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 1.2 2003/06/17 04:29:26 dillon 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(pw)
  41         char *pw;
  42 {
  43         int ic, i, k, temp, pf[2], pid;
  44         unsigned rnd;
  45         long seed;
  46
  47         strncpy(buf, pw, 8);
  48         while (*pw)
  49                 *pw++ = '\0';
  50         buf[8] = buf[0];
  51         buf[9] = buf[1];
  52         pipe(pf);
  53         if ((pid=fork())==0) {
  54                 close(0);
  55                 close(1);
  56                 dup(pf[0]);
  57                 dup(pf[1]);
  58                 execlp("makekey", "-", (char *)0);
  59                 execl("/usr/libexec/makekey", "-", (char *)0);  /* BSDI */
  60                 execl("/usr/lib/makekey", "-", (char *)0);
  61                 execl("/usr/bin/makekey", "-", (char *)0);      /* IBM */
  62                 execl("/lib/makekey", "-", (char *)0);
  63                 perror("makekey");
  64                 fprintf(stderr, "enigma: cannot execute 'makekey', aborting\n");
  65                 exit(1);
  66         }
  67         write(pf[1], buf, 10);
  68         close(pf[1]);
  69         i=wait((int *)NULL);
  70         if (i<0) perror("enigma: wait");
  71         if (i!=pid) {
  72                 fprintf(stderr, "enigma: expected pid %d, got pid %d\n", pid, i);
  73                 exit(1);
  74         }
  75         if ((i=read(pf[0], buf, 13)) != 13) {
  76                 fprintf(stderr, "enigma: cannot generate key, read %d\n",i);
  77                 exit(1);
  78         }
  79         seed = 123;
  80         for (i=0; i<13; i++)
  81                 seed = seed*buf[i] + i;
  82         for(i=0;i<ROTORSZ;i++) {
  83                 t1[i] = i;
  84                 deck[i] = i;
  85         }
  86         for(i=0;i<ROTORSZ;i++) {
  87                 seed = 5*seed + buf[i%13];
  88                 if( sizeof(long) > 4 )  {
  89                         /* Force seed to stay in 32-bit signed math */
  90                         if( seed & 0x80000000 )
  91                                 seed = seed | (-1L & ~0xFFFFFFFFL);
  92                         else
  93                                 seed &= 0x7FFFFFFF;
  94                 }
  95                 rnd = seed % 65521;
  96                 k = ROTORSZ-1 - i;
  97                 ic = (rnd&MASK)%(k+1);
  98                 rnd >>= 8;
  99                 temp = t1[k];
 100                 t1[k] = t1[ic];
 101                 t1[ic] = temp;
 102                 if(t3[k]!=0) continue;
 103                 ic = (rnd&MASK) % k;
 104                 while(t3[ic]!=0) ic = (ic+1) % k;
 105                 t3[k] = ic;
 106                 t3[ic] = k;
 107         }
 108         for(i=0;i<ROTORSZ;i++)
 109                 t2[t1[i]&MASK] = i;
 110 }
 111
 112 int
 113 main(argc, argv)
 114         int argc;
 115         char *argv[];
 116 {
 117         register int i, n1, n2, nr1, nr2;
 118         int secureflg = 0, kflag = 0;
 119         char *cp;
 120
 121         if (argc > 1 && argv[1][0] == '-') {
 122                 if (argv[1][1] == 's') {
 123                         argc--;
 124                         argv++;
 125                         secureflg = 1;
 126                 } else if (argv[1][1] == 'k') {
 127                         argc--;
 128                         argv++;
 129                         kflag = 1;
 130                 }
 131         }
 132         if (kflag) {
 133                 if ((cp = getenv(MINUSKVAR)) == NULL) {
 134                         fprintf(stderr, "%s not set\n", MINUSKVAR);
 135                         exit(1);
 136                 }
 137                 setup(cp);
 138         } else if (argc != 2) {
 139                 setup(getpass("Enter key:"));
 140         }
 141         else
 142                 setup(argv[1]);
 143         n1 = 0;
 144         n2 = 0;
 145         nr2 = 0;
 146
 147         while((i=getchar()) != -1) {
 148                 if (secureflg) {
 149                         nr1 = deck[n1]&MASK;
 150                         nr2 = deck[nr1]&MASK;
 151                 } else {
 152                         nr1 = n1;
 153                 }
 154                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 155                 putchar(i);
 156                 n1++;
 157                 if(n1==ROTORSZ) {
 158                         n1 = 0;
 159                         n2++;
 160                         if(n2==ROTORSZ) n2 = 0;
 161                         if (secureflg) {
 162                                 shuffle(deck);
 163                         } else {
 164                                 nr2 = n2;
 165                         }
 166                 }
 167         }
 168
 169         return 0;
 170 }
 171
 172 void
 173 shuffle(deckary)
 174         char deckary[];
 175 {
 176         int i, ic, k, temp;
 177         unsigned rnd;
 178         static long seed = 123;
 179
 180         for(i=0;i<ROTORSZ;i++) {
 181                 seed = 5*seed + buf[i%13];
 182                 rnd = seed % 65521;
 183                 k = ROTORSZ-1 - i;
 184                 ic = (rnd&MASK)%(k+1);
 185                 temp = deckary[k];
 186                 deckary[k] = deckary[ic];
 187                 deckary[ic] = temp;
 188         }
 189 }