des_impl.c

/* Copyright (C) 1992 Eric Young - see COPYING for more details */
/* Collected from libdes and modified for SECURE RPC by Martin Kuck 1994 */
#include <string.h>
#include "des.h"


static const unsigned long des_SPtrans[8][64] =
{
  {				/* nibble 0 */
    0x00820200, 0x00020000, 0x80800000, 0x80820200,
    0x00800000, 0x80020200, 0x80020000, 0x80800000,
    0x80020200, 0x00820200, 0x00820000, 0x80000200,
    0x80800200, 0x00800000, 0x00000000, 0x80020000,
    0x00020000, 0x80000000, 0x00800200, 0x00020200,
    0x80820200, 0x00820000, 0x80000200, 0x00800200,
    0x80000000, 0x00000200, 0x00020200, 0x80820000,
    0x00000200, 0x80800200, 0x80820000, 0x00000000,
    0x00000000, 0x80820200, 0x00800200, 0x80020000,
    0x00820200, 0x00020000, 0x80000200, 0x00800200,
    0x80820000, 0x00000200, 0x00020200, 0x80800000,
    0x80020200, 0x80000000, 0x80800000, 0x00820000,
    0x80820200, 0x00020200, 0x00820000, 0x80800200,
    0x00800000, 0x80000200, 0x80020000, 0x00000000,
    0x00020000, 0x00800000, 0x80800200, 0x00820200,
    0x80000000, 0x80820000, 0x00000200, 0x80020200},

  {				/* nibble 1 */
    0x10042004, 0x00000000, 0x00042000, 0x10040000,
    0x10000004, 0x00002004, 0x10002000, 0x00042000,
    0x00002000, 0x10040004, 0x00000004, 0x10002000,
    0x00040004, 0x10042000, 0x10040000, 0x00000004,
    0x00040000, 0x10002004, 0x10040004, 0x00002000,
    0x00042004, 0x10000000, 0x00000000, 0x00040004,
    0x10002004, 0x00042004, 0x10042000, 0x10000004,
    0x10000000, 0x00040000, 0x00002004, 0x10042004,
    0x00040004, 0x10042000, 0x10002000, 0x00042004,
    0x10042004, 0x00040004, 0x10000004, 0x00000000,
    0x10000000, 0x00002004, 0x00040000, 0x10040004,
    0x00002000, 0x10000000, 0x00042004, 0x10002004,
    0x10042000, 0x00002000, 0x00000000, 0x10000004,
    0x00000004, 0x10042004, 0x00042000, 0x10040000,
    0x10040004, 0x00040000, 0x00002004, 0x10002000,
    0x10002004, 0x00000004, 0x10040000, 0x00042000},

  {				/* nibble 2 */
    0x41000000, 0x01010040, 0x00000040, 0x41000040,
    0x40010000, 0x01000000, 0x41000040, 0x00010040,
    0x01000040, 0x00010000, 0x01010000, 0x40000000,
    0x41010040, 0x40000040, 0x40000000, 0x41010000,
    0x00000000, 0x40010000, 0x01010040, 0x00000040,
    0x40000040, 0x41010040, 0x00010000, 0x41000000,
    0x41010000, 0x01000040, 0x40010040, 0x01010000,
    0x00010040, 0x00000000, 0x01000000, 0x40010040,
    0x01010040, 0x00000040, 0x40000000, 0x00010000,
    0x40000040, 0x40010000, 0x01010000, 0x41000040,
    0x00000000, 0x01010040, 0x00010040, 0x41010000,
    0x40010000, 0x01000000, 0x41010040, 0x40000000,
    0x40010040, 0x41000000, 0x01000000, 0x41010040,
    0x00010000, 0x01000040, 0x41000040, 0x00010040,
    0x01000040, 0x00000000, 0x41010000, 0x40000040,
    0x41000000, 0x40010040, 0x00000040, 0x01010000},

