When we talk about HCE methodology, many interacting architectural components come to mind. The core terms describing this architecture are listed below:
GCM/FCM (Google/Firebase Cloud Messaging): A service developed by Google that allows instant push notifications to be sent to users.
FCM is the new version of GCM under the Firebase brand.
Remote Payment: An HCE payment method used in place of NFC, based on dedicated payment switches.
WSP (Wallet Service Provider): The service provider that manages the HCE cloud.
Eligibility Check: The set of checks that validates whether a phone is suitable for the mobile payment application. For example, checking whether the phone is rooted is one such check.
HCE Library: The set of libraries that manages all the HCE functions required by the mobile payment application. Card emulation is performed in this library.
Whitebox Cryptography Library: A software-based library that creates a virtual secure element on the running operating system. It is the sub-application that provides the security of the mobile payment application.
LDE (Local Database Encrypted): The local database containing all the information required by the mobile payment application.
Cloud Communicator: The HCE sub-library that provides communication between the HCE Cloud and the mobile payment application (MPA).
HCE Library Interface: The HCE sub-library that manages the mobile payment application's interface.
SCK (Secure Channel Keys) (Mobile Keys): Symmetric keys used to create a secure channel between the MPA and the HCE cloud. They are stored in the LDE and the HCE cloud. They are initialized during HCE activation.
SUK (Single Usage Keys): The key set used to generate standard payment cryptograms. It is held in the MPA and may also be held in the HCE cloud.
Token: The specific data set generated for each HCE transaction.
Digitized Card: The digital version of any physical card, stored securely in the cloud or in a digital environment.
Handset: Simply means smartphone. For HCE purposes, it means a smartphone running Android 4.4 or higher.
