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

/*
 *	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
9c79dca0 BJ	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	}