  {				/* nibble 3 */
    0x00100402, 0x04000400, 0x00000002, 0x04100402,
    0x00000000, 0x04100000, 0x04000402, 0x00100002,
    0x04100400, 0x04000002, 0x04000000, 0x00000402,
    0x04000002, 0x00100402, 0x00100000, 0x04000000,
    0x04100002, 0x00100400, 0x00000400, 0x00000002,
    0x00100400, 0x04000402, 0x04100000, 0x00000400,
    0x00000402, 0x00000000, 0x00100002, 0x04100400,
    0x04000400, 0x04100002, 0x04100402, 0x00100000,
    0x04100002, 0x00000402, 0x00100000, 0x04000002,
    0x00100400, 0x04000400, 0x00000002, 0x04100000,
    0x04000402, 0x00000000, 0x00000400, 0x00100002,
    0x00000000, 0x04100002, 0x04100400, 0x00000400,
    0x04000000, 0x04100402, 0x00100402, 0x00100000,
    0x04100402, 0x00000002, 0x04000400, 0x00100402,
    0x00100002, 0x00100400, 0x04100000, 0x04000402,
    0x00000402, 0x04000000, 0x04000002, 0x04100400},

  {				/* nibble 4 */
    0x02000000, 0x00004000, 0x00000100, 0x02004108,
    0x02004008, 0x02000100, 0x00004108, 0x02004000,
    0x00004000, 0x00000008, 0x02000008, 0x00004100,
    0x02000108, 0x02004008, 0x02004100, 0x00000000,
    0x00004100, 0x02000000, 0x00004008, 0x00000108,
    0x02000100, 0x00004108, 0x00000000, 0x02000008,
    0x00000008, 0x02000108, 0x02004108, 0x00004008,
    0x02004000, 0x00000100, 0x00000108, 0x02004100,
    0x02004100, 0x02000108, 0x00004008, 0x02004000,
    0x00004000, 0x00000008, 0x02000008, 0x02000100,
    0x02000000, 0x00004100, 0x02004108, 0x00000000,
    0x00004108, 0x02000000, 0x00000100, 0x00004008,
    0x02000108, 0x00000100, 0x00000000, 0x02004108,
    0x02004008, 0x02004100, 0x00000108, 0x00004000,
    0x00004100, 0x02004008, 0x02000100, 0x00000108,
    0x00000008, 0x00004108, 0x02004000, 0x02000008},

  {				/* nibble 5 */
    0x20000010, 0x00080010, 0x00000000, 0x20080800,
    0x00080010, 0x00000800, 0x20000810, 0x00080000,
    0x00000810, 0x20080810, 0x00080800, 0x20000000,
    0x20000800, 0x20000010, 0x20080000, 0x00080810,
    0x00080000, 0x20000810, 0x20080010, 0x00000000,
    0x00000800, 0x00000010, 0x20080800, 0x20080010,
    0x20080810, 0x20080000, 0x20000000, 0x00000810,
    0x00000010, 0x00080800, 0x00080810, 0x20000800,
    0x00000810, 0x20000000, 0x20000800, 0x00080810,
    0x20080800, 0x00080010, 0x00000000, 0x20000800,
    0x20000000, 0x00000800, 0x20080010, 0x00080000,
    0x00080010, 0x20080810, 0x00080800, 0x00000010,
    0x20080810, 0x00080800, 0x00080000, 0x20000810,
    0x20000010, 0x20080000, 0x00080810, 0x00000000,
    0x00000800, 0x20000010, 0x20000810, 0x20080800,
    0x20080000, 0x00000810, 0x00000010, 0x20080010},

  {				/* nibble 6 */
    0x00001000, 0x00000080, 0x00400080, 0x00400001,
    0x00401081, 0x00001001, 0x00001080, 0x00000000,
    0x00400000, 0x00400081, 0x00000081, 0x00401000,
    0x00000001, 0x00401080, 0x00401000, 0x00000081,
    0x00400081, 0x00001000, 0x00001001, 0x00401081,
    0x00000000, 0x00400080, 0x00400001, 0x00001080,
    0x00401001, 0x00001081, 0x00401080, 0x00000001,
    0x00001081, 0x00401001, 0x00000080, 0x00400000,
    0x00001081, 0x00401000, 0x00401001, 0x00000081,
    0x00001000, 0x00000080, 0x00400000, 0x00401001,
    0x00400081, 0x00001081, 0x00001080, 0x00000000,
    0x00000080, 0x00400001, 0x00000001, 0x00400080,
    0x00000000, 0x00400081, 0x00400080, 0x00001080,
    0x00000081, 0x00001000, 0x00401081, 0x00400000,
    0x00401080, 0x00000001, 0x00001001, 0x00401081,
    0x00400001, 0x00401080, 0x00401000, 0x00001001},

