HashUtil.cpp

/**
 * HashUtil (MD5 hashing)
 *
 * Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
 * rights reserved.
 *
 * License to copy and use this software is granted provided that it
 * is identified as the "RSA Data Security, Inc. MD5 Message-Digest
 * Algorithm" in all material mentioning or referencing this software
 * or this function.
 *
 * License is also granted to make and use derivative works provided
 * that such works are identified as "derived from the RSA Data
 * Security, Inc. MD5 Message-Digest Algorithm" in all material
 * mentioning or referencing the derived work.
 *
 * RSA Data Security, Inc. makes no representations concerning either
 * the merchantability of this software or the suitability of this
 * software for any particular purpose. It is provided "as is"
 * without express or implied warranty of any kind.
 *
 * These notices must be retained in any copies of any part of this
 * documentation and/or software.
 *
 * @author  RSA Data Security, Inc. (http://www.rsasecurity.com)
 * @date  21/08/04
 * @see RFC1321
 */

#include "HashUtil.h"

unsigned char HashUtil::m_PADDING[64] = {
	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/** 
 * MD5 initialization. Begins an MD5 operation, writing a new context.
 */
void HashUtil::MD5Init(MD5_CTX* context)
{
	context->count[0] = context->count[1] = 0;
	// Load magic initialization constants.
	context->state[0] = 0x67452301;
	context->state[1] = 0xefcdab89;
	context->state[2] = 0x98badcfe;
	context->state[3] = 0x10325476;
}

/**
 * MD5 block update operation. Continues an MD5 message-digest
 * operation, processing another message block, and updating the
 * context.
 */
void HashUtil::MD5Update(MD5_CTX* context, unsigned char* input, unsigned int inputLen)
{
	unsigned int i, index, partLen;

	// Compute number of bytes mod 64
	index = (unsigned int)((context->count[0] >> 3) & 0x3F);

	/* Update number of bits */
	if ((context->count[0] += ((unsigned int)inputLen << 3)) < ((unsigned int)inputLen << 3)) {
		context->count[1]++;
	}

	context->count[1] += ((unsigned int)inputLen >> 29);

	partLen = 64 - index;

	// Transform as many times as possible.
	if (inputLen >= partLen) {
		MD5_memcpy((unsigned char*)&context->buffer[index], (unsigned char*)input, partLen);
		MD5Transform(context->state, context->buffer);

		for (i = partLen; i + 63 < inputLen; i += 64) {
			MD5Transform(context->state, &input[i]);
		}

		index = 0;

	} else {
		i = 0;
	}

	// Buffer remaining input
	MD5_memcpy((unsigned char*)&context->buffer[index], (unsigned char*)&input[i], inputLen - i);
}

/**
 * MD5 finalization. Ends an MD5 message-digest operation, writing the the message digest and zeroizing the context.
 */
void HashUtil::MD5Final(unsigned char digest[16], MD5_CTX* context)
{
	unsigned char bits[8];
	unsigned int index, padLen;

	// Save number of bits
	MD5_Encode(bits, context->count, 8);

	// Pad out to 56 mod 64.
	index = (unsigned int)((context->count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	MD5Update(context, m_PADDING, padLen);

	// Append length (before padding)
	MD5Update(context, bits, 8);

	// Store state in digest
	MD5_Encode(digest, context->state, 16);

	// Zeroize sensitive information.
	MD5_memset((unsigned char*)context, 0, sizeof(*context));
}

/**
 * MD5 basic transformation. Transforms state based on block.
 */
void HashUtil::MD5Transform(unsigned int state[4], unsigned char block[64])
{
	unsigned int a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	MD5_Decode(x, block, 64);

	/* Round 1 */
	FF(a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */
	FF(d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */
	FF(c, d, a, b, x[2], S13, 0x242070db); /* 3 */
	FF(b, c, d, a, x[3], S14, 0xc1bdceee); /* 4 */
	FF(a, b, c, d, x[4], S11, 0xf57c0faf); /* 5 */
	FF(d, a, b, c, x[5], S12, 0x4787c62a); /* 6 */
	FF(c, d, a, b, x[6], S13, 0xa8304613); /* 7 */
	FF(b, c, d, a, x[7], S14, 0xfd469501); /* 8 */
	FF(a, b, c, d, x[8], S11, 0x698098d8); /* 9 */
	FF(d, a, b, c, x[9], S12, 0x8b44f7af); /* 10 */
	FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
	FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
	FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
	FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
	FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
	FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

