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 1.4 2003/11/04 16:36:35 drhodus Exp $
  14  */
  15
  16 #include <sys/types.h>
  17 #include <sys/wait.h>
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23
  24 #define MINUSKVAR "CrYpTkEy"
  25
  26 #define ECHO 010
  27 #define ROTORSZ 256
  28 #define MASK 0377
  29 char    t1[ROTORSZ];
  30 char    t2[ROTORSZ];
  31 char    t3[ROTORSZ];
  32 char    deck[ROTORSZ];
  33 char    buf[13];
  34
  35 int     main(int, char *[]);
  36 void    shuffle(char *);
  37 void    setup(char *);
  38
  39 void
  40 setup(char *pw)
  41 {
  42         int ic, i, k, temp;
  43         char salt[3];
  44         unsigned rnd;
  45         long seed;
  46
  47         strncpy(salt, pw, sizeof(salt));
  48         memcpy(buf, crypt(pw, salt), sizeof(buf));
  49         seed = 123;
  50         for (i=0; i<13; i++)
  51                 seed = seed*buf[i] + i;
  52         for(i=0;i<ROTORSZ;i++) {
  53                 t1[i] = i;
  54                 deck[i] = i;
  55         }
  56         for(i=0;i<ROTORSZ;i++) {
  57                 seed = 5*seed + buf[i%13];
  58                 if( sizeof(long) > 4 )  {
  59                         /* Force seed to stay in 32-bit signed math */
  60                         if( seed & 0x80000000 )
  61                                 seed = seed | (-1L & ~0xFFFFFFFFL);
  62                         else
  63                                 seed &= 0x7FFFFFFF;
  64                 }
  65                 rnd = seed % 65521;
  66                 k = ROTORSZ-1 - i;
  67                 ic = (rnd&MASK)%(k+1);
  68                 rnd >>= 8;
  69                 temp = t1[k];
  70                 t1[k] = t1[ic];
  71                 t1[ic] = temp;
  72                 if(t3[k]!=0) continue;
  73                 ic = (rnd&MASK) % k;
  74                 while(t3[ic]!=0) ic = (ic+1) % k;
  75                 t3[k] = ic;
  76                 t3[ic] = k;
  77         }
  78         for(i=0;i<ROTORSZ;i++)
  79                 t2[t1[i]&MASK] = i;
  80 }
  81
  82 int
  83 main(int argc, char **argv)
  84 {
  85         register int i, n1, n2, nr1, nr2;
  86         int secureflg = 0, kflag = 0;
  87         char *cp;
  88
  89         if (argc > 1 && argv[1][0] == '-') {
  90                 if (argv[1][1] == 's') {
  91                         argc--;
  92                         argv++;
  93                         secureflg = 1;
  94                 } else if (argv[1][1] == 'k') {
  95                         argc--;
  96                         argv++;
  97                         kflag = 1;
  98                 }
  99         }
 100         if (kflag) {
 101                 if ((cp = getenv(MINUSKVAR)) == NULL) {
 102                         fprintf(stderr, "%s not set\n", MINUSKVAR);
 103                         exit(1);
 104                 }
 105                 setup(cp);
 106         } else if (argc != 2) {
 107                 setup(getpass("Enter key:"));
 108         }
 109         else
 110                 setup(argv[1]);
 111         n1 = 0;
 112         n2 = 0;
 113         nr2 = 0;
 114
 115         while((i=getchar()) != -1) {
 116                 if (secureflg) {
 117                         nr1 = deck[n1]&MASK;
 118                         nr2 = deck[nr1]&MASK;
 119                 } else {
 120                         nr1 = n1;
 121                 }
 122                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 123                 putchar(i);
 124                 n1++;
 125                 if(n1==ROTORSZ) {
 126                         n1 = 0;
 127                         n2++;
 128                         if(n2==ROTORSZ) n2 = 0;
 129                         if (secureflg) {
 130                                 shuffle(deck);
 131                         } else {
 132                                 nr2 = n2;
 133                         }
 134                 }
 135         }
 136
 137         return 0;
 138 }
 139
 140 void
 141 shuffle(char *deckary)
 142 {
 143         int i, ic, k, temp;
 144         unsigned rnd;
 145         static long seed = 123;
 146
 147         for(i=0;i<ROTORSZ;i++) {
 148                 seed = 5*seed + buf[i%13];
 149                 rnd = seed % 65521;
 150                 k = ROTORSZ-1 - i;
 151                 ic = (rnd&MASK)%(k+1);
 152                 temp = deckary[k];
 153                 deckary[k] = deckary[ic];
 154                 deckary[ic] = temp;
 155         }
 156 }