This paper presents a low power boost converter for thermoelectric energy harvesting that demonstrates an efficiency that is 15% higher than the state-of-the-art for voltage conversion ratios above 20. This is achieved by utilizing a technique allowing synchronous rectification in the discontinuous conduction mode. A low-power method for input voltage monitoring is presented. The low input voltage requirements allow operation from a thermoelectric generator powered by body heat. The converter, fabricated in a 0.13 μm CMOS process, operates from input voltages ranging from 20 mV to 250 mV while supplying a regulated 1 V output. The converter consumes 1.6 (1.1) μW of quiescent power, delivers up to 25 (175) μW of output power, and is 46 (75)% efficient for a 20 mV and 100 mV input, respectively.

A 20 mV Input Boost Converter With Efficient Digital Control for Thermoelectric Energy Harvesting

Nowadays, there is a trend to design complex, yet secure systems. In this context, the Trusted Execution Environment (TEE) was designed to enrich the previously defined trusted platforms. TEE is commonly known as an isolated processing environment in which applications can be securely executed irrespective of the rest of the system. However, TEE still lacks a precise definition as well as representative building blocks that systematize its design. Existing definitions of TEE are largely inconsistent and unspecific, which leads to confusion in the use of the term and its differentiation from related concepts, such as secure execution environment (SEE). In this paper, we propose a precise definition of TEE and analyze its core properties. Furthermore, we discuss important concepts related to TEE, such as trust and formal verification. We give a short survey on the existing academic and industrial ARM TrustZone-based TEE, and compare them using our proposed definition. Finally, we discuss some known attacks on deployed TEE as well as its wide use to guarantee security in diverse applications.

https://hal.archives-ouvertes.fr/hal-01246364/document

Trusted Execution Environment: What It is, and What It is Not

A system, apparatus, method, and machine readable medium are described for performing advanced authentication techniques and associated applications. For example, one embodiment of a method comprises: receiving a policy identifying a set of acceptable authentication capabilities; determining a set of client authentication capabilities; and filtering the set of acceptable authentication capabilities based on the determined set of client authentication capabilities to arrive at a filtered set of one or more authentication capabilities for authenticating a user of the client.

Advanced authentication techniques and applications

Wireless Sensor Networks (WSNs) constitute one of the most promising third-millennium technologies and have wide range of applications in our surrounding environment. The reason behind the vast adoption of WSNs in various applications is that they have tremendously appealing features, e.g., low production cost, low installation cost, unattended network operation, autonomous and longtime operation. WSNs have started to merge with the Internet of Things (IoT) through the introduction of Internet access capability in sensor nodes and sensing ability in Internet-connected devices. Thereby, the IoT is providing access to huge amount of data, collected by the WSNs, over the Internet. Hence, the security of IoT should start with foremost securing WSNs ahead of the other components. However, owing to the absence of a physical line-of-defense, i.e., there is no dedicated infrastructure such as gateways to watch and observe the flowing information in the network, security of WSNs along with IoT is of a big concern to the scientific community. More specifically, for the application areas in which CIA (confidentiality, integrity, availability) has prime importance, WSNs and emerging IoT technology might constitute an open avenue for the attackers. Besides, recent integration and collaboration of WSNs with IoT will open new challenges and problems in terms of security. Hence, this would be a nightmare for the individuals using these systems as well as the security administrators who are managing those networks. Therefore, a detailed review of security attacks towards WSNs and IoT, along with the techniques for prevention, detection, and mitigation of those attacks are provided in this paper. In this text, attacks are categorized and treated into mainly two parts, most or all types of attacks towards WSNs and IoT are investigated under that umbrella: “Passive Attacks” and “Active Attacks”. Understanding these attacks and their associated defense mechanisms will help paving a secure path towards the proliferation and public acceptance of IoT technology.

/pdf/security-of-the-internet-of-things-vulnerabilities-attacks-5f8nyperis.pdf

Security of the Internet of Things: Vulnerabilities, Attacks, and Countermeasures

Device-to-device (D2D) communication presents a new paradigm in mobile networking to facilitate data exchange between physically proximate devices. The development of D2D is driven by mobile operators to harvest short range communications for improving network performance and supporting proximity-based services. In this paper, we investigate two fundamental and interrelated aspects of D2D communication, security and privacy, which are essential for the adoption and deployment of D2D. We present an extensive review of the state-of-the-art solutions for enhancing security and privacy in D2D communication. By summarizing the challenges, requirements, and features of different proposals, we identify lessons to be learned from existing studies and derive a set of “best practices.” The primary goal of our work is to equip researchers and developers with a better understanding of the underlying problems and the potential solutions for D2D security and privacy. To inspire follow-up research, we identify open problems and highlight future directions with regard to system and communication design. To the best of our knowledge, this is the first comprehensive review to address the fundamental security and privacy issues in D2D communication.

Security and Privacy in Device-to-Device (D2D) Communication: A Review

One of the promising usages of Physically Unclonable Functions (PUFs) is to generate cryptographic keys from PUFs for secure storage of key material. This usage has attractive properties such as physical unclonability and enhanced resistance against hardware attacks. In order to extract a reliable cryptographic key from a noisy PUF response a fuzzy extractor is used to convert non-uniform random PUF responses into nearly uniform randomness. Bosch et al. in 2008 proposed a fuzzy extractor suitable for efficient hardware implementation using two-stage concatenated codes, where the inner stage is a conventional error correcting code and the outer stage is a repetition code. In this paper we show that the combination of PUFs with repetition code approaches is not without risk and must be approached carefully. For example, PUFs with min-entropy lower than 66% may yield zero leftover entropy in the generated key for some repetition code configurations. In addition, we find that many of the fuzzy extractor designs in the literature are too optimistic with respect to entropy estimation. For high security applications, we recommend a conservative estimation of entropy loss based on the theoretical work of fuzzy extractors and present parameters for generating 128-bit keys from memory based PUFs.

Entropy loss in PUF-based key generation schemes: The repetition code pitfall

Power side-channel attacks (PSCA), e.g. Differential Power Analysis (DPA) and Correlation Power Analysis (CPA), are major threats to the security of crypto engines in SoC platforms. Circuit-level SCA countermeasures to achieve data-independent supply current patterns via implementation of crypto engines using non-conventional logic (complemented [1] or charge recovery [2]) and local switched-capacitor-based supply current equalization [3] have been demonstrated. The feasibility of using bandwidth-limited integrated low dropout regulators, multi-phase switched-capacitor VRs with phase-randomization and integrated inductive voltage regulators (IVR) to enhance PSCA resistance have been explored before via simulation studies [4]. In this paper, we demonstrate improved PSCA resistance offered by an on-die all-digital high-frequency IVR in 130nm CMOS [5] for a standard (unprotected) 128b Advanced Encryption Standard (AES) core designed in static CMOS logic. The IVR features a configurable digital proportional-integral-derivative (PID) controller, a digital discontinuous conduction mode (DCM) controller, and a loop randomization (LR) block, all of which are utilized to enhance PSCA resistance with minimal power/performance/area overheads, while maintaining adequate local voltage regulation and transient performance.

8.1 Improved power-side-channel-attack resistance of an AES-128 core via a security-aware integrated buck voltage regulator

This paper demonstrates the improved power and electromagnetic (EM) side-channel attack (SCA) resistance of 128-bit Advanced Encryption Standard (AES) engines in 130-nm CMOS using random fast voltage dithering (RFVD) enabled by integrated voltage regulator (IVR) with the bond-wire inductors and an on-chip all-digital clock modulation (ADCM) circuit. RFVD scheme transforms the current signatures with random variations in AES input supply while adding random shifts in the clock edges in the presence of global and local supply noises. The measured power signatures at the supply node of the AES engines show upto 37 $\times $ reduction in peak for higher order test vector leakage assessment (TVLA) metric and upto 692 $\times $ increase in minimum traces required to disclose (MTD) the secret encryption key with correlation power analysis (CPA). Similarly, SCA on the measured EM signatures from the chip demonstrates a reduction of upto 11.3 $\times $ in TVLA peak and upto 37 $\times $ increase in correlation EM analysis (CEMA) MTD.

Improved Power/EM Side-Channel Attack Resistance of 128-Bit AES Engines With Random Fast Voltage Dithering

Trusted computing technologies for mobile devices have been researched, developed, and deployed over the past decade. Although their use has been limited so far, ongoing standardization may change this by opening up these technologies for easy access by developers and users. In this survey, we describe the current state of trusted computing solutions for mobile devices from research, standardization, and deployment perspectives.

Mobile Trusted Computing

This paper demonstrates an integrated inductive voltage regulator (IVR) for improving power side-channel-attack (PSCA) resistance of 128-bit Advanced Encryption Standard (AES-128) engines. An inductive IVR is shown to transform the current signatures generated by an encryption engine. Furthermore, an all-digital circuit block, referred to as the loop-randomizer, is introduced to randomize the IVR transformations. A 130-nm test-chip with an inductive IVR with 11.6-nH inductance, 3.2-nF capacitance, and 125-MHz switching frequency is used to drive two different architectures of AES-128 engine: high performance and low power. The measurements demonstrate that the IVR with loop randomizer eliminates information leakage while incurring only 3% overhead in performance and 5% overhead in power over a baseline IVR-AES system. Moreover, while a key-byte can be extracted for the standalone high-performance and low-power AES (LP-AES) with only 5000 and 1000 measurements, respectively, the proposed IVR inhibits key extraction even with 500 000 measurements.

Anand Rajan

Papers

Entropy loss in PUF-based key generation schemes: The repetition code pitfall

8.1 Improved power-side-channel-attack resistance of an AES-128 core via a security-aware integrated buck voltage regulator

Improved Power/EM Side-Channel Attack Resistance of 128-Bit AES Engines With Random Fast Voltage Dithering

Mobile Trusted Computing

Reducing Power Side-Channel Information Leakage of AES Engines Using Fully Integrated Inductive Voltage Regulator