Objectives: Current techniques in brain stimulation are still largely based on a phrenologic approach that a single brain target can treat a brain disorder. Nevertheless, meta-analyses of brain implants indicate an overall success rate of 50% improvement in 50% of patients, irrespective of the brain-related disorder. Thus, there is still a large margin for improvement. The goal of this manuscript is to 1) develop a general theoretical framework of brain functioning that is amenable to surgical neuromodulation, and 2) describe the engineering requirements of the next generation of implantable brain stimulators that follow from this theoretic model. Materials and Methods: A neuroscience and engineering literature review was performed to develop a universal theoretical model of brain functioning and dysfunctioning amenable to surgical neuromodulation. Results: Even though a single target can modulate an entire network, research in network science reveals that many brain disorders are the consequence of maladaptive interactions among multiple networks rather than a single network. Consequently, targeting the main connector hubs of those multiple interacting networks involved in a brain disorder is theoretically more beneficial. We, thus, envision next-generation network implants that will rely on distributed, multisite neuromodulation targeting correlated and anticorrelated interacting brain networks, juxtaposing alternative implant configurations, and finally providing solid recommendations for the realization of such implants. In doing so, this study pinpoints the potential shortcomings of other similar efforts in the field, which somehow fall short of the requirements. Conclusion: The concept of network stimulation holds great promise as a universal approach for treating neurologic and psychiatric disorders.

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Next-generation personalized healthcare devices are undergoing extreme miniaturization in order to improve user acceptability. However, such developments make it difficult to incorporate cryptographic primitives using available target tech-nologies since these algorithms are notorious for their energy consumption. Besides, strengthening these schemes against side-channel attacks further adds to the device overheads. Therefore, viable alternatives among emerging technologies are being sought. In this work, we investigate the possibility of using memristors for implementing lightweight encryption. We propose a 40-nm RRAM-based GIFT-cipher implementation using a 1TIR configuration with promising results; it exhibits roughly half the energy consumption of a CMOS-only implementation. More importantly, its non-volatile and reconfigurable substitution boxes offer an energy-efficient protection mechanism against side-channel attacks. The complete cipher takes 0.0034 mm2of area, and encrypting a 128-bit block consumes a mere 242 pJ.@en

A Medical Body Area Network (MBAN) is an ensemble of collaborating, potentially heterogeneous, medical devices located inside, on the surface of or around the human body with the objective of tackling one or multiple medical conditions of the MBAN host. These devices-which are a special category of Wireless Body Area Networks (WBANs)–collect, process and transfer medical data outside of the network, while in some cases they also administer medical treatment autonomously. Since communication is so pivotal to their operation, the newfangled IEEE 802.15.6 standard is aimed at the communication aspects of WBANs. It places a set of physical and communication constraints while it also includes association/disassociation protocols and security services that WBAN applications need to comply with. However, the security specifications put forward by the standard can be easily shown to be insufficient when considering realistic MBAN use cases and need further enhancements. The present work addresses these shortcomings by, first, providing a structured analysis of the IEEE 802.15.6 security features and, afterwards, proposing comprehensive and tangible recommendations on improving the standard’s security.@en

Implantable Medical Devices (IMDs) belong to a class of highly life-critical, resource-constrained, deeply embedded systems out there. Their gradual conversion to wirelessly accessible devices in recent years has made them amenable to numerous successful ethical-hacking attempts. These attacks were made possible due to the absence of proper security provisions in IMDs. IMD manufacturers have only very recently started taking cybersecurity threats seriously, a move that will force development teams to overhaul IMD designs and grow sharper reflexes in an industry that has historically opted for small, careful steps. Thus, valid concerns arise regarding the technical feasibility but, chiefly, the economic viability of adding security to IMDs. In this work, we assess the economic repercussions of securing IMDs by employing the concept of technical debt (TD) on the evolving IMD software. Our quantitative analysis reveals that security-related costs are currently well in hand, however, security-code TD amasses faster and will eventually overtake medical-code TD. The economic viability of IMDs will, thus, be ensured only if security-development efforts are allocated significant resources within the next decade.

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Modern Implantable Medical Devices (IMDs) are vulnerable to security attacks because of their wireless connectivity to the outside world. One of the main security challenges is establishing trust between the IMD and an external reader/programmer in order to facilitate secure communication. Numerous device-pairing schemes have been proposed to address this specific challenge. However, they alone cannot protect against a battery-depletion attack in which the adversary is able to keep the IMD occupied with continuous authentication requests until the battery empties. As a result, energy harvesting has been employed as an ancillary mechanism for implementing Zero-Power Defense (ZPD) functionality in order to protect against such a low-cost attack. In this paper, we propose SecureEcho, a device-pairing scheme based on MHz-range ultrasound that establishes trust between the IMD and an external reader. In addition, SecureEcho achieves ZPD without requiring any energy harvesting, which significantly reduces the design complexity. We also provide a proof-of-concept implementation and a first ever security evaluation of the ultrasound channel, which proves that it is infeasible for the attacker to eavesdrop or insert messages even from a range of a few millimeters.

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The wireless capabilities of modern Implantable Medical Devices (IMDs) make them vulnerable to security attacks. One prominent attack, which has disastrous consequences for the patient’s wellbeing, is the battery Denial-of-Service attack whereby the IMD is occupied with continuous authentication requests from an adversary with the aim of depleting its battery. Zero-Power Defense (ZPD), based on energy harvesting, is known to be an excellent protection against these attacks. This paper raises essential design considerations for employing ZPD techniques in commercial IMDs, offers a critical review of ZPD techniques found in literature and, subsequently, gives crucial recommendations for developing comprehensive ZPD solutions.

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Over the past decade, focus on the security and privacy aspects of implantable medical devices (IMDs) has intensified, driven by the multitude of cybersecurity vulnerabilities found in various existing devices. However, due to their strict computational, energy and physical constraints, conventional security protocols are not directly applicable to IMