/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Tom Truscott.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <afsconfig.h>
#include <afs/param.h>

RCSID
    ("$Header: /cvs/openafs/src/des/crypt.c,v 1.16 2009/03/16 01:34:36 shadow Exp $");

#ifdef AFS_NT40_ENV
#include <windows.h>
#endif
#include <stdlib.h>
#ifdef HAVE_STRING_H
#include <string.h>
#else
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#endif

/*
 * UNIX password, and DES, encryption.
 * By Tom Truscott, trt@rti.rti.org,
 * from algorithms by Robert W. Baldwin and James Gillogly.
 *
 * References:
 * "Mathematical Cryptology for Computer Scientists and Mathematicians,"
 * by Wayne Patterson, 1987, ISBN 0-8476-7438-X.
 *
 * "Password Security: A Case History," R. Morris and Ken Thompson,
 * Communications of the ACM, vol. 22, pp. 594-597, Nov. 1979.
 *
 * "DES will be Totally Insecure within Ten Years," M.E. Hellman,
 * IEEE Spectrum, vol. 16, pp. 32-39, July 1979.
 */

/* =====  Configuration ==================== */

/*
 * define "MUST_ALIGN" if your compiler cannot load/store
 * long integers at arbitrary (e.g. odd) memory locations.
 * (Either that or never pass unaligned addresses to des_cipher!)
 */
#if !defined(vax)
#define	MUST_ALIGN
#endif

#ifdef CHAR_BITS
#if CHAR_BITS != 8
#error C_block structure assumes 8 bit characters
#endif
#endif

/*
 * define "LONG_IS_32_BITS" only if sizeof(long)==4.
 * This avoids use of bit fields (your compiler may be sloppy with them).
 */

/* XXX shouldn't this be !AFS_64BIT_ENV ? */
#if !defined(cray) && !defined(AFS_ALPHA_LINUX20_ENV) && !defined(AFS_IA64_LINUX20_ENV) && !defined(AFS_AMD64_LINUX20_ENV) && !defined(AFS_PPC64_LINUX20_ENV) & !defined(AFS_S390X_LINUX20_ENV)
#define	LONG_IS_32_BITS
#endif

/*
 * define "B64" to be the declaration for a 64 bit integer.
 * XXX this feature is currently unused, see "endian" comment below.
 */
#if defined(cray)
#define	B64	long
#endif
#if defined(convex)
#define	B64	long long
#endif

/*
 * define "LARGEDATA" to get faster permutations, by using about 72 kilobytes
 * of lookup tables.  This speeds up des_setkey() and des_cipher(), but has
 * little effect on crypt().
 */
#if defined(notdef)
#define	LARGEDATA
#endif

/* compile with "-DSTATIC=int" when profiling */
#ifndef STATIC
#define	STATIC	static
#endif
#ifdef CRYPT_DEBUG
STATIC prtab();
#endif

