Hiding real value of password field from server

Hi,
We are using vaadin in our project but the issue is that whenever value of a textfield (or any other component) is changed, it is sent to the server. Now what I need is to stop the value of the passwordField from being sent to server without encryption. In other words I need the http request to take encrypted value, not the real value of the password field to sync with server. 
How can i achieve that?