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615 lines
17 KiB
615 lines
17 KiB
/* des.c, /atalk-ii/source, Garth Conboy, 11/03/90 */
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/* Public domain code. */
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/* GC - Cleaned up a little and ANSI-ized.
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GC - (04/21/92): Now part of general sources; used by Arap.
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Sofware DES functions
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written 12 Dec 1986 by Phil Karn, KA9Q; large sections adapted from
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the 1977 public-domain program by Jim Gillogly
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*/
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#define ForUseWithPacerAppleTalk 1
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#if ForUseWithPacerAppleTalk
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#include "atalk.h"
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#else
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#include <stdio.h>
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#include <stdlib.h>
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#include <stddef.h>
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#include <string.h>
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#define is ==
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#define isnt !=
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#define and &&
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#define or ||
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#define not !
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#define empty 0
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#define LittleEndian 0 /* 0 for big endian (Motorola/civilized format)
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1 for little endian (Intel/VAX format) */
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#endif
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/* External entries */
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extern int desinit(int mode); /* Initialize the DES package */
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extern void desdone(void); /* De-initialize the DES package */
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extern void setkey(char *key); /* Set key sechedule array from 64
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bit key (will use only 56 bits). */
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extern void endes(char *block); /* In-place encryption of 64-bit block */
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extern void dedes(char *block); /* In-place decryption of 64-bit block */
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/* Static routines */
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static void spinit(void);
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static void perminit(char perm[16][16][8], char p[64]);
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static void permute(char *inblock, char perm[16][16][8], char *outblock);
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static void round(int num, long unsigned *block);
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static long unsigned f(long unsigned r, unsigned char subkey[8]);
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#if LittleEndian
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static unsigned long byteswap(long unsigned x);
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#endif
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/* Tables defined in the Data Encryption Standard documents */
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/* initial permutation IP */
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static 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 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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* This is for reference only; it is unused in the code
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* as the f() function performs it implicitly for speed
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*/
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#if 0
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static 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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#endif
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/* permuted choice table (key) */
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static char pc1[] = {
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57, 49, 41, 33, 25, 17, 9,
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1, 58, 50, 42, 34, 26, 18,
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10, 2, 59, 51, 43, 35, 27,
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19, 11, 3, 60, 52, 44, 36,
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63, 55, 47, 39, 31, 23, 15,
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7, 62, 54, 46, 38, 30, 22,
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14, 6, 61, 53, 45, 37, 29,
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21, 13, 5, 28, 20, 12, 4
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};
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/* number left rotations of pc1 */
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static char totrot[] = {
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1,2,4,6,8,10,12,14,15,17,19,21,23,25,27,28
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};
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/* permuted choice key (table) */
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static char pc2[] = {
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14, 17, 11, 24, 1, 5,
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3, 28, 15, 6, 21, 10,
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23, 19, 12, 4, 26, 8,
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16, 7, 27, 20, 13, 2,
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41, 52, 31, 37, 47, 55,
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30, 40, 51, 45, 33, 48,
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44, 49, 39, 56, 34, 53,
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46, 42, 50, 36, 29, 32
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};
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/* The (in)famous S-boxes */
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static char si[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 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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/* End of DES-defined tables */
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/* Lookup tables initialized once only at startup by desinit() */
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static long (*sp)[64]; /* Combined S and P boxes */
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static char (*iperm)[16][8]; /* Initial and final permutations */
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static char (*fperm)[16][8];
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/* 8 6-bit subkeys for each of 16 rounds, initialized by setkey() */
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static unsigned char (*kn)[8];
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/* bit 0 is left-most in byte */
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static int bytebit[] = {
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0200,0100,040,020,010,04,02,01
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};
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static int nibblebit[] = {
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010,04,02,01
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};
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static int desmode;
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/* Allocate space and initialize DES lookup arrays
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* mode == 0: standard Data Encryption Algorithm
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* mode == 1: DEA without initial and final permutations for speed