  {				/* nibble 7 */
    0x08200020, 0x08208000, 0x00008020, 0x00000000,
    0x08008000, 0x00200020, 0x08200000, 0x08208020,
    0x00000020, 0x08000000, 0x00208000, 0x00008020,
    0x00208020, 0x08008020, 0x08000020, 0x08200000,
    0x00008000, 0x00208020, 0x00200020, 0x08008000,
    0x08208020, 0x08000020, 0x00000000, 0x00208000,
    0x08000000, 0x00200000, 0x08008020, 0x08200020,
    0x00200000, 0x00008000, 0x08208000, 0x00000020,
    0x00200000, 0x00008000, 0x08000020, 0x08208020,
    0x00008020, 0x08000000, 0x00000000, 0x00208000,
    0x08200020, 0x08008020, 0x08008000, 0x00200020,
    0x08208000, 0x00000020, 0x00200020, 0x08008000,
    0x08208020, 0x00200000, 0x08200000, 0x08000020,
    0x00208000, 0x00008020, 0x08008020, 0x08200000,
    0x00000020, 0x08208000, 0x00208020, 0x00000000,
    0x08000000, 0x08200020, 0x00008000, 0x00208020}};

static const unsigned long des_skb[8][64] =
{
  {				/* for C bits (numbered as per FIPS 46) 1 2 3 4 5 6 */
    0x00000000, 0x00000010, 0x20000000, 0x20000010,
    0x00010000, 0x00010010, 0x20010000, 0x20010010,
    0x00000800, 0x00000810, 0x20000800, 0x20000810,
    0x00010800, 0x00010810, 0x20010800, 0x20010810,
    0x00000020, 0x00000030, 0x20000020, 0x20000030,
    0x00010020, 0x00010030, 0x20010020, 0x20010030,
    0x00000820, 0x00000830, 0x20000820, 0x20000830,
    0x00010820, 0x00010830, 0x20010820, 0x20010830,
    0x00080000, 0x00080010, 0x20080000, 0x20080010,
    0x00090000, 0x00090010, 0x20090000, 0x20090010,
    0x00080800, 0x00080810, 0x20080800, 0x20080810,
    0x00090800, 0x00090810, 0x20090800, 0x20090810,
    0x00080020, 0x00080030, 0x20080020, 0x20080030,
    0x00090020, 0x00090030, 0x20090020, 0x20090030,
    0x00080820, 0x00080830, 0x20080820, 0x20080830,
    0x00090820, 0x00090830, 0x20090820, 0x20090830},
  {				/* for C bits (numbered as per FIPS 46) 7 8 10 11 12 13 */
    0x00000000, 0x02000000, 0x00002000, 0x02002000,
    0x00200000, 0x02200000, 0x00202000, 0x02202000,
    0x00000004, 0x02000004, 0x00002004, 0x02002004,
    0x00200004, 0x02200004, 0x00202004, 0x02202004,
    0x00000400, 0x02000400, 0x00002400, 0x02002400,
    0x00200400, 0x02200400, 0x00202400, 0x02202400,
    0x00000404, 0x02000404, 0x00002404, 0x02002404,
    0x00200404, 0x02200404, 0x00202404, 0x02202404,
    0x10000000, 0x12000000, 0x10002000, 0x12002000,
    0x10200000, 0x12200000, 0x10202000, 0x12202000,
    0x10000004, 0x12000004, 0x10002004, 0x12002004,
    0x10200004, 0x12200004, 0x10202004, 0x12202004,
    0x10000400, 0x12000400, 0x10002400, 0x12002400,
    0x10200400, 0x12200400, 0x10202400, 0x12202400,
    0x10000404, 0x12000404, 0x10002404, 0x12002404,
    0x10200404, 0x12200404, 0x10202404, 0x12202404},
