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: src/usr.bin/enigma/enigma.c,v 1.2.6.3 2001/08/01 23:51:34 obrien Exp $";
  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 int     main(int, char *[]);
  38 void    shuffle(char *);
  39 void    setup(char *);
  40
  41 void
  42 setup(pw)
  43         char *pw;
  44 {
  45         int ic, i, k, temp, pf[2], pid;
  46         unsigned rnd;
  47         long seed;
  48
  49         strncpy(buf, pw, 8);
  50         while (*pw)
  51                 *pw++ = '\0';
  52         buf[8] = buf[0];
  53         buf[9] = buf[1];
  54         pipe(pf);
  55         if ((pid=fork())==0) {
  56                 close(0);
  57                 close(1);
  58                 dup(pf[0]);
  59                 dup(pf[1]);
  60                 execlp("makekey", "-", (char *)0);
  61                 execl("/usr/libexec/makekey", "-", (char *)0);  /* BSDI */
  62                 execl("/usr/lib/makekey", "-", (char *)0);
  63                 execl("/usr/bin/makekey", "-", (char *)0);      /* IBM */
  64                 execl("/lib/makekey", "-", (char *)0);
  65                 perror("makekey");
  66                 fprintf(stderr, "enigma: cannot execute 'makekey', aborting\n");
  67                 exit(1);
  68         }
  69         write(pf[1], buf, 10);
  70         close(pf[1]);
  71         i=wait((int *)NULL);
  72         if (i<0) perror("enigma: wait");
  73         if (i!=pid) {
  74                 fprintf(stderr, "enigma: expected pid %d, got pid %d\n", pid, i);
  75                 exit(1);
  76         }
  77         if ((i=read(pf[0], buf, 13)) != 13) {
  78                 fprintf(stderr, "enigma: cannot generate key, read %d\n",i);
  79                 exit(1);
  80         }
  81         seed = 123;
  82         for (i=0; i<13; i++)
  83                 seed = seed*buf[i] + i;
  84         for(i=0;i<ROTORSZ;i++) {
  85                 t1[i] = i;
  86                 deck[i] = i;
  87         }
  88         for(i=0;i<ROTORSZ;i++) {
  89                 seed = 5*seed + buf[i%13];
  90                 if( sizeof(long) > 4 )  {
  91                         /* Force seed to stay in 32-bit signed math */
  92                         if( seed & 0x80000000 )
  93                                 seed = seed | (-1L & ~0xFFFFFFFFL);
  94                         else
  95                                 seed &= 0x7FFFFFFF;
  96                 }
  97                 rnd = seed % 65521;
  98                 k = ROTORSZ-1 - i;
  99                 ic = (rnd&MASK)%(k+1);
 100                 rnd >>= 8;
 101                 temp = t1[k];
 102                 t1[k] = t1[ic];
 103                 t1[ic] = temp;
 104                 if(t3[k]!=0) continue;
 105                 ic = (rnd&MASK) % k;
 106                 while(t3[ic]!=0) ic = (ic+1) % k;
 107                 t3[k] = ic;
 108                 t3[ic] = k;
 109         }
 110         for(i=0;i<ROTORSZ;i++)
 111                 t2[t1[i]&MASK] = i;
 112 }
 113
 114 int
 115 main(argc, argv)
 116         int argc;
 117         char *argv[];
 118 {
 119         register int i, n1, n2, nr1, nr2;
 120         int secureflg = 0, kflag = 0;
 121         char *cp;
 122
 123         if (argc > 1 && argv[1][0] == '-') {
 124                 if (argv[1][1] == 's') {
 125                         argc--;
 126                         argv++;
 127                         secureflg = 1;
 128                 } else if (argv[1][1] == 'k') {
 129                         argc--;
 130                         argv++;
 131                         kflag = 1;
 132                 }
 133         }
 134         if (kflag) {
 135                 if ((cp = getenv(MINUSKVAR)) == NULL) {
 136                         fprintf(stderr, "%s not set\n", MINUSKVAR);
 137                         exit(1);
 138                 }
 139                 setup(cp);
 140         } else if (argc != 2) {
 141                 setup(getpass("Enter key:"));
 142         }
 143         else
 144                 setup(argv[1]);
 145         n1 = 0;
 146         n2 = 0;
 147         nr2 = 0;
 148
 149         while((i=getchar()) != -1) {
 150                 if (secureflg) {
 151                         nr1 = deck[n1]&MASK;
 152                         nr2 = deck[nr1]&MASK;
 153                 } else {
 154                         nr1 = n1;
 155                 }
 156                 i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
 157                 putchar(i);
 158                 n1++;
 159                 if(n1==ROTORSZ) {
 160                         n1 = 0;
 161                         n2++;
 162                         if(n2==ROTORSZ) n2 = 0;
 163                         if (secureflg) {
 164                                 shuffle(deck);
 165                         } else {
 166                                 nr2 = n2;
 167                         }
 168                 }
 169         }
 170
 171         return 0;
 172 }
 173
 174 void
 175 shuffle(deckary)
 176         char deckary[];
 177 {
 178         int i, ic, k, temp;
 179         unsigned rnd;
 180         static long seed = 123;
 181
 182         for(i=0;i<ROTORSZ;i++) {
 183                 seed = 5*seed + buf[i%13];
 184                 rnd = seed % 65521;
 185                 k = ROTORSZ-1 - i;
 186                 ic = (rnd&MASK)%(k+1);
 187                 temp = deckary[k];
 188                 deckary[k] = deckary[ic];
 189                 deckary[ic] = temp;
 190         }
 191 }