MD5Checksum.cpp

#include "StdAfx.h"
#include "MD5Checksum.h"
#include "MD5ChecksumDefines.h"

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


/*****************************************************************************************

*****************************************************************************************/
CString CMD5Checksum::GetMD5(const CString& strFilePath)
{
	try
	{ 
		CFile file;
		if(file.Open(strFilePath,CFile::modeRead)==0)
			return _T("");

		CMD5Checksum MD5Checksum;   //checksum object 
		int nLength = 0;       //number of bytes read from the file
		const int nBufferSize = 1024; //checksum the file in blocks of 1024 bytes
		BYTE Buffer[nBufferSize];   //buffer for data read from the file

		//checksum the file in blocks of 1024 bytes
		while ((nLength = file.Read( Buffer, nBufferSize )) > 0 )
		{ 
			MD5Checksum.Update( Buffer, nLength );
		}

		file.Close();

		//finalise the checksum and return it
		return MD5Checksum.Final();
	}

	//report any file exceptions in debug mode only
	catch (CFileException* e )
	{ 
		TRACE0("CMD5Checksum::GetMD5: CFileException caught"); 
		throw e;
	}
}

/*****************************************************************************************
FUNCTION:  CMD5Checksum::RotateLeft
DETAILS:  private
DESCRIPTION: Rotates the bits in a 32 bit DWORD left by a specified amount
RETURNS:  The rotated DWORD 
ARGUMENTS:  DWORD x : the value to be rotated
int n   : the number of bits to rotate by
*****************************************************************************************/
DWORD CMD5Checksum::RotateLeft(DWORD x, int n)
{ 
	//check that DWORD is 4 bytes long - true in Visual C++ 6 and 32 bit Windows
	ASSERT( sizeof(x) == 4 );

	//rotate and return x
	return (x << n) | (x >> (32-n));
}


/*****************************************************************************************
FUNCTION:  CMD5Checksum::FF
DETAILS:  protected
DESCRIPTION: Implementation of basic MD5 transformation algorithm
RETURNS:  none
ARGUMENTS:  DWORD &A, B, C, D : Current (partial) checksum
DWORD X           : Input data
DWORD S     : MD5_SXX Transformation constant
DWORD T     : MD5_TXX Transformation constant
NOTES:   None
*****************************************************************************************/
void CMD5Checksum::FF( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T)
{ 
	DWORD F = (B & C) | (~B & D);
	A += F + X + T;
	A = RotateLeft(A, S);
	A += B;
}


/*****************************************************************************************
FUNCTION:  CMD5Checksum::GG
DETAILS:  protected
DESCRIPTION: Implementation of basic MD5 transformation algorithm
RETURNS:  none
ARGUMENTS:  DWORD &A, B, C, D : Current (partial) checksum
DWORD X           : Input data
DWORD S      : MD5_SXX Transformation constant
DWORD T      : MD5_TXX Transformation constant
NOTES:   None
*****************************************************************************************/
void CMD5Checksum::GG( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T)
{ 
	DWORD G = (B & D) | (C & ~D);
	A += G + X + T;
	A = RotateLeft(A, S);
	A += B;
}


/*****************************************************************************************
FUNCTION:  CMD5Checksum::HH
DETAILS:  protected
DESCRIPTION: Implementation of basic MD5 transformation algorithm
RETURNS:  none
ARGUMENTS:  DWORD &A, B, C, D : Current (partial) checksum
DWORD X           : Input data
DWORD S      : MD5_SXX Transformation constant
DWORD T      : MD5_TXX Transformation constant
NOTES:   None
*****************************************************************************************/
void CMD5Checksum::HH( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T)
{ 
	DWORD H = (B ^ C ^ D);
	A += H + X + T;
	A = RotateLeft(A, S);
	A += B;
}


/*****************************************************************************************
FUNCTION:  CMD5Checksum::II
DETAILS:  protected
DESCRIPTION: Implementation of basic MD5 transformation algorithm
RETURNS:  none
ARGUMENTS:  DWORD &A, B, C, D : Current (partial) checksum
DWORD X           : Input data
DWORD S      : MD5_SXX Transformation constant
DWORD T      : MD5_TXX Transformation constant
NOTES:   None
*****************************************************************************************/
void CMD5Checksum::II( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T)
{ 
	DWORD I = (C ^ (B | ~D));
	A += I + X + T;
	A = RotateLeft(A, S);
	A += B;
}


