/* Investigate cycles in DES output feedback mode (experimental) * Phil Karn */#include <stdio.h>main(){	char key[8],start[8],work[8];	long update;	register int i;	long iter;	desinit(0);	printf("Enter key: ");	get8(key);	printf("Setting key: "); put8(key); printf("\n");	setkey(key);	printf("Enter starting value: ");	get8(start);	printf("Starting value: "); put8(start); printf("\n");	printf("Update interval: ");	scanf("%ld",&update);	for(i=0;i<8;i++)		work[i] = start[i];	for(iter = 0;; iter++){		endes(work);		if((iter % update) == 0){			printf("%ld ",iter);			put8(work); printf("\n");		}		for(i=0;i<8;i++){			if(work[i] != start[i])				break;		}		if(i == 8){			printf("CYCLE FOUND after %ld iterations\n",iter);			exit(0);		}	}}get8(cp)char *cp;{	int i,t;	for(i=0;i<8;i++){		scanf("%2x",&t);		*cp++ = t;	}}put8(cp)char *cp;{	int i;	for(i=0;i<8;i++){		printf("%2x ",*cp++ & 0xff);	}}