/*
 * passlib/src/des.c - des c encryption routines
 *
 * this file is a direct copy of FreeBSD's des-crypt.c,
 * taken from http://svn.freebsd.org/base/stable/8/secure/lib/libcrypt/crypt-des.c
 * the following changes were made from the original:
 *     - mild refactoring of frontend functions
 *     - changed to use C99 types
 *     - disabled all support for decryption
 *     - removed dep on htonl/ntohl to make win32 compat easier
 *
 * ============================================================================
 *
 * FreeSec: libcrypt for NetBSD
 *
 * Copyright (c) 1994 David Burren
 * All rights reserved.
 *
 * Adapted for FreeBSD-2.0 by Geoffrey M. Rehmet
 *	this file should now *only* export crypt(), in order to make
 *	binaries of libcrypt exportable from the USA
 *
 * Adapted for FreeBSD-4.0 by Mark R V Murray
 *	this file should now *only* export crypt_des(), in order to make
 *	a module that can be optionally included in libcrypt.
 *
 * 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. Neither the name of the author nor the names of other contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 * This is an original implementation of the DES and the crypt(3) interfaces
 * by David Burren <davidb@werj.com.au>.
 *
 * An excellent reference on the underlying algorithm (and related
 * algorithms) is:
 *
 *	B. Schneier, Applied Cryptography: protocols, algorithms,
 *	and source code in C, John Wiley & Sons, 1994.
 *
 * Note that in that book's description of DES the lookups for the initial,
 * pbox, and final permutations are inverted (this has been brought to the
 * attention of the author).  A list of errata for this book has been
 * posted to the sci.crypt newsgroup by the author and is available for FTP.
 *
 * ARCHITECTURE ASSUMPTIONS:
 *	It is assumed that the 8-byte arrays passed by reference can be
 *	addressed as arrays of uint32_t's (ie. the CPU is not picky about
 *	alignment).
 */

/**************************************************************************
 * includes
 **************************************************************************/
#include <string.h>
#include "des.h"

/**************************************************************************
 * private types
 **************************************************************************/

/* holds parsed key & salt info */
typedef struct
{
    uint32_t	saltbits;
    uint32_t	en_keysl[16], en_keysr[16];
/*    uint32_t	de_keysl[16], de_keysr[16]; */

} des_ctx_t;

/**************************************************************************
 * static des tables
 **************************************************************************/

static uint8_t	IP[64] = {
	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
};

static uint8_t	inv_key_perm[64];
static uint8_t	key_perm[56] = {
	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 uint8_t	key_shifts[16] = {
	1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
};

static uint8_t	inv_comp_perm[56];
static uint8_t	comp_perm[48] = {
	14, 17, 11, 24,  1,  5,  3, 28, 15,  6, 21, 10,
	23, 19, 12,  4, 26,  8, 16,  7, 27, 20, 13,  2,
	41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,
	44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32
};

/*
 *	No E box is used, as it's replaced by some ANDs, shifts, and ORs.
 */

static uint8_t	u_sbox[8][64];
static uint8_t	sbox[8][64] = {
	{
		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
	},
	{
		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
	},
	{
		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
	},
	{
		 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
	},
	{
		 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
	},
	{
		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
	},
	{
		 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
	},
	{
		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 uint8_t	un_pbox[32];
static uint8_t	pbox[32] = {
	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 uint32_t	bits32[32] =
{
	0x80000000, 0x40000000, 0x20000000, 0x10000000,
	0x08000000, 0x04000000, 0x02000000, 0x01000000,
	0x00800000, 0x00400000, 0x00200000, 0x00100000,
	0x00080000, 0x00040000, 0x00020000, 0x00010000,
	0x00008000, 0x00004000, 0x00002000, 0x00001000,
	0x00000800, 0x00000400, 0x00000200, 0x00000100,
	0x00000080, 0x00000040, 0x00000020, 0x00000010,
	0x00000008, 0x00000004, 0x00000002, 0x00000001
};

static uint8_t	bits8[8] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 };

/**************************************************************************
 * derived des tables - filled in by des_init_tables()
 **************************************************************************/

static int		des_initialised = 0;
static uint32_t	*bits28, *bits24;
static uint8_t	init_perm[64], final_perm[64];
static uint8_t	m_sbox[4][4096];
static uint32_t	psbox[4][256];
static uint32_t	ip_maskl[8][256], ip_maskr[8][256];
static uint32_t	fp_maskl[8][256], fp_maskr[8][256];
static uint32_t	key_perm_maskl[8][128], key_perm_maskr[8][128];
static uint32_t	comp_maskl[8][128], comp_maskr[8][128];

