QSslSocket is an SSL-encrypted network socket class, from the Qt library
QSslSocket is a class in the qt library that provides a Secure Sockets Layer (ssl)-encrypted network socket. It is part of the QtNetwork module and was introduced in Qt 4.3. 
The most common way to use QSslSocket is to construct an object and start a secure connection by calling connectToHostEncrypted(). This method starts an immediate SSL handshake once the connection has been established.