/*
 * 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).
 */


/* Parts busybox doesn't need or had optimized */
#define USE_PRECOMPUTED_u_sbox 1
#define USE_REPETITIVE_SPEEDUP 0
#define USE_ip_mask 0
#define USE_de_keys 0


/* A pile of data */
static const uint8_t IP[64] ALIGN1 = {
        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 const uint8_t key_perm[56] ALIGN1 = {
        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 const uint8_t key_shifts[16] ALIGN1 = {
        1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
};

static const uint8_t comp_perm[48] ALIGN1 = {
        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.
 */
#if !USE_PRECOMPUTED_u_sbox
static const 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
        }
};
#else /* precomputed, with half-bytes packed into one byte */
static const uint8_t u_sbox[8][32] = {
        {       0x0e, 0xf4, 0x7d, 0x41, 0xe2, 0x2f, 0xdb, 0x18,
                0xa3, 0x6a, 0xc6, 0xbc, 0x95, 0x59, 0x30, 0x87,
                0xf4, 0xc1, 0x8e, 0x28, 0x4d, 0x96, 0x12, 0x7b,
                0x5f, 0xbc, 0x39, 0xe7, 0xa3, 0x0a, 0x65, 0xd0,
        },
        {       0x3f, 0xd1, 0x48, 0x7e, 0xf6, 0x2b, 0x83, 0xe4,
                0xc9, 0x07, 0x12, 0xad, 0x6c, 0x90, 0xb5, 0x5a,
                0xd0, 0x8e, 0xa7, 0x1b, 0x3a, 0xf4, 0x4d, 0x21,
                0xb5, 0x68, 0x7c, 0xc6, 0x09, 0x53, 0xe2, 0x9f,
        },
        {       0xda, 0x70, 0x09, 0x9e, 0x36, 0x43, 0x6f, 0xa5,
                0x21, 0x8d, 0x5c, 0xe7, 0xcb, 0xb4, 0xf2, 0x18,
                0x1d, 0xa6, 0xd4, 0x09, 0x68, 0x9f, 0x83, 0x70,
                0x4b, 0xf1, 0xe2, 0x3c, 0xb5, 0x5a, 0x2e, 0xc7,
        },
        {       0xd7, 0x8d, 0xbe, 0x53, 0x60, 0xf6, 0x09, 0x3a,
                0x41, 0x72, 0x28, 0xc5, 0x1b, 0xac, 0xe4, 0x9f,
                0x3a, 0xf6, 0x09, 0x60, 0xac, 0x1b, 0xd7, 0x8d,
                0x9f, 0x41, 0x53, 0xbe, 0xc5, 0x72, 0x28, 0xe4,
        },
        {       0xe2, 0xbc, 0x24, 0xc1, 0x47, 0x7a, 0xdb, 0x16,
                0x58, 0x05, 0xf3, 0xaf, 0x3d, 0x90, 0x8e, 0x69,
                0xb4, 0x82, 0xc1, 0x7b, 0x1a, 0xed, 0x27, 0xd8,
                0x6f, 0xf9, 0x0c, 0x95, 0xa6, 0x43, 0x50, 0x3e,
        },
        {       0xac, 0xf1, 0x4a, 0x2f, 0x79, 0xc2, 0x96, 0x58,
                0x60, 0x1d, 0xd3, 0xe4, 0x0e, 0xb7, 0x35, 0x8b,
                0x49, 0x3e, 0x2f, 0xc5, 0x92, 0x58, 0xfc, 0xa3,
                0xb7, 0xe0, 0x14, 0x7a, 0x61, 0x0d, 0x8b, 0xd6,
        },
        {       0xd4, 0x0b, 0xb2, 0x7e, 0x4f, 0x90, 0x18, 0xad,
                0xe3, 0x3c, 0x59, 0xc7, 0x25, 0xfa, 0x86, 0x61,
                0x61, 0xb4, 0xdb, 0x8d, 0x1c, 0x43, 0xa7, 0x7e,
                0x9a, 0x5f, 0x06, 0xf8, 0xe0, 0x25, 0x39, 0xc2,
        },
        {       0x1d, 0xf2, 0xd8, 0x84, 0xa6, 0x3f, 0x7b, 0x41,
                0xca, 0x59, 0x63, 0xbe, 0x05, 0xe0, 0x9c, 0x27,
                0x27, 0x1b, 0xe4, 0x71, 0x49, 0xac, 0x8e, 0xd2,
                0xf0, 0xc6, 0x9a, 0x0d, 0x3f, 0x53, 0x65, 0xb8,
        },
};
#endif

