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         char *cryptpw;
  43
  44         strncpy(salt, pw, sizeof(salt));
  45         cryptpw = crypt(pw, salt);
  46         if (cryptpw == NULL) {
  47                 fprintf(stderr, "crypt(3) failure\n");
  48                 exit(1);
  49         }
  50         memcpy(buf, cryptpw, sizeof(buf));
  51         seed = 123;
  52         for (i=0; i<13; i++)
  53                 seed = seed*buf[i] + i;
  54         for(i=0;i<ROTORSZ;i++) {
  55                 t1[i] = i;
  56                 deck[i] = i;
  57         }
  58         for(i=0;i<ROTORSZ;i++) {
  59                 seed = 5*seed + buf[i%13];
  60                 if( sizeof(long) > 4 )  {
  61                         /* Force seed to stay in 32-bit signed math */
  62                         if( seed & 0x80000000 )
  63                                 seed = seed | (-1L & ~0xFFFFFFFFL);
  64                         else
  65                                 seed &= 0x7FFFFFFF;
  66                 }
  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 long 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 }