  {				/* for C bits (numbered as per FIPS 46) 14 15 16 17 19 20 */
    0x00000000, 0x00000001, 0x00040000, 0x00040001,
    0x01000000, 0x01000001, 0x01040000, 0x01040001,
    0x00000002, 0x00000003, 0x00040002, 0x00040003,
    0x01000002, 0x01000003, 0x01040002, 0x01040003,
    0x00000200, 0x00000201, 0x00040200, 0x00040201,
    0x01000200, 0x01000201, 0x01040200, 0x01040201,
    0x00000202, 0x00000203, 0x00040202, 0x00040203,
    0x01000202, 0x01000203, 0x01040202, 0x01040203,
    0x08000000, 0x08000001, 0x08040000, 0x08040001,
    0x09000000, 0x09000001, 0x09040000, 0x09040001,
    0x08000002, 0x08000003, 0x08040002, 0x08040003,
    0x09000002, 0x09000003, 0x09040002, 0x09040003,
    0x08000200, 0x08000201, 0x08040200, 0x08040201,
    0x09000200, 0x09000201, 0x09040200, 0x09040201,
    0x08000202, 0x08000203, 0x08040202, 0x08040203,
    0x09000202, 0x09000203, 0x09040202, 0x09040203},
  {				/* for C bits (numbered as per FIPS 46) 21 23 24 26 27 28 */
    0x00000000, 0x00100000, 0x00000100, 0x00100100,
    0x00000008, 0x00100008, 0x00000108, 0x00100108,
    0x00001000, 0x00101000, 0x00001100, 0x00101100,
    0x00001008, 0x00101008, 0x00001108, 0x00101108,
    0x04000000, 0x04100000, 0x04000100, 0x04100100,
    0x04000008, 0x04100008, 0x04000108, 0x04100108,
    0x04001000, 0x04101000, 0x04001100, 0x04101100,
    0x04001008, 0x04101008, 0x04001108, 0x04101108,
    0x00020000, 0x00120000, 0x00020100, 0x00120100,
    0x00020008, 0x00120008, 0x00020108, 0x00120108,
    0x00021000, 0x00121000, 0x00021100, 0x00121100,
    0x00021008, 0x00121008, 0x00021108, 0x00121108,
    0x04020000, 0x04120000, 0x04020100, 0x04120100,
    0x04020008, 0x04120008, 0x04020108, 0x04120108,
    0x04021000, 0x04121000, 0x04021100, 0x04121100,
    0x04021008, 0x04121008, 0x04021108, 0x04121108},
  {				/* for D bits (numbered as per FIPS 46) 1 2 3 4 5 6 */
    0x00000000, 0x10000000, 0x00010000, 0x10010000,
    0x00000004, 0x10000004, 0x00010004, 0x10010004,
    0x20000000, 0x30000000, 0x20010000, 0x30010000,
    0x20000004, 0x30000004, 0x20010004, 0x30010004,
    0x00100000, 0x10100000, 0x00110000, 0x10110000,
    0x00100004, 0x10100004, 0x00110004, 0x10110004,
    0x20100000, 0x30100000, 0x20110000, 0x30110000,
    0x20100004, 0x30100004, 0x20110004, 0x30110004,
    0x00001000, 0x10001000, 0x00011000, 0x10011000,
    0x00001004, 0x10001004, 0x00011004, 0x10011004,
    0x20001000, 0x30001000, 0x20011000, 0x30011000,
    0x20001004, 0x30001004, 0x20011004, 0x30011004,
    0x00101000, 0x10101000, 0x00111000, 0x10111000,
    0x00101004, 0x10101004, 0x00111004, 0x10111004,
    0x20101000, 0x30101000, 0x20111000, 0x30111000,
    0x20101004, 0x30101004, 0x20111004, 0x30111004},
