I’m a big fan of OpenPGP. Not only do I use it to sign and encrypt e-mails but I also use it to sign and encrypt files that I upload to services such as Dropbox and Amazon S3. But mostly due to a lack of time I didn’t have much luck finding a decent iPhone app for OpenPGP. The main problem is that all of the OpenPGP apps aren’t free and I don’t like spending money unless I know I’m getting a good product. I finally decided to drop a whopping $1.99 and try the app that had the best reviews, iPGMail.
Due to the limitations of the iPhone, namely it doesn’t let you write plugins for other apps, iPGMail and other iOS OpenPGP solutions aren’t as slick as something like GPGTools. But iPGMail is as easy to use as you’re going to get. You can either copy the encrypted body content of an e-mail and paste it into iPGMail to decrypt it or, if the encrypted e-mail came in as an attachment (which is what I always do), you can tap and hold on the attachment icon and the option of opening it with iPGMail will appear. Additionally you can encrypt and upload or download and decrypt files from Dropbox, which is a feature I appreciate.
The app allows you to generate 4096-bit keypairs or, more importantly to me, import an already existing keypair. Because my e-mail server lies in my apartment I just e-mailed my keypair (in an encrypted format, of course). When I opened the e-mail on the iPhone and tap and held the attachment icon I was able to open it in iPGMail and import it.
I’m not saying that this app is the best thing since sliced bread because I haven’t had a lot of time to play with it. But so far I like what I see and it has done everything I’ve wanted in an OpenPGP app on my iPhone.