md5_ref.cpp

/* MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
*/

/* 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.
*/
//	2/5/06 gmilow - Modified 

#include "stdafx.h"
#include "globals.h"	// includes correct md5_ref.h if USE_OSSL_REF is defined

#if defined(USE_MD5_REF)

// Constants for MD5Transform routine
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static VOID MD5_Transform(DWORD [4], BYTE [64]);
static VOID Encode(BYTE *, DWORD *, UINT);
static VOID Decode(DWORD *, BYTE *, UINT);
static VOID MD5_memcpy(BYTE *, BYTE *, UINT);
static VOID MD5_memset(BYTE *, INT, UINT);

static BYTE 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
};

// F, G, H and I are basic MD5 functions.
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

// ROTATE_LEFT rotates x left n bits.
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

// FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
// Rotation is separate from addition to prevent recomputation.
#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (DWORD)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}
#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (DWORD)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (DWORD)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (DWORD)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}

// MD5 initialization. Begins an MD5 operation, writing a new context.
VOID MD5_Init (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 MD5_Update (MD5_CTX * context, BYTE * input, UINT inputLen)
{
	UINT i, index, partLen;

	// Compute number of bytes (that we already had) mod 64
	index = (UINT)((context->count[0] >> 3) & 0x3F);

	// Update number of bits
	if ((context->count[0] += ((DWORD)inputLen << 3))   < ((DWORD)inputLen << 3))
		context->count[1]++;
	context->count[1] += ((DWORD)inputLen >> 29);

	// partLen is the number of bytes we need to fill the buffer. It is possible that
	// there are bytes left to process
	partLen = 64 - index;

	// Transform as many times as possible
	if (inputLen >= partLen) {
		MD5_memcpy((BYTE *)&context->buffer[index], (BYTE *)input, partLen);
		MD5_Transform (context->state, context->buffer);

		for (i = partLen; i + 63 < inputLen; i += 64)
			MD5_Transform (context->state, &input[i]);

		index = 0;
	}
	else
		i = 0;

	// Buffer remaining input that we could not process
	MD5_memcpy((BYTE *)&context->buffer[index], (BYTE *)&input[i], inputLen-i);
}

// MD5 finalization. Ends an MD5 message-digest operation, writing the
// the message digest and zeroizing the context
VOID MD5_Final (BYTE digest[16], MD5_CTX * context)
{
	BYTE bits[8];
	UINT index, padLen;

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

	// Pad out to 56 mod 64.
	index = (UINT)((context->count[0] >> 3) & 0x3f); // get the number of bytes left in the buffer
	
	// is it possible to append the bit and the length to this buffer? otherwise we have to 'pad'
	// enough bytes to fill the next buffer so that there is only space left for the length
	padLen = (index < 56) ? (56 - index) : (120 - index);
	MD5_Update (context, PADDING, padLen);

	// Append length (before padding); ahhmmm.... we do this AFTER the padding, don't we?
	MD5_Update (context, bits, 8);

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

	// Zeroize sensitive information
	//MD5_memset ((BYTE *)context, 0, sizeof (*context));
}

// MD5 basic transformation. Transforms state based on block. Everytime 64 bytes are processed
static VOID MD5_Transform (DWORD state[4], BYTE block[64])
{
	DWORD a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	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 ((BYTE *)x, 0, sizeof (x));
}

// Encodes input (DWORD) into output (BYTE). Assumes len is a multiple of 4
static VOID Encode (BYTE * output, DWORD * input, UINT len)
{
	UINT i, j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[j] = (BYTE)(input[i] & 0xff);
		output[j+1] = (BYTE)((input[i] >> 8) & 0xff);
		output[j+2] = (BYTE)((input[i] >> 16) & 0xff);
		output[j+3] = (BYTE)((input[i] >> 24) & 0xff);
	}
}

// Decodes input (BYTE) into output (DWORD). Assumes len is a multiple of 4
static VOID Decode (DWORD * output, BYTE * input, UINT len)
{
	UINT i, j;

	for (i = 0, j = 0; j < len; i++, j += 4)
		output[i] = ((DWORD)input[j]) | (((DWORD)input[j+1]) << 8) |
		(((DWORD)input[j+2]) << 16) | (((DWORD)input[j+3]) << 24);
}

// Note: Replace "for loop" with standard memcpy if possible
static VOID MD5_memcpy (BYTE * output, BYTE * input, UINT len)
{
	/* UINT i;

	for (i = 0; i < len; i++)
		output[i] = input[i];*/
	memcpy(output, input, len);
}

// Note: Replace "for loop" with standard memset if possible.
static VOID MD5_memset (BYTE * output, INT value, UINT len)
{
	/*UINT i;

	for (i = 0; i < len; i++)
		((char *)output)[i] = (char)value;*/

	memset(output, value, len);
}

#endif	//USE_MD5_REF