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/types.h>
  14 #include <sys/wait.h>
  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 void    shuffle(char *);
  33
  34 void
  35 setup(pw)
  36         char *pw;
  37 {
  38         int ic, i, k, temp, pf[2], pid;
  39         unsigned random;
  40         long seed;
  41
  42         strncpy(buf, pw, 8);
  43         while (*pw)
  44                 *pw++ = '\0';
  45         buf[8] = buf[0];
  46         buf[9] = buf[1];
  47         pipe(pf);
  48         if ((pid=fork())==0) {
  49                 close(0);
  50                 close(1);
  51                 dup(pf[0]);
  52                 dup(pf[1]);
  53                 execlp("makekey", "-", 0);
  54                 execl("/usr/libexec/makekey", "-", 0);  /* BSDI */
  55                 execl("/usr/lib/makekey", "-", 0);
  56                 execl("/usr/bin/makekey", "-", 0);      /* IBM */
  57                 execl("/lib/makekey", "-", 0);
  58                 perror("makekey");
  59                 fprintf(stderr, "enigma: cannot execute 'makekey', aborting\n");
  60                 exit(1);
  61         }
  62         write(pf[1], buf, 10);
  63         close(pf[1]);
  64         i=wait((int *)NULL);
  65         if (i<0) perror("enigma: wait");
  66         if (i!=pid) {
  67                 fprintf(stderr, "enigma: expected pid %d, got pid %d\n", pid, i);
  68                 exit(1);
  69         }
  70         if ((i=read(pf[0], buf, 13)) != 13) {
  71                 fprintf(stderr, "enigma: cannot generate key, read %d\n",i);
  72                 exit(1);
  73         }
  74         seed = 123;
  75         for (i=0; i<13; i++)
  76                 seed = seed*buf[i] + i;
  77         for(i=0;i<ROTORSZ;i++) {
  78                 t1[i] = i;
  79                 deck[i] = i;
  80         }
  81         for(i=0;i<ROTORSZ;i++) {
  82                 seed = 5*seed + buf[i%13];
  83                 if( sizeof(long) > 4 )  {
  84                         /* Force seed to stay in 32-bit signed math */
  85                         if( seed & 0x80000000 )
  86                                 seed = seed | (-1L & ~0xFFFFFFFFL);
  87                         else
  88                                 seed &= 0x7FFFFFFF;
  89                 }
  90                 random = seed % 65521;
  91                 k = ROTORSZ-1 - i;
  92                 ic = (random&MASK)%(k+1);
  93                 random >>= 8;
  94                 temp = t1[k];
  95                 t1[k] = t1[ic];
  96                 t1[ic] = temp;
  97                 if(t3[k]!=0) continue;
  98                 ic = (random&MASK) % k;
  99                 while(t3[ic]!=0) ic = (ic+1) % k;
 100                 t3[k] = ic;
 101                 t3[ic] = k;
 102         }
 103         for(i=0;i<ROTORSZ;i++)
 104                 t2[t1[i]&MASK] = i;
 105 }
 106
 107 int
 108 main(argc, argv)
 109         char *argv[];
 110 {
 111         register int i, n1, n2, nr1, nr2;
 112         int secureflg = 0, kflag = 0;
 113         char *cp;
 114
 115         if (argc > 1 && argv[1][0] == '-') {
 116                 if (argv[1][1] == 's') {
 117                         argc--;
 118                         argv++;
 119                         secureflg = 1;
 120                 } else if (argv[1][1] == 'k') {
 121                         argc--;
 122                         argv++;
 123                         kflag = 1;
 124                 }
 125         }
 126         if (kflag) {
 127                 if ((cp = getenv(MINUSKVAR)) == NULL) {
 128                         fprintf(stderr, "%s not set\n", MINUSKVAR);
 129                         exit(1);
 130                 }
 131                 setup(cp);
 132         } else if (argc != 2) {
 133                 setup(getpass("Enter key:"));
 134         }
 135         else
 136                 setup(argv[1]);
 137         n1 = 0;
 138         n2 = 0;
 139         nr2 = 0;
 140
 141         while((i=getchar()) != -1) {
 142                 if (secureflg) {
 143                         nr1 = deck[n1]&MASK;
 144                         nr2 = deck[nr1]&MASK;
 145                 } else {
 146                         nr1 = n1;
 147                 }
 148                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 149                 putchar(i);
 150                 n1++;
 151                 if(n1==ROTORSZ) {
 152                         n1 = 0;
 153                         n2++;
 154                         if(n2==ROTORSZ) n2 = 0;
 155                         if (secureflg) {
 156                                 shuffle(deck);
 157                         } else {
 158                                 nr2 = n2;
 159                         }
 160                 }
 161         }
 162
 163         return 0;
 164 }
 165
 166 void
 167 shuffle(deck)
 168         char deck[];
 169 {
 170         int i, ic, k, temp;
 171         unsigned random;
 172         static long seed = 123;
 173
 174         for(i=0;i<ROTORSZ;i++) {
 175                 seed = 5*seed + buf[i%13];
 176                 random = seed % 65521;
 177                 k = ROTORSZ-1 - i;
 178                 ic = (random&MASK)%(k+1);
 179                 temp = deck[k];
 180                 deck[k] = deck[ic];
 181                 deck[ic] = temp;
 182         }
 183 }