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* mode == 2: DEA without permutations and with 128-byte key (completely
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* independent subkeys for each round)
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*/
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int desinit(int mode)
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{
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if (sp isnt empty) /* Already inited? */
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return(0);
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desmode = mode;
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if ((sp = (long (*)[64])malloc(sizeof(long) * 8 * 64)) is empty)
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return(-1);
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spinit();
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if ((kn = (unsigned char (*)[8])malloc(sizeof(char) * 8 * 16)) is empty)
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{
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free(sp);
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return(-1);
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}
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if (mode is 1 or mode is 2) /* No permutations */
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return 0;
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if ((iperm = (char (*)[16][8])malloc(sizeof(char) * 16 * 16 * 8)) is empty)
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{
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free(sp);
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free(kn);
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return(-1);
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}
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perminit(iperm,ip);
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if ((fperm = (char (*)[16][8])malloc(sizeof(char) * 16 * 16 * 8)) is empty)
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{
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free(sp);
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free(kn);
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free(iperm);
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return(-1);
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}
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perminit(fperm,fp);
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return(0);
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} /* desinit */
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/* Free up storage used by DES */
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void desdone(void)
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{
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if (sp is empty)
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return; /* Already done */
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free(sp);
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free(kn);
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if (iperm isnt empty)
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free(iperm);
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if (fperm isnt empty)
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free(fperm);
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sp = empty;
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iperm = empty;
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fperm = empty;
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kn = empty;
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} /* desdone */
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/* Set key (initialize key schedule array) */
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void setkey(char *key) /* 64 bits (will use only 56) */
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{
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#if defined(StaticForSmallStack)
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StaticForSmallStack char pc1m[56]; /* place to modify pc1 into */
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StaticForSmallStack char pcr[56]; /* place to rotate pc1 into */
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#else
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char pc1m[56]; /* place to modify pc1 into */
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char pcr[56]; /* place to rotate pc1 into */
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#endif
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register int i,j,l;
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int m;
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/* In mode 2, the 128 bytes of subkey are set directly from the
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* user's key, allowing him to use completely independent
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* subkeys for each round. Note that the user MUST specify a
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* full 128 bytes.
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*
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* I would like to think that this technique gives the NSA a real
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* headache, but I'm not THAT naive.
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*/
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if(desmode is 2)
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{
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for (i = 0; i < 16; i++)
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for (j = 0; j < 8; j++)
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kn[i][j] = *key++;
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return;
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}
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/* Clear key schedule */
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for (i = 0; i < 16; i++)
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for (j = 0; j < 8; j++)
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kn[i][j]=0;
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for (j = 0; j < 56; j++)
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{ /* convert pc1 to bits of key */
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l = pc1[j]-1; /* integer bit location */
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m = l & 07; /* find bit */
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pc1m[j] = (char)((key[l>>3] & /* find which key byte l is in */
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bytebit[m]) /* and which bit of that byte */
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? 1 : 0); /* and store 1-bit result */
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}
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for (i = 0; i < 16; i++) /* key chunk for each iteration */
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{
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for (j = 0; j < 56; j++) /* rotate pc1 the right amount */
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pcr[j] = pc1m[(l = j + totrot[i]) < (j < 28 ? 28 : 56) ? l : l - 28];
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/* rotate left and right halves independently */
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for (j = 0; j < 48; j++) /* select bits individually */
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{
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/* check bit that goes to kn[j] */
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if (pcr[pc2[j]-1])
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{
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/* mask it in if it's there */
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l = j % 6;
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kn[i][j/6] |= (unsigned char)(bytebit[l] >> 2);
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}
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}
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}
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} /* setkey */
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/* In-place encryption of 64-bit block */
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void endes(char *block)
