sending encrypted data via mail using smtp

[vermarajeev]

This is what I was asking.
If you encode the data to base 64 before sending it.
Also, I asked if you tested this base 64 encoding/decoding locally.
Maybe you don't decode from base64 ok.
Regards

The decoding from base64 is taken care by smtp once I use

Content-Transfer-Encoding: base64

after the DATA tag used for smtp.

I imagine you cannot post the code, but are you sure there aren't any differences between plain files? Not even a byte?
Do you handle well SMTP transparency and the end of data message indicator?
Because a plain file might work even if you miss a byte, but an encoded file won't.

I can here is the small sample

void SynsupMail::sendMessage()
{
	QString message;
	string msg;
 
	QFile f ( textFilename->text() ); //textFilename->text() contains file path. The file can be en
									  //encrypted using AES::CBC or a plain text
	if ( f.open (IO_ReadOnly) )
		{
			// file opened successfully
			QTextStream t ( &f );
			// read the contents of the file into message
			while( ! t.eof() )
				{
				message += t.readLine();
				message += "\n";
				}
			f.close();		
 
			//encode the data using base64 using crypto++ library for Qt3, in Qt4
            //there is a function tobase64().			
			StringSource (string(message.data()), true, new Base64Encoder(new StringSink(msg))) ;		
 
			Smtp *smtp = new Smtp( textFrom->text(), textTo->text(), textSubject->text(),
			QString(msg.data()), fileName, );		
		}
}

void SynsupMail::sendMessage()
{
	QString message;
	string msg;
	
	QFile f ( textFilename->text() ); //textFilename->text() contains file path. The file can be en
									  //encrypted using AES::CBC or a plain text
	if ( f.open (IO_ReadOnly) )
		{
			// file opened successfully
			QTextStream t ( &f );
			// read the contents of the file into message
			while( ! t.eof() )
				{
				message += t.readLine();
				message += "\n";
				}
			f.close();		
			
			//encode the data using base64 using crypto++ library for Qt3, in Qt4
            //there is a function tobase64().			
			StringSource (string(message.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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All the code in smtp.cpp is same as that of /examples/network/mail except this
else if in function void Smtp::readyRead(). I made this modification to
send the file as an attachment

else if ( state == Body && responseLine[0] == '3' )
	{
		 QString fileName("");
 		 QString version;
 		 version += QString("MIME-Version: 1.0\r\n");
 
 		 QString Header;
 		 Header += QString("Content-Type: multipart/mixed; ")  + 
		 QString("boundary=unique-boundary-1\r\n") ;	 		
 
 		 QString headerContent;
 		 headerContent += QString("--unique-boundary-1\r\n");
 		 headerContent += QString("Content-Type: application/octet-stream ") + QString("\r\n");
 
		 headerContent += QString("Content-Transfer-Encoding: base64\r\n");
 		 headerContent += QString("Content-Disposition: attachment;") + 
		 QString( "filename=" ) + _fileName ;
 
		 //t is QTextStream	
		 *t << version;		 
		 *t << address;
 		 *t << Header;
 		 *t << headerContent;		 		 
 
 		 *t << message; 
 		 QString closeTag;
 		 closeTag += QString("--unique-boundary-1--\r\n");
 
 		 *t << closeTag << ".\r\n";	
		 state = Quit;
	}

else if ( state == Body && responseLine[0] == '3' )
	{
		 QString fileName("");
 		 QString version;
 		 version += QString("MIME-Version: 1.0\r\n");
		 		 
 		 QString Header;
 		 Header += QString("Content-Type: multipart/mixed; ")  + 
		 QString("boundary=unique-boundary-1\r\n") ;	 		
		 		 		 		 
 		 QString headerContent;
 		 headerContent += QString("--unique-boundary-1\r\n");
 		 headerContent += QString("Content-Type: application/octet-stream ") + QString("\r\n");

		 headerContent += QString("Content-Transfer-Encoding: base64\r\n");
 		 headerContent += QString("Content-Disposition: attachment;") + 
		 QString( "filename=" ) + _fileName ;

		 //t is QTextStream	
		 *t << version;		 
		 *t << address;
 		 *t << Header;
 		 *t << headerContent;		 		 
		 		 
 		 *t << message; 
 		 QString closeTag;
 		 closeTag += QString("--unique-boundary-1--\r\n");

 		 *t << closeTag << ".\r\n";	
		 state = Quit;
	}

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These are the things that happen,
Plain text file--->

plaintext file --> Encoding base64 --> Over N/w --> SMTP decodes base64 --> plaintext file to receiver

Encrypted file (encrypted with AES::CBC)--->

Encrypted file --> Encoding base64 --> Over N/w --> SMTP decodes base64 --> Encrypted file

M i doing anything wrong above ?