You’ll want to choose a very strong passphrase for this file, because anyone who has the file and can get your passphrase will be able to read your encrypted messages. First, you need to export your keypair from your desktop mail client into a PKCS#12 file. While it’s conceptually very simple to do so, keeping your keys secure requires some care. In order to read encrypted email on your phone, you naturally need to install your keypair on the device. A version for Android phones is now available in the Android Market. Our iPhone/iPad app is now available in the App store.
Our mobile SMIME reader apps enable us to read these messages securely on our devices. We can see that we’ve received an encrypted message, but can’t read the message until we return to a desktop machine with access to the appropriate keypair. One consistent annoyance we’ve found when we encrypt our messages, though, is that it reduces the usefulness of our mobile devices. We like to use encrypted email when we have sensitive conversations.