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{
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register int i;
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unsigned long work[2]; /* Working data storage */
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long unsigned tmp;
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permute(block, iperm, (char *)work); /* Initial Permutation */
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#if LittleEndian
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work[0] = byteswap(work[0]);
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work[1] = byteswap(work[1]);
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#endif
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/* Do the 16 rounds */
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for (i = 0; i < 16; i++)
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round(i, work);
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/* Left/right half swap */
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tmp = work[0];
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work[0] = work[1];
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work[1] = tmp;
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#if LittleEndian
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work[0] = byteswap(work[0]);
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work[1] = byteswap(work[1]);
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#endif
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permute((char *)work, fperm, block); /* Inverse initial permutation */
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} /* endes */
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/* In-place decryption of 64-bit block */
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void dedes(char *block)
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{
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register int i;
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unsigned long work[2]; /* Working data storage */
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long unsigned tmp;
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permute(block, iperm, (char *)work); /* Initial permutation */
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#if LittleEndian
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work[0] = byteswap(work[0]);
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work[1] = byteswap(work[1]);
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#endif
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/* Left/right half swap */
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tmp = work[0];
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work[0] = work[1];
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work[1] = tmp;
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/* Do the 16 rounds in reverse order */
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for (i = 15; i >= 0; i--)
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round(i,work);
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#if LittleEndian
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work[0] = byteswap(work[0]);
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work[1] = byteswap(work[1]);
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#endif
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permute((char *)work, fperm, block); /* Inverse initial permutation */
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} /* dedes */
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/* Permute inblock with perm */
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static void permute(char *inblock,
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char perm[16][16][8], /* 2K bytes defining perm. */
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char *outblock) /* result into outblock,64 bits */
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{
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register int i,j;
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register char *ib, *ob; /* ptr to input or output block */
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register char *p, *q;
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if (perm is empty)
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{
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/* No permutation, just copy */
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for (i = 8; i isnt 0; i--)
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*outblock++ = *inblock++;
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return;
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}
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/* Clear output block */
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for (i = 8, ob = outblock; i isnt 0; i--)
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*ob++ = 0;
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ib = inblock;
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for (j = 0; j < 16; j += 2, ib++) /* for each input nibble */
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{
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ob = outblock;
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p = perm[j][(*ib >> 4) & 017];
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q = perm[j + 1][*ib & 017];
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for (i = 8; i isnt 0; i--) /* and each output byte */
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*ob++ |= (char)(*p++ | *q++); /* OR the masks together */
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}
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} /* permute */
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/* Do one DES cipher round */
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static void round(int num, /* i.e. the num-th one */
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long unsigned *block)
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{
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/* The rounds are numbered from 0 to 15. On even rounds
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* the right half is fed to f() and the result exclusive-ORs
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* the left half; on odd rounds the reverse is done.
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*/
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if (num & 1)
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block[1] ^= f(block[0],kn[num]);
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else
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block[0] ^= f(block[1],kn[num]);
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} /* round */
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/* The nonlinear function f(r,k), the heart of DES */
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static long unsigned f(long unsigned r, /* 32 bits */
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unsigned char subkey[8]) /* 48-bit key for this round */
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{
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register unsigned long rval, rt;
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#ifdef TRACE
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unsigned char *cp;
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int i;
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printf("f(%08lx, %02x %02x %02x %02x %02x %02x %02x %02x) = ",
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r,
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subkey[0], subkey[1], subkey[2],
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subkey[3], subkey[4], subkey[5],
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subkey[6], subkey[7]);
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#endif
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/* Run E(R) ^ K through the combined S & P boxes
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* This code takes advantage of a convenient regularity in
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* E, namely that each group of 6 bits in E(R) feeding
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* a single S-box is a contiguous segment of R.
