237 lines
7.6 KiB
C
237 lines
7.6 KiB
C
/* Portable C version of des() function */
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#include <stdint.h>
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#include "des.h"
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/* Tables defined in the Data Encryption Standard documents
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* Three of these tables, the initial permutation, the final
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* permutation and the expansion operator, are regular enough that
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* for speed, we hard-code them. They're here for reference only.
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* Also, the S and P boxes are used by a separate program, gensp.c,
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* to build the combined SP box, Spbox[]. They're also here just
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* for reference.
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*/
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#ifdef notdef
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/* initial permutation IP */
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static unsigned char ip[] = {
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58, 50, 42, 34, 26, 18, 10, 2,
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60, 52, 44, 36, 28, 20, 12, 4,
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62, 54, 46, 38, 30, 22, 14, 6,
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64, 56, 48, 40, 32, 24, 16, 8,
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57, 49, 41, 33, 25, 17, 9, 1,
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59, 51, 43, 35, 27, 19, 11, 3,
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61, 53, 45, 37, 29, 21, 13, 5,
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63, 55, 47, 39, 31, 23, 15, 7
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};
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/* final permutation IP^-1 */
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static unsigned char fp[] = {
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40, 8, 48, 16, 56, 24, 64, 32,
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39, 7, 47, 15, 55, 23, 63, 31,
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38, 6, 46, 14, 54, 22, 62, 30,
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37, 5, 45, 13, 53, 21, 61, 29,
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36, 4, 44, 12, 52, 20, 60, 28,
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35, 3, 43, 11, 51, 19, 59, 27,
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34, 2, 42, 10, 50, 18, 58, 26,
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33, 1, 41, 9, 49, 17, 57, 25
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};
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/* expansion operation matrix */
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static unsigned char ei[] = {
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32, 1, 2, 3, 4, 5,
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4, 5, 6, 7, 8, 9,
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8, 9, 10, 11, 12, 13,
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12, 13, 14, 15, 16, 17,
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16, 17, 18, 19, 20, 21,
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20, 21, 22, 23, 24, 25,
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24, 25, 26, 27, 28, 29,
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28, 29, 30, 31, 32, 1
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};
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/* The (in)famous S-boxes */
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static unsigned char sbox[8][64] = {
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/* S1 */
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14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
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0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
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4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
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15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13,
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/* S2 */
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15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
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3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
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0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
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13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9,
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/* S3 */
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10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
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13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
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13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
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1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12,
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/* S4 */
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7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
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13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
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10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
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3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14,
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/* S5 */
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2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
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14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
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4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
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11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3,
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/* S6 */
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12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
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10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
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9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
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4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13,
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/* S7 */
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4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
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13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
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1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
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6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12,
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/* S8 */
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13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
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1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
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7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
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2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11
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};
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/* 32-bit permutation function P used on the output of the S-boxes */
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static unsigned char p32i[] = {
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16, 7, 20, 21,
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29, 12, 28, 17,
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1, 15, 23, 26,
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5, 18, 31, 10,
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2, 8, 24, 14,
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32, 27, 3, 9,
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19, 13, 30, 6,
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22, 11, 4, 25
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};
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#endif
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int Asmversion = 0;
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/* Combined SP lookup table, linked in
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* For best results, ensure that this is aligned on a 32-bit boundary;
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* Borland C++ 3.1 doesn't guarantee this!
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*/
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extern uint64_t Spbox[8][64]; /* Combined S and P boxes */
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/* Primitive function F.
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* Input is r, subkey array in keys, output is XORed into l.
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* Each round consumes eight 6-bit subkeys, one for
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* each of the 8 S-boxes, 2 longs for each round.
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* Each long contains four 6-bit subkeys, each taking up a byte.
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* The first long contains, from high to low end, the subkeys for
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* S-boxes 1, 3, 5 & 7; the second contains the subkeys for S-boxes
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* 2, 4, 6 & 8 (using the origin-1 S-box numbering in the standard,
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* not the origin-0 numbering used elsewhere in this code)
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* See comments elsewhere about the pre-rotated values of r and Spbox.
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*/
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#define F(l,r,key){\
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work = ((r >> 4) | (r << 28)) ^ key[0];\
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l ^= Spbox[6][work & 0x3f];\
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l ^= Spbox[4][(work >> 8) & 0x3f];\
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l ^= Spbox[2][(work >> 16) & 0x3f];\
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l ^= Spbox[0][(work >> 24) & 0x3f];\
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work = r ^ key[1];\
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l ^= Spbox[7][work & 0x3f];\
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l ^= Spbox[5][(work >> 8) & 0x3f];\
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l ^= Spbox[3][(work >> 16) & 0x3f];\
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l ^= Spbox[1][(work >> 24) & 0x3f];\
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}
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/* Encrypt or decrypt a block of data in ECB mode */
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void
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des(unsigned long ks[16][2],unsigned char block[8])
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/* Key schedule */
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/* Data block */
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{
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unsigned long left,right,work;
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/* Read input block and place in left/right in big-endian order */
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left = ((unsigned long)block[0] << 24)
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| ((unsigned long)block[1] << 16)
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| ((unsigned long)block[2] << 8)
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| (unsigned long)block[3];
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right = ((unsigned long)block[4] << 24)
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| ((unsigned long)block[5] << 16)
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| ((unsigned long)block[6] << 8)
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| (unsigned long)block[7];
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/* Hoey's clever initial permutation algorithm, from Outerbridge
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* (see Schneier p 478)
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*
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* The convention here is the same as Outerbridge: rotate each
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* register left by 1 bit, i.e., so that "left" contains permuted
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* input bits 2, 3, 4, ... 1 and "right" contains 33, 34, 35, ... 32
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* (using origin-1 numbering as in the FIPS). This allows us to avoid
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* one of the two rotates that would otherwise be required in each of
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* the 16 rounds.
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*/
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work = ((left >> 4) ^ right) & 0x0f0f0f0f;
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right ^= work;
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left ^= work << 4;
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work = ((left >> 16) ^ right) & 0xffff;
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right ^= work;
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left ^= work << 16;
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work = ((right >> 2) ^ left) & 0x33333333;
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left ^= work;
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right ^= (work << 2);
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work = ((right >> 8) ^ left) & 0xff00ff;
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left ^= work;
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right ^= (work << 8);
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right = (right << 1) | (right >> 31);
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work = (left ^ right) & 0xaaaaaaaa;
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left ^= work;
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right ^= work;
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left = (left << 1) | (left >> 31);
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/* Now do the 16 rounds */
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F(left,right,ks[0]);
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F(right,left,ks[1]);
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F(left,right,ks[2]);
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F(right,left,ks[3]);
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F(left,right,ks[4]);
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F(right,left,ks[5]);
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F(left,right,ks[6]);
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F(right,left,ks[7]);
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F(left,right,ks[8]);
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F(right,left,ks[9]);
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F(left,right,ks[10]);
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F(right,left,ks[11]);
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F(left,right,ks[12]);
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F(right,left,ks[13]);
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F(left,right,ks[14]);
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F(right,left,ks[15]);
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/* Inverse permutation, also from Hoey via Outerbridge and Schneier */
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right = (right << 31) | (right >> 1);
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work = (left ^ right) & 0xaaaaaaaa;
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left ^= work;
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right ^= work;
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left = (left >> 1) | (left << 31);
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work = ((left >> 8) ^ right) & 0xff00ff;
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right ^= work;
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left ^= work << 8;
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work = ((left >> 2) ^ right) & 0x33333333;
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right ^= work;
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left ^= work << 2;
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work = ((right >> 16) ^ left) & 0xffff;
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left ^= work;
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right ^= work << 16;
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work = ((right >> 4) ^ left) & 0x0f0f0f0f;
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left ^= work;
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right ^= work << 4;
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/* Put the block back into the user's buffer with final swap */
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block[0] = right >> 24;
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block[1] = right >> 16;
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block[2] = right >> 8;
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block[3] = right;
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block[4] = left >> 24;
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block[5] = left >> 16;
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block[6] = left >> 8;
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block[7] = left;
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}
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