[GPGTools is now compatible with Mavericks]. For those of you that don’t know what GPGTools is, it is the easiest way to setup encrypted email on your Mac. It installs two things:
1. A Mail.app plugin that allows you to toggle signing and encryption on a per-email basis with a couple of nice and easy to use buttons.
2. It installs a GPG Key manager app that helps you create an encryption key, and optionally send it to a key server for others to search.
Once you get this installed it is pretty easy to start sending secured emails. You will be prompted to enter your password to read/send encrypted emails, but that’s just about the hardest part. (The most confusing part is that you have to do a key exchange first, before you can send and receive encrypted emails. That’s why many people, including me, post their public keys on contact pages.)
They have a [nice screencast for new users here], and good [instructions to get setup here].
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