I’ve been a big fan of the GPGTools suite for Mac for quite a while but I discovered some neat features when right-clicking on a file in Finder today. It’s a bit disappointing that I didn’t find these sooner!
Encrypting files is simple: just click OpenPGP: Encrypt File and a window will pop asking you which key you’d like to use for encryption. You also have the option of encrypting it with a password. Decrypting, signing, and validating files is easy and extremely fast. In addition, you’ll get Growl notifications upon success or failure.
GPGTools also integrates with Mail.app to allow for seamless signing, encrypting, decrypting and verification of email content. There’s a preview version available that integrates quite well with Mountain Lion’s Mail.app, but you can only acquire it via donation.