/* * A one-rotor machine designed along the lines of Enigma * but considerably trivialized. */ #define ECHO 010 #include <stdio.h> #define ROTORSZ 256 #define MASK 0377 char t1[ROTORSZ]; char t2[ROTORSZ]; char t3[ROTORSZ]; char *getpass(); setup(pw) char *pw; { int ic, i, k, temp, pf[2]; unsigned random; char buf[13]; long seed; strncpy(buf, pw, 8); while (*pw) *pw++ = '\0'; buf[8] = buf[0]; buf[9] = buf[1]; pipe(pf); if (fork()==0) { close(0); close(1); dup(pf[0]); dup(pf[1]); execl("/usr/lib/makekey", "-", 0); execl("/lib/makekey", "-", 0); exit(1); } write(pf[1], buf, 10); wait((int *)NULL); if (read(pf[0], buf, 13) != 13) { fprintf(stderr, "crypt: cannot generate key\n"); exit(1); } seed = 123; for (i=0; i<13; i++) seed = seed*buf[i] + i; for(i=0;i<ROTORSZ;i++) t1[i] = i; for(i=0;i<ROTORSZ;i++) { seed = 5*seed + buf[i%13]; random = seed % 65521; k = ROTORSZ-1 - i; ic = (random&MASK)%(k+1); random >>= 8; temp = t1[k]; t1[k] = t1[ic]; t1[ic] = temp; if(t3[k]!=0) continue; ic = (random&MASK) % k; while(t3[ic]!=0) ic = (ic+1) % k; t3[k] = ic; t3[ic] = k; } for(i=0;i<ROTORSZ;i++) t2[t1[i]&MASK] = i; } main(argc, argv) char *argv[]; { register i, n1, n2; if (argc != 2){ setup(getpass("Enter key:")); } else setup(argv[1]); n1 = 0; n2 = 0; while((i=getchar()) >=0) { i = t2[(t3[(t1[(i+n1)&MASK]+n2)&MASK]-n2)&MASK]-n1; putchar(i); n1++; if(n1==ROTORSZ) { n1 = 0; n2++; if(n2==ROTORSZ) n2 = 0; } } return 0; }