In the last decade, Remote Attestation (RA) emerged as a distinct security service for detecting attacks on embedded devices, cyber-physical systems (CPS) and Internet of Things (IoT) devices. RA involves verification of current internal state of an untrusted remote hardware platform (prover) by a trusted entity (verifier). RA can help the latter establish a static or dynamic root of trust in the prover and can also be used to construct other security services, such as software updates and secure deletion. Various RA techniques with different assumptions, security features and complexities, have been proposed for the single-prover scenario. However, the advent of IoT brought about the paradigm of many interconnected devices, thus triggering the need for efficient collective attestation of a (possibly mobile) group or swarm of provers. Though recent work has yielded some initial concepts for swarm attestation, several key issues remain unaddressed, and practical realizations have not been explored. This paper's main goal is to advance swarm attestation by bringing it closer to reality. To this end, it makes two contributions: (1) a new metric, called QoSA: Quality of Swarm Attestation, that captures the information offered by a swarm attestation technique; this allows comparing efficacy of multiple protocols, and (2) two practical attestation protocols -- called LISAa and LISAs -- for mobile swarms, with different QoSA features and communication and computation complexities. Security of proposed protocols is analyzed and their performance is assessed based on experiments with prototype implementations.

The recent advent of ubiquitous technologies has raised an important concern for citizens: the need to protect their privacy. So far, this wish was not heard of industrials, but national and international regulation authorities, as the European Commission recently published some guidelines to enforce customers' privacy in RFID systems: "Privacy by designâ is the way to be followed as stated in EC Recommendation of 12.5.2009. Research on privacy is an active domain but there is still a wide gap between theory and everyday life's applications. Filling this gap will require academia to design protocols and algorithms that fit the real-life constraints. In this paper, we provide a comprehensive analysis of privacy-friendly authentication protocols devoted to RFID that: 1) are based on well-established symmetric-key cryptographic building blocks; 2) require a reader complexity lower than O(N) where N is the number of provers in the system. These two properties are sine qua non conditions for deploying privacy-friendly authentication protocols in large-scale applications, for example, access control in mass transportation. We describe existing protocols fulfilling these requirements and point out their drawbacks and weaknesses. We especially introduce attacks on CHT, CTI,YA-TRAP*, and the variant of OSK/AO with mutual authentication. We also raise that some protocols, such as O-RAP, O-FRAP, and OSK/BF, are not resistant to timing attacks. Finally, we select some candidates that are, according to our criteria, the most appropriate ones for practical uses.

Remote Attestation (RA) is a popular means of detecting malware presence on embedded and IoT devices. It is especially relevant to low-end devices that are incapable of protecting themselves against infection. Malware that is aware of ongoing or impending RA and aims to avoid detection can relocate itself during computation of the attestation measurement. In order to thwart such behavior, prior RA techniques are either non-interruptible or explicitly forbid modification of storage during measurement computation. However, since the latter can be a time-consuming task, this curtails availability of device's other (main) functions, which is especially undesirable, or even dangerous, for devices with time-and/or safety-critical missions. In this paper, we propose SMARM, a light-weight technique, based on shuffled measurements, as a defense against roving malware. In SMARM, memory is measured in a randomized and secret order. This does not impact device's availability - the measurement process can be interrupted, even by malware, which can relocate itself at will. We analyze various malware behaviors and show that, while malware can escape detection in a single attestation instance, it is highly unlikely to avoid eventual detection.