/*****************************************************************************************
FUNCTION:  CMD5Checksum::ByteToDWord
DETAILS:  private
DESCRIPTION: Transfers the data in an 8 bit array to a 32 bit array
RETURNS:  void
ARGUMENTS:  DWORD* Output : the 32 bit (unsigned long) destination array 
BYTE* Input   : the 8 bit (unsigned char) source array
UINT nLength  : the number of 8 bit data items in the source array
NOTES:   Four BYTES from the input array are transferred to each DWORD entry
of the output array. The first BYTE is transferred to the bits (0-7) 
of the output DWORD, the second BYTE to bits 8-15 etc. 
The algorithm assumes that the input array is a multiple of 4 bytes long
so that there is a perfect fit into the array of 32 bit words.
*****************************************************************************************/
void CMD5Checksum::ByteToDWord(DWORD* Output, BYTE* Input, UINT nLength)
{ 
	//entry invariants
	ASSERT( nLength % 4 == 0 );
	ASSERT( AfxIsValidAddress(Output, nLength/4, TRUE) );
	ASSERT( AfxIsValidAddress(Input, nLength, FALSE) );

	//initialisations
	UINT i=0; //index to Output array
	UINT j=0; //index to Input array

	//transfer the data by shifting and copying
	for ( ; j < nLength; i++, j += 4)
	{ 
		Output[i] = (ULONG)Input[j]   | 
			(ULONG)Input[j+1] << 8 | 
			(ULONG)Input[j+2] << 16 | 
			(ULONG)Input[j+3] << 24;
	}
}

/*****************************************************************************************
FUNCTION:  CMD5Checksum::Transform
DETAILS:  protected
DESCRIPTION: MD5 basic transformation algorithm;  transforms 'm_lMD5'
RETURNS:  void
ARGUMENTS:  BYTE Block[64]
NOTES:   An MD5 checksum is calculated by four rounds of 'Transformation'.
The MD5 checksum currently held in m_lMD5 is merged by the 
transformation process with data passed in 'Block'.  
*****************************************************************************************/
void CMD5Checksum::Transform(BYTE Block[64])
{ 
	//initialise local data with current checksum
	ULONG a = m_lMD5[0];
	ULONG b = m_lMD5[1];
	ULONG c = m_lMD5[2];
	ULONG d = m_lMD5[3];

	//copy BYTES from input 'Block' to an array of ULONGS 'X'
	ULONG X[16];
	ByteToDWord( X, Block, 64 );

	//Perform Round 1 of the transformation
	FF (a, b, c, d, X[ 0], MD5_S11, MD5_T01); 
	FF (d, a, b, c, X[ 1], MD5_S12, MD5_T02); 
	FF (c, d, a, b, X[ 2], MD5_S13, MD5_T03); 
	FF (b, c, d, a, X[ 3], MD5_S14, MD5_T04); 
	FF (a, b, c, d, X[ 4], MD5_S11, MD5_T05); 
	FF (d, a, b, c, X[ 5], MD5_S12, MD5_T06); 
	FF (c, d, a, b, X[ 6], MD5_S13, MD5_T07); 
	FF (b, c, d, a, X[ 7], MD5_S14, MD5_T08); 
	FF (a, b, c, d, X[ 8], MD5_S11, MD5_T09); 
	FF (d, a, b, c, X[ 9], MD5_S12, MD5_T10); 
	FF (c, d, a, b, X[10], MD5_S13, MD5_T11); 
	FF (b, c, d, a, X[11], MD5_S14, MD5_T12); 
	FF (a, b, c, d, X[12], MD5_S11, MD5_T13); 
	FF (d, a, b, c, X[13], MD5_S12, MD5_T14); 
	FF (c, d, a, b, X[14], MD5_S13, MD5_T15); 
	FF (b, c, d, a, X[15], MD5_S14, MD5_T16);

	//Perform Round 2 of the transformation
	GG (a, b, c, d, X[ 1], MD5_S21, MD5_T17); 
	GG (d, a, b, c, X[ 6], MD5_S22, MD5_T18); 
	GG (c, d, a, b, X[11], MD5_S23, MD5_T19); 
	GG (b, c, d, a, X[ 0], MD5_S24, MD5_T20); 
	GG (a, b, c, d, X[ 5], MD5_S21, MD5_T21); 
	GG (d, a, b, c, X[10], MD5_S22, MD5_T22); 
	GG (c, d, a, b, X[15], MD5_S23, MD5_T23); 
	GG (b, c, d, a, X[ 4], MD5_S24, MD5_T24); 
	GG (a, b, c, d, X[ 9], MD5_S21, MD5_T25); 
	GG (d, a, b, c, X[14], MD5_S22, MD5_T26); 
	GG (c, d, a, b, X[ 3], MD5_S23, MD5_T27); 
	GG (b, c, d, a, X[ 8], MD5_S24, MD5_T28); 
	GG (a, b, c, d, X[13], MD5_S21, MD5_T29); 
	GG (d, a, b, c, X[ 2], MD5_S22, MD5_T30); 
	GG (c, d, a, b, X[ 7], MD5_S23, MD5_T31); 
	GG (b, c, d, a, X[12], MD5_S24, MD5_T32);

