The best practice for any code base which runs on a user's computer is to publish it. This builds trust and encourages the creation of derivative works and improvements.
You can find the complete client source in .zip file format on this site. For links plus detailed instructions on how to build this source into a working client yourself, see this page. You can obtain the javadocs for the Silent-Vault client here.
Sources for the original Voucher-Safe client, and the current command line client (CLI) can be downloaded from the Voucher-Safe dev site. (Note that you'll need to register a login there in order to access the file galleries.) Although source for the Voucher-Safe server plugins is not yet published, you can download the API javadocs for them.