/* ==================================== */

/*
 * Cipher-block representation (Bob Baldwin):
 *
 * DES operates on groups of 64 bits, numbered 1..64 (sigh).  One
 * representation is to store one bit per byte in an array of bytes.  Bit N of
 * the NBS spec is stored as the LSB of the Nth byte (index N-1) in the array.
 * Another representation stores the 64 bits in 8 bytes, with bits 1..8 in the
 * first byte, 9..16 in the second, and so on.  The DES spec apparently has
 * bit 1 in the MSB of the first byte, but that is particularly noxious so we
 * bit-reverse each byte so that bit 1 is the LSB of the first byte, bit 8 is
 * the MSB of the first byte.  Specifically, the 64-bit input data and key are
 * converted to LSB format, and the output 64-bit block is converted back into
 * MSB format.
 *
 * DES operates internally on groups of 32 bits which are expanded to 48 bits
 * by permutation E and shrunk back to 32 bits by the S boxes.  To speed up
 * the computation, the expansion is applied only once, the expanded
 * representation is maintained during the encryption, and a compression
 * permutation is applied only at the end.  To speed up the S-box lookups,
 * the 48 bits are maintained as eight 6 bit groups, one per byte, which
 * directly feed the eight S-boxes.  Within each byte, the 6 bits are the
 * most significant ones.  The low two bits of each byte are zero.  (Thus,
 * bit 1 of the 48 bit E expansion is stored as the "4"-valued bit of the
 * first byte in the eight byte representation, bit 2 of the 48 bit value is
 * the "8"-valued bit, and so on.)  In fact, a combined "SPE"-box lookup is
 * used, in which the output is the 64 bit result of an S-box lookup which
 * has been permuted by P and expanded by E, and is ready for use in the next
 * iteration.  Two 32-bit wide tables, SPE[0] and SPE[1], are used for this
 * lookup.  Since each byte in the 48 bit path is a multiple of four, indexed
 * lookup of SPE[0] and SPE[1] is simple and fast.  The key schedule and
 * "salt" are also converted to this 8*(6+2) format.  The SPE table size is
 * 8*64*8 = 4K bytes.
 *
 * To speed up bit-parallel operations (such as XOR), the 8 byte
 * representation is "union"ed with 32 bit values "i0" and "i1", and, on
 * machines which support it, a 64 bit value "b64".  This data structure,
 * "C_block", has two problems.  First, alignment restrictions must be
 * honored.  Second, the byte-order (e.g. little-endian or big-endian) of
 * the architecture becomes visible.
 *
 * The byte-order problem is unfortunate, since on the one hand it is good
 * to have a machine-independent C_block representation (bits 1..8 in the
 * first byte, etc.), and on the other hand it is good for the LSB of the
 * first byte to be the LSB of i0.  We cannot have both these things, so we
 * currently use the "little-endian" representation and avoid any multi-byte
 * operations that depend on byte order.  This largely precludes use of the
 * 64-bit datatype since the relative order of i0 and i1 are unknown.  It
 * also inhibits grouping the SPE table to look up 12 bits at a time.  (The
 * 12 bits can be stored in a 16-bit field with 3 low-order zeroes and 1
 * high-order zero, providing fast indexing into a 64-bit wide SPE.)  On the
 * other hand, 64-bit datatypes are currently rare, and a 12-bit SPE lookup
 * requires a 128 kilobyte table, so perhaps this is not a big loss.
 *
 * Permutation representation (Jim Gillogly):
 *
 * A transformation is defined by its effect on each of the 8 bytes of the
 * 64-bit input.  For each byte we give a 64-bit output that has the bits in
 * the input distributed appropriately.  The transformation is then the OR
 * of the 8 sets of 64-bits.  This uses 8*256*8 = 16K bytes of storage for
 * each transformation.  Unless LARGEDATA is defined, however, a more compact
 * table is used which looks up 16 4-bit "chunks" rather than 8 8-bit chunks.
 * The smaller table uses 16*16*8 = 2K bytes for each transformation.  This
 * is slower but tolerable, particularly for password encryption in which
 * the SPE transformation is iterated many times.  The small tables total 9K
 * bytes, the large tables total 72K bytes.
 *
 * The transformations used are:
 * IE3264: MSB->LSB conversion, initial permutation, and expansion.
 *	This is done by collecting the 32 even-numbered bits and applying
 *	a 32->64 bit transformation, and then collecting the 32 odd-numbered
 *	bits and applying the same transformation.  Since there are only
 *	32 input bits, the IE3264 transformation table is half the size of
 *	the usual table.
 * CF6464: Compression, final permutation, and LSB->MSB conversion.
 *	This is done by two trivial 48->32 bit compressions to obtain
 *	a 64-bit block (the bit numbering is given in the "CIFP" table)
 *	followed by a 64->64 bit "cleanup" transformation.  (It would
 *	be possible to group the bits in the 64-bit block so that 2
 *	identical 32->32 bit transformations could be used instead,
 *	saving a factor of 4 in space and possibly 2 in time, but
 *	byte-ordering and other complications rear their ugly head.
 *	Similar opportunities/problems arise in the key schedule
 *	transforms.)
 * PC1ROT: MSB->LSB, PC1 permutation, rotate, and PC2 permutation.
 *	This admittedly baroque 64->64 bit transformation is used to
 *	produce the first code (in 8*(6+2) format) of the key schedule.
 * PC2ROT[0]: Inverse PC2 permutation, rotate, and PC2 permutation.
 *	It would be possible to define 15 more transformations, each
 *	with a different rotation, to generate the entire key schedule.
 *	To save space, however, we instead permute each code into the
 *	next by using a transformation that "undoes" the PC2 permutation,
 *	rotates the code, and then applies PC2.  Unfortunately, PC2
 *	transforms 56 bits into 48 bits, dropping 8 bits, so PC2 is not
 *	invertible.  We get around that problem by using a modified PC2
 *	which retains the 8 otherwise-lost bits in the unused low-order
 *	bits of each byte.  The low-order bits are cleared when the
 *	codes are stored into the key schedule.
 * PC2ROT[1]: Same as PC2ROT[0], but with two rotations.
 *	This is faster than applying PC2ROT[0] twice,
 *
 * The Bell Labs "salt" (Bob Baldwin):
 *
 * The salting is a simple permutation applied to the 48-bit result of E.
 * Specifically, if bit i (1 <= i <= 24) of the salt is set then bits i and
 * i+24 of the result are swapped.  The salt is thus a 24 bit number, with
 * 16777216 possible values.  (The original salt was 12 bits and could not
 * swap bits 13..24 with 36..48.)
 *
 * It is possible, but ugly, to warp the SPE table to account for the salt
 * permutation.  Fortunately, the conditional bit swapping requires only
 * about four machine instructions and can be done on-the-fly with about an
 * 8% performance penalty.
 */

