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 ROTORSZ 256
  26 #define MASK 0377
  27 static char     t1[ROTORSZ];
  28 static char     t2[ROTORSZ];
  29 static char     t3[ROTORSZ];
  30 static char     deck[ROTORSZ];
  31 static char     buf[13];
  32
  33 static void     shuffle(char *);
  34 static void     setup(char *);
  35
  36 static void
  37 setup(char *pw)
  38 {
  39         int ic, i, k, temp;
  40         char salt[3];
  41         unsigned rnd;
  42         int32_t seed;
  43         char *cryptpw;
  44
  45         if (crypt_set_format("des") == 0) {
  46                 fprintf(stderr, "crypt_set_format(\"des\") failed.\n");
  47                 exit(1);
  48         }
  49
  50         strlcpy(salt, pw, sizeof(salt));
  51         cryptpw = crypt(pw, salt);
  52         if (cryptpw == NULL) {
  53                 fprintf(stderr, "crypt(3) failure\n");
  54                 exit(1);
  55         }
  56         memcpy(buf, cryptpw, sizeof(buf));
  57         seed = 123;
  58         for (i=0; i<13; i++)
  59                 seed = seed*buf[i] + i;
  60         for(i=0;i<ROTORSZ;i++) {
  61                 t1[i] = i;
  62                 deck[i] = i;
  63         }
  64         for(i=0;i<ROTORSZ;i++) {
  65                 seed = 5*seed + buf[i%13];
  66                 rnd = seed % 65521;
  67                 k = ROTORSZ-1 - i;
  68                 ic = (rnd&MASK)%(k+1);
  69                 rnd >>= 8;
  70                 temp = t1[k];
  71                 t1[k] = t1[ic];
  72                 t1[ic] = temp;
  73                 if(t3[k]!=0) continue;
  74                 ic = (rnd&MASK) % k;
  75                 while(t3[ic]!=0) ic = (ic+1) % k;
  76                 t3[k] = ic;
  77                 t3[ic] = k;
  78         }
  79         for(i=0;i<ROTORSZ;i++)
  80                 t2[t1[i]&MASK] = i;
  81 }
  82
  83 int
  84 main(int argc, char *argv[])
  85 {
  86         int i, n1, n2, nr1, nr2;
  87         int secureflg = 0, kflag = 0;
  88         char *cp;
  89
  90         if (argc > 1 && argv[1][0] == '-') {
  91                 if (argv[1][1] == 's') {
  92                         argc--;
  93                         argv++;
  94                         secureflg = 1;
  95                 } else if (argv[1][1] == 'k') {
  96                         argc--;
  97                         argv++;
  98                         kflag = 1;
  99                 }
 100         }
 101         if (kflag) {
 102                 if ((cp = getenv(MINUSKVAR)) == NULL) {
 103                         fprintf(stderr, "%s not set\n", MINUSKVAR);
 104                         exit(1);
 105                 }
 106                 setup(cp);
 107         } else if (argc != 2) {
 108                 setup(getpass("Enter key:"));
 109         }
 110         else
 111                 setup(argv[1]);
 112         n1 = 0;
 113         n2 = 0;
 114         nr2 = 0;
 115
 116         while((i=getchar()) != -1) {
 117                 if (secureflg) {
 118                         nr1 = deck[n1]&MASK;
 119                         nr2 = deck[nr1]&MASK;
 120                 } else {
 121                         nr1 = n1;
 122                 }
 123                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 124                 putchar(i);
 125                 n1++;
 126                 if(n1==ROTORSZ) {
 127                         n1 = 0;
 128                         n2++;
 129                         if(n2==ROTORSZ) n2 = 0;
 130                         if (secureflg) {
 131                                 shuffle(deck);
 132                         } else {
 133                                 nr2 = n2;
 134                         }
 135                 }
 136         }
 137
 138         return 0;
 139 }
 140
 141 static void
 142 shuffle(char deckary[])
 143 {
 144         int i, ic, k, temp;
 145         unsigned rnd;
 146         static int32_t seed = 123;
 147
 148         for(i=0;i<ROTORSZ;i++) {
 149                 seed = 5*seed + buf[i%13];
 150                 rnd = seed % 65521;
 151                 k = ROTORSZ-1 - i;
 152                 ic = (rnd&MASK)%(k+1);
 153                 temp = deckary[k];
 154                 deckary[k] = deckary[ic];
 155                 deckary[ic] = temp;
 156         }
 157 }