// MD5.cpp: implementation of the CMD5 class.
//

#include "stdafx.h"
#include "MD5.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
//#define new DEBUG_NEW
#endif


#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 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) + (UINT)(ac); \
		(a) = ROTATE_LEFT ((a), (s)); \
		(a) += (b); \
	}
#define GG(a, b, c, d, x, s, ac) { \
		(a) += G ((b), (c), (d)) + (x) + (UINT)(ac); \
		(a) = ROTATE_LEFT ((a), (s)); \
		(a) += (b); \
	}
#define HH(a, b, c, d, x, s, ac) { \
		(a) += H ((b), (c), (d)) + (x) + (UINT)(ac); \
		(a) = ROTATE_LEFT ((a), (s)); \
		(a) += (b); \
	}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (UINT)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}

static void MD5Transform(UINT uState[4], BYTE byBlock[64]);
static void Encode(BYTE* byOutput, UINT* uInput, UINT uLen);
static void Decode(UINT* uOutput, BYTE* byInput, UINT uLen);

//////////////////////////////////////////////////////////////////////
// Construction/Destruction

CMD5::CMD5()
{
}

CMD5::~CMD5()
{
}


void CMD5::GetHash(LPSTR pszStr, LPSTR pszHash)
{
	MD5_CTX md5ctx;
	BYTE    byDigest[16];

	MD5Init(&md5ctx);
	MD5Update(&md5ctx, (BYTE*)pszStr, (UINT)strlen(pszStr));
	MD5Final(byDigest, &md5ctx);

	pszHash[0] = NULL;

	char szTemp[5];
	for (int i = 0; i < 16; i++) {
		sprintf(szTemp, "%02X", byDigest[i]);
		strcat(pszHash, szTemp);
	}
}

void CMD5::MD5Init(MD5_CTX* md5ctx)
{
	md5ctx->count[0] = md5ctx->count[1] = 0;

	md5ctx->state[0] = 0x67452301;
	md5ctx->state[1] = 0xefcdab89;
	md5ctx->state[2] = 0x98badcfe;
	md5ctx->state[3] = 0x10325476;
}

void CMD5::MD5Update (MD5_CTX* md5ctx, BYTE* byInput, UINT uInputLen)
{
	UINT i, uIndex, nPartLen;

	uIndex = (UINT)((md5ctx->count[0] >> 3) & 0x3F);

	if ((md5ctx->count[0] += ((UINT)uInputLen << 3)) < ((UINT)uInputLen << 3))
		md5ctx->count[1]++;

	md5ctx->count[1] += ((UINT)uInputLen >> 29);
	nPartLen = 64 - uIndex;

	if (uInputLen >= nPartLen) {
		memcpy(&md5ctx->buffer[uIndex], byInput, nPartLen);
		MD5Transform(md5ctx->state, md5ctx->buffer);

		for (i = nPartLen; i + 63 < uInputLen; i += 64)
			MD5Transform (md5ctx->state, &byInput[i]);

		uIndex = 0;
	}
	else
		i = 0;

	memcpy(&md5ctx->buffer[uIndex], &byInput[i], uInputLen - i);
}

void CMD5::MD5Final(BYTE* byDigest, MD5_CTX* md5ctx)
{
	BYTE byBits[8];
	UINT uIndex, nPadLen;

	Encode(byBits, md5ctx->count, 8);

	uIndex  = (UINT)((md5ctx->count[0] >> 3) & 0x3f);
	nPadLen = uIndex < 56 ? (56 - uIndex) : (120 - uIndex);
	MD5Update(md5ctx, PADDING, nPadLen);

	MD5Update(md5ctx, byBits, 8);

	Encode (byDigest, md5ctx->state, 16);
	memset (md5ctx, 0, sizeof(*md5ctx));
}


static void MD5Transform(UINT uState[4], BYTE byBlock[64])
{
	UINT a = uState[0], b = uState[1], c = uState[2], d = uState[3], x[16];

	Decode(x, byBlock, 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 */

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

	// Zeroize sensitive information.
	memset(x, 0, sizeof(x));
}

static void Encode(BYTE* byOutput, UINT* uInput, UINT uLen)
{
	for (UINT i = 0, j = 0; j < uLen; i++, j += 4) {
		byOutput[j]     = (BYTE)(uInput[i] & 0xff);
		byOutput[j + 1] = (BYTE)((uInput[i] >> 8) & 0xff);
		byOutput[j + 2] = (BYTE)((uInput[i] >> 16) & 0xff);
		byOutput[j + 3] = (BYTE)((uInput[i] >> 24) & 0xff);
	}
}

static void Decode(UINT* uOutput, BYTE* byInput, UINT uLen)
{
	for (UINT i = 0, j = 0; j < uLen; i++, j += 4)
		uOutput[i] = ((UINT)byInput[j]) | (((UINT)byInput[j + 1]) << 8) |
			(((UINT)byInput[j + 2]) << 16) | (((UINT)byInput[j + 3]) << 24);
}