/**************************************************************************
 * functions
 **************************************************************************/

/* initialize derived static tables if not already done */
void
des_init_tables(void)
{
	int	i, j, b, k, inbit, obit;
	uint32_t	*p, *il, *ir, *fl, *fr;

	if (des_initialised)
        return;

	bits24 = (bits28 = bits32 + 4) + 4;

	/*
	 * Invert the S-boxes, reordering the input bits.
	 */
	for (i = 0; i < 8; i++)
		for (j = 0; j < 64; j++) {
			b = (j & 0x20) | ((j & 1) << 4) | ((j >> 1) & 0xf);
			u_sbox[i][j] = sbox[i][b];
		}

	/*
	 * Convert the inverted S-boxes into 4 arrays of 8 bits.
	 * Each will handle 12 bits of the S-box input.
	 */
	for (b = 0; b < 4; b++)
		for (i = 0; i < 64; i++)
			for (j = 0; j < 64; j++)
				m_sbox[b][(i << 6) | j] =
					(uint8_t)((u_sbox[(b << 1)][i] << 4) |
					u_sbox[(b << 1) + 1][j]);

	/*
	 * Set up the initial & final permutations into a useful form, and
	 * initialise the inverted key permutation.
	 */
	for (i = 0; i < 64; i++) {
		init_perm[final_perm[i] = IP[i] - 1] = (uint8_t)i;
		inv_key_perm[i] = 255;
	}

	/*
	 * Invert the key permutation and initialise the inverted key
	 * compression permutation.
	 */
	for (i = 0; i < 56; i++) {
		inv_key_perm[key_perm[i] - 1] = (uint8_t)i;
		inv_comp_perm[i] = 255;
	}

	/*
	 * Invert the key compression permutation.
	 */
	for (i = 0; i < 48; i++) {
		inv_comp_perm[comp_perm[i] - 1] = (uint8_t)i;
	}

	/*
	 * Set up the OR-mask arrays for the initial and final permutations,
	 * and for the key initial and compression permutations.
	 */
	for (k = 0; k < 8; k++) {
		for (i = 0; i < 256; i++) {
			*(il = &ip_maskl[k][i]) = 0L;
			*(ir = &ip_maskr[k][i]) = 0L;
			*(fl = &fp_maskl[k][i]) = 0L;
			*(fr = &fp_maskr[k][i]) = 0L;
			for (j = 0; j < 8; j++) {
				inbit = 8 * k + j;
				if (i & bits8[j]) {
					if ((obit = init_perm[inbit]) < 32)
						*il |= bits32[obit];
					else
						*ir |= bits32[obit-32];
					if ((obit = final_perm[inbit]) < 32)
						*fl |= bits32[obit];
					else
						*fr |= bits32[obit - 32];
				}
			}
		}
		for (i = 0; i < 128; i++) {
			*(il = &key_perm_maskl[k][i]) = 0L;
			*(ir = &key_perm_maskr[k][i]) = 0L;
			for (j = 0; j < 7; j++) {
				inbit = 8 * k + j;
				if (i & bits8[j + 1]) {
					if ((obit = inv_key_perm[inbit]) == 255)
						continue;
					if (obit < 28)
						*il |= bits28[obit];
					else
						*ir |= bits28[obit - 28];
				}
			}
			*(il = &comp_maskl[k][i]) = 0L;
			*(ir = &comp_maskr[k][i]) = 0L;
			for (j = 0; j < 7; j++) {
				inbit = 7 * k + j;
				if (i & bits8[j + 1]) {
					if ((obit=inv_comp_perm[inbit]) == 255)
						continue;
					if (obit < 24)
						*il |= bits24[obit];
					else
						*ir |= bits24[obit - 24];
				}
			}
		}
	}

	/*
	 * Invert the P-box permutation, and convert into OR-masks for
	 * handling the output of the S-box arrays setup above.
	 */
	for (i = 0; i < 32; i++)
		un_pbox[pbox[i] - 1] = (uint8_t)i;

	for (b = 0; b < 4; b++)
		for (i = 0; i < 256; i++) {
			*(p = &psbox[b][i]) = 0L;
			for (j = 0; j < 8; j++) {
				if (i & bits8[j])
					*p |= bits32[un_pbox[8 * b + j]];
			}
		}

	des_initialised = 1;
}

/* unpack des block (uint8_t[8]) into 2 native-endian 32-bit ints */
static inline void
unpack_block(uint32_t *left, uint32_t *right, const uint8_t *block)
{
    /* TODO: could optimize this when under big endian systems */
    *left = (
        (block[0]<<24)|
        (block[1]<<16)|
        (block[2]<<8)|
        (block[3])
    );
    *right = (
        (block[4]<<24)|
        (block[5]<<16)|
        (block[6]<<8)|
        (block[7])
    );
}