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*/
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rt = (r >> 1) | ((r & 1) ? (long unsigned)0x80000000 : (long unsigned)0);
|
|
rval = 0;
|
|
rval |= (long unsigned)sp[0][((rt >> 26) ^ *subkey++) & 0x3f];
|
|
rval |= (long unsigned)sp[1][((rt >> 22) ^ *subkey++) & 0x3f];
|
|
rval |= (long unsigned)sp[2][((rt >> 18) ^ *subkey++) & 0x3f];
|
|
rval |= (long unsigned)sp[3][((rt >> 14) ^ *subkey++) & 0x3f];
|
|
rval |= (long unsigned)sp[4][((rt >> 10) ^ *subkey++) & 0x3f];
|
|
rval |= (long unsigned)sp[5][((rt >> 6) ^ *subkey++) & 0x3f];
|
|
rval |= (long unsigned)sp[6][((rt >> 2) ^ *subkey++) & 0x3f];
|
|
rt = (r << 1) | ((r & 0x80000000) ? (long unsigned)1 : (long unsigned)0);
|
|
rval |= (long unsigned)sp[7][(rt ^ *subkey) & 0x3f];
|
|
|
|
#ifdef TRACE
|
|
printf(" %08lx\n",rval);
|
|
#endif
|
|
|
|
return(rval);
|
|
|
|
} /* f */
|
|
|
|
/* Initialize a perm array */
|
|
|
|
static void perminit(char perm[16][16][8], /* 64-bit, either init or final */
|
|
char p[64])
|
|
{
|
|
register int l, j, k;
|
|
int i,m;
|
|
|
|
/* Clear the permutation array */
|
|
|
|
for (i = 0; i < 16; i++)
|
|
for (j = 0; j < 16; j++)
|
|
for (k = 0; k < 8; k++)
|
|
perm[i][j][k] = 0;
|
|
|
|
for (i = 0; i < 16; i++) /* each input nibble position */
|
|
for (j = 0; j < 16; j++) /* each possible input nibble */
|
|
for (k = 0; k < 64; k++) /* each output bit position */
|
|
{
|
|
l = p[k] - 1; /* where does this bit come from */
|
|
if ((l >> 2) isnt i) /* does it come from input position? */
|
|
continue; /* if not, bit k is 0 */
|
|
if (!(j & nibblebit[l & 3]))
|
|
continue; /* any such bit in input? */
|
|
m = k & 07; /* which bit is this in the byte */
|
|
perm[i][j][k>>3] |= (char)bytebit[m];
|
|
}
|
|
|
|
} /* perminit */
|
|
|
|
/* Initialize the lookup table for the combined S and P boxes */
|
|
static void spinit(void)
|
|
{
|
|
#if defined(StaticForSmallStack)
|
|
StaticForSmallStack char pbox[32];
|
|
#else
|
|
char pbox[32];
|
|
#endif
|
|
int p,i,s,j,rowcol;
|
|
long val;
|
|
|
|
/* Compute pbox, the inverse of p32i. This is easier to work with. */
|
|
|
|
for (p = 0; p < 32; p++)
|
|
for (i = 0; i < 32; i++)
|
|
if (p32i[i]-1 is p)
|
|
{
|
|
pbox[p] = (char)i;
|
|
break;
|
|
}
|
|
|
|
for (s = 0; s < 8; s++) /* For each S-box */
|
|
for (i = 0; i < 64; i++) /* For each possible input */
|
|
{
|
|
val = 0;
|
|
|
|
/* The row number is formed from the first and last
|
|
* bits; the column number is from the middle 4
|
|
*/
|
|
|
|
rowcol = (i & 32) | ((i & 1) ? 16 : 0) | ((i >> 1) & 0xf);
|
|
for (j = 0; j < 4; j++) /* For each output bit */
|
|
if (si[s][rowcol] & (8 >> (short)j))
|
|
val |= 1L << (short)(31 - pbox[4*s + j]);
|
|
|
|
sp[s][i] = val;
|
|
|
|
#ifdef DEBUG
|
|
#if (not defined(IamNot)) or (IamNot a WindowsNT)
|
|
printf("sp[%d][%2d] = %08lx\n",s,i,sp[s][i]);
|
|
#endif
|
|
#endif
|
|
}
|
|
|
|
} /* spinit */
|
|
|
|
#if LittleEndian
|
|
|
|
/* Byte swap a long */
|
|
|
|
static unsigned long byteswap(long unsigned x)
|
|
{
|
|
register char *cp, tmp;
|
|
|
|
cp = (char *)&x;
|
|
|
|
tmp = cp[3];
|
|
cp[3] = cp[0];
|
|
cp[0] = tmp;
|
|
|
|
tmp = cp[2];
|
|
cp[2] = cp[1];
|
|
cp[1] = tmp;
|
|
|
|
return(x);
|
|
}
|
|
#endif
|