typedef union {
    unsigned char b[8];
    struct {
#if defined(LONG_IS_32_BITS)
	/* long is often faster than a 32-bit bit field */
	long i0;
	long i1;
#else
	long i0:32;
	long i1:32;
#endif
    } b32;
#if defined(B64)
    B64 b64;
#endif
} C_block;

/*
 * Convert twenty-four-bit long in host-order
 * to six bits (and 2 low-order zeroes) per char little-endian format.
 */
#define	TO_SIX_BIT(rslt, src) {						\
		C_block cvt;						\
		cvt.b[0] = (unsigned char) src; src >>= 6;		\
		cvt.b[1] = (unsigned char) src; src >>= 6;		\
		cvt.b[2] = (unsigned char) src; src >>= 6;		\
		cvt.b[3] = (unsigned char) src;				\
		rslt = (cvt.b32.i0 & 0x3f3f3f3fL) << 2;			\
	}

/*
 * These macros may someday permit efficient use of 64-bit integers.
 */
#define	ZERO(d,d0,d1)			d0 = 0, d1 = 0
#define	LOAD(d,d0,d1,bl)		d0 = (bl).b32.i0, d1 = (bl).b32.i1
#define	LOADREG(d,d0,d1,s,s0,s1)	d0 = s0, d1 = s1
#define	OR(d,d0,d1,bl)			d0 |= (bl).b32.i0, d1 |= (bl).b32.i1
#define	STORE(s,s0,s1,bl)		(bl).b32.i0 = (s0), (bl).b32.i1 = (s1)
#define	DCL_BLOCK(d,d0,d1)		long d0, d1

#if defined(LARGEDATA)
	/* Waste memory like crazy.  Also, do permutations in line */
#define	LGCHUNKBITS	3
#define	CHUNKBITS	(1<<LGCHUNKBITS)
#define	PERM6464(d,d0,d1,cpp,p)				\
	LOAD(d,d0,d1,(p)[(0<<CHUNKBITS)+(cpp)[0]]);		\
	OR (d,d0,d1,(p)[(1<<CHUNKBITS)+(cpp)[1]]);		\
	OR (d,d0,d1,(p)[(2<<CHUNKBITS)+(cpp)[2]]);		\
	OR (d,d0,d1,(p)[(3<<CHUNKBITS)+(cpp)[3]]);		\
	OR (d,d0,d1,(p)[(4<<CHUNKBITS)+(cpp)[4]]);		\
	OR (d,d0,d1,(p)[(5<<CHUNKBITS)+(cpp)[5]]);		\
	OR (d,d0,d1,(p)[(6<<CHUNKBITS)+(cpp)[6]]);		\
	OR (d,d0,d1,(p)[(7<<CHUNKBITS)+(cpp)[7]]);
#define	PERM3264(d,d0,d1,cpp,p)				\
	LOAD(d,d0,d1,(p)[(0<<CHUNKBITS)+(cpp)[0]]);		\
	OR (d,d0,d1,(p)[(1<<CHUNKBITS)+(cpp)[1]]);		\
	OR (d,d0,d1,(p)[(2<<CHUNKBITS)+(cpp)[2]]);		\
	OR (d,d0,d1,(p)[(3<<CHUNKBITS)+(cpp)[3]]);
#else
	/* "small data" */
#define	LGCHUNKBITS	2
#define	CHUNKBITS	(1<<LGCHUNKBITS)
#define	PERM6464(d,d0,d1,cpp,p)				\
	{ C_block tblk; permute(cpp,&tblk,p,8); LOAD (d,d0,d1,tblk); }
#define	PERM3264(d,d0,d1,cpp,p)				\
	{ C_block tblk; permute(cpp,&tblk,p,4); LOAD (d,d0,d1,tblk); }

STATIC void
permute(unsigned char *cp, C_block *out, register C_block *p, int chars_in)
{
    register DCL_BLOCK(D, D0, D1);
    register C_block *tp;
    register int t;