	//Perform Round 3 of the transformation
	HH (a, b, c, d, X[ 5], MD5_S31, MD5_T33); 
	HH (d, a, b, c, X[ 8], MD5_S32, MD5_T34); 
	HH (c, d, a, b, X[11], MD5_S33, MD5_T35); 
	HH (b, c, d, a, X[14], MD5_S34, MD5_T36); 
	HH (a, b, c, d, X[ 1], MD5_S31, MD5_T37); 
	HH (d, a, b, c, X[ 4], MD5_S32, MD5_T38); 
	HH (c, d, a, b, X[ 7], MD5_S33, MD5_T39); 
	HH (b, c, d, a, X[10], MD5_S34, MD5_T40); 
	HH (a, b, c, d, X[13], MD5_S31, MD5_T41); 
	HH (d, a, b, c, X[ 0], MD5_S32, MD5_T42); 
	HH (c, d, a, b, X[ 3], MD5_S33, MD5_T43); 
	HH (b, c, d, a, X[ 6], MD5_S34, MD5_T44); 
	HH (a, b, c, d, X[ 9], MD5_S31, MD5_T45); 
	HH (d, a, b, c, X[12], MD5_S32, MD5_T46); 
	HH (c, d, a, b, X[15], MD5_S33, MD5_T47); 
	HH (b, c, d, a, X[ 2], MD5_S34, MD5_T48);

	//Perform Round 4 of the transformation
	II (a, b, c, d, X[ 0], MD5_S41, MD5_T49); 
	II (d, a, b, c, X[ 7], MD5_S42, MD5_T50); 
	II (c, d, a, b, X[14], MD5_S43, MD5_T51); 
	II (b, c, d, a, X[ 5], MD5_S44, MD5_T52); 
	II (a, b, c, d, X[12], MD5_S41, MD5_T53); 
	II (d, a, b, c, X[ 3], MD5_S42, MD5_T54); 
	II (c, d, a, b, X[10], MD5_S43, MD5_T55); 
	II (b, c, d, a, X[ 1], MD5_S44, MD5_T56); 
	II (a, b, c, d, X[ 8], MD5_S41, MD5_T57); 
	II (d, a, b, c, X[15], MD5_S42, MD5_T58); 
	II (c, d, a, b, X[ 6], MD5_S43, MD5_T59); 
	II (b, c, d, a, X[13], MD5_S44, MD5_T60); 
	II (a, b, c, d, X[ 4], MD5_S41, MD5_T61); 
	II (d, a, b, c, X[11], MD5_S42, MD5_T62); 
	II (c, d, a, b, X[ 2], MD5_S43, MD5_T63); 
	II (b, c, d, a, X[ 9], MD5_S44, MD5_T64);

	//add the transformed values to the current checksum
	m_lMD5[0] += a;
	m_lMD5[1] += b;
	m_lMD5[2] += c;
	m_lMD5[3] += d;
}


/*****************************************************************************************
CONSTRUCTOR: CMD5Checksum
DESCRIPTION: Initialises member data
ARGUMENTS:  None
NOTES:   None
*****************************************************************************************/
CMD5Checksum::CMD5Checksum()
{ 
	// zero members
	memset( m_lpszBuffer, 0, 64 );
	m_nCount[0] = m_nCount[1] = 0;

	// Load magic state initialization constants
	m_lMD5[0] = MD5_INIT_STATE_0;
	m_lMD5[1] = MD5_INIT_STATE_1;
	m_lMD5[2] = MD5_INIT_STATE_2;
	m_lMD5[3] = MD5_INIT_STATE_3;
}

/*****************************************************************************************
FUNCTION:  CMD5Checksum::DWordToByte
DETAILS:  private
DESCRIPTION: Transfers the data in an 32 bit array to a 8 bit array
RETURNS:  void
ARGUMENTS:  BYTE* Output  : the 8 bit destination array 
DWORD* Input  : the 32 bit source array
UINT nLength  : the number of 8 bit data items in the source array
NOTES:   One DWORD from the input array is transferred into four BYTES 
in the output array. The first (0-7) bits of the first DWORD are 
transferred to the first output BYTE, bits bits 8-15 are transferred from
the second BYTE etc. 

