2.9BSD - /usr/src/cmd/crypt.c

   1: /*
   2:  *	A one-rotor machine designed along the lines of Enigma
   3:  *	but considerably trivialized.
   4:  */
   5: 
   6: #define ECHO 010
   7: #include <stdio.h>
   8: #define ROTORSZ 256
   9: #define MASK 0377
  10: char    t1[ROTORSZ];
  11: char    t2[ROTORSZ];
  12: char    t3[ROTORSZ];
  13: char    *getpass();
  14: 
  15: setup(pw)
  16: char *pw;
  17: {
  18:     int ic, i, k, temp, pf[2];
  19:     unsigned random;
  20:     char buf[13];
  21:     long seed;
  22: 
  23:     strncpy(buf, pw, 8);
  24:     while (*pw)
  25:         *pw++ = '\0';
  26:     buf[8] = buf[0];
  27:     buf[9] = buf[1];
  28:     pipe(pf);
  29:     if (fork()==0) {
  30:         close(0);
  31:         close(1);
  32:         dup(pf[0]);
  33:         dup(pf[1]);
  34:         execl("/usr/lib/makekey", "-", 0);
  35:         execl("/lib/makekey", "-", 0);
  36:         exit(1);
  37:     }
  38:     write(pf[1], buf, 10);
  39:     wait((int *)NULL);
  40:     if (read(pf[0], buf, 13) != 13) {
  41:         fprintf(stderr, "crypt: cannot generate key\n");
  42:         exit(1);
  43:     }
  44:     seed = 123;
  45:     for (i=0; i<13; i++)
  46:         seed = seed*buf[i] + i;
  47:     for(i=0;i<ROTORSZ;i++)
  48:         t1[i] = i;
  49:     for(i=0;i<ROTORSZ;i++) {
  50:         seed = 5*seed + buf[i%13];
  51:         random = seed % 65521;
  52:         k = ROTORSZ-1 - i;
  53:         ic = (random&MASK)%(k+1);
  54:         random >>= 8;
  55:         temp = t1[k];
  56:         t1[k] = t1[ic];
  57:         t1[ic] = temp;
  58:         if(t3[k]!=0) continue;
  59:         ic = (random&MASK) % k;
  60:         while(t3[ic]!=0) ic = (ic+1) % k;
  61:         t3[k] = ic;
  62:         t3[ic] = k;
  63:     }
  64:     for(i=0;i<ROTORSZ;i++)
  65:         t2[t1[i]&MASK] = i;
  66: }
  67: 
  68: main(argc, argv)
  69: char *argv[];
  70: {
  71:     register i, n1, n2;
  72: 
  73:     if (argc != 2){
  74:         setup(getpass("Enter key:"));
  75:     }
  76:     else
  77:         setup(argv[1]);
  78:     n1 = 0;
  79:     n2 = 0;
  80: 
  81:     while((i=getchar()) >=0) {
  82:         i = t2[(t3[(t1[(i+n1)&MASK]+n2)&MASK]-n2)&MASK]-n1;
  83:         putchar(i);
  84:         n1++;
  85:         if(n1==ROTORSZ) {
  86:             n1 = 0;
  87:             n2++;
  88:             if(n2==ROTORSZ) n2 = 0;
  89:         }
  90:     }
  91: }

Defined functions

Defined variables

Defined macros