xref: /freebsd/usr.bin/enigma/enigma.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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 #include <sys/cdefs.h>
14 __FBSDID("$FreeBSD$");
15 
16 #include <sys/types.h>
17 
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <string.h>
21 #include <unistd.h>
22 
23 #define MINUSKVAR "CrYpTkEy"
24 
25 #define ECHO 010
26 #define ROTORSZ 256
27 #define MASK 0377
28 char	t1[ROTORSZ];
29 char	t2[ROTORSZ];
30 char	t3[ROTORSZ];
31 char	deck[ROTORSZ];
32 char	buf[13];
33 
34 void	shuffle(char *);
35 void	setup(char *);
36 
37 void
38 setup(char *pw)
39 {
40 	int ic, i, k, temp;
41 	char salt[3];
42 	unsigned rnd;
43 	int32_t seed;
44 
45 	strlcpy(salt, pw, sizeof(salt));
46 	memcpy(buf, crypt(pw, salt), sizeof(buf));
47 	seed = 123;
48 	for (i=0; i<13; i++)
49 		seed = seed*buf[i] + i;
50 	for(i=0;i<ROTORSZ;i++) {
51 		t1[i] = i;
52 		deck[i] = i;
53 	}
54 	for(i=0;i<ROTORSZ;i++) {
55 		seed = 5*seed + buf[i%13];
56 		rnd = seed % 65521;
57 		k = ROTORSZ-1 - i;
58 		ic = (rnd&MASK)%(k+1);
59 		rnd >>= 8;
60 		temp = t1[k];
61 		t1[k] = t1[ic];
62 		t1[ic] = temp;
63 		if(t3[k]!=0) continue;
64 		ic = (rnd&MASK) % k;
65 		while(t3[ic]!=0) ic = (ic+1) % k;
66 		t3[k] = ic;
67 		t3[ic] = k;
68 	}
69 	for(i=0;i<ROTORSZ;i++)
70 		t2[t1[i]&MASK] = i;
71 }
72 
73 int
74 main(int argc, char *argv[])
75 {
76 	int i, n1, n2, nr1, nr2;
77 	int secureflg = 0, kflag = 0;
78 	char *cp;
79 
80 	if (argc > 1 && argv[1][0] == '-') {
81 		if (argv[1][1] == 's') {
82 			argc--;
83 			argv++;
84 			secureflg = 1;
85 		} else if (argv[1][1] == 'k') {
86 			argc--;
87 			argv++;
88 			kflag = 1;
89 		}
90 	}
91 	if (kflag) {
92 		if ((cp = getenv(MINUSKVAR)) == NULL) {
93 			fprintf(stderr, "%s not set\n", MINUSKVAR);
94 			exit(1);
95 		}
96 		setup(cp);
97 	} else if (argc != 2) {
98 		setup(getpass("Enter key:"));
99 	}
100 	else
101 		setup(argv[1]);
102 	n1 = 0;
103 	n2 = 0;
104 	nr2 = 0;
105 
106 	while((i=getchar()) != -1) {
107 		if (secureflg) {
108 			nr1 = deck[n1]&MASK;
109 			nr2 = deck[nr1]&MASK;
110 		} else {
111 			nr1 = n1;
112 		}
113 		i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
114 		putchar(i);
115 		n1++;
116 		if(n1==ROTORSZ) {
117 			n1 = 0;
118 			n2++;
119 			if(n2==ROTORSZ) n2 = 0;
120 			if (secureflg) {
121 				shuffle(deck);
122 			} else {
123 				nr2 = n2;
124 			}
125 		}
126 	}
127 
128 	return 0;
129 }
130 
131 void
132 shuffle(char deckary[])
133 {
134 	int i, ic, k, temp;
135 	unsigned rnd;
136 	static int32_t seed = 123;
137 
138 	for(i=0;i<ROTORSZ;i++) {
139 		seed = 5*seed + buf[i%13];
140 		rnd = seed % 65521;
141 		k = ROTORSZ-1 - i;
142 		ic = (rnd&MASK)%(k+1);
143 		temp = deckary[k];
144 		deckary[k] = deckary[ic];
145 		deckary[ic] = temp;
146 	}
147 }
148