  {				/* for D bits (numbered as per FIPS 46) 8 9 11 12 13 14 */
    0x00000000, 0x08000000, 0x00000008, 0x08000008,
    0x00000400, 0x08000400, 0x00000408, 0x08000408,
    0x00020000, 0x08020000, 0x00020008, 0x08020008,
    0x00020400, 0x08020400, 0x00020408, 0x08020408,
    0x00000001, 0x08000001, 0x00000009, 0x08000009,
    0x00000401, 0x08000401, 0x00000409, 0x08000409,
    0x00020001, 0x08020001, 0x00020009, 0x08020009,
    0x00020401, 0x08020401, 0x00020409, 0x08020409,
    0x02000000, 0x0A000000, 0x02000008, 0x0A000008,
    0x02000400, 0x0A000400, 0x02000408, 0x0A000408,
    0x02020000, 0x0A020000, 0x02020008, 0x0A020008,
    0x02020400, 0x0A020400, 0x02020408, 0x0A020408,
    0x02000001, 0x0A000001, 0x02000009, 0x0A000009,
    0x02000401, 0x0A000401, 0x02000409, 0x0A000409,
    0x02020001, 0x0A020001, 0x02020009, 0x0A020009,
    0x02020401, 0x0A020401, 0x02020409, 0x0A020409},
  {				/* for D bits (numbered as per FIPS 46) 16 17 18 19 20 21 */
    0x00000000, 0x00000100, 0x00080000, 0x00080100,
    0x01000000, 0x01000100, 0x01080000, 0x01080100,
    0x00000010, 0x00000110, 0x00080010, 0x00080110,
    0x01000010, 0x01000110, 0x01080010, 0x01080110,
    0x00200000, 0x00200100, 0x00280000, 0x00280100,
    0x01200000, 0x01200100, 0x01280000, 0x01280100,
    0x00200010, 0x00200110, 0x00280010, 0x00280110,
    0x01200010, 0x01200110, 0x01280010, 0x01280110,
    0x00000200, 0x00000300, 0x00080200, 0x00080300,
    0x01000200, 0x01000300, 0x01080200, 0x01080300,
    0x00000210, 0x00000310, 0x00080210, 0x00080310,
    0x01000210, 0x01000310, 0x01080210, 0x01080310,
    0x00200200, 0x00200300, 0x00280200, 0x00280300,
    0x01200200, 0x01200300, 0x01280200, 0x01280300,
    0x00200210, 0x00200310, 0x00280210, 0x00280310,
    0x01200210, 0x01200310, 0x01280210, 0x01280310},
  {				/* for D bits (numbered as per FIPS 46) 22 23 24 25 27 28 */
    0x00000000, 0x04000000, 0x00040000, 0x04040000,
    0x00000002, 0x04000002, 0x00040002, 0x04040002,
    0x00002000, 0x04002000, 0x00042000, 0x04042000,
    0x00002002, 0x04002002, 0x00042002, 0x04042002,
    0x00000020, 0x04000020, 0x00040020, 0x04040020,
    0x00000022, 0x04000022, 0x00040022, 0x04040022,
    0x00002020, 0x04002020, 0x00042020, 0x04042020,
    0x00002022, 0x04002022, 0x00042022, 0x04042022,
    0x00000800, 0x04000800, 0x00040800, 0x04040800,
    0x00000802, 0x04000802, 0x00040802, 0x04040802,
    0x00002800, 0x04002800, 0x00042800, 0x04042800,
    0x00002802, 0x04002802, 0x00042802, 0x04042802,
    0x00000820, 0x04000820, 0x00040820, 0x04040820,
    0x00000822, 0x04000822, 0x00040822, 0x04040822,
    0x00002820, 0x04002820, 0x00042820, 0x04042820,
    0x00002822, 0x04002822, 0x00042822, 0x04042822},
};