static const uint8_t pbox[32] ALIGN1 = {
        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 const uint32_t bits32[32] ALIGN4 = {
        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 const uint8_t bits8[8] ALIGN1 = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 };


static int
ascii_to_bin(char ch)
{
        if (ch > 'z')
                return 0;
        if (ch >= 'a')
                return (ch - 'a' + 38);
        if (ch > 'Z')
                return 0;
        if (ch >= 'A')
                return (ch - 'A' + 12);
        if (ch > '9')
                return 0;
        if (ch >= '.')
                return (ch - '.');
        return 0;
}


/* Static stuff that stays resident and doesn't change after
 * being initialized, and therefore doesn't need to be made
 * reentrant. */
struct const_des_ctx {
#if USE_ip_mask
        uint8_t init_perm[64]; /* referenced 2 times */
#endif
        uint8_t final_perm[64]; /* 2 times */
        uint8_t m_sbox[4][4096]; /* 5 times */
};
#define C (*cctx)
#define init_perm  (C.init_perm )
#define final_perm (C.final_perm)
#define m_sbox     (C.m_sbox    )

static struct const_des_ctx*
const_des_init(void)
{
        unsigned i, j, b;
        struct const_des_ctx *cctx;

#if !USE_PRECOMPUTED_u_sbox
        uint8_t u_sbox[8][64];

        cctx = xmalloc(sizeof(*cctx));

        /* 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];
                }
        }
        for (i = 0; i < 8; i++) {
                fprintf(stderr, "\t{\t");
                for (j = 0; j < 64; j+=2)
                        fprintf(stderr, " 0x%02x,", u_sbox[i][j] + u_sbox[i][j+1]*16);
                fprintf(stderr, "\n\t},\n");
        }
        /*
         * 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]);
#else
        cctx = xmalloc(sizeof(*cctx));

        /*
         * 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++) {
                uint8_t lo, hi;
                hi = u_sbox[(b << 1)][i / 2];
                if (!(i & 1))
                        hi <<= 4;
                lo = u_sbox[(b << 1) + 1][j / 2];
                if (j & 1)
                        lo >>= 4;
                m_sbox[b][(i << 6) | j] = (hi & 0xf0) | (lo & 0x0f);
        }
#endif

        /*
         * Set up the initial & final permutations into a useful form.
         */
        for (i = 0; i < 64; i++) {
                final_perm[i] = IP[i] - 1;
#if USE_ip_mask
                init_perm[final_perm[i]] = (uint8_t)i;
#endif
        }

        return cctx;
}


struct des_ctx {
        const struct const_des_ctx *const_ctx;
        uint32_t saltbits; /* referenced 5 times */
#if USE_REPETITIVE_SPEEDUP
        uint32_t old_salt; /* 3 times */
        uint32_t old_rawkey0, old_rawkey1; /* 3 times each */
#endif
        uint8_t un_pbox[32]; /* 2 times */
        uint8_t inv_comp_perm[56]; /* 3 times */
        uint8_t inv_key_perm[64]; /* 3 times */
        uint32_t en_keysl[16], en_keysr[16]; /* 2 times each */
#if USE_de_keys
        uint32_t de_keysl[16], de_keysr[16]; /* 2 times each */
#endif
#if USE_ip_mask
        uint32_t ip_maskl[8][256], ip_maskr[8][256]; /* 9 times each */
#endif
        uint32_t fp_maskl[8][256], fp_maskr[8][256]; /* 9 times each */
        uint32_t key_perm_maskl[8][128], key_perm_maskr[8][128]; /* 9 times */
        uint32_t comp_maskl[8][128], comp_maskr[8][128]; /* 9 times each */
        uint32_t psbox[4][256]; /* 5 times */
};
#define D (*ctx)
#define const_ctx       (D.const_ctx      )
#define saltbits        (D.saltbits       )
#define old_salt        (D.old_salt       )
#define old_rawkey0     (D.old_rawkey0    )
#define old_rawkey1     (D.old_rawkey1    )
#define un_pbox         (D.un_pbox        )
#define inv_comp_perm   (D.inv_comp_perm  )
#define inv_key_perm    (D.inv_key_perm   )
#define en_keysl        (D.en_keysl       )
#define en_keysr        (D.en_keysr       )
#define de_keysl        (D.de_keysl       )
#define de_keysr        (D.de_keysr       )
#define ip_maskl        (D.ip_maskl       )
#define ip_maskr        (D.ip_maskr       )
#define fp_maskl        (D.fp_maskl       )
#define fp_maskr        (D.fp_maskr       )
#define key_perm_maskl  (D.key_perm_maskl )
#define key_perm_maskr  (D.key_perm_maskr )
#define comp_maskl      (D.comp_maskl     )
#define comp_maskr      (D.comp_maskr     )
#define psbox           (D.psbox          )