/* pack 2 native-endian 32-bit ints into des block (uint8_t[8]) */
static inline void
pack_block(uint8_t *block, uint32_t left, uint32_t right)
{
    /* TODO: could optimize this when under big endian systems */
    block[0] = (left>>24);
    block[1] = ((left>>16)&0xff);
    block[2] = ((left>>8)&0xff);
    block[3] = (left&0xff);

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

/* set salt portion of des_ctx_t */
static void
des_set_salt(des_ctx_t *ctx, uint32_t salt)
{
	uint32_t obit=0x800000, saltbit=1, saltbits=0;
	int	i;
	for (i = 0; i < 24; i++) {
		if (salt & saltbit)
			saltbits |= obit;
		saltbit <<= 1;
		obit >>= 1;
	}
	ctx->saltbits = saltbits;
}

/* derive key schedule, store in des_ctx_t */
static int
des_set_key(des_ctx_t *ctx, const uint8_t *key)
{
    /* NOTE: key must be 8 bytes long */
	uint32_t	k0, k1, rawkey0, rawkey1;
	int		shifts, round;

    des_init_tables();

    unpack_block(&rawkey0, &rawkey1, key);

	/*
	 *	Do key permutation and split into two 28-bit subkeys.
	 */
	k0 = key_perm_maskl[0][rawkey0 >> 25]
	   | key_perm_maskl[1][(rawkey0 >> 17) & 0x7f]
	   | key_perm_maskl[2][(rawkey0 >> 9) & 0x7f]
	   | key_perm_maskl[3][(rawkey0 >> 1) & 0x7f]
	   | key_perm_maskl[4][rawkey1 >> 25]
	   | key_perm_maskl[5][(rawkey1 >> 17) & 0x7f]
	   | key_perm_maskl[6][(rawkey1 >> 9) & 0x7f]
	   | key_perm_maskl[7][(rawkey1 >> 1) & 0x7f];
	k1 = key_perm_maskr[0][rawkey0 >> 25]
	   | key_perm_maskr[1][(rawkey0 >> 17) & 0x7f]
	   | key_perm_maskr[2][(rawkey0 >> 9) & 0x7f]
	   | key_perm_maskr[3][(rawkey0 >> 1) & 0x7f]
	   | key_perm_maskr[4][rawkey1 >> 25]
	   | key_perm_maskr[5][(rawkey1 >> 17) & 0x7f]
	   | key_perm_maskr[6][(rawkey1 >> 9) & 0x7f]
	   | key_perm_maskr[7][(rawkey1 >> 1) & 0x7f];
	/*
	 *	Rotate subkeys and do compression permutation.
	 */
	shifts = 0;
	for (round = 0; round < 16; round++) {
		uint32_t	t0, t1;

		shifts += key_shifts[round];

		t0 = (k0 << shifts) | (k0 >> (28 - shifts));
		t1 = (k1 << shifts) | (k1 >> (28 - shifts));

/*		ctx->de_keysl[15 - round] = */
		ctx->en_keysl[round] = comp_maskl[0][(t0 >> 21) & 0x7f]
				| comp_maskl[1][(t0 >> 14) & 0x7f]
				| comp_maskl[2][(t0 >> 7) & 0x7f]
				| comp_maskl[3][t0 & 0x7f]
				| comp_maskl[4][(t1 >> 21) & 0x7f]
				| comp_maskl[5][(t1 >> 14) & 0x7f]
				| comp_maskl[6][(t1 >> 7) & 0x7f]
				| comp_maskl[7][t1 & 0x7f];

/*		ctx->de_keysr[15 - round] = */
		ctx->en_keysr[round] = comp_maskr[0][(t0 >> 21) & 0x7f]
				| comp_maskr[1][(t0 >> 14) & 0x7f]
				| comp_maskr[2][(t0 >> 7) & 0x7f]
				| comp_maskr[3][t0 & 0x7f]
				| comp_maskr[4][(t1 >> 21) & 0x7f]
				| comp_maskr[5][(t1 >> 14) & 0x7f]
				| comp_maskr[6][(t1 >> 7) & 0x7f]
				| comp_maskr[7][t1 & 0x7f];
	}
	return(0);
}

