Have you tried to send a request, fetch the response from the network, decrypt it to an html file stored locally and then to load the local web page?

Is there any reason you’re not using SSL? I mean: it does exactly what you describe already, an a transparent way.

Yes SSL is a solution. But enryption is not the only task I’m looking to achieve. I even want to tamper the received data(append, remove or completely change the data).

I think you best bet is to subclass QNetworkAccessManager and QNetworkReply. In your subclass of QNAM, you reimplement the createRequest method to return your own subclass of QNetworkReply. Your custom reply class can manipulate the data as it streams in or just when it is read out.