As we discussed in Part 1 of this series, host card emulation (HCE) allows the transfer of information with near field communication (NFC) to happen between a terminal configured to exchange NFC radio information with an NFC card and a mobile device application configured to emulate the functional responses of an NFC card. HCE requires that the NFC protocol be routed to the main operating system of the mobile device instead of being routed to a local hardware-based secure element chip.
Here we look at exactly how HCE works from a technical perspective.
Host card emulation allows an application to emulate a card and talk directly to an NFC reader.
As explained on the Android developer site, when NFC card emulation is provided using the secure element, a user holds the device over an NFC terminal and the NFC controller in the device routes all data from the reader directly to the secure element (Figure 1). However, when an NFC card is emulated using host-based card emulation, the data is routed to the host CPU on which Android applications are running directly, instead of routing the NFC protocol frames to a secure element (Figure 2).
According to their website, Android 4.4 supports several NFC protocols that are common in the market today, including emulating cards that are based on the NFC-Forum ISO-DEP specification (based on ISO/IEC 14443-4) and process Application Protocol Data Units (APDUs) as defined in the ISO/IEC 7816-4 specification. Android mandates emulating ISO-DEP only on top of the Nfc-A (ISO/IEC 14443-3 Type A) technology. Support for Nfc-B (ISO/IEC 14443-4 Type B) technology is optional.
Although the mobile phone will still have to be NFC-enabled, with HCE support now coming prepackaged in Android 4.4. Anyone looking to deploy a payment system across multiple carriers will have a much easier solution to turn to.
Beyond the technical aspects, what are the real-world benefits of HCE?
The main benefit of HCE is that it is open source, allowing issuers (like banks and credit unions) and other payment providers to create NFC-enabled payment apps without needing permission from a mobile network operator (MNO) or dealing with complex trusted service managers (TSM). Managing payment credentials in the cloud will also be technically easier and less expensive. With an HCE-based solution, the complexity of managing the secure element, something that was hindering past NFC implementations, will no longer be an issue as the secure element will be in the cloud rather than part of the phone. With a software solution to the secure element, banks can offer cloud-based payments without the need to coordinate with individual carriers. This means an organization can implement payment services globally rather than through the MNO.
The benefits to retailers are also very big. For most, HCE will require no change to the existing acceptance infrastructure. The technology also does not need network connectivity at the time of payment unlike many cloud services. And because HCE will interrogate the processor rather than the SIM on the phone, transaction speeds will be faster.
While the roll-out of HCE applications are just in their infancy, the technology does seem to be very promising and is being heralded as a game changer in the NFC space.
About the Author:
Robert P. Sabella has 20+ years of legal and entrepreneurial experience and is considered one of the most innovative leaders in developing and bringing new technologies to market. He is the founder of the NFC Bootcamp™ training series and has recently co-founded the AccelerateNFC incubator program, dedicated to fostering start-ups in bringing NFC technology to the market. He is co-author of RFID+™ and a prolific writer and speaker on NFC and RFID.