/* des encrypt single block using prepared context - returns 1 on err, 0 on sucess */
static int
do_des(des_ctx_t *ctx, const uint8_t *input, uint8_t *output, long count)
{
	/*
	 *	l_in, r_in, l_out, and r_out are in pseudo-"big-endian" format.
	 */
    uint32_t    lt, rt;
	uint32_t	l, r, *kl, *kr, *kl1, *kr1;
	uint32_t	f, r48l, r48r;
	int		round;

	if (count == 0) {
		return(1);
	} else if (count > 0) {
		/*
		 * Encrypting
		 */
		kl1 = ctx->en_keysl;
		kr1 = ctx->en_keysr;
	} else {
        return(1);
		/*
		 * Decrypting
		 */
/*		count = -count;
		kl1 = ctx->de_keysl;
		kr1 = ctx->de_keysr; */
	}

    /* load input into lt & rt */
    unpack_block(&lt, &rt, input);

	/*
	 *	Do initial permutation (IP).
	 */
	l = ip_maskl[0][lt >> 24]
	  | ip_maskl[1][(lt >> 16) & 0xff]
	  | ip_maskl[2][(lt >> 8) & 0xff]
	  | ip_maskl[3][lt & 0xff]
	  | ip_maskl[4][rt >> 24]
	  | ip_maskl[5][(rt >> 16) & 0xff]
	  | ip_maskl[6][(rt >> 8) & 0xff]
	  | ip_maskl[7][rt & 0xff];
	r = ip_maskr[0][lt >> 24]
	  | ip_maskr[1][(lt >> 16) & 0xff]
	  | ip_maskr[2][(lt >> 8) & 0xff]
	  | ip_maskr[3][lt & 0xff]
	  | ip_maskr[4][rt >> 24]
	  | ip_maskr[5][(rt >> 16) & 0xff]
	  | ip_maskr[6][(rt >> 8) & 0xff]
	  | ip_maskr[7][rt & 0xff];

	while (count--) {
		/*
		 * Do each round.
		 */
		kl = kl1;
		kr = kr1;
		round = 16;
		while (round--) {
			/*
			 * Expand R to 48 bits (simulate the E-box).
			 */
			r48l	= ((r & 0x00000001) << 23)
				| ((r & 0xf8000000) >> 9)
				| ((r & 0x1f800000) >> 11)
				| ((r & 0x01f80000) >> 13)
				| ((r & 0x001f8000) >> 15);

			r48r	= ((r & 0x0001f800) << 7)
				| ((r & 0x00001f80) << 5)
				| ((r & 0x000001f8) << 3)
				| ((r & 0x0000001f) << 1)
				| ((r & 0x80000000) >> 31);
			/*
			 * Do salting for crypt() and friends, and
			 * XOR with the permuted key.
			 */
			f = (r48l ^ r48r) & ctx->saltbits;
			r48l ^= f ^ *kl++;
			r48r ^= f ^ *kr++;
			/*
			 * Do sbox lookups (which shrink it back to 32 bits)
			 * and do the pbox permutation at the same time.
			 */
			f = psbox[0][m_sbox[0][r48l >> 12]]
			  | psbox[1][m_sbox[1][r48l & 0xfff]]
			  | psbox[2][m_sbox[2][r48r >> 12]]
			  | psbox[3][m_sbox[3][r48r & 0xfff]];
			/*
			 * Now that we've permuted things, complete f().
			 */
			f ^= l;
			l = r;
			r = f;
		}
		r = l;
		l = f;
	}
	/*
	 * Do final permutation (inverse of IP).
	 */
	lt	= fp_maskl[0][l >> 24]
		| fp_maskl[1][(l >> 16) & 0xff]
		| fp_maskl[2][(l >> 8) & 0xff]
		| fp_maskl[3][l & 0xff]
		| fp_maskl[4][r >> 24]
		| fp_maskl[5][(r >> 16) & 0xff]
		| fp_maskl[6][(r >> 8) & 0xff]
		| fp_maskl[7][r & 0xff];
	rt	= fp_maskr[0][l >> 24]
		| fp_maskr[1][(l >> 16) & 0xff]
		| fp_maskr[2][(l >> 8) & 0xff]
		| fp_maskr[3][l & 0xff]
		| fp_maskr[4][r >> 24]
		| fp_maskr[5][(r >> 16) & 0xff]
		| fp_maskr[6][(r >> 8) & 0xff]
		| fp_maskr[7][r & 0xff];
    pack_block(output, lt, rt);
	return(0);
}

/* public frontend - encrypt a single block using specified params */
int
des_cipher_block(const uint8_t *key, const uint8_t *input, uint8_t *output, long salt, long count)
{
    des_ctx_t ctx;
    int rc;
	if (!des_initialised)
		des_init_tables();
    des_set_key(&ctx, key);
	des_set_salt(&ctx, salt);
    rc = do_des(&ctx, input, output, count);
    memset(&ctx, 0, sizeof(ctx));
    return rc;
}