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 1.6 2005/01/05 18:42:33 liamfoy Exp $
  14  */
  15
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <string.h>
  19 #include <unistd.h>
  20
  21 #define MINUSKVAR "CrYpTkEy"
  22
  23 #define ECHO 010
  24 #define ROTORSZ 256
  25 #define MASK 0377
  26 char    t1[ROTORSZ];
  27 char    t2[ROTORSZ];
  28 char    t3[ROTORSZ];
  29 char    deck[ROTORSZ];
  30 char    buf[13];
  31
  32 static void     shuffle(char *);
  33 static void     setup(const char *);
  34
  35 static void
  36 setup(const char *pw)
  37 {
  38         int ic, i, k, temp;
  39         char salt[3];
  40         unsigned rnd;
  41         long seed;
  42
  43         strncpy(salt, pw, sizeof(salt));
  44         memcpy(buf, crypt(pw, salt), sizeof(buf));
  45         seed = 123;
  46         for (i=0; i<13; i++)
  47                 seed = seed*buf[i] + i;
  48         for(i=0;i<ROTORSZ;i++) {
  49                 t1[i] = i;
  50                 deck[i] = i;
  51         }
  52         for(i=0;i<ROTORSZ;i++) {
  53                 seed = 5*seed + buf[i%13];
  54                 if( sizeof(long) > 4 )  {
  55                         /* Force seed to stay in 32-bit signed math */
  56                         if( seed & 0x80000000 )
  57                                 seed = seed | (-1L & ~0xFFFFFFFFL);
  58                         else
  59                                 seed &= 0x7FFFFFFF;
  60                 }
  61                 rnd = seed % 65521;
  62                 k = ROTORSZ-1 - i;
  63                 ic = (rnd&MASK)%(k+1);
  64                 rnd >>= 8;
  65                 temp = t1[k];
  66                 t1[k] = t1[ic];
  67                 t1[ic] = temp;
  68                 if(t3[k]!=0) continue;
  69                 ic = (rnd&MASK) % k;
  70                 while(t3[ic]!=0) ic = (ic+1) % k;
  71                 t3[k] = ic;
  72                 t3[ic] = k;
  73         }
  74         for(i=0;i<ROTORSZ;i++)
  75                 t2[t1[i]&MASK] = i;
  76 }
  77
  78 int
  79 main(int argc, char **argv)
  80 {
  81         int i, n1, n2, nr1, nr2;
  82         int secureflg = 0, kflag = 0;
  83         char *cp;
  84
  85         if (argc > 1 && argv[1][0] == '-') {
  86                 if (argv[1][1] == 's') {
  87                         argc--;
  88                         argv++;
  89                         secureflg = 1;
  90                 } else if (argv[1][1] == 'k') {
  91                         argc--;
  92                         argv++;
  93                         kflag = 1;
  94                 }
  95         }
  96         if (kflag) {
  97                 if ((cp = getenv(MINUSKVAR)) == NULL) {
  98                         fprintf(stderr, "%s not set\n", MINUSKVAR);
  99                         exit(1);
 100                 }
 101                 setup(cp);
 102         } else if (argc != 2) {
 103                 setup(getpass("Enter key:"));
 104         }
 105         else
 106                 setup(argv[1]);
 107         n1 = 0;
 108         n2 = 0;
 109         nr2 = 0;
 110
 111         while((i=getchar()) != -1) {
 112                 if (secureflg) {
 113                         nr1 = deck[n1]&MASK;
 114                         nr2 = deck[nr1]&MASK;
 115                 } else {
 116                         nr1 = n1;
 117                 }
 118                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 119                 putchar(i);
 120                 n1++;
 121                 if(n1==ROTORSZ) {
 122                         n1 = 0;
 123                         n2++;
 124                         if(n2==ROTORSZ) n2 = 0;
 125                         if (secureflg) {
 126                                 shuffle(deck);
 127                         } else {
 128                                 nr2 = n2;
 129                         }
 130                 }
 131         }
 132
 133         return 0;
 134 }
 135
 136 static void
 137 shuffle(char *deckary)
 138 {
 139         int i, ic, k, temp;
 140         unsigned rnd;
 141         static long seed = 123;
 142
 143         for(i=0;i<ROTORSZ;i++) {
 144                 seed = 5*seed + buf[i%13];
 145                 rnd = seed % 65521;
 146                 k = ROTORSZ-1 - i;
 147                 ic = (rnd&MASK)%(k+1);
 148                 temp = deckary[k];
 149                 deckary[k] = deckary[ic];
 150                 deckary[ic] = temp;
 151         }
 152 }