The Secure Element is part of the NFC chip described in NFC and used to store the commands, signatures and cryptographic keys used in ApplePay transactions.
The programming interface is spread across the following binaries:
- /lib/exec/seld
- /usr/lib/libnfshared.dylib
Unlike the PN548 element - the commands for the secure element appear to be embedded in the seld daemon.
Communication to the secure element is performed through XPC calls to seld.