mitm check

#include <stdio.h>
#include <stdlib.h>
#include <string.h>



main() {

unsigned char pka[5] = {"AAAA"};
unsigned char pkm[5] = {"CCCC"};
unsigned char pkb[5] = {"BBBB"};

unsigned char ka[5] = {"KKKK"};
unsigned char km[5] = {"MMMM"};
unsigned char kb[5] = {"LLLL"};

unsigned char pac[5];

unsigned int i=0;
unsigned char start=0x00;

unsigned char an,bn,tempya,tempyb;
unsigned char temp[5];


memcpy(pac,pka,sizeof(pac));
printf("Alice send packet to Bob %s\n",pac);


memcpy(pac,pkm,sizeof(pac));
printf("MITM changes packet and forwards it to Bob %s\n",pac);


printf("Bob creates number\n");
start = pac[0];
for(i=0;i<0xff;i++) {
	start = start^i;
	if(start == kb[0]) {
		printf("Bob found number to use %2X\n",i);
		bn=i;
		goto skip;
	}
}
skip:
memcpy(pac,pkb,sizeof(pac));
printf("Bob sends packet to Alice %s\n",pac);

memcpy(pac,pkm,sizeof(pac));
printf("MITM changes packet and forwards it to Alice %s\n",pac);

printf("Alice creates number\n");
start = pac[0];
for(i=0;i<0xff;i++) {
	start = start^i;
	if(start == ka[0]) {
		printf("Alice found number to use %2X\n",i);
		an=i;
		goto skip1;
	}
}
skip1:

memcpy(pac,ka,sizeof(pac));
printf("Alice sends key to Bob %s\n",pac);

memcpy(pac,km,sizeof(pac));
printf("MITM changes packet and forwards it to Bob %s as its key\n",pac);


printf("Bob modfies packet to Alice using mitm key\n");
start = pac[0];
for(i=0;i<0xff;i++) {
	start = start^i;
	if(start == pkm[0]) {
		printf("bob modfied to %2X, using mitm instead of alice\n",i);
		tempyb=i;
		goto skip2;
	}
}
skip2:

temp[0] = kb[0]^tempyb;
temp[1] = kb[1]^tempyb;
temp[2] = kb[2]^tempyb;
temp[3] = kb[3]^tempyb;
memcpy(pac,temp,sizeof(pac));
printf("Bob sends key to Alice %s \n",pac);

memcpy(pac,km,sizeof(pac));
printf("MITM changes packet and forwards it to Bob %s as its key\n",pac);

printf("Alice modfies packet to Bob using mitm key\n");
start = pac[0];
for(i=0;i<0xff;i++) {
	start = start^i;
	if(start == pkm[0]) {
		printf("alice modfied to %2X using mitm key instead of bobs\n",i);
		tempya=i;
		goto skip3;
	}
}
skip3:
temp[0] = ka[0]^tempya;
temp[1] = ka[1]^tempya;
temp[2] = ka[2]^tempya;
temp[3] = ka[3]^tempya;
memcpy(pac,temp,sizeof(pac));
printf("Alice sends packet to BOB %s\n",pac);


printf("MITM changes packet to something..ENTER DATA(4 chars :)\n");
gets(pac);

printf("Bob trys to decode it\n");
start = pac[0];
for(i=0;i<tempyb;i++) {
	start = start^i;
}
printf("Hash check = %2X instead of %2X(bob) %2X(Alice)\n",start,tempyb,tempya);




exit(1);
















}