Manuel Menghin

NIZE - a Near Field Communication interface enabling zero energy standby for everyday electronic devices

Standby power consumption of electric devices is a growing waste of energy. Between 5% and 14% of the residential electrical power consumption is caused by devices being in standby mode. Depending on the device type, more than 50% of standby power consumption could be saved by applying state-of-the-art power management techniques. By implementing a zero energy standby design and outsourcing power consuming user interfaces, even more electrical power can be saved. Here we present a novel Near Field Communication (NFC) interfacing method for everyday electronic devices. By implementing this interface, the target device can be shut down during idle times. Thus, standby power consumption is eliminated completely. If user interaction is requested, NFC provides the electrical energy to switch on the target devices power supply and to start the device. Furthermore, any control, status, and maintenance information can be transmitted over NFC. By outsourcing high power dissipating and unoptimized user interfaces (touch screens, WiFi, etc.) to the power optimized NFC reader, further energy savings are possible also during running state. This paper demonstrates the implementation and integration of this novel interfacing technique into common consumer electronics. Two implementation approaches are presented. A simple, energy harvesting-based approach illustrates the basic working principle. The second, more sophisticated approach, enables also authentication, encrypted data transfer, user interface outsourcing, configuration and control tasks, etc. A proof of concept is demonstrated by means of an access control terminal.

A Flexible and Lightweight ECC-Based Authentication Solution for Resource Constrained Systems

RFID-based and NFC-based applications can be found, apart from others, in security critical application fields, such as payment or access control. For this purpose, Elliptic-Curve Cryptography (ECC) is commonly used hardware integrated in resource constrained applications in order to provide authenticity and data integrity. On the one hand, specialized crypto hardware approaches provide good performance and consume low power. On the other hand, they often lack flexibility, caused, for example, by hardware integrated protocols and cryptographic parameters. Here we present a flexible and lightweight ECC-based authentication solution that takes into account resource constrained systems. This technique permits to shift parts of the computational intense ECC calculations from the resource constrained device to the authentication terminal. By employing a security controller with a small multi-purpose hardware acceleration core, high computation speed is achieved and a maximum level of flexibility is maintained at the same time. We demonstrate the feasible implementation of the proposed technique by means of an Android-based reader / smart card system, which represent a prime example of contemporary power-constrained and performance-constrained embedded systems. An ECC-based authentication can be carried out on average within 25 ms and checked against a back-end server within 66 ms in a secured manner. Thus, a secured and flexible one-way authentication system is given that shows high performance. This solution can be utilized in a wide variety of application fields, such as anti-counterfeiting, where flexibility and low chip prices are essential.

Emulation-Based Test and Verification of a Design's Functional, Performance, Power, and Supply Voltage Behavior

Test and verification are essential parts during a products development cycle. Simulation and emulation are well known techniques to test and verify the functionality of a design-under-test (DUT) before its tape-out. However, there are additional issues like peak power consumption and supply voltage drops, which can compromise a hardwares functionality. These issues are only partly covered by nowadays functional hardware emulation test and verification approaches. This paper presents a comprehensive emulation methodology. It combines functional hardware emulation with model-based performance, power, and supply voltage analysis techniques. The DUT, which has to be available in a hardware description language, is integrated into a FPGA along with designated analysis units. These analysis units implement models of the DUTs performance, power consumption, and supply voltage behavior. The presented emulation methodology allows a designer to test designs in such a way that the cycle accurate results are taken online, in real-time, and verify both functional and performance behavior, as well as power consumption and supply voltage levels. The proposed comprehensive emulation methodology is used, as an example of application, to verify the design of a LEON3 multi-core processor system as well as a RF-powered contacatless smart card. The depicted results demonstrate that this emulation approach is suitable to detect functional misbehavior caused by power and supply voltage hazards and how they influence the performance of the system.

Adaptive Field Strength Scaling: A Power Optimization Technique for Contactless Reader / Smart Card Systems

Many near field communication (NFC)-based reader / smart card applications are operated at a maximum magnetic field strength to increase the smart cards operational stability. However, a maximum magnetic field strength is worthwhile only in situations of high smart card power requirements (e.g., performing cryptographic operations) or long distance communications. As a result, electrical power is wasted, which limits the run-time of mobile battery-operated reader devices. Here we present an adaptive field strength scaling (AFSS) methodology. The strength of the readers emitted magnetic field is modified depending on the instantaneous power consumption requirements of the smart card. When the smart card consumes less power, the magnetic field strength is reduced. Whereas when it consumes more power, the magnetic field strength is increased. Thus, the power consumption of the reader / smart card system as a whole is optimized while preserving the smart cards operational stability. In this work, we present the design and implementation of two different AFSS approaches. A reader / smart card hardware emulation platform is used to prove the AFSS techniques feasibility and proper functionality. Experimental tests demonstrate that the energy consumption of the AFSS enhanced reader / smart card system can be reduced by up to 54% compared to current commonly used approaches. Furthermore, we show that the smart cards stability is preserved if the AFSS technique is applied.

NFC-DynFS: A way to realize dynamic field strength scaling during communication

Near Field Communication (NFC) shows potential in multiple areas like payment, identification, transport, etc. To enable these features to a larger group of users, NFC-capability is nowadays integrated in mobile devices like smart phones. This integration unfortunately leads to an increase of the devices battery drain because the transponder is powered by the provided magnetic field of the mobile device. To decrease this drain, power-management techniques like magnetic field strength scaling are used. Through this scaling the power transfer can be reduced to the transponders required level. The challenge of this technique is to dynamically adapt the magnetic field strength to physical relation changes of the transponder even during communication. Without this adaption, scaling down the field can lead to the transponders undersupply or energy is wasted through oversupply. This paper proposes a method, named NFC-DynFS, to realize this adaption and to proper scale the magnetic field strength. In a case study a system, to read digital business cards using NFC-DynFS, is simulated and implemented on real hardware. The power consumption results are evaluated and compared to implementations without NFC-DynFS. Furthermore, possible undersupplies of the transponder are investigated. It can be shown that, compared to implementations without field strength scaling, approximately 26% of the energy can be saved and an undersupply of the transponder can be avoided, until the readers power transmission limit is reached.

