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
  13 #include <sys/cdefs.h>
  14 __FBSDID("$FreeBSD$");
  15
  16 #include <sys/types.h>
  17
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include <unistd.h>
  22
  23 #define MINUSKVAR "CrYpTkEy"
  24
  25 #define ECHO 010
  26 #define ROTORSZ 256
  27 #define MASK 0377
  28 char    t1[ROTORSZ];
  29 char    t2[ROTORSZ];
  30 char    t3[ROTORSZ];
  31 char    deck[ROTORSZ];
  32 char    buf[13];
  33
  34 void    shuffle(char *);
  35 void    setup(char *);
  36
  37 void
  38 setup(char *pw)
  39 {
  40         int ic, i, k, temp;
  41         char salt[3];
  42         unsigned rnd;
  43         int32_t seed;
  44
  45         strlcpy(salt, pw, sizeof(salt));
  46         memcpy(buf, crypt(pw, salt), sizeof(buf));
  47         seed = 123;
  48         for (i=0; i<13; i++)
  49                 seed = seed*buf[i] + i;
  50         for(i=0;i<ROTORSZ;i++) {
  51                 t1[i] = i;
  52                 deck[i] = i;
  53         }
  54         for(i=0;i<ROTORSZ;i++) {
  55                 seed = 5*seed + buf[i%13];
  56                 rnd = seed % 65521;
  57                 k = ROTORSZ-1 - i;
  58                 ic = (rnd&MASK)%(k+1);
  59                 rnd >>= 8;
  60                 temp = t1[k];
  61                 t1[k] = t1[ic];
  62                 t1[ic] = temp;
  63                 if(t3[k]!=0) continue;
  64                 ic = (rnd&MASK) % k;
  65                 while(t3[ic]!=0) ic = (ic+1) % k;
  66                 t3[k] = ic;
  67                 t3[ic] = k;
  68         }
  69         for(i=0;i<ROTORSZ;i++)
  70                 t2[t1[i]&MASK] = i;
  71 }
  72
  73 int
  74 main(int argc, char *argv[])
  75 {
  76         int i, n1, n2, nr1, nr2;
  77         int secureflg = 0, kflag = 0;
  78         char *cp;
  79
  80         if (argc > 1 && argv[1][0] == '-') {
  81                 if (argv[1][1] == 's') {
  82                         argc--;
  83                         argv++;
  84                         secureflg = 1;
  85                 } else if (argv[1][1] == 'k') {
  86                         argc--;
  87                         argv++;
  88                         kflag = 1;
  89                 }
  90         }
  91         if (kflag) {
  92                 if ((cp = getenv(MINUSKVAR)) == NULL) {
  93                         fprintf(stderr, "%s not set\n", MINUSKVAR);
  94                         exit(1);
  95                 }
  96                 setup(cp);
  97         } else if (argc != 2) {
  98                 setup(getpass("Enter key:"));
  99         }
 100         else
 101                 setup(argv[1]);
 102         n1 = 0;
 103         n2 = 0;
 104         nr2 = 0;
 105
 106         while((i=getchar()) != -1) {
 107                 if (secureflg) {
 108                         nr1 = deck[n1]&MASK;
 109                         nr2 = deck[nr1]&MASK;
 110                 } else {
 111                         nr1 = n1;
 112                 }
 113                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 114                 putchar(i);
 115                 n1++;
 116                 if(n1==ROTORSZ) {
 117                         n1 = 0;
 118                         n2++;
 119                         if(n2==ROTORSZ) n2 = 0;
 120                         if (secureflg) {
 121                                 shuffle(deck);
 122                         } else {
 123                                 nr2 = n2;
 124                         }
 125                 }
 126         }
 127
 128         return 0;
 129 }
 130
 131 void
 132 shuffle(char deckary[])
 133 {
 134         int i, ic, k, temp;
 135         unsigned rnd;
 136         static int32_t seed = 123;
 137
 138         for(i=0;i<ROTORSZ;i++) {
 139                 seed = 5*seed + buf[i%13];
 140                 rnd = seed % 65521;
 141                 k = ROTORSZ-1 - i;
 142                 ic = (rnd&MASK)%(k+1);
 143                 temp = deckary[k];
 144                 deckary[k] = deckary[ic];
 145                 deckary[ic] = temp;
 146         }
 147 }