usr.bin/enigma/enigma.c

   1 /*
   2  *      "enigma.c" is in file cbw.tar from
   3  *      anonymous FTP host watmsg.waterloo.edu: pub/crypt/cbw.tar.Z
   4  *
   5  *      A one-rotor machine designed along the lines of Enigma
   6  *      but considerably trivialized.
   7  *
   8  *      A public-domain replacement for the UNIX "crypt" command.
   9  *
  10  *      Upgraded to function properly on 64-bit machines.
  11  *
  12  * $FreeBSD: src/usr.bin/enigma/enigma.c,v 1.2.6.3 2001/08/01 23:51:34 obrien Exp $
  13  * $DragonFly: src/usr.bin/enigma/enigma.c,v 1.5 2004/07/31 11:18:43 eirikn Exp $
  14  */
  15
  16 #include <sys/types.h>
  17 #include <sys/wait.h>
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23
  24 #define MINUSKVAR "CrYpTkEy"
  25
  26 #define ECHO 010
  27 #define ROTORSZ 256
  28 #define MASK 0377
  29 char    t1[ROTORSZ];
  30 char    t2[ROTORSZ];
  31 char    t3[ROTORSZ];
  32 char    deck[ROTORSZ];
  33 char    buf[13];
  34
  35 void    shuffle(char *);
  36 void    setup(char *);
  37
  38 void
  39 setup(char *pw)
  40 {
  41         int ic, i, k, temp;
  42         char salt[3];
  43         unsigned rnd;
  44         long seed;
  45
  46         strncpy(salt, pw, sizeof(salt));
  47         memcpy(buf, crypt(pw, salt), sizeof(buf));
  48         seed = 123;
  49         for (i=0; i<13; i++)
  50                 seed = seed*buf[i] + i;
  51         for(i=0;i<ROTORSZ;i++) {
  52                 t1[i] = i;
  53                 deck[i] = i;
  54         }
  55         for(i=0;i<ROTORSZ;i++) {
  56                 seed = 5*seed + buf[i%13];
  57                 if( sizeof(long) > 4 )  {
  58                         /* Force seed to stay in 32-bit signed math */
  59                         if( seed & 0x80000000 )
  60                                 seed = seed | (-1L & ~0xFFFFFFFFL);
  61                         else
  62                                 seed &= 0x7FFFFFFF;
  63                 }
  64                 rnd = seed % 65521;
  65                 k = ROTORSZ-1 - i;
  66                 ic = (rnd&MASK)%(k+1);
  67                 rnd >>= 8;
  68                 temp = t1[k];
  69                 t1[k] = t1[ic];
  70                 t1[ic] = temp;
  71                 if(t3[k]!=0) continue;
  72                 ic = (rnd&MASK) % k;
  73                 while(t3[ic]!=0) ic = (ic+1) % k;
  74                 t3[k] = ic;
  75                 t3[ic] = k;
  76         }
  77         for(i=0;i<ROTORSZ;i++)
  78                 t2[t1[i]&MASK] = i;
  79 }
  80
  81 int
  82 main(int argc, char **argv)
  83 {
  84         register int i, n1, n2, nr1, nr2;
  85         int secureflg = 0, kflag = 0;
  86         char *cp;
  87
  88         if (argc > 1 && argv[1][0] == '-') {
  89                 if (argv[1][1] == 's') {
  90                         argc--;
  91                         argv++;
  92                         secureflg = 1;
  93                 } else if (argv[1][1] == 'k') {
  94                         argc--;
  95                         argv++;
  96                         kflag = 1;
  97                 }
  98         }
  99         if (kflag) {
 100                 if ((cp = getenv(MINUSKVAR)) == NULL) {
 101                         fprintf(stderr, "%s not set\n", MINUSKVAR);
 102                         exit(1);
 103                 }
 104                 setup(cp);
 105         } else if (argc != 2) {
 106                 setup(getpass("Enter key:"));
 107         }
 108         else
 109                 setup(argv[1]);
 110         n1 = 0;
 111         n2 = 0;
 112         nr2 = 0;
 113
 114         while((i=getchar()) != -1) {
 115                 if (secureflg) {
 116                         nr1 = deck[n1]&MASK;
 117                         nr2 = deck[nr1]&MASK;
 118                 } else {
 119                         nr1 = n1;
 120                 }
 121                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 122                 putchar(i);
 123                 n1++;
 124                 if(n1==ROTORSZ) {
 125                         n1 = 0;
 126                         n2++;
 127                         if(n2==ROTORSZ) n2 = 0;
 128                         if (secureflg) {
 129                                 shuffle(deck);
 130                         } else {
 131                                 nr2 = n2;
 132                         }
 133                 }
 134         }
 135
 136         return 0;
 137 }
 138
 139 void
 140 shuffle(char *deckary)
 141 {
 142         int i, ic, k, temp;
 143         unsigned rnd;
 144         static long seed = 123;
 145
 146         for(i=0;i<ROTORSZ;i++) {
 147                 seed = 5*seed + buf[i%13];
 148                 rnd = seed % 65521;
 149                 k = ROTORSZ-1 - i;
 150                 ic = (rnd&MASK)%(k+1);
 151                 temp = deckary[k];
 152                 deckary[k] = deckary[ic];
 153                 deckary[ic] = temp;
 154         }
 155 }