Now that Android supports Card Emulation on the Nexus 5 with Android 4.4, is it likely that some apps may become available that allow me to effectively duplicate a smartcard (e.g. Smart Card that opens doors in my office) and use my phone in their place?
Would be pretty handy.
Cheers!
No, this is not likely. Typically, copying/cloning arbitary cards using Android HCE is not possible.
Many access control systems use the card ID (UID) to identify the card (or even to make an access control desicion!). With Android HCE, an app cannot set the emulated card ID.
Many access control systems use cards/acces tokes that are not based on ISO 14443-4 (ISO-DEP) + ISO 7816-4 smartcard protocol. With Android HCE an app can only emulate smartcard applications that use ISO 7816-4 APDUs and application structure.
Even if the access control system does not use the card ID and uses an ISO 7816-4 smartcard application, it is very likely that the card contains some cryptographic secret (secret key) that cannot be extracted from the card through smartcard commands.
来源：https://stackoverflow.com/questions/21841875/host-card-emulation-android-4-4