static struct des_ctx*
des_init(struct des_ctx *ctx, const struct const_des_ctx *cctx)
{
        int i, j, b, k, inbit, obit;
        uint32_t p;
        const uint32_t *bits28, *bits24;

        if (!ctx)
                ctx = xmalloc(sizeof(*ctx));
        const_ctx = cctx;

#if USE_REPETITIVE_SPEEDUP
        old_rawkey0 = old_rawkey1 = 0;
        old_salt = 0;
#endif
        //saltbits = 0; /* not needed: we call setup_salt() before do_des() */
        bits28 = bits32 + 4;
        bits24 = bits28 + 4;

        /* Initialise the inverted key permutation. */
        for (i = 0; i < 64; 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++) {
                uint32_t il, ir;
                uint32_t fl, fr;
                for (i = 0; i < 256; i++) {
#if USE_ip_mask
                        il = 0;
                        ir = 0;
#endif
                        fl = 0;
                        fr = 0;
                        for (j = 0; j < 8; j++) {
                                inbit = 8 * k + j;
                                if (i & bits8[j]) {
#if USE_ip_mask
                                        obit = init_perm[inbit];
                                        if (obit < 32)
                                                il |= bits32[obit];
                                        else
                                                ir |= bits32[obit - 32];
#endif
                                        obit = final_perm[inbit];
                                        if (obit < 32)
                                                fl |= bits32[obit];
                                        else
                                                fr |= bits32[obit - 32];
                                }
                        }
#if USE_ip_mask
                        ip_maskl[k][i] = il;
                        ip_maskr[k][i] = ir;
#endif
                        fp_maskl[k][i] = fl;
                        fp_maskr[k][i] = fr;
                }
                for (i = 0; i < 128; i++) {
                        il = 0;
                        ir = 0;
                        for (j = 0; j < 7; j++) {
                                inbit = 8 * k + j;
                                if (i & bits8[j + 1]) {
                                        obit = inv_key_perm[inbit];
                                        if (obit == 255)
                                                continue;
                                        if (obit < 28)
                                                il |= bits28[obit];
                                        else
                                                ir |= bits28[obit - 28];
                                }
                        }
                        key_perm_maskl[k][i] = il;
                        key_perm_maskr[k][i] = ir;
                        il = 0;
                        ir = 0;
                        for (j = 0; j < 7; j++) {
                                inbit = 7 * k + j;
                                if (i & bits8[j + 1]) {
                                        obit = inv_comp_perm[inbit];
                                        if (obit == 255)
                                                continue;
                                        if (obit < 24)
                                                il |= bits24[obit];
                                        else
                                                ir |= bits24[obit - 24];
                                }
                        }
                        comp_maskl[k][i] = il;
                        comp_maskr[k][i] = ir;
                }
        }

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

        return ctx;
}

/* Accepts 24-bit salt at max */
static void
setup_salt(struct des_ctx *ctx, uint32_t salt)
{
        uint32_t invbits;

