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 #ifndef lint
  14 static const char rcsid[] =
  15   "$FreeBSD$";
  16 #endif /* not lint */
  17
  18 #include <sys/types.h>
  19 #include <sys/wait.h>
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25
  26 #define MINUSKVAR "CrYpTkEy"
  27
  28 #define ECHO 010
  29 #define ROTORSZ 256
  30 #define MASK 0377
  31 char    t1[ROTORSZ];
  32 char    t2[ROTORSZ];
  33 char    t3[ROTORSZ];
  34 char    deck[ROTORSZ];
  35 char    buf[13];
  36
  37 void    shuffle(char *);
  38 void    setup(char *);
  39
  40 void
  41 setup(pw)
  42         char *pw;
  43 {
  44         int ic, i, k, temp, pf[2], pid;
  45         unsigned rnd;
  46         long seed;
  47
  48         strncpy(buf, pw, 8);
  49         while (*pw)
  50                 *pw++ = '\0';
  51         buf[8] = buf[0];
  52         buf[9] = buf[1];
  53         pipe(pf);
  54         if ((pid=fork())==0) {
  55                 close(0);
  56                 close(1);
  57                 dup(pf[0]);
  58                 dup(pf[1]);
  59                 execlp("makekey", "-", (char *)0);
  60                 execl("/usr/libexec/makekey", "-", (char *)0);  /* BSDI */
  61                 execl("/usr/lib/makekey", "-", (char *)0);
  62                 execl("/usr/bin/makekey", "-", (char *)0);      /* IBM */
  63                 execl("/lib/makekey", "-", (char *)0);
  64                 perror("makekey");
  65                 fprintf(stderr, "enigma: cannot execute 'makekey', aborting\n");
  66                 exit(1);
  67         }
  68         write(pf[1], buf, 10);
  69         close(pf[1]);
  70         i=wait((int *)NULL);
  71         if (i<0) perror("enigma: wait");
  72         if (i!=pid) {
  73                 fprintf(stderr, "enigma: expected pid %d, got pid %d\n", pid, i);
  74                 exit(1);
  75         }
  76         if ((i=read(pf[0], buf, 13)) != 13) {
  77                 fprintf(stderr, "enigma: cannot generate key, read %d\n",i);
  78                 exit(1);
  79         }
  80         seed = 123;
  81         for (i=0; i<13; i++)
  82                 seed = seed*buf[i] + i;
  83         for(i=0;i<ROTORSZ;i++) {
  84                 t1[i] = i;
  85                 deck[i] = i;
  86         }
  87         for(i=0;i<ROTORSZ;i++) {
  88                 seed = 5*seed + buf[i%13];
  89                 if( sizeof(long) > 4 )  {
  90                         /* Force seed to stay in 32-bit signed math */
  91                         if( seed & 0x80000000 )
  92                                 seed = seed | (-1L & ~0xFFFFFFFFL);
  93                         else
  94                                 seed &= 0x7FFFFFFF;
  95                 }
  96                 rnd = seed % 65521;
  97                 k = ROTORSZ-1 - i;
  98                 ic = (rnd&MASK)%(k+1);
  99                 rnd >>= 8;
 100                 temp = t1[k];
 101                 t1[k] = t1[ic];
 102                 t1[ic] = temp;
 103                 if(t3[k]!=0) continue;
 104                 ic = (rnd&MASK) % k;
 105                 while(t3[ic]!=0) ic = (ic+1) % k;
 106                 t3[k] = ic;
 107                 t3[ic] = k;
 108         }
 109         for(i=0;i<ROTORSZ;i++)
 110                 t2[t1[i]&MASK] = i;
 111 }
 112
 113 int
 114 main(argc, argv)
 115         int argc;
 116         char *argv[];
 117 {
 118         register int i, n1, n2, nr1, nr2;
 119         int secureflg = 0, kflag = 0;
 120         char *cp;
 121
 122         if (argc > 1 && argv[1][0] == '-') {
 123                 if (argv[1][1] == 's') {
 124                         argc--;
 125                         argv++;
 126                         secureflg = 1;
 127                 } else if (argv[1][1] == 'k') {
 128                         argc--;
 129                         argv++;
 130                         kflag = 1;
 131                 }
 132         }
 133         if (kflag) {
 134                 if ((cp = getenv(MINUSKVAR)) == NULL) {
 135                         fprintf(stderr, "%s not set\n", MINUSKVAR);
 136                         exit(1);
 137                 }
 138                 setup(cp);
 139         } else if (argc != 2) {
 140                 setup(getpass("Enter key:"));
 141         }
 142         else
 143                 setup(argv[1]);
 144         n1 = 0;
 145         n2 = 0;
 146         nr2 = 0;
 147
 148         while((i=getchar()) != -1) {
 149                 if (secureflg) {
 150                         nr1 = deck[n1]&MASK;
 151                         nr2 = deck[nr1]&MASK;
 152                 } else {
 153                         nr1 = n1;
 154                 }
 155                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 156                 putchar(i);
 157                 n1++;
 158                 if(n1==ROTORSZ) {
 159                         n1 = 0;
 160                         n2++;
 161                         if(n2==ROTORSZ) n2 = 0;
 162                         if (secureflg) {
 163                                 shuffle(deck);
 164                         } else {
 165                                 nr2 = n2;
 166                         }
 167                 }
 168         }
 169
 170         return 0;
 171 }
 172
 173 void
 174 shuffle(deckary)
 175         char deckary[];
 176 {
 177         int i, ic, k, temp;
 178         unsigned rnd;
 179         static long seed = 123;
 180
 181         for(i=0;i<ROTORSZ;i++) {
 182                 seed = 5*seed + buf[i%13];
 183                 rnd = seed % 65521;
 184                 k = ROTORSZ-1 - i;
 185                 ic = (rnd&MASK)%(k+1);
 186                 temp = deckary[k];
 187                 deckary[k] = deckary[ic];
 188                 deckary[ic] = temp;
 189         }
 190 }