#define c2l(c,l)	(l =((unsigned long)(*((c)++)))    , \
			 l|=((unsigned long)(*((c)++)))<< 8, \
			 l|=((unsigned long)(*((c)++)))<<16, \
			 l|=((unsigned long)(*((c)++)))<<24)

#define l2c(l,c)	(*((c)++)=(unsigned char)(((l)    )&0xff), \
			 *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
			 *((c)++)=(unsigned char)(((l)>>16)&0xff), \
			 *((c)++)=(unsigned char)(((l)>>24)&0xff))

/*
 * IP and FP
 * The problem is more of a geometric problem that random bit fiddling.
 *  0  1  2  3  4  5  6  7      62 54 46 38 30 22 14  6
 *  8  9 10 11 12 13 14 15      60 52 44 36 28 20 12  4
 * 16 17 18 19 20 21 22 23      58 50 42 34 26 18 10  2
 * 24 25 26 27 28 29 30 31  to  56 48 40 32 24 16  8  0
 *
 * 32 33 34 35 36 37 38 39      63 55 47 39 31 23 15  7
 * 40 41 42 43 44 45 46 47      61 53 45 37 29 21 13  5
 * 48 49 50 51 52 53 54 55      59 51 43 35 27 19 11  3
 * 56 57 58 59 60 61 62 63      57 49 41 33 25 17  9  1
 *
 * The output has been subject to swaps of the form
 * 0 1 -> 3 1 but the odd and even bits have been put into
 * 2 3    2 0
 * different words.  The main trick is to remember that
 * t=((l>>size)^r)&(mask);
 * r^=t;
 * l^=(t<<size);
 * can be used to swap and move bits between words.
 *
 * So l =  0  1  2  3  r = 16 17 18 19
 *         4  5  6  7      20 21 22 23
 *         8  9 10 11      24 25 26 27
 *        12 13 14 15      28 29 30 31
 * becomes (for size == 2 and mask == 0x3333)
 * t =   2^16  3^17 -- --   l =  0  1 16 17  r =  2  3 18 19
 *       6^20  7^21 -- --        4  5 20 21       6  7 22 23
 *      10^24 11^25 -- --        8  9 24 25      10 11 24 25
 *      14^28 15^29 -- --       12 13 28 29      14 15 28 29
 *
 * Thanks for hints from Richard Outerbridge - he told me IP&FP
 * could be done in 15 xor, 10 shifts and 5 ands.
 * When I finally started to think of the problem in 2D
 * I first got ~42 operations without xors.  When I remembered
 * how to use xors :-) I got it to its final state.
 */

#define PERM_OP(a,b,t,n,m) ((t)=((((a)>>(n))^(b))&(m)),\
	(b)^=(t),\
	(a)^=((t)<<(n)))

#define HPERM_OP(a,t,n,m) ((t)=((((a)<<(16-(n)))^(a))&(m)),\
	(a)=(a)^(t)^(t>>(16-(n))))


/* The changes to this macro may help or hinder, depending on the
 * compiler and the achitecture.  gcc2 always seems to do well :-).
 * Inspired by Dana How <how@isl.stanford.edu>
 * DO NOT use the alternative version on machines with 8 byte longs.
 */
#ifdef ALT_ECB
#define D_ENCRYPT(L,R,S) \
	u=((R^s[S  ])<<2);	\
	t= R^s[S+1]; \
	t=((t>>2)+(t<<30)); \
	L^= \
	*(const unsigned long *)(des_SP+0x0100+((t    )&0xfc))+ \
	*(const unsigned long *)(des_SP+0x0300+((t>> 8)&0xfc))+ \
	*(const unsigned long *)(des_SP+0x0500+((t>>16)&0xfc))+ \
	*(const unsigned long *)(des_SP+0x0700+((t>>24)&0xfc))+ \
	*(const unsigned long *)(des_SP+       ((u    )&0xfc))+ \
  	*(const unsigned long *)(des_SP+0x0200+((u>> 8)&0xfc))+ \
  	*(const unsigned long *)(des_SP+0x0400+((u>>16)&0xfc))+ \
 	*(const unsigned long *)(des_SP+0x0600+((u>>24)&0xfc));
#else /* original version */
#define D_ENCRYPT(L,R,S)	\
	u=(R^s[S  ]); \
	t=R^s[S+1]; \
	t=((t>>4)+(t<<28)); \
	L^=	des_SPtrans[1][(t    )&0x3f]| \
		des_SPtrans[3][(t>> 8)&0x3f]| \
		des_SPtrans[5][(t>>16)&0x3f]| \
		des_SPtrans[7][(t>>24)&0x3f]| \
		des_SPtrans[0][(u    )&0x3f]| \
		des_SPtrans[2][(u>> 8)&0x3f]| \
		des_SPtrans[4][(u>>16)&0x3f]| \
		des_SPtrans[6][(u>>24)&0x3f];
#endif