    ZERO(D, D0, D1);
    do {
	t = *cp++;
	tp = &p[t & 0xf];
	OR(D, D0, D1, *tp);
	p += (1 << CHUNKBITS);
	tp = &p[t >> 4];
	OR(D, D0, D1, *tp);
	p += (1 << CHUNKBITS);
    } while (--chars_in > 0);
    STORE(D, D0, D1, *out);
}
#endif /* LARGEDATA */

STATIC void init_des(void);
STATIC void init_perm(C_block [64 / CHUNKBITS][1 << CHUNKBITS], 
		      unsigned char [64], int, int);
STATIC int des_setkey(const char *key);
STATIC int des_cipher(const char *in, char *out, long salt, int num_iter);



/* =====  (mostly) Standard DES Tables ==================== */

static unsigned char IP[] = {	/* initial permutation */
    58, 50, 42, 34, 26, 18, 10, 2,
    60, 52, 44, 36, 28, 20, 12, 4,
    62, 54, 46, 38, 30, 22, 14, 6,
    64, 56, 48, 40, 32, 24, 16, 8,
    57, 49, 41, 33, 25, 17, 9, 1,
    59, 51, 43, 35, 27, 19, 11, 3,
    61, 53, 45, 37, 29, 21, 13, 5,
    63, 55, 47, 39, 31, 23, 15, 7,
};

/* The final permutation is the inverse of IP - no table is necessary */

static unsigned char ExpandTr[] = {	/* expansion operation */
    32, 1, 2, 3, 4, 5,
    4, 5, 6, 7, 8, 9,
    8, 9, 10, 11, 12, 13,
    12, 13, 14, 15, 16, 17,
    16, 17, 18, 19, 20, 21,
    20, 21, 22, 23, 24, 25,
    24, 25, 26, 27, 28, 29,
    28, 29, 30, 31, 32, 1,
};

static unsigned char PC1[] = {	/* permuted choice table 1 */
    57, 49, 41, 33, 25, 17, 9,
    1, 58, 50, 42, 34, 26, 18,
    10, 2, 59, 51, 43, 35, 27,
    19, 11, 3, 60, 52, 44, 36,

    63, 55, 47, 39, 31, 23, 15,
    7, 62, 54, 46, 38, 30, 22,
    14, 6, 61, 53, 45, 37, 29,
    21, 13, 5, 28, 20, 12, 4,
};

static unsigned char Rotates[] = {	/* PC1 rotation schedule */
    1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1,
};

/* note: each "row" of PC2 is left-padded with bits that make it invertible */
static unsigned char PC2[] = {	/* permuted choice table 2 */
    9, 18, 14, 17, 11, 24, 1, 5,
    22, 25, 3, 28, 15, 6, 21, 10,
    35, 38, 23, 19, 12, 4, 26, 8,
    43, 54, 16, 7, 27, 20, 13, 2,

    0, 0, 41, 52, 31, 37, 47, 55,
    0, 0, 30, 40, 51, 45, 33, 48,
    0, 0, 44, 49, 39, 56, 34, 53,
    0, 0, 46, 42, 50, 36, 29, 32,
};

static unsigned char S[8][64] = {	/* 48->32 bit substitution tables */
    /* S[1]                 */
    {14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
     0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
     4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
     15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13,},
    /* S[2]                 */
    {15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
     3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
     0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
     13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9,},
    /* S[3]                 */
    {10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
     13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
     13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
     1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12,},
    /* S[4]                 */
    {7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
     13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
     10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
     3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14,},
    /* S[5]                 */
    {2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
     14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
     4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
     11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3,},
    /* S[6]                 */
    {12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
     10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
     9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
     4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13,},
    /* S[7]                 */
    {4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
     13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
     1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
     6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12,},
    /* S[8]                 */
    {13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
     1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
     7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
     2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11,}
};

static unsigned char P32Tr[] = {	/* 32-bit permutation function */
    16, 7, 20, 21,
    29, 12, 28, 17,
    1, 15, 23, 26,
    5, 18, 31, 10,
    2, 8, 24, 14,
    32, 27, 3, 9,
    19, 13, 30, 6,
    22, 11, 4, 25,
};

static unsigned char CIFP[] = {	/* compressed/interleaved permutation */
    1, 2, 3, 4, 17, 18, 19, 20,
    5, 6, 7, 8, 21, 22, 23, 24,
    9, 10, 11, 12, 25, 26, 27, 28,
    13, 14, 15, 16, 29, 30, 31, 32,

