ktable.py

#This Python script computed the k table
import math
import sys

final_list = []

for i in range(0, 64):
	final_list.append(math.floor(math.fabs(math.sin(i + 1)) * math.pow(2, 32)))

c = 0
sys.stdout.write("{ ")

for i in final_list:
	sys.stdout.write(hex(int(i)))
	sys.stdout.write(",")
	c += 1
	if c % 4 == 0:
		sys.stdout.write("\n")
	else:
		sys.stdout.write(" ")

sys.stdout.write(" }\n")

md5.c

/*
*
*       MD5 algorithm implementation
*               by luc99a
*
*       The k table has been computed by a Python script
*       which i will post on this Git
*
*       debug_print_char_array() is a function used to debug
*       it has no use in the implementation
*
*       the code still needs improovement, but it was made just
*       for fun
*
*       I'm sorry, it's not commented
*
*
*
*/

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

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

unsigned int K[] = {    0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
	       		0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
			0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
			0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
			0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
			0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
			0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
			0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
			0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
			0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
			0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05,
			0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
			0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
			0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
			0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
			0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391     };

unsigned int a = 0x67452301;
unsigned int b = 0xefcdab89;
unsigned int c = 0x98badcfe;
unsigned int d = 0x10325476;

void debug_print_char_array(char* ptr, size_t size);
void md5_digest(char* string, char* dest);
void process_chunk(char* chunk);
unsigned int rotate_left(unsigned int n, int i);

void debug_print_char_array(char* ptr, size_t size) {
	size_t i = 0;
	for (; i < size; i++) {
		printf("%d: %d\n", (int)i, ptr[i]);
	}
}

void md5_digest(char* string, char* dest) {
	size_t string_len = strlen(string);
	char* allocated;
	int chunks = 1 + (string_len + 8) / 64;
	unsigned long len = (unsigned long)string_len * 8;
	int j = string_len + 1;
	int i = 0;
	allocated = (char*) malloc(chunks * 64);
	strncpy(allocated, string, string_len);
	allocated[string_len] = 0x80;
	for (; j < chunks * 64; j++) {
		allocated[j] = 0;
	}
	j -= 8;
	memcpy(allocated + j, &len, 8);
	for (; i < chunks; i++) {
		process_chunk(allocated + (i * 64));
	}
	memcpy(dest, &a, sizeof(int));
	memcpy(dest + sizeof(int), &b, sizeof(int));
	memcpy(dest + (sizeof(int) * 2), &c, sizeof(int));
	memcpy(dest + (sizeof(int) * 3), &d, sizeof(int));
	free(allocated);
}

void process_chunk(char* chunk) {
	unsigned int A = a;
	unsigned int B = b;
	unsigned int C = c;
	unsigned int D = d;
	unsigned int F;
	unsigned int g;
	unsigned int d_temp;
	union m {
		unsigned int u[16];
		char c[64];
	} M;
	int i = 0;
	memcpy(M.c, chunk, 64);
	for (; i < 64; i++) {
		if (i <= 15) {
			F = D ^ (B & (C ^ D));
			g = i;
		} else if (i >= 16 && i <= 31) {
			F = C ^ (D & (B ^ C));
			g = (5 * i + 1) % 16;
		} else if (i >= 32 && i <= 47) {
			F = B ^ C ^ D;
			g = (3 * i + 5) % 16;
		} else if (i >= 48) {
			F = C ^ (B | (~D));
			g = (7 * i) % 16;
		}
		d_temp = D;
		D = C;
		C = B;
		B = B + rotate_left((A + F + K[i] + M.u[g]), s[i]);
		A = d_temp;
	}
	a += A;
	b += B;
	c += C;
	d += D;
}

unsigned int rotate_left(unsigned int n, int i) {
	return ((n) << i) | ((n) >> (32 - i));
}

int main(int argc, char** argv) {
	unsigned char buf[33];
	md5_digest("luc99a md5 algorithm", buf);
	int i = 0;
	for (; i < (sizeof(int) * 4); i++) {
		printf("%02x", buf[i]);
	}
	printf("\n");
}