I know it's a silly question but ,
My client asked for encrypting some information form their payment system to prevent user stealing personal information. The system is web-base and written by ASP.NET
We have tried some annoying solution such as JavaScript no right-click or css-no-print but apparently my client didn't like it.
so are there any commercial solution to encrypt information in aspx produced html pages?
or someone can tell me how to pursuit my client to stop these "prevent stealing" idea in a web-base system?
If your client is worried about data being stolen "over-the-wire", do what Jaxidian mentioned and using SSL.
If your client is worried about users stealing data from pages they view, then tell them there's nothing they can do in a web app to stop that. Users need to download a page to view on their computers so no matter what you do, HTML web pages can always have their content downloaded by a user, even if you add some hoops to make it more difficult.
The only way to stop a user from stealing data from pages they view is to not make your app web-based. You'll have to write a native app that gets installed on users' machines with strict DRM in order to stop them from copying content. And even then, DRM can be cracked. Just look at Sony.
If your client was referring to encrypting data within your database, then you should look into AES Encryption in .NET.