    33, 34, 35, 36, 49, 50, 51, 52,
    37, 38, 39, 40, 53, 54, 55, 56,
    41, 42, 43, 44, 57, 58, 59, 60,
    45, 46, 47, 48, 61, 62, 63, 64,
};

static unsigned char itoa64[] =	/* 0..63 => ascii-64 */
    "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";


/* =====  Tables that are initialized at run time  ==================== */


static unsigned char a64toi[128];	/* ascii-64 => 0..63 */

/* Initial key schedule permutation */
static C_block PC1ROT[64 / CHUNKBITS][1 << CHUNKBITS];

/* Subsequent key schedule rotation permutations */
static C_block PC2ROT[2][64 / CHUNKBITS][1 << CHUNKBITS];

/* Initial permutation/expansion table */
static C_block IE3264[32 / CHUNKBITS][1 << CHUNKBITS];

/* Table that combines the S, P, and E operations.  */
static long SPE[2][8][64];

/* compressed/interleaved => final permutation table */
static C_block CF6464[64 / CHUNKBITS][1 << CHUNKBITS];


/* ==================================== */


static C_block constdatablock;	/* encryption constant */
static char cryptresult[1 + 4 + 4 + 11 + 1];	/* encrypted result */

/*
 * Return a pointer to static data consisting of the "setting"
 * followed by an encryption produced by the "key" and "setting".
 */
char *
crypt(register const char *key, register const char *setting)
{
    register char *encp;
    register long i;
    register int t;
    long salt;
    int num_iter, salt_size;
    C_block keyblock, rsltblock;


    for (i = 0; i < 8; i++) {
	if ((t = 2 * (unsigned char)(*key)) != 0)
	    key++;
	keyblock.b[i] = t;
    }
    if (des_setkey((char *)keyblock.b))	/* also initializes "a64toi" */
	return (NULL);

    encp = &cryptresult[0];
    switch (*setting) {
    case '_':			/* was EFMT1 */
	/*
	 * Involve the rest of the password 8 characters at a time.
	 */
	while (*key) {
	    if (des_cipher((char *)&keyblock, (char *)&keyblock, 0L, 1))
		return (NULL);
	    for (i = 0; i < 8; i++) {
		if ((t = 2 * (unsigned char)(*key)) != 0)
		    key++;
		keyblock.b[i] ^= t;
	    }
	    if (des_setkey((char *)keyblock.b))
		return (NULL);
	}

	*encp++ = *setting++;

	/* get iteration count */
	num_iter = 0;
	for (i = 4; --i >= 0;) {
	    if ((t = (unsigned char)setting[i]) == '\0')
		t = '.';
	    encp[i] = t;
	    num_iter = (num_iter << 6) | a64toi[t];
	}
	setting += 4;
	encp += 4;
	salt_size = 4;
	break;
    default:
	num_iter = 25;
	salt_size = 2;
    }

    salt = 0;
    for (i = salt_size; --i >= 0;) {
	if ((t = (unsigned char)setting[i]) == '\0')
	    t = '.';
	encp[i] = t;
	salt = (salt << 6) | a64toi[t];
    }
    encp += salt_size;
    if (des_cipher
	((char *)&constdatablock, (char *)&rsltblock, salt, num_iter))
	return (NULL);

    /*
     * Encode the 64 cipher bits as 11 ascii characters.
     */
    i = ((long)((rsltblock.b[0] << 8) | rsltblock.b[1]) << 8) | rsltblock.
	b[2];
    encp[3] = itoa64[i & 0x3f];
    i >>= 6;
    encp[2] = itoa64[i & 0x3f];
    i >>= 6;
    encp[1] = itoa64[i & 0x3f];
    i >>= 6;
    encp[0] = itoa64[i];
    encp += 4;
    i = ((long)((rsltblock.b[3] << 8) | rsltblock.b[4]) << 8) | rsltblock.
	b[5];
    encp[3] = itoa64[i & 0x3f];
    i >>= 6;
    encp[2] = itoa64[i & 0x3f];
    i >>= 6;
    encp[1] = itoa64[i & 0x3f];
    i >>= 6;
    encp[0] = itoa64[i];
    encp += 4;
    i = ((long)((rsltblock.b[6]) << 8) | rsltblock.b[7]) << 2;
    encp[2] = itoa64[i & 0x3f];
    i >>= 6;
    encp[1] = itoa64[i & 0x3f];
    i >>= 6;
    encp[0] = itoa64[i];

    encp[3] = 0;

    return (cryptresult);
}


/*
 * The Key Schedule, filled in by des_setkey() or setkey().
 */
#define	KS_SIZE	16
static C_block KS[KS_SIZE];

