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         if (crypt_set_format("des") == 0) {
  47                 fprintf(stderr, "crypt_set_format(\"des\") failed.\n");
  48                 exit(1);
  49         }
  50
  51         strlcpy(salt, pw, sizeof(salt));
  52         cryptpw = crypt(pw, salt);
  53         if (cryptpw == NULL) {
  54                 fprintf(stderr, "crypt(3) failure\n");
  55                 exit(1);
  56         }
  57         memcpy(buf, cryptpw, sizeof(buf));
  58         seed = 123;
  59         for (i=0; i<13; i++)
  60                 seed = seed*buf[i] + i;
  61         for(i=0;i<ROTORSZ;i++) {
  62                 t1[i] = i;
  63                 deck[i] = i;
  64         }
  65         for(i=0;i<ROTORSZ;i++) {
  66                 seed = 5*seed + buf[i%13];
  67                 rnd = seed % 65521;
  68                 k = ROTORSZ-1 - i;
  69                 ic = (rnd&MASK)%(k+1);
  70                 rnd >>= 8;
  71                 temp = t1[k];
  72                 t1[k] = t1[ic];
  73                 t1[ic] = temp;
  74                 if(t3[k]!=0) continue;
  75                 ic = (rnd&MASK) % k;
  76                 while(t3[ic]!=0) ic = (ic+1) % k;
  77                 t3[k] = ic;
  78                 t3[ic] = k;
  79         }
  80         for(i=0;i<ROTORSZ;i++)
  81                 t2[t1[i]&MASK] = i;
  82 }
  83
  84 int
  85 main(int argc, char *argv[])
  86 {
  87         int i, n1, n2, nr1, nr2;
  88         int secureflg = 0, kflag = 0;
  89         char *cp;
  90
  91         if (argc > 1 && argv[1][0] == '-') {
  92                 if (argv[1][1] == 's') {
  93                         argc--;
  94                         argv++;
  95                         secureflg = 1;
  96                 } else if (argv[1][1] == 'k') {
  97                         argc--;
  98                         argv++;
  99                         kflag = 1;
 100                 }
 101         }
 102         if (kflag) {
 103                 if ((cp = getenv(MINUSKVAR)) == NULL) {
 104                         fprintf(stderr, "%s not set\n", MINUSKVAR);
 105                         exit(1);
 106                 }
 107                 setup(cp);
 108         } else if (argc != 2) {
 109                 setup(getpass("Enter key:"));
 110         }
 111         else
 112                 setup(argv[1]);
 113         n1 = 0;
 114         n2 = 0;
 115         nr2 = 0;
 116
 117         while((i=getchar()) != -1) {
 118                 if (secureflg) {
 119                         nr1 = deck[n1]&MASK;
 120                         nr2 = deck[nr1]&MASK;
 121                 } else {
 122                         nr1 = n1;
 123                 }
 124                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 125                 putchar(i);
 126                 n1++;
 127                 if(n1==ROTORSZ) {
 128                         n1 = 0;
 129                         n2++;
 130                         if(n2==ROTORSZ) n2 = 0;
 131                         if (secureflg) {
 132                                 shuffle(deck);
 133                         } else {
 134                                 nr2 = n2;
 135                         }
 136                 }
 137         }
 138
 139         return 0;
 140 }
 141
 142 static void
 143 shuffle(char deckary[])
 144 {
 145         int i, ic, k, temp;
 146         unsigned rnd;
 147         static int32_t seed = 123;
 148
 149         for(i=0;i<ROTORSZ;i++) {
 150                 seed = 5*seed + buf[i%13];
 151                 rnd = seed % 65521;
 152                 k = ROTORSZ-1 - i;
 153                 ic = (rnd&MASK)%(k+1);
 154                 temp = deckary[k];
 155                 deckary[k] = deckary[ic];
 156                 deckary[ic] = temp;
 157         }
 158 }