Look for secure microSD cards: they are smartcards with a microSD form factor and a couple of GB of normal flash storage. You can store private keys in there an

Look for secure microSD cards: they are smartcards with a microSD form factor and a couple of GB of normal flash storage. You can store private keys in there and negotiate certificates with a PKI server, resulting in a full-fledged S/MIME-compatible mail in your pocket. Take the card off: without your keys the BlackBerry cannot decrypt anything. Steal the phone unlocked: you have three attempts to guess the smartcard PIN. As far as I know, BlackBerry devices are the only mobile platform supporting such local hardware keystores natively. It has taken years for Apple to implement on iOS half of the crypto available in BlackBerry devices, and they are still knee-deep in badly implemented security. Android and Windows Mobile are not even trying.