Custom UI element and client side question

Hi, I’m currently developing a web application and evaluating Vaadin.
The framework looks great, I am working on convincing the development manager to pick it.

I have several questions:

  1. Maybe I haven’t looked around too well, but say I am using a Table (Grid) and I want some of the elements to have lines crossing the whole line and extending outside
    (something I guess will need a canvas-like feature) is it possible? Can I add a table on top of a canvas so I can “paint” whatever-I-want on the table?

  2. We will need to bring encrypted data from the server to the client, and the user will be providing a key to decrypt it, which will result the actual data needed to be rendered.
    How can it be done in Vaadin if Vaadin relies on the server so much.