"Necessary keys are generated within the app so the private key never leaves the device"
Funny. With my email+PGP setup, my private key never even enters the device - https://grepular.com/An_NFC_PGP_SmartCard_For_Android
Funny. With my email+PGP setup, my private key never even enters the device - https://grepular.com/An_NFC_PGP_SmartCard_For_Android