md5checksum.cpp

MD5加密解密,包装为c++ 类,方便使用.

	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("0%x",lpszMD5[i]);
		}
		else
		{	
			Str.Format("%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;
	}
}