sending encrypted data via mail using smtp

[vermarajeev]

Load the encrypted message in a QByteArray and replace the required bytes.

Regards

Hey marcel, I'll make changes what you have suggested and let you know the status.
Thanks

[vermarajeev]

Hi marcel, I modified the code as you said. I'm unable to
revert the operation after receiving the file, the contents
gets deleted, Can you please check the code below.


//Sending message------>

void SynsupMail::sendMessage()
{
	QByteArray dat;
	string msg;
       	QFile f ( textFilename->text() );
      	if ( f.open (IO_ReadOnly) )
      	{   
        	  // file opened successfully   
          	dat = f.readAll();
      	} 
	else
	{
		// problems opening the file - emit a warning message
		QMessageBox::warning( this, tr("error"), 
			tr("Error opening file %1").arg( textFilename->text() ) );
		enableSubmit();
		return;
	}	
	f.close();
	StringSource ( string(QString(dat).data()), true, new Base64Encoder(new StringSink(msg))); 
	Smtp *smtp = new Smtp( textFrom->text(), textTo->text(),
		textSubject->text(),
		QString(msg.data()), fileName );
}

void SynsupMail::sendMessage()
{
	QByteArray dat;
	string msg;
       	QFile f ( textFilename->text() );
      	if ( f.open (IO_ReadOnly) )
      	{   
        	  // file opened successfully   
          	dat = f.readAll();
      	} 
	else
	{
		// problems opening the file - emit a warning message
		QMessageBox::warning( this, tr("error"), 
			tr("Error opening file %1").arg( textFilename->text() ) );
		enableSubmit();
		return;
	}	
	f.close();
	StringSource ( string(QString(dat).data()), true, new Base64Encoder(new StringSink(msg))); 
	Smtp *smtp = new Smtp( textFrom->text(), textTo->text(),
		textSubject->text(),
		QString(msg.data()), fileName );
}

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Smtp::Smtp( const QString &from, const QString &to,
		const QString &subject,
		const QString &body, const QString &fileName)
	{
		address = QString::fromLatin1( "From: " ) + from +
	 		 QString::fromLatin1( "\nTo: " ) + to +
	 		 QString::fromLatin1( "\nSubject: " ) + subject + "\n";
 
	 	message = QString::fromLatin1( "\n\n" ) + body + "\n";
 
	 	/*replace( message, QString::fromLatin1( "\n" ),
	 		 QString::fromLatin1( "\r\n" ) );*/
	 	replace( message, QString::fromLatin1( "\r\n.\r\n" ),
	 		 QString::fromLatin1( "\r\n..\r\n" ) );
	 	replace( address, QString::fromLatin1( "\n" ),
	 		 QString::fromLatin1( "\r\n" ) );
	 	replace( address, QString::fromLatin1( "\r\n.\r\n" ),
	 		 QString::fromLatin1( "\r\n..\r\n" ) );
	}

Smtp::Smtp( const QString &from, const QString &to,
		const QString &subject,
		const QString &body, const QString &fileName)
	{
		address = QString::fromLatin1( "From: " ) + from +
	 		 QString::fromLatin1( "\nTo: " ) + to +
	 		 QString::fromLatin1( "\nSubject: " ) + subject + "\n";
	
	 	message = QString::fromLatin1( "\n\n" ) + body + "\n";
	 
	 	/*replace( message, QString::fromLatin1( "\n" ),
	 		 QString::fromLatin1( "\r\n" ) );*/
	 	replace( message, QString::fromLatin1( "\r\n.\r\n" ),
	 		 QString::fromLatin1( "\r\n..\r\n" ) );
	 	replace( address, QString::fromLatin1( "\n" ),
	 		 QString::fromLatin1( "\r\n" ) );
	 	replace( address, QString::fromLatin1( "\r\n.\r\n" ),
	 		 QString::fromLatin1( "\r\n..\r\n" ) );
	}

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//Receiving message------>

int SysupClass::openFile( const char* infile )
{
	QByteArray dat;
       	QFile f ( infile );
      	if ( f.open (IO_ReadOnly) )
      	{   
        	  // file opened successfully   
          	dat = f.readAll();
      	} 
	else 
	{
		f.close();
		return -1;
	}
	f.close();
 
	//Here I might not be correct to reverse the operation
	//i.e removing \r\n..\r\n 	
	/*QString ss = dat;
	replace( ss, QString::fromLatin1( "\r\n..\r\n" ),
                     QString::fromLatin1( "\r\n.\r\n" ) );*/
 
	QFile f1 ( strcat(infile, ".mod") );
	if ( f1.open (IO_WriteOnly|IO_Truncate) )
		{
		// file opened successfully
		f1.writeBlock(ss, ss.length());
		}
	f1.close();
 
	//decrypt the file with AES::CBC mode
}

int SysupClass::openFile( const char* infile )
{
	QByteArray dat;
       	QFile f ( infile );
      	if ( f.open (IO_ReadOnly) )
      	{   
        	  // file opened successfully   
          	dat = f.readAll();
      	} 
	else 
	{
		f.close();
		return -1;
	}
	f.close();
	
	//Here I might not be correct to reverse the operation
	//i.e removing \r\n..\r\n 	
	/*QString ss = dat;
	replace( ss, QString::fromLatin1( "\r\n..\r\n" ),
                     QString::fromLatin1( "\r\n.\r\n" ) );*/

	QFile f1 ( strcat(infile, ".mod") );
	if ( f1.open (IO_WriteOnly|IO_Truncate) )
		{
		// file opened successfully
		f1.writeBlock(ss, ss.length());
		}
	f1.close();

	//decrypt the file with AES::CBC mode
}

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wysota--->
I'm unable to understand these points
3. divide it into blocks 64 (or 80 or whatever) bytes each ---- need some more explanation
4. concatenate blocks using newlines (\r\n) ----- ---- need some more explanation
5. pass the result into the mail stream adding a base64 header --------- ---- need some more explanations
If possible please correct me with my code above and tell me how can I achieve the above three points