/*
 * Set up the key schedule from the key.
 */
STATIC int
des_setkey(register const char *key)
{
    register DCL_BLOCK(K, K0, K1);
    register C_block *ptabp;
    register int i;
    static int des_ready = 0;

    if (!des_ready) {
	init_des();
	des_ready = 1;
    }

    PERM6464(K, K0, K1, (unsigned char *)key, (C_block *) PC1ROT);
    key = (char *)&KS[0];
    STORE(K & ~0x03030303L, K0 & ~0x03030303L, K1, *(C_block *) key);
    for (i = 1; i < 16; i++) {
	key += sizeof(C_block);
	STORE(K, K0, K1, *(C_block *) key);
	ptabp = (C_block *) PC2ROT[Rotates[i] - 1];
	PERM6464(K, K0, K1, (unsigned char *)key, ptabp);
	STORE(K & ~0x03030303L, K0 & ~0x03030303L, K1, *(C_block *) key);
    }
    return (0);
}

/*
 * Encrypt (or decrypt if num_iter < 0) the 8 chars at "in" with abs(num_iter)
 * iterations of DES, using the the given 24-bit salt and the pre-computed key
 * schedule, and store the resulting 8 chars at "out" (in == out is permitted).
 *
 * NOTE: the performance of this routine is critically dependent on your
 * compiler and machine architecture.
 */
STATIC int
des_cipher(const char *in, char *out, long salt, int num_iter)
{
    /* variables that we want in registers, most important first */
#if defined(pdp11)
    register int j;
#endif
    register long L0, L1, R0, R1, k;
    register C_block *kp;
    register int ks_inc, loop_count;
    C_block B;

    L0 = salt;
    TO_SIX_BIT(salt, L0);	/* convert to 4*(6+2) format */

#if defined(vax) || defined(pdp11)
    salt = ~salt;		/* "x &~ y" is faster than "x & y". */
#define	SALT (~salt)
#else
#define	SALT salt
#endif

#if defined(MUST_ALIGN)
    B.b[0] = in[0];
    B.b[1] = in[1];
    B.b[2] = in[2];
    B.b[3] = in[3];
    B.b[4] = in[4];
    B.b[5] = in[5];
    B.b[6] = in[6];
    B.b[7] = in[7];
    LOAD(L, L0, L1, B);
#else
    LOAD(L, L0, L1, *(C_block *) in);
#endif
    LOADREG(R, R0, R1, L, L0, L1);
    L0 &= 0x55555555L;
    L1 &= 0x55555555L;
    L0 = (L0 << 1) | L1;	/* L0 is the even-numbered input bits */
    R0 &= 0xaaaaaaaaL;
    R1 = (R1 >> 1) & 0x55555555L;
    L1 = R0 | R1;		/* L1 is the odd-numbered input bits */
    STORE(L, L0, L1, B);
    PERM3264(L, L0, L1, B.b, (C_block *) IE3264);	/* even bits */
    PERM3264(R, R0, R1, B.b + 4, (C_block *) IE3264);	/* odd bits */

    if (num_iter >= 0) {	/* encryption */
	kp = &KS[0];
	ks_inc = sizeof(*kp);
    } else {			/* decryption */
	num_iter = -num_iter;
	kp = &KS[KS_SIZE - 1];
	ks_inc = -((long)sizeof(*kp));
    }

    while (--num_iter >= 0) {
	loop_count = 8;
	do {

#define	SPTAB(t, i)	(*(long *)((unsigned char *)t + i*(sizeof(long)/4)))
#if defined(gould)
	    /* use this if B.b[i] is evaluated just once ... */
#define	DOXOR(x,y,i)	x^=SPTAB(SPE[0][i],B.b[i]); y^=SPTAB(SPE[1][i],B.b[i]);
#else
#if defined(pdp11)
	    /* use this if your "long" int indexing is slow */
#define	DOXOR(x,y,i)	j=B.b[i]; x^=SPTAB(SPE[0][i],j); y^=SPTAB(SPE[1][i],j);
#else
	    /* use this if "k" is allocated to a register ... */
#define	DOXOR(x,y,i)	k=B.b[i]; x^=SPTAB(SPE[0][i],k); y^=SPTAB(SPE[1][i],k);
#endif
#endif

