Add an extra level of security to your application with client side encryption. Even over an SSL connection, there are attacks which could expose your users' sensitive information. Using JSEncrypt, learn how to encrypt on the client side and decrypt on the server side.
Part of a good User Experience is making your application easy to use for your users. However, a few bad apples often cause a hinderance to your UX/UI by the addition of Captchas. Learn how to create invisible captchas to protect your forms while delivering a good UX.
Be default, Refile does not have a way to secure file downloads. It relies on a generated hash that is unknown to users unless the page renders that image or has a download to that file. This is okay sometimes, however, protecting the file from being downloaded for those who have the URL is a bit more involved.