#if USE_REPETITIVE_SPEEDUP
        if (salt == old_salt)
                return;
        old_salt = salt;
#endif

        invbits = 0;

        salt |= (1 << 24);
        do {
                invbits = (invbits << 1) + (salt & 1);
                salt >>= 1;
        } while (salt != 1);

        saltbits = invbits;
}

static void
des_setkey(struct des_ctx *ctx, const char *key)
{
        uint32_t k0, k1, rawkey0, rawkey1;
        int shifts, round;

        rawkey0 = ntohl(*(const uint32_t *) key);
        rawkey1 = ntohl(*(const uint32_t *) (key + 4));

#if USE_REPETITIVE_SPEEDUP
        if ((rawkey0 | rawkey1)
         && rawkey0 == old_rawkey0
         && rawkey1 == old_rawkey1
        ) {
                /*
                 * Already setup for this key.
                 * This optimisation fails on a zero key (which is weak and
                 * has bad parity anyway) in order to simplify the starting
                 * conditions.
                 */
                return;
        }
        old_rawkey0 = rawkey0;
        old_rawkey1 = rawkey1;
#endif

        /*
         * 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));

#if USE_de_keys
                de_keysl[15 - round] =
#endif
                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];

#if USE_de_keys
                de_keysr[15 - round] =
#endif
                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];
        }
}


static void
do_des(struct des_ctx *ctx, /*uint32_t l_in, uint32_t r_in,*/ uint32_t *l_out, uint32_t *r_out, int count)
{
        const struct const_des_ctx *cctx = const_ctx;
        /*
         * l_in, r_in, l_out, and r_out are in pseudo-"big-endian" format.
         */
        uint32_t l, r, *kl, *kr;
        uint32_t f = f; /* silence gcc */
        uint32_t r48l, r48r;
        int round;

        /* Do initial permutation (IP). */
#if USE_ip_mask
        uint32_t l_in = 0;
        uint32_t r_in = 0;
        l = ip_maskl[0][l_in >> 24]
          | ip_maskl[1][(l_in >> 16) & 0xff]
          | ip_maskl[2][(l_in >> 8) & 0xff]
          | ip_maskl[3][l_in & 0xff]
          | ip_maskl[4][r_in >> 24]
          | ip_maskl[5][(r_in >> 16) & 0xff]
          | ip_maskl[6][(r_in >> 8) & 0xff]
          | ip_maskl[7][r_in & 0xff];
        r = ip_maskr[0][l_in >> 24]
          | ip_maskr[1][(l_in >> 16) & 0xff]
          | ip_maskr[2][(l_in >> 8) & 0xff]
          | ip_maskr[3][l_in & 0xff]
          | ip_maskr[4][r_in >> 24]
          | ip_maskr[5][(r_in >> 16) & 0xff]
          | ip_maskr[6][(r_in >> 8) & 0xff]
          | ip_maskr[7][r_in & 0xff];
#elif 0 /* -65 bytes (using the fact that l_in == r_in == 0) */
        l = r = 0;
        for (round = 0; round < 8; round++) {
                l |= ip_maskl[round][0];
                r |= ip_maskr[round][0];
        }
        bb_error_msg("l:%x r:%x", l, r); /* reports 0, 0 always! */
#else /* using the fact that ip_maskX[] is constant (written to by des_init) */
        l = r = 0;
#endif

        do {
                /* Do each round. */
                kl = en_keysl;
                kr = en_keysr;
                round = 16;
                do {
                        /* 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) & 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;
                } while (--round);
                r = l;
                l = f;
        } while (--count);

        /* Do final permutation (inverse of IP). */
        *l_out  = 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];
        *r_out  = 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];
}

#define DES_OUT_BUFSIZE 21

static void
to64_msb_first(char *s, unsigned v)
{
#if 0
        *s++ = ascii64[(v >> 18) & 0x3f]; /* bits 23..18 */
        *s++ = ascii64[(v >> 12) & 0x3f]; /* bits 17..12 */
        *s++ = ascii64[(v >> 6) & 0x3f]; /* bits 11..6 */
        *s   = ascii64[v & 0x3f]; /* bits 5..0 */
#endif
        *s++ = i64c(v >> 18); /* bits 23..18 */
        *s++ = i64c(v >> 12); /* bits 17..12 */
        *s++ = i64c(v >> 6); /* bits 11..6 */
        *s   = i64c(v); /* bits 5..0 */
}

static char *
NOINLINE
des_crypt(struct des_ctx *ctx, char output[DES_OUT_BUFSIZE],
                const unsigned char *key, const unsigned char *salt_str)
{
        uint32_t salt, r0, r1, keybuf[2];
        uint8_t *q;