#define	CRUNCH(p0, p1, q0, q1)	\
			k = (q0 ^ q1) & SALT;	\
			B.b32.i0 = k ^ q0 ^ kp->b32.i0;		\
			B.b32.i1 = k ^ q1 ^ kp->b32.i1;		\
			kp = (C_block *)((char *)kp+ks_inc);	\
							\
			DOXOR(p0, p1, 0);		\
			DOXOR(p0, p1, 1);		\
			DOXOR(p0, p1, 2);		\
			DOXOR(p0, p1, 3);		\
			DOXOR(p0, p1, 4);		\
			DOXOR(p0, p1, 5);		\
			DOXOR(p0, p1, 6);		\
			DOXOR(p0, p1, 7);

	    CRUNCH(L0, L1, R0, R1);
	    CRUNCH(R0, R1, L0, L1);
	} while (--loop_count != 0);
	kp = (C_block *) ((char *)kp - (ks_inc * KS_SIZE));


	/* swap L and R */
	L0 ^= R0;
	L1 ^= R1;
	R0 ^= L0;
	R1 ^= L1;
	L0 ^= R0;
	L1 ^= R1;
    }

    /* store the encrypted (or decrypted) result */
    L0 = ((L0 >> 3) & 0x0f0f0f0fL) | ((L1 << 1) & 0xf0f0f0f0L);
    L1 = ((R0 >> 3) & 0x0f0f0f0fL) | ((R1 << 1) & 0xf0f0f0f0L);
    STORE(L, L0, L1, B);
    PERM6464(L, L0, L1, B.b, (C_block *) CF6464);
#if defined(MUST_ALIGN)
    STORE(L, L0, L1, B);
    out[0] = B.b[0];
    out[1] = B.b[1];
    out[2] = B.b[2];
    out[3] = B.b[3];
    out[4] = B.b[4];
    out[5] = B.b[5];
    out[6] = B.b[6];
    out[7] = B.b[7];
#else
    STORE(L, L0, L1, *(C_block *) out);
#endif
    return (0);
}


/*
 * Initialize various tables.  This need only be done once.  It could even be
 * done at compile time, if the compiler were capable of that sort of thing.
 */
STATIC void
init_des(void)
{
    register int i, j;
    register long k;
    register int tableno;
    static unsigned char perm[64], tmp32[32];	/* "static" for speed */

    /*
     * table that converts chars "./0-9A-Za-z"to integers 0-63.
     */
    for (i = 0; i < 64; i++)
	a64toi[itoa64[i]] = i;

    /*
     * PC1ROT - bit reverse, then PC1, then Rotate, then PC2.
     */
    for (i = 0; i < 64; i++)
	perm[i] = 0;
    for (i = 0; i < 64; i++) {
	if ((k = PC2[i]) == 0)
	    continue;
	k += Rotates[0] - 1;
	if ((k % 28) < Rotates[0])
	    k -= 28;
	k = PC1[k];
	if (k > 0) {
	    k--;
	    k = (k | 07) - (k & 07);
	    k++;
	}
	perm[i] = (unsigned char)k;
    }
#ifdef CRYPT_DEBUG
    prtab("pc1tab", perm, 8);
#endif
    init_perm(PC1ROT, perm, 8, 8);

    /*
     * PC2ROT - PC2 inverse, then Rotate (once or twice), then PC2.
     */
    for (j = 0; j < 2; j++) {
	unsigned char pc2inv[64];
	for (i = 0; i < 64; i++)
	    perm[i] = pc2inv[i] = 0;
	for (i = 0; i < 64; i++) {
	    if ((k = PC2[i]) == 0)
		continue;
	    pc2inv[k - 1] = i + 1;
	}
	for (i = 0; i < 64; i++) {
	    if ((k = PC2[i]) == 0)
		continue;
	    k += j;
	    if ((k % 28) <= j)
		k -= 28;
	    perm[i] = pc2inv[k];
	}
#ifdef CRYPT_DEBUG
	prtab("pc2tab", perm, 8);
#endif
	init_perm(PC2ROT[j], perm, 8, 8);
    }

    /*
     * Bit reverse, then initial permutation, then expansion.
     */
    for (i = 0; i < 8; i++) {
	for (j = 0; j < 8; j++) {
	    k = (j < 2) ? 0 : IP[ExpandTr[i * 6 + j - 2] - 1];
	    if (k > 32)
		k -= 32;
	    else if (k > 0)
		k--;
	    if (k > 0) {
		k--;
		k = (k | 07) - (k & 07);
		k++;
	    }
	    perm[i * 8 + j] = (unsigned char)k;
	}
    }
#ifdef CRYPT_DEBUG
    prtab("ietab", perm, 8);
#endif
    init_perm(IE3264, perm, 4, 8);

