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 static char     t1[ROTORSZ];
  29 static char     t2[ROTORSZ];
  30 static char     t3[ROTORSZ];
  31 static char     deck[ROTORSZ];
  32 static char     buf[13];
  33
  34 static void     shuffle(char *);
  35 static void     setup(char *);
  36
  37 static void
  38 setup(char *pw)
  39 {
  40         int ic, i, k, temp;
  41         char salt[3];
  42         unsigned rnd;
  43         int32_t seed;
  44         char *cryptpw;
  45
  46         strlcpy(salt, pw, sizeof(salt));
  47         cryptpw = crypt(pw, salt);
  48         if (cryptpw == NULL) {
  49                 fprintf(stderr, "crypt(3) failure\n");
  50                 exit(1);
  51         }
  52         memcpy(buf, cryptpw, sizeof(buf));
  53         seed = 123;
  54         for (i=0; i<13; i++)
  55                 seed = seed*buf[i] + i;
  56         for(i=0;i<ROTORSZ;i++) {
  57                 t1[i] = i;
  58                 deck[i] = i;
  59         }
  60         for(i=0;i<ROTORSZ;i++) {
  61                 seed = 5*seed + buf[i%13];
  62                 rnd = seed % 65521;
  63                 k = ROTORSZ-1 - i;
  64                 ic = (rnd&MASK)%(k+1);
  65                 rnd >>= 8;
  66                 temp = t1[k];
  67                 t1[k] = t1[ic];
  68                 t1[ic] = temp;
  69                 if(t3[k]!=0) continue;
  70                 ic = (rnd&MASK) % k;
  71                 while(t3[ic]!=0) ic = (ic+1) % k;
  72                 t3[k] = ic;
  73                 t3[ic] = k;
  74         }
  75         for(i=0;i<ROTORSZ;i++)
  76                 t2[t1[i]&MASK] = i;
  77 }
  78
  79 int
  80 main(int argc, char *argv[])
  81 {
  82         int i, n1, n2, nr1, nr2;
  83         int secureflg = 0, kflag = 0;
  84         char *cp;
  85
  86         if (argc > 1 && argv[1][0] == '-') {
  87                 if (argv[1][1] == 's') {
  88                         argc--;
  89                         argv++;
  90                         secureflg = 1;
  91                 } else if (argv[1][1] == 'k') {
  92                         argc--;
  93                         argv++;
  94                         kflag = 1;
  95                 }
  96         }
  97         if (kflag) {
  98                 if ((cp = getenv(MINUSKVAR)) == NULL) {
  99                         fprintf(stderr, "%s not set\n", MINUSKVAR);
 100                         exit(1);
 101                 }
 102                 setup(cp);
 103         } else if (argc != 2) {
 104                 setup(getpass("Enter key:"));
 105         }
 106         else
 107                 setup(argv[1]);
 108         n1 = 0;
 109         n2 = 0;
 110         nr2 = 0;
 111
 112         while((i=getchar()) != -1) {
 113                 if (secureflg) {
 114                         nr1 = deck[n1]&MASK;
 115                         nr2 = deck[nr1]&MASK;
 116                 } else {
 117                         nr1 = n1;
 118                 }
 119                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 120                 putchar(i);
 121                 n1++;
 122                 if(n1==ROTORSZ) {
 123                         n1 = 0;
 124                         n2++;
 125                         if(n2==ROTORSZ) n2 = 0;
 126                         if (secureflg) {
 127                                 shuffle(deck);
 128                         } else {
 129                                 nr2 = n2;
 130                         }
 131                 }
 132         }
 133
 134         return 0;
 135 }
 136
 137 static void
 138 shuffle(char deckary[])
 139 {
 140         int i, ic, k, temp;
 141         unsigned rnd;
 142         static int32_t seed = 123;
 143
 144         for(i=0;i<ROTORSZ;i++) {
 145                 seed = 5*seed + buf[i%13];
 146                 rnd = seed % 65521;
 147                 k = ROTORSZ-1 - i;
 148                 ic = (rnd&MASK)%(k+1);
 149                 temp = deckary[k];
 150                 deckary[k] = deckary[ic];
 151                 deckary[ic] = temp;
 152         }
 153 }