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: releng/11.0/usr.bin/enigma/enigma.c 279296 2015-02-25 20:47:25Z delphij $");
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	if (crypt_set_format("des") == 0) {
47		fprintf(stderr, "crypt_set_format(\"des\") failed.\n");
48		exit(1);
49	}
50
51	strlcpy(salt, pw, sizeof(salt));
52	cryptpw = crypt(pw, salt);
53	if (cryptpw == NULL) {
54		fprintf(stderr, "crypt(3) failure\n");
55		exit(1);
56	}
57	memcpy(buf, cryptpw, sizeof(buf));
58	seed = 123;
59	for (i=0; i<13; i++)
60		seed = seed*buf[i] + i;
61	for(i=0;i<ROTORSZ;i++) {
62		t1[i] = i;
63		deck[i] = i;
64	}
65	for(i=0;i<ROTORSZ;i++) {
66		seed = 5*seed + buf[i%13];
67		rnd = seed % 65521;
68		k = ROTORSZ-1 - i;
69		ic = (rnd&MASK)%(k+1);
70		rnd >>= 8;
71		temp = t1[k];
72		t1[k] = t1[ic];
73		t1[ic] = temp;
74		if(t3[k]!=0) continue;
75		ic = (rnd&MASK) % k;
76		while(t3[ic]!=0) ic = (ic+1) % k;
77		t3[k] = ic;
78		t3[ic] = k;
79	}
80	for(i=0;i<ROTORSZ;i++)
81		t2[t1[i]&MASK] = i;
82}
83
84int
85main(int argc, char *argv[])
86{
87	int i, n1, n2, nr1, nr2;
88	int secureflg = 0, kflag = 0;
89	char *cp;
90
91	if (argc > 1 && argv[1][0] == '-') {
92		if (argv[1][1] == 's') {
93			argc--;
94			argv++;
95			secureflg = 1;
96		} else if (argv[1][1] == 'k') {
97			argc--;
98			argv++;
99			kflag = 1;
100		}
101	}
102	if (kflag) {
103		if ((cp = getenv(MINUSKVAR)) == NULL) {
104			fprintf(stderr, "%s not set\n", MINUSKVAR);
105			exit(1);
106		}
107		setup(cp);
108	} else if (argc != 2) {
109		setup(getpass("Enter key:"));
110	}
111	else
112		setup(argv[1]);
113	n1 = 0;
114	n2 = 0;
115	nr2 = 0;
116
117	while((i=getchar()) != -1) {
118		if (secureflg) {
119			nr1 = deck[n1]&MASK;
120			nr2 = deck[nr1]&MASK;
121		} else {
122			nr1 = n1;
123		}
124		i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
125		putchar(i);
126		n1++;
127		if(n1==ROTORSZ) {
128			n1 = 0;
129			n2++;
130			if(n2==ROTORSZ) n2 = 0;
131			if (secureflg) {
132				shuffle(deck);
133			} else {
134				nr2 = n2;
135			}
136		}
137	}
138
139	return 0;
140}
141
142static void
143shuffle(char deckary[])
144{
145	int i, ic, k, temp;
146	unsigned rnd;
147	static int32_t seed = 123;
148
149	for(i=0;i<ROTORSZ;i++) {
150		seed = 5*seed + buf[i%13];
151		rnd = seed % 65521;
152		k = ROTORSZ-1 - i;
153		ic = (rnd&MASK)%(k+1);
154		temp = deckary[k];
155		deckary[k] = deckary[ic];
156		deckary[ic] = temp;
157	}
158}
159