How to encrypt Paypal button in Java

I'm looking for a good example/class that would take my certificates in argument, and generate the signed button to use for paypal.

I find that link https://www.paypal.com/us/cgi-bin/webscr?cmd=p/xcl/rec/ewp-code that contain a Java class using BouncyCastle, but when importing the new version of BouncyCastle, some part of the Paypal code are deprecated and I don't know how to change them.

I also find an alternative to开发者_如何学运维 BouncyCastle, Keyczar, but I can't find any example on how to encrypt the paypal button.

Thank you for your help!

I have written a button generator in Java for a project, you can find the code here.

It's also using bouncy castle, but it's a fairly recent version. It also uses velocity to generate the button code based on a template (included).