        /* Bad salt? Mimic crypt() API - return NULL */
        if (!salt_str[0] || !salt_str[1])
                return NULL;

        /*
         * Copy the key, shifting each character up by one bit
         * and padding with zeros.
         */
        q = (uint8_t *)keybuf;
        while (q - (uint8_t *)keybuf != 8) {
                *q = *key << 1;
                if (*q)
                        key++;
                q++;
        }
        des_setkey(ctx, (char *)keybuf);

        /*
         * salt_str - 2 chars of salt (converted to 12 bits)
         * key - up to 8 characters
         */
        output[0] = salt_str[0];
        output[1] = salt_str[1];
        salt = (ascii_to_bin(salt_str[1]) << 6)
             |  ascii_to_bin(salt_str[0]);
        setup_salt(ctx, salt); /* set ctx->saltbits for do_des() */

        /* Do it. */
        do_des(ctx, /*0, 0,*/ &r0, &r1, 25 /* count */);

        /* Now encode the result. */
#if 0
{
        uint32_t l = (r0 >> 8);
        q = (uint8_t *)output + 2;
        *q++ = ascii64[(l >> 18) & 0x3f]; /* bits 31..26 of r0 */
        *q++ = ascii64[(l >> 12) & 0x3f]; /* bits 25..20 of r0 */
        *q++ = ascii64[(l >> 6) & 0x3f]; /* bits 19..14 of r0 */
        *q++ = ascii64[l & 0x3f]; /* bits 13..8 of r0 */
        l = ((r0 << 16) | (r1 >> 16));
        *q++ = ascii64[(l >> 18) & 0x3f]; /* bits 7..2 of r0 */
        *q++ = ascii64[(l >> 12) & 0x3f]; /* bits 1..2 of r0 and 31..28 of r1 */
        *q++ = ascii64[(l >> 6) & 0x3f]; /* bits 27..22 of r1 */
        *q++ = ascii64[l & 0x3f]; /* bits 21..16 of r1 */
        l = r1 << 2;
        *q++ = ascii64[(l >> 12) & 0x3f]; /* bits 15..10 of r1 */
        *q++ = ascii64[(l >> 6) & 0x3f]; /* bits 9..4 of r1 */
        *q++ = ascii64[l & 0x3f]; /* bits 3..0 of r1 + 00 */
        *q = 0;
}
#else
        /* Each call takes low-order 24 bits and stores 4 chars */
        /* bits 31..8 of r0 */
        to64_msb_first(output + 2, (r0 >> 8));
        /* bits 7..0 of r0 and 31..16 of r1 */
        to64_msb_first(output + 6, (r0 << 16) | (r1 >> 16));
        /* bits 15..0 of r1 and two zero bits (plus extra zero byte) */
        to64_msb_first(output + 10, (r1 << 8));
        /* extra zero byte is encoded as '.', fixing it */
        output[13] = '\0';
#endif

        return output;
}

#undef USE_PRECOMPUTED_u_sbox
#undef USE_REPETITIVE_SPEEDUP
#undef USE_ip_mask
#undef USE_de_keys

#undef C
#undef init_perm
#undef final_perm
#undef m_sbox
#undef D
#undef const_ctx
#undef saltbits
#undef old_salt
#undef old_rawkey0
#undef old_rawkey1
#undef un_pbox
#undef inv_comp_perm
#undef inv_key_perm
#undef en_keysl
#undef en_keysr
#undef de_keysl
#undef de_keysr
#undef ip_maskl
#undef ip_maskr
#undef fp_maskl
#undef fp_maskr
#undef key_perm_maskl
#undef key_perm_maskr
#undef comp_maskl
#undef comp_maskr
#undef psbox