    /*
     * Compression, then final permutation, then bit reverse.
     */
    for (i = 0; i < 64; i++) {
	k = IP[CIFP[i] - 1];
	if (k > 0) {
	    k--;
	    k = (k | 07) - (k & 07);
	    k++;
	}
	perm[k - 1] = i + 1;
    }
#ifdef CRYPT_DEBUG
    prtab("cftab", perm, 8);
#endif
    init_perm(CF6464, perm, 8, 8);

    /*
     * SPE table
     */
    for (i = 0; i < 48; i++)
	perm[i] = P32Tr[ExpandTr[i] - 1];
    for (tableno = 0; tableno < 8; tableno++) {
	for (j = 0; j < 64; j++) {
	    k = (((j >> 0) & 01) << 5) | (((j >> 1) & 01) << 3) |
		(((j >> 2) & 01) << 2) | (((j >> 3) & 01) << 1) |
		(((j >> 4) & 01) << 0) | (((j >> 5) & 01) << 4);
	    k = S[tableno][k];
	    k = (((k >> 3) & 01) << 0) | (((k >> 2) & 01) << 1) |
		(((k >> 1) & 01) << 2) | (((k >> 0) & 01) << 3);
	    for (i = 0; i < 32; i++)
		tmp32[i] = 0;
	    for (i = 0; i < 4; i++)
		tmp32[4 * tableno + i] = (k >> i) & 01;
	    k = 0;
	    for (i = 24; --i >= 0;)
		k = (k << 1) | tmp32[perm[i] - 1];
	    TO_SIX_BIT(SPE[0][tableno][j], k);
	    k = 0;
	    for (i = 24; --i >= 0;)
		k = (k << 1) | tmp32[perm[i + 24] - 1];
	    TO_SIX_BIT(SPE[1][tableno][j], k);
	}
    }
}

/*
 * Initialize "perm" to represent transformation "p", which rearranges
 * (perhaps with expansion and/or contraction) one packed array of bits
 * (of size "chars_in" characters) into another array (of size "chars_out"
 * characters).
 *
 * "perm" must be all-zeroes on entry to this routine.
 */
STATIC void
init_perm(C_block perm[64 / CHUNKBITS][1 << CHUNKBITS], 
	  unsigned char p[64], int chars_in, int chars_out)
{
    register int i, j, k, l;

    for (k = 0; k < chars_out * 8; k++) {	/* each output bit position */
	l = p[k] - 1;		/* where this bit comes from */
	if (l < 0)
	    continue;		/* output bit is always 0 */
	i = l >> LGCHUNKBITS;	/* which chunk this bit comes from */
	l = 1 << (l & (CHUNKBITS - 1));	/* mask for this bit */
	for (j = 0; j < (1 << CHUNKBITS); j++) {	/* each chunk value */
	    if ((j & l) != 0)
		perm[i][j].b[k >> 3] |= 1 << (k & 07);
	}
    }
}

/*
 * "setkey" routine (for backwards compatibility)
 */
#if 0				/* static and doesn't appear to be referenced */
STATIC int
setkey(key)
     register const char *key;
{
    register int i, j, k;
    C_block keyblock;

    for (i = 0; i < 8; i++) {
	k = 0;
	for (j = 0; j < 8; j++) {
	    k <<= 1;
	    k |= (unsigned char)*key++;
	}
	keyblock.b[i] = k;
    }
    return (des_setkey((char *)keyblock.b));
}
#endif

#if 0
/*
 * "encrypt" routine (for backwards compatibility)
 */
int
encrypt(block, flag)
     register char *block;
     int flag;
{
    register int i, j, k;
    C_block cblock;

    for (i = 0; i < 8; i++) {
	k = 0;
	for (j = 0; j < 8; j++) {
	    k <<= 1;
	    k |= (unsigned char)*block++;
	}
	cblock.b[i] = k;
    }
    if (des_cipher((char *)&cblock, (char *)&cblock, 0L, (flag ? -1 : 1)))
	return (1);
    for (i = 7; i >= 0; i--) {
	k = cblock.b[i];
	for (j = 7; j >= 0; j--) {
	    *--block = k & 01;
	    k >>= 1;
	}
    }
    return (0);
}
#endif

#ifdef CRYPT_DEBUG
STATIC
prtab(char *s, unsigned char *t, int num_rows)
{
    register int i, j;

    (void)printf("%s:\n", s);
    for (i = 0; i < num_rows; i++) {
	for (j = 0; j < 8; j++) {
	    (void)printf("%3d", t[i * 8 + j]);
	}
	(void)printf("\n");
    }
    (void)printf("\n");
}
#endif
