| 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 | } |