Emulation-Based Fault Effect Analysis for Resource Constrained, Secure, and Dependable Systems

Testing hardware and software components regarding their fault detection and fault handling capabilities is of vital importance. However, considering the fact that security systems are built using several distributed hardware components (e.g., reader/smart card authentication system), testing each component individually is insufficient. Because novel system-wide multi-fault attack campaigns can be conducted, fault propagation as well as fault handling of the entire system must be regarded. State-of-the-art emulation-based fault analysis approaches neglect this system aspect as well as the fault impact on power dissipation and power supply. Here, we present a novel analysis methodology that characterizes the behavior of complete systems during the design phase, in terms of fault handling, power dissipation, and power supply. Emulation-based techniques are applied to provide cycle accurate analysis information of the system-under-test in real time. The presented approach is of importance when it comes to test resource constrained, dependable, and high secure system designs. We demonstrate the application of this approach by means of a reader/smart card authentication system. Furthermore, we show how system level-based multi-fault attacks can be emulated and how the resulting system behavior (e.g., power consumption, power supply, information leakage) can be exploited to extract security relevant information.

PtNBridge -- A Power-Aware and Trustworthy Near Field Communication Bridge to Embedded Systems

More than 500 million Near Field Communication (NFC) devices will be delivered in 2014. This technology enables a lot of application fields like using it for bridges to embedded systems (e.g., smart meters). With this wireless bridge the user can interact with the embedded system using an off-the-shelf NFC-enabled smart phone. The user of such a bridge also trusts in the systems security. Furthermore, this security should not lead to an excessive battery drain of the smart phone nor the embedded system. This publication deals with these concerns and shows a method called PtNBridge. The method secures the whole communication path from the smart phone application to the accessed module in the embedded system (e.g., power sensor of the smart meter). To take account of the energy consumption, the PtNBridge has been analyzed and optimized to avoid an excessive battery drain. Two variants of the PtNBridge have been implemented, which aim for two different goals of power-aware security.

Emulation-based design evaluation of reader/smart card systems

Design exploration and evaluation are essential tasks during a products development cycle. Simulation and hardware emulation are common techniques to explore and evaluate the functionality of hardware/software designs. However, when it comes to distributed secure applications, like contactless reader/smart card systems, non-functional design properties and system aspects (e.g., conctactless power transfer, power consumption) have to be regarded too. State-of-the-art simulation-based and emulation-based design exploration tools cover these design issues and system aspects only to some extent. Here we present a design exploration framework for complete reader/smart card systems using state-of-the-art model-based emulation and estimation techniques. This novel system-based approach is of high importance because of the high availability of battery powered mobile readers (i.e. smart phones) and novel mobile application fields. Contactless power transfer and power consumption analyses of reader and smart cards can be performed for each clock cycle and in real time. Thus, novel system-level power and security optimization techniques can be evaluated considering the reader/smart card system as a whole. We demonstrate the application of our exploration framework by means of a typical Diffie-Hellman key exchange between reader and smart card and highlight power optimization possibilities.

Using field strength scaling to save energy in mobile HF-band RFID-systems

AbstractRadio frequency identification (RFID) is a technology enabling a contactless exchange of data. This technology features the possibility to wirelessly transfer power to the transponder (opponent). HF-RFID is used in mobile devices like smart phones and shows potential for applications like payment, identification, etc. Unfortunately, the needed functionality increases the battery drain of the device. As a countermeasure, power-management techniques are implemented. However, these techniques commonly do not consider the whole system, which also consists of the communication to the transponder, to prevent wasting energy. One cross-system technique of reducing the wasted energy is magnetic field strength scaling, which regulates the power transfer to the transponder. This article shows three investigations made, regarding field strength scaling to prevent this wastage of energy. The results of one investigation, how to use field strength scaling at card detection phase in form of the PTF-Determinator method, is described in detail. This method determines the Power Transfer Function (PTF) during run-time and scales the provided power accordingly to save energy. As a case study the PTF-Determinator is integrated in an application to read digital business cards. The resulting power consumption and timing has been evaluated by simulation and measurement of a development platform for mobile phones. Furthermore, the impact of field strength scaling to the energy consumption of a state of the art NFC-enhanced smart phone has been analyzed. The results of the case study shows that up to 26% less transmission energy (energy drain of NFC) is needed, if field strength scaling is applied (proofen by measurement). According to this result a smart phone’s battery drain (energy drain of the whole system) can be decreased by up to 13% by using field strength scaling for this case study.

Development Framework for Model Driven Architecture to Accomplish Power-Aware Embedded Systems

Developing an embedded system today means integrating a bundle of features into a constrained and complex system. Examples are Near Field Communication (NFC) handsets like smart phones, which will hit the 1.2billion mark in 2017. Model Driven Architecture (MDA) is an approach to handle this complexity. Challenges in MDA are the verification of power-requirements across the development phases and to find the suitable abstraction for the power models for higher abstraction levels. Therefore, we propose a framework for MDA to support cross-verification of these requirements. We implemented this framework and made a case study of developing a power-aware NFC-System. The case study shows that the framework allows a power-verification with an accuracy of 10%.