#define ITERATIONS 16

static const char shifts2[16] =
{0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0};

static void des_set_key (char *, unsigned long *) internal_function;
static void des_encrypt (unsigned long *, unsigned long *, int)
     internal_function;
int _des_crypt (char *, unsigned, struct desparams *);

static void
internal_function
des_set_key (char *key, unsigned long *schedule)
{
  register unsigned long c, d, t, s;
  register unsigned char *in;
  register unsigned long *k;
  register int i;

  k = (unsigned long *) schedule;
  in = (unsigned char *) key;

  c2l (in, c);
  c2l (in, d);

  /* I now do it in 47 simple operations :-)
   * Thanks to John Fletcher (john_fletcher@lccmail.ocf.llnl.gov)
   * for the inspiration. :-) */
  PERM_OP (d, c, t, 4, 0x0f0f0f0f);
  HPERM_OP (c, t, -2, 0xcccc0000);
  HPERM_OP (d, t, -2, 0xcccc0000);
  PERM_OP (d, c, t, 1, 0x55555555);
  PERM_OP (c, d, t, 8, 0x00ff00ff);
  PERM_OP (d, c, t, 1, 0x55555555);
  d = (((d & 0x000000ff) << 16) | (d & 0x0000ff00) |
       ((d & 0x00ff0000) >> 16) | ((c & 0xf0000000) >> 4));
  c &= 0x0fffffff;

  for (i = 0; i < ITERATIONS; i++)
    {
      if (shifts2[i])
	{
	  c = ((c >> 2) | (c << 26));
	  d = ((d >> 2) | (d << 26));
	}
      else
	{
	  c = ((c >> 1) | (c << 27));
	  d = ((d >> 1) | (d << 27));
	}
      c &= 0x0fffffff;
      d &= 0x0fffffff;
      /* could be a few less shifts but I am to lazy at this
       * point in time to investigate */
      s = des_skb[0][(c) & 0x3f] |
	des_skb[1][((c >> 6) & 0x03) | ((c >> 7) & 0x3c)] |
	des_skb[2][((c >> 13) & 0x0f) | ((c >> 14) & 0x30)] |
	des_skb[3][((c >> 20) & 0x01) | ((c >> 21) & 0x06) | ((c >> 22) & 0x38)];
      t = des_skb[4][(d) & 0x3f] |
	des_skb[5][((d >> 7) & 0x03) | ((d >> 8) & 0x3c)] |
	des_skb[6][(d >> 15) & 0x3f] |
	des_skb[7][((d >> 21) & 0x0f) | ((d >> 22) & 0x30)];

      /* table contained 0213 4657 */
      *(k++) = ((t << 16) | (s & 0x0000ffff)) & 0xffffffff;
      s = ((s >> 16) | (t & 0xffff0000));

      s = (s << 4) | (s >> 28);
      *(k++) = s & 0xffffffff;
    }
}


static void
internal_function
des_encrypt (unsigned long *buf, unsigned long *schedule, int encrypt)
{
  register unsigned long l, r, t, u;
#ifdef ALT_ECB
  register const unsigned char *des_SP = (const unsigned char *) des_SPtrans;
#endif
  register int i;
  register unsigned long *s;

  l = buf[0];
  r = buf[1];

  /* do IP */
  PERM_OP (r, l, t, 4, 0x0f0f0f0f);
  PERM_OP (l, r, t, 16, 0x0000ffff);
  PERM_OP (r, l, t, 2, 0x33333333);
  PERM_OP (l, r, t, 8, 0x00ff00ff);
  PERM_OP (r, l, t, 1, 0x55555555);
  /* r and l are reversed - remember that :-) - fix
   * it in the next step */

