I just released 0.1.0 of CarrierWave_SecureFile – a gem for Rails to encrypt and decrypt file uploads and downloads using a Blowfish cypher. Requires Ruby 1.9, Rails 3.1 (though it should work on any version of Rails 3).
Check it out on RubyGems.org. Click the homepage link for the Git repo.
Enjoy!
A few stupid little bugs have been fixed. Use version 0.1.2 now. Thanks!