	/* Round 2 */
	GG(a, b, c, d, x[1], S21, 0xf61e2562); /* 17 */
	GG(d, a, b, c, x[6], S22, 0xc040b340); /* 18 */
	GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
	GG(b, c, d, a, x[0], S24, 0xe9b6c7aa); /* 20 */
	GG(a, b, c, d, x[5], S21, 0xd62f105d); /* 21 */
	GG(d, a, b, c, x[10], S22, 0x2441453); /* 22 */
	GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
	GG(b, c, d, a, x[4], S24, 0xe7d3fbc8); /* 24 */
	GG(a, b, c, d, x[9], S21, 0x21e1cde6); /* 25 */
	GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
	GG(c, d, a, b, x[3], S23, 0xf4d50d87); /* 27 */
	GG(b, c, d, a, x[8], S24, 0x455a14ed); /* 28 */
	GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
	GG(d, a, b, c, x[2], S22, 0xfcefa3f8); /* 30 */
	GG(c, d, a, b, x[7], S23, 0x676f02d9); /* 31 */
	GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

	/* Round 3 */
	HH(a, b, c, d, x[5], S31, 0xfffa3942); /* 33 */
	HH(d, a, b, c, x[8], S32, 0x8771f681); /* 34 */
	HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
	HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
	HH(a, b, c, d, x[1], S31, 0xa4beea44); /* 37 */
	HH(d, a, b, c, x[4], S32, 0x4bdecfa9); /* 38 */
	HH(c, d, a, b, x[7], S33, 0xf6bb4b60); /* 39 */
	HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
	HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
	HH(d, a, b, c, x[0], S32, 0xeaa127fa); /* 42 */
	HH(c, d, a, b, x[3], S33, 0xd4ef3085); /* 43 */
	HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */
	HH(a, b, c, d, x[9], S31, 0xd9d4d039); /* 45 */
	HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
	HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
	HH(b, c, d, a, x[2], S34, 0xc4ac5665); /* 48 */

	/* Round 4 */
	II(a, b, c, d, x[0], S41, 0xf4292244); /* 49 */
	II(d, a, b, c, x[7], S42, 0x432aff97); /* 50 */
	II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
	II(b, c, d, a, x[5], S44, 0xfc93a039); /* 52 */
	II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
	II(d, a, b, c, x[3], S42, 0x8f0ccc92); /* 54 */
	II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
	II(b, c, d, a, x[1], S44, 0x85845dd1); /* 56 */
	II(a, b, c, d, x[8], S41, 0x6fa87e4f); /* 57 */
	II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
	II(c, d, a, b, x[6], S43, 0xa3014314); /* 59 */
	II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
	II(a, b, c, d, x[4], S41, 0xf7537e82); /* 61 */
	II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
	II(c, d, a, b, x[2], S43, 0x2ad7d2bb); /* 63 */
	II(b, c, d, a, x[9], S44, 0xeb86d391); /* 64 */

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;

	// Zeroize sensitive information.
	MD5_memset((unsigned char*)x, 0, sizeof(x));
}

/**
 * Encodes input (unsigned int) into output (unsigned char). Assumes len is a multiple of 4.
 */
void HashUtil::MD5_Encode(unsigned char* output, unsigned int* input, unsigned int len)
{
	for (unsigned int i = 0, j = 0; j < len; i++, j += 4) {
		output[j] = (unsigned char)(input[i] & 0xff);
		output[j + 1] = (unsigned char)((input[i] >> 8) & 0xff);
		output[j + 2] = (unsigned char)((input[i] >> 16) & 0xff);
		output[j + 3] = (unsigned char)((input[i] >> 24) & 0xff);
	}
}

/**
 * Decodes input (unsigned char) into output (unsigned int). Assumes len is a multiple of 4.
 */
void HashUtil::MD5_Decode(unsigned int* output, unsigned char* input, unsigned int len)
{
	for (unsigned int i = 0, j = 0; j < len; i++, j += 4) {
		output[i] = ((unsigned int)input[j]) | (((unsigned int)input[j + 1]) << 8) | (((unsigned int)input[j + 2]) << 16) | (((unsigned int)input[j + 3]) << 24);
	}
}

/**
 * Note: Replace "for loop" with standard memcpy if possible.
 */
void HashUtil::MD5_memcpy(unsigned char* output, unsigned char* input, unsigned int len)
{
	for (unsigned int i = 0; i < len; i++) {
		output[i] = input[i];
	}
}

/**
 * Note: Replace "for loop" with standard memset if possible.
 */
void HashUtil::MD5_memset(unsigned char* output, int value, unsigned int len)
{
	for (unsigned int i = 0; i < len; i++) {
		((char*)output)[i] = (char)value;
	}
}

unsigned char* HashUtil::getMD5Sum(unsigned char* pData, int size)
{
	MD5_CTX context;

	unsigned char* pDigest = new unsigned char[16];

	MD5Init(&context);
	MD5Update(&context, pData, size);
	MD5Final(pDigest, &context);

	return pDigest;
}