Gnu Privacy Guard remains geek ware, meaning that it is difficult to set up and use by an average Mac user. The learning curve for new users can be extremely steep with a lot of questions asked along the way. However, patience provides rich rewards because GPG lets you:
1) Digitally sign your email with a verified public key. This let's receivers verify that you, and only you, have sent them an email. This can be extremely important.
2) Use unbreakable encryption on any file and any email. You can even use overkill encryption if you wish to be especially careful. With in already incredible amount of cybercrime and cyber-espionage on the Internet, this can be profoundly important.
If you use the email features, keep in mind that encrypting email on your end requires the use of a source email address associated with your GPG key AS WELL AS a receiving email that ALSO has its own publicly available key. Otherwise, no encryption is allowed. However, digital signing is always available.
I have so far tested the current versions of GPGTools and GPGMail with OS X 10.7.5 and had total success. The new version of GPGMail provides support for OS X 10.8. I will be testing these current versions with 10.8.3 and 10.8.4 beta. If there are issues with either, I will post here in another message.
Installing GPGTools/GPGMail is extremely easy. The hard part begins when you have to create your first key, upload your public key to the public server, and begin to use its features. Never by stymied by the learning curve. All of the features work. It simply takes patience and time to figure them out and gain enough experience to be comfortable with them. Excellent documentation is now available. You'll find links to the docs at the end of the installation process. Read them carefully through, then use them step-by-step to get yourself going.
The effort put into creating GPGTools and keeping them compatible with ever changing OS X is slow and painstaking. Please appreciate these efforts by putting GPG to work for you and by donating to the open source project. GPG is entirely free for all Mac users and it works beautifully once you understand the geeky details involved. Thank you to everyone who contributes to this terrific and critical project!
If you are a USA citizen and need a reminder of what GPG is for, here is the 4th Amendment of the US Constitution:
"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."
Here is what Benjamin Franklin had to say about liberty and safety::
"They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety."