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
28static char	t1[ROTORSZ];
29static char	t2[ROTORSZ];
30static char	t3[ROTORSZ];
31static char	deck[ROTORSZ];
32static char	buf[13];
33
34static void	shuffle(char *);
35static void	setup(char *);
36
37static void
38setup(char *pw)
39{
40	int ic, i, k, temp;
41	char salt[3];
42	unsigned rnd;
43	int32_t seed;
44	char *cryptpw;
45
46	strlcpy(salt, pw, sizeof(salt));
47	cryptpw = crypt(pw, salt);
48	if (cryptpw == NULL) {
49		fprintf(stderr, "crypt(3) failure\n");
50		exit(1);
51	}
52	memcpy(buf, cryptpw, sizeof(buf));
53	seed = 123;
54	for (i=0; i<13; i++)
55		seed = seed*buf[i] + i;
56	for(i=0;i<ROTORSZ;i++) {
57		t1[i] = i;
58		deck[i] = i;
59	}
60	for(i=0;i<ROTORSZ;i++) {
61		seed = 5*seed + buf[i%13];
62		rnd = seed % 65521;
63		k = ROTORSZ-1 - i;
64		ic = (rnd&MASK)%(k+1);
65		rnd >>= 8;
66		temp = t1[k];
67		t1[k] = t1[ic];
68		t1[ic] = temp;
69		if(t3[k]!=0) continue;
70		ic = (rnd&MASK) % k;
71		while(t3[ic]!=0) ic = (ic+1) % k;
72		t3[k] = ic;
73		t3[ic] = k;
74	}
75	for(i=0;i<ROTORSZ;i++)
76		t2[t1[i]&MASK] = i;
77}
78
79int
80main(int argc, char *argv[])
81{
82	int i, n1, n2, nr1, nr2;
83	int secureflg = 0, kflag = 0;
84	char *cp;
85
86	if (argc > 1 && argv[1][0] == '-') {
87		if (argv[1][1] == 's') {
88			argc--;
89			argv++;
90			secureflg = 1;
91		} else if (argv[1][1] == 'k') {
92			argc--;
93			argv++;
94			kflag = 1;
95		}
96	}
97	if (kflag) {
98		if ((cp = getenv(MINUSKVAR)) == NULL) {
99			fprintf(stderr, "%s not set\n", MINUSKVAR);
100			exit(1);
101		}
102		setup(cp);
103	} else if (argc != 2) {
104		setup(getpass("Enter key:"));
105	}
106	else
107		setup(argv[1]);
108	n1 = 0;
109	n2 = 0;
110	nr2 = 0;
111
112	while((i=getchar()) != -1) {
113		if (secureflg) {
114			nr1 = deck[n1]&MASK;
115			nr2 = deck[nr1]&MASK;
116		} else {
117			nr1 = n1;
118		}
119		i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
120		putchar(i);
121		n1++;
122		if(n1==ROTORSZ) {
123			n1 = 0;
124			n2++;
125			if(n2==ROTORSZ) n2 = 0;
126			if (secureflg) {
127				shuffle(deck);
128			} else {
129				nr2 = n2;
130			}
131		}
132	}
133
134	return 0;
135}
136
137static void
138shuffle(char deckary[])
139{
140	int i, ic, k, temp;
141	unsigned rnd;
142	static int32_t seed = 123;
143
144	for(i=0;i<ROTORSZ;i++) {
145		seed = 5*seed + buf[i%13];
146		rnd = seed % 65521;
147		k = ROTORSZ-1 - i;
148		ic = (rnd&MASK)%(k+1);
149		temp = deckary[k];
150		deckary[k] = deckary[ic];
151		deckary[ic] = temp;
152	}
153}
154