The algorithm assumes that the output array is a multiple of 4 bytes long
so that there is a perfect fit of 8 bit BYTES into the 32 bit DWORDs.
*****************************************************************************************/
void CMD5Checksum::DWordToByte(BYTE* Output, DWORD* Input, UINT nLength )
{ 
	//entry invariants
	ASSERT( nLength % 4 == 0 );
	ASSERT( AfxIsValidAddress(Output, nLength, TRUE) );
	ASSERT( AfxIsValidAddress(Input, nLength/4, FALSE) );

	//transfer the data by shifting and copying
	UINT i = 0;
	UINT j = 0;
	for ( ; j < nLength; i++, j += 4) 
	{ 
		Output[j]  = (UCHAR)(Input[i] & 0xff    );
		Output[j+1] = (UCHAR)((Input[i] >> 8) & 0xff);
		Output[j+2] = (UCHAR)((Input[i] >> 16) & 0xff);
		Output[j+3] = (UCHAR)((Input[i] >> 24) & 0xff);
	}
}


/*****************************************************************************************
FUNCTION:  CMD5Checksum::Final
DETAILS:  protected
DESCRIPTION: Implementation of main MD5 checksum algorithm; ends the checksum calculation.
RETURNS:  CString : the final hexadecimal MD5 checksum result 
ARGUMENTS:  None
NOTES:   Performs the final MD5 checksum calculation ('Update' does most of the work,
this function just finishes the calculation.) 
*****************************************************************************************/
CString CMD5Checksum::Final()
{ 
	//Save number of bits
	BYTE Bits[8];
	DWordToByte( Bits, m_nCount, 8 );

	//Pad out to 56 mod 64.
	UINT nIndex = (UINT)((m_nCount[0] >> 3) & 0x3f);
	UINT nPadLen = (nIndex < 56) ? (56 - nIndex) : (120 - nIndex);
	Update( PADDING, nPadLen );

	//Append length (before padding)
	Update( Bits, 8 );

	//Store final state in 'lpszMD5'
	const int nMD5Size = 16;
	unsigned char lpszMD5[ nMD5Size ];
	DWordToByte( lpszMD5, m_lMD5, nMD5Size );

	//Convert the hexadecimal checksum to a CString
	CString strMD5;
	for ( int i=0; i < nMD5Size; i++) 
	{ 
		CString Str;
		if (lpszMD5[i] == 0) 
		{ 
			Str = CString("00");
		}
		else if (lpszMD5[i] <= 15)  
		{ 
			Str.Format(_T("0%X"),lpszMD5[i]);
		}
		else
		{ 
			Str.Format(_T("%X"),lpszMD5[i]);
		}

		ASSERT( Str.GetLength() == 2 );
		strMD5 += Str;
	}
	ASSERT( strMD5.GetLength() == 32 );
	return strMD5;
}


/*****************************************************************************************
FUNCTION:  CMD5Checksum::Update
DETAILS:  protected
DESCRIPTION: Implementation of main MD5 checksum algorithm
RETURNS:  void
ARGUMENTS:  BYTE* Input    : input block
UINT nInputLen : length of input block
NOTES:   Computes the partial MD5 checksum for 'nInputLen' bytes of data in 'Input'
*****************************************************************************************/
void CMD5Checksum::Update( BYTE* Input, ULONG nInputLen )
{ 
	//Compute number of bytes mod 64
	UINT nIndex = (UINT)((m_nCount[0] >> 3) & 0x3F);

	//Update number of bits
	if ( ( m_nCount[0] += nInputLen << 3 )  <  ( nInputLen << 3) )
	{ 
		m_nCount[1]++;
	}
	m_nCount[1] += (nInputLen >> 29);

	//Transform as many times as possible.
	UINT i=0;  
	UINT nPartLen = 64 - nIndex;
	if (nInputLen >= nPartLen)  
	{ 
		memcpy( &m_lpszBuffer[nIndex], Input, nPartLen );
		Transform( m_lpszBuffer );
		for (i = nPartLen; i + 63 < nInputLen; i += 64) 
		{ 
			Transform( &Input[i] );
		}
		nIndex = 0;
	} 
	else 
	{
		i = 0;
	}

	// Buffer remaining input
	memcpy( &m_lpszBuffer[nIndex], &Input[i], nInputLen-i);
}



CString CMD5Checksum::GetMD5OfString(CString strString)
{
	try
	{ 
		CMD5Checksum MD5Checksum;   //checksum object 
		int nLength = strString.GetLength();       //number of bytes read from the file
		//const int nBufferSize = 1024; //checksum the file in blocks of 1024 bytes
		BYTE *Buffer;   //buffer for data read from the file
		Buffer=(BYTE*)(strString.GetBuffer(nLength));
		//checksum the file in blocks of 1024 bytes
		//while ((nLength = File.Read( Buffer, nBufferSize )) > 0 )
		//{ 
		MD5Checksum.Update( Buffer, nLength );
		//}
		//finalise the checksum and return it
		return MD5Checksum.Final();
	}

	//report any file exceptions in debug mode only
	catch (CFileException* e )
	{ 
		TRACE0("CMD5Checksum::GetMD5: CFileException caught"); 
		throw e;
	}
}