  /* Things have been modified so that the initial rotate is
   * done outside the loop.  This required the
   * des_SPtrans values in sp.h to be rotated 1 bit to the right.
   * One perl script later and things have a 5% speed up on a sparc2.
   * Thanks to Richard Outerbridge <71755.204@CompuServe.COM>
   * for pointing this out. */
  t = (r << 1) | (r >> 31);
  r = (l << 1) | (l >> 31);
  l = t;

  /* clear the top bits on machines with 8byte longs */
  l &= 0xffffffff;
  r &= 0xffffffff;

  s = (unsigned long *) schedule;
  /* I don't know if it is worth the effort of loop unrolling the
   * inner loop */
  if (encrypt)
    {
      for (i = 0; i < 32; i += 4)
	{
	  D_ENCRYPT (l, r, i + 0);	/*  1 */
	  D_ENCRYPT (r, l, i + 2);	/*  2 */
	}
    }
  else
    {
      for (i = 30; i > 0; i -= 4)
	{
	  D_ENCRYPT (l, r, i - 0);	/* 16 */
	  D_ENCRYPT (r, l, i - 2);	/* 15 */
	}
    }
  l = (l >> 1) | (l << 31);
  r = (r >> 1) | (r << 31);
  /* clear the top bits on machines with 8byte longs */
  l &= 0xffffffff;
  r &= 0xffffffff;

  /* swap l and r
   * we will not do the swap so just remember they are
   * reversed for the rest of the subroutine
   * luckily FP fixes this problem :-) */

  PERM_OP (r, l, t, 1, 0x55555555);
  PERM_OP (l, r, t, 8, 0x00ff00ff);
  PERM_OP (r, l, t, 2, 0x33333333);
  PERM_OP (l, r, t, 16, 0x0000ffff);
  PERM_OP (r, l, t, 4, 0x0f0f0f0f);

  buf[0] = l;
  buf[1] = r;

  l = r = t = u = 0;
}


int
_des_crypt (char *buf, unsigned len, struct desparams *desp)
{
  unsigned long schedule[32];
  register unsigned long tin0, tin1;
  register unsigned long tout0, tout1, xor0, xor1;
  register unsigned char *in, *out;
  unsigned long tbuf[2];
  unsigned char *iv, *oiv;
  int cbc_mode;

  cbc_mode = (desp->des_mode == CBC) ? 1 : 0;

  in = (unsigned char *) buf;
  out = (unsigned char *) buf;
  oiv = iv = (unsigned char *) desp->des_ivec;

  des_set_key (desp->des_key, schedule);

  tin0 = tin1 = 0;		/* For GCC */
  if (desp->des_dir == ENCRYPT)
    {
      c2l (iv, tout0);
      c2l (iv, tout1);
      for (; len > 0; len -= 8)
	{
	  c2l (in, tin0);
	  c2l (in, tin1);
	  if (cbc_mode)
	    {
	      tin0 ^= tout0;
	      tin1 ^= tout1;
	    }
	  tbuf[0] = tin0;
	  tbuf[1] = tin1;
	  des_encrypt (tbuf, schedule, 1);
	  tout0 = tbuf[0];
	  tout1 = tbuf[1];
	  l2c (tout0, out);
	  l2c (tout1, out);
	}
      l2c (tout0, oiv);
      l2c (tout1, oiv);
    }
  else
    {
      c2l (iv, xor0);
      c2l (iv, xor1);
      for (; len > 0; len -= 8)
	{
	  c2l (in, tin0);
	  c2l (in, tin1);
	  tbuf[0] = tin0;
	  tbuf[1] = tin1;
	  des_encrypt (tbuf, schedule, 0);
	  if (cbc_mode)
	    {
	      tout0 = tbuf[0] ^ xor0;
	      tout1 = tbuf[1] ^ xor1;
	      xor0 = tin0;
	      xor1 = tin1;
	    }
	  else
	    {
	      tout0 = tbuf[0];
	      tout1 = tbuf[1];
	    }
	  l2c (tout0, out);
	  l2c (tout1, out);
	}
      l2c (tin0, oiv);
      l2c (tin1, oiv);
    }
  tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
  tbuf[0] = tbuf[1] = 0;
  __bzero (schedule, sizeof (schedule));

  return (1);
}