[unix-history] / usr / src / cmd / crypt.c

static char *sccsid = "@(#)crypt.c	4.1 (Berkeley) 10/1/80";
/*
 *	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;
		}
	}
}
Commit	Line	Data
31cef89c	1	static char *sccsid = "@(#)crypt.c 4.1 (Berkeley) 10/1/80";
9c79dca0 BJ	2	/*
	3	* A one-rotor machine designed along the lines of Enigma
	4	* but considerably trivialized.
	5	*/
	6
	7	#define ECHO 010
	8	#include <stdio.h>
	9	#define ROTORSZ 256
	10	#define MASK 0377
	11	char t1[ROTORSZ];
	12	char t2[ROTORSZ];
	13	char t3[ROTORSZ];
	14	char *getpass();
	15
	16	setup(pw)
	17	char *pw;
	18	{
	19	int ic, i, k, temp, pf[2];
	20	unsigned random;
	21	char buf[13];
	22	long seed;
	23
	24	strncpy(buf, pw, 8);
	25	while (*pw)
	26	*pw++ = '\0';
	27	buf[8] = buf[0];
	28	buf[9] = buf[1];
	29	pipe(pf);
	30	if (fork()==0) {
	31	close(0);
	32	close(1);
	33	dup(pf[0]);
	34	dup(pf[1]);
	35	execl("/usr/lib/makekey", "-", 0);
	36	execl("/lib/makekey", "-", 0);
	37	exit(1);
	38	}
	39	write(pf[1], buf, 10);
	40	wait((int *)NULL);
	41	if (read(pf[0], buf, 13) != 13) {
	42	fprintf(stderr, "crypt: cannot generate key\n");
	43	exit(1);
	44	}
	45	seed = 123;
	46	for (i=0; i<13; i++)
	47	seed = seed*buf[i] + i;
	48	for(i=0;i<ROTORSZ;i++)
	49	t1[i] = i;
	50	for(i=0;i<ROTORSZ;i++) {
	51	seed = 5*seed + buf[i%13];
	52	random = seed % 65521;
	53	k = ROTORSZ-1 - i;
	54	ic = (random&MASK)%(k+1);
	55	random >>= 8;
	56	temp = t1[k];
	57	t1[k] = t1[ic];
	58	t1[ic] = temp;
	59	if(t3[k]!=0) continue;
	60	ic = (random&MASK) % k;
	61	while(t3[ic]!=0) ic = (ic+1) % k;
	62	t3[k] = ic;
	63	t3[ic] = k;
	64	}
	65	for(i=0;i<ROTORSZ;i++)
66	t2[t1[i]&MASK] = i;
67	}
68
69	main(argc, argv)
70	char *argv[];
71	{
72	register i, n1, n2;
73
74	if (argc != 2){
75	setup(getpass("Enter key:"));
76	}
77	else
78	setup(argv[1]);
79	n1 = 0;
80	n2 = 0;
81
82	while((i=getchar()) >=0) {
83	i = t2[(t3[(t1[(i+n1)&MASK]+n2)&MASK]-n2)&MASK]-n1;
84	putchar(i);
85	n1++;
86	if(n1==ROTORSZ) {
87	n1 = 0;
88	n2++;
89	if(n2==ROTORSZ) n2 = 0;
90	}
91	}
92	}