0x00000002L,
  0x00200002L, 0x04000000L, 0x04000800L, 0x00200000L,
  0x04200800L, 0x00000802L, 0x00200802L, 0x04200800L,
  0x00000802L, 0x04000002L, 0x04200802L, 0x04200000L,
  0x00200800L, 0x00000000L, 0x00000002L, 0x04200802L,
  0x00000000L, 0x00200802L, 0x04200000L, 0x00000800L,
  0x04000002L, 0x04000800L, 0x00000800L, 0x00200002L
};

static unsigned long SP8[64] = {
  0x10001040L, 0x00001000L, 0x00040000L, 0x10041040L,
  0x10000000L, 0x10001040L, 0x00000040L, 0x10000000L,
  0x00040040L, 0x10040000L, 0x10041040L, 0x00041000L,
  0x10041000L, 0x00041040L, 0x00001000L, 0x00000040L,
  0x10040000L, 0x10000040L, 0x10001000L, 0x00001040L,
  0x00041000L, 0x00040040L, 0x10040040L, 0x10041000L,
  0x00001040L, 0x00000000L, 0x00000000L, 0x10040040L,
  0x10000040L, 0x10001000L, 0x00041040L, 0x00040000L,
  0x00041040L, 0x00040000L, 0x10041000L, 0x00001000L,
  0x00000040L, 0x10040040L, 0x00001000L, 0x00041040L,
  0x10001000L, 0x00000040L, 0x10000040L, 0x10040000L,
  0x10040040L, 0x10000000L, 0x00040000L, 0x10001040L,
  0x00000000L, 0x10041040L, 0x00040040L, 0x10000040L,
  0x10040000L, 0x10001000L, 0x10001040L, 0x00000000L,
  0x10041040L, 0x00041000L, 0x00041000L, 0x00001040L,
  0x00001040L, 0x00040040L, 0x10000000L, 0x10041000L
};

void DesCrypt::desfunc(unsigned long *block, unsigned long *keys)
{
  unsigned long fval, work, right, leftt;
  int round;

  leftt = block[0];
  right = block[1];
  work = ((leftt >> 4) ^ right) & 0x0f0f0f0fL;
  right ^= work;
  leftt ^= (work << 4);
  work = ((leftt >> 16) ^ right) & 0x0000ffffL;
  right ^= work;
  leftt ^= (work << 16);
  work = ((right >> 2) ^ leftt) & 0x33333333L;
  leftt ^= work;
  right ^= (work << 2);
  work = ((right >> 8) ^ leftt) & 0x00ff00ffL;
  leftt ^= work;
  right ^= (work << 8);
  right = ((right << 1) | ((right >> 31) & 1L)) & 0xffffffffL;
  work = (leftt ^ right) & 0xaaaaaaaaL;
  leftt ^= work;
  right ^= work;
  leftt = ((leftt << 1) | ((leftt >> 31) & 1L)) & 0xffffffffL;

  for (round = 0; round < 8; round++) {
    work  = (right << 28) | (right >> 4);
    work ^= *keys++;
    fval  = SP7[ work		 & 0x3fL];
    fval |= SP5[(work >>  8) & 0x3fL];
    fval |= SP3[(work >> 16) & 0x3fL];
    fval |= SP1[(work >> 24) & 0x3fL];
    work  = right ^ *keys++;
    fval |= SP8[ work		 & 0x3fL];
    fval |= SP6[(work >>  8) & 0x3fL];
    fval |= SP4[(work >> 16) & 0x3fL];
    fval |= SP2[(work >> 24) & 0x3fL];
    leftt ^= fval;
    work  = (leftt << 28) | (leftt >> 4);
    work ^= *keys++;
    fval  = SP7[ work		 & 0x3fL];
    fval |= SP5[(work >>  8) & 0x3fL];
    fval |= SP3[(work >> 16) & 0x3fL];
    fval |= SP1[(work >> 24) & 0x3fL];
    work  = leftt ^ *keys++;
    fval |= SP8[ work		 & 0x3fL];
    fval |= SP6[(work >>  8) & 0x3fL];
    fval |= SP4[(work >> 16) & 0x3fL];
    fval |= SP2[(work >> 24) & 0x3fL];
    right ^= fval;
  }

  right = (right << 31) | (right >> 1);
  work = (leftt ^ right) & 0xaaaaaaaaL;
  leftt ^= work;
  right ^= work;
  leftt = (leftt << 31) | (leftt >> 1);
  work = ((leftt >> 8) ^ right) & 0x00ff00ffL;
  right ^= work;
  leftt ^= (work << 8);
  work = ((leftt >> 2) ^ right) & 0x33333333L;
  right ^= work;
  leftt ^= (work << 2);
  work = ((right >> 16) ^ leftt) & 0x0000ffffL;
  leftt ^= work;
  right ^= (work << 16);
  work = ((right >> 4) ^ leftt) & 0x0f0f0f0fL;
  leftt ^= work;
  right ^= (work << 4);
  *block++ = right;
  *block = leftt;
  return;
}
