YubiKey now has OpenPGP smartcard functionality. The new YubiKey NEO can even operate over NFC with OpenKeychain for Android. You can use K-9 and store your PGP

YubiKey now has OpenPGP smartcard functionality. The new YubiKey NEO can even operate over NFC with OpenKeychain for Android. You can use K-9 and store your PGP key on a physical token (the YubiKey). Quite useful if your threat model includes a compromised phone (e.g. malware) but not physical access (e.g. border crossings).