src/crypto/des/internal.h

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * 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 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 cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.] */

#ifndef OPENSSL_HEADER_DES_INTERNAL_H
#define OPENSSL_HEADER_DES_INTERNAL_H

#include <openssl/base.h>

#if defined(__cplusplus)
extern "C" {
#endif


#define c2l(c, l)                         \
  do {                                    \
    (l) = ((uint32_t)(*((c)++)));         \
    (l) |= ((uint32_t)(*((c)++))) << 8L;  \
    (l) |= ((uint32_t)(*((c)++))) << 16L; \
    (l) |= ((uint32_t)(*((c)++))) << 24L; \
  } while (0)

#define l2c(l, c)                                    \
  do {                                               \
    *((c)++) = (unsigned char)(((l)) & 0xff);        \
    *((c)++) = (unsigned char)(((l) >> 8L) & 0xff);  \
    *((c)++) = (unsigned char)(((l) >> 16L) & 0xff); \
    *((c)++) = (unsigned char)(((l) >> 24L) & 0xff); \
  } while (0)

/* NOTE - c is not incremented as per c2l */
#define c2ln(c, l1, l2, n)                     \
  do {                                         \
    (c) += (n);                                \
    (l1) = (l2) = 0;                           \
    switch (n) {                               \
      case 8:                                  \
        (l2) = ((uint32_t)(*(--(c)))) << 24L;  \
      case 7:                                  \
        (l2) |= ((uint32_t)(*(--(c)))) << 16L; \
      case 6:                                  \
        (l2) |= ((uint32_t)(*(--(c)))) << 8L;  \
      case 5:                                  \
        (l2) |= ((uint32_t)(*(--(c))));        \
      case 4:                                  \
        (l1) = ((uint32_t)(*(--(c)))) << 24L;  \
      case 3:                                  \
        (l1) |= ((uint32_t)(*(--(c)))) << 16L; \
      case 2:                                  \
        (l1) |= ((uint32_t)(*(--(c)))) << 8L;  \
      case 1:                                  \
        (l1) |= ((uint32_t)(*(--(c))));        \
    }                                          \
  } while (0)

/* NOTE - c is not incremented as per l2c */
#define l2cn(l1, l2, c, n)                                \
  do {                                                    \
    (c) += (n);                                           \
    switch (n) {                                          \
      case 8:                                             \
        *(--(c)) = (unsigned char)(((l2) >> 24L) & 0xff); \
      case 7:                                             \
        *(--(c)) = (unsigned char)(((l2) >> 16L) & 0xff); \
      case 6:                                             \
        *(--(c)) = (unsigned char)(((l2) >> 8L) & 0xff);  \
      case 5:                                             \
        *(--(c)) = (unsigned char)(((l2)) & 0xff);        \
      case 4:                                             \
        *(--(c)) = (unsigned char)(((l1) >> 24L) & 0xff); \
      case 3:                                             \
        *(--(c)) = (unsigned char)(((l1) >> 16L) & 0xff); \
      case 2:                                             \
        *(--(c)) = (unsigned char)(((l1) >> 8L) & 0xff);  \
      case 1:                                             \
        *(--(c)) = (unsigned char)(((l1)) & 0xff);        \
    }                                                     \
  } while (0)

/* 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)          \
  do {                                  \
    (t) = ((((a) >> (n)) ^ (b)) & (m)); \
    (b) ^= (t);                         \
    (a) ^= ((t) << (n));                \
  } while (0)

#define IP(l, r)                        \
  do {                                  \
    uint32_t tt;                        \
    PERM_OP(r, l, tt, 4, 0x0f0f0f0fL);  \
    PERM_OP(l, r, tt, 16, 0x0000ffffL); \
    PERM_OP(r, l, tt, 2, 0x33333333L);  \
    PERM_OP(l, r, tt, 8, 0x00ff00ffL);  \
    PERM_OP(r, l, tt, 1, 0x55555555L);  \
  } while (0)

#define FP(l, r)                        \
  do {                                  \
    uint32_t tt;                        \
    PERM_OP(l, r, tt, 1, 0x55555555L);  \
    PERM_OP(r, l, tt, 8, 0x00ff00ffL);  \
    PERM_OP(l, r, tt, 2, 0x33333333L);  \
    PERM_OP(r, l, tt, 16, 0x0000ffffL); \
    PERM_OP(l, r, tt, 4, 0x0f0f0f0fL);  \
  } while (0)

#define LOAD_DATA(ks, R, S, u, t, E0, E1) \
  do {                                    \
    (u) = (R) ^ (ks)->subkeys[S][0];      \
    (t) = (R) ^ (ks)->subkeys[S][1];      \
  } while (0)

#define D_ENCRYPT(ks, LL, R, S)                                                \
  do {                                                                         \
    LOAD_DATA(ks, R, S, u, t, E0, E1);                                         \
    t = ROTATE(t, 4);                                                          \
    (LL) ^=                                                                    \
        DES_SPtrans[0][(u >> 2L) & 0x3f] ^ DES_SPtrans[2][(u >> 10L) & 0x3f] ^ \
        DES_SPtrans[4][(u >> 18L) & 0x3f] ^                                    \
        DES_SPtrans[6][(u >> 26L) & 0x3f] ^ DES_SPtrans[1][(t >> 2L) & 0x3f] ^ \
        DES_SPtrans[3][(t >> 10L) & 0x3f] ^                                    \
        DES_SPtrans[5][(t >> 18L) & 0x3f] ^ DES_SPtrans[7][(t >> 26L) & 0x3f]; \
  } while (0)

#define ITERATIONS 16
#define HALF_ITERATIONS 8

#define ROTATE(a, n) (((a) >> (n)) + ((a) << (32 - (n))))


#if defined(__cplusplus)
} /* extern C */
#endif

#endif /* OPENSSL_HEADER_DES_INTERNAL_H */