md5 propagation study

md5_propagation.c

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

#define BYTE_TO_BINARY_PATTERN "%c%c%c%c%c%c%c%c"
#define BYTE_TO_BINARY(byte)  \
  (byte & 0x80 ? '1' : '0'), \
  (byte & 0x40 ? '1' : '0'), \
  (byte & 0x20 ? '1' : '0'), \
  (byte & 0x10 ? '1' : '0'), \
  (byte & 0x08 ? '1' : '0'), \
  (byte & 0x04 ? '1' : '0'), \
  (byte & 0x02 ? '1' : '0'), \
  (byte & 0x01 ? '1' : '0') 

unsigned int rot(unsigned int val, unsigned int idx)
{
	return val << idx | val >> (32 - idx);
}

unsigned int f(unsigned int A, unsigned int B, unsigned int C, unsigned int D){

	unsigned int T = 0;

	unsigned int n = 0;
	unsigned int s = 0;

	unsigned int index[16] = {7,12,17,22,5,9,14,20,4,11,16,23,6,10,15,21};

	for(n = 0; n < 64; n++)
	{	
		A = A | B | C | D;	
		s = 4 * (n % 16) + n % 4;
		A = rot(A ,index[s]);
		T = A;
		A = D;
		D = C;
		C = B;
		B = T;
		printf("round %2i:",n);
		printf(" "BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN,
		BYTE_TO_BINARY(A>>24), BYTE_TO_BINARY(A>>16), BYTE_TO_BINARY(A>>8), BYTE_TO_BINARY(A));		
		printf(" "BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN,
		BYTE_TO_BINARY(B>>24), BYTE_TO_BINARY(B>>16), BYTE_TO_BINARY(B>>8), BYTE_TO_BINARY(B));
		printf(" "BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN,
		BYTE_TO_BINARY(C>>24), BYTE_TO_BINARY(C>>16), BYTE_TO_BINARY(C>>8), BYTE_TO_BINARY(C));
		printf(" "BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN BYTE_TO_BINARY_PATTERN,
		BYTE_TO_BINARY(D>>24), BYTE_TO_BINARY(D>>16), BYTE_TO_BINARY(D>>8), BYTE_TO_BINARY(D));
		printf("\n");
		if(A == B  && A == C && A == D && A == 0xFFFFFFFF)
			return n;
	}
	return 64;
}

int main()
{
	unsigned int res[128];
	unsigned int i;
	unsigned int max = 0;
	for(i = 0; i < 32; i ++)
	{
	printf("%8x\n",1 << i);
	res[i] = f(0,0,0,1 << i);
	}
	for(i = 0; i < 32; i ++)
	{
	printf("%8x\n",1 << i);
	res[32+i] = f(0,0, 1 << i,0);
	}
	for(i = 0; i < 32; i ++)
	{
	printf("%8x\n",1 << i);
	res[64+i] = f(0,1 << i,0,0);
	}
	for(i = 0; i < 32; i ++)
	{
	printf("%8x\n",1 << i);
	res[96+i] = f(1 << i,0,0,0);
	}
	for(i = 0; i < 128; i++){
		if(res[i] > max)
			max = res[i];
	}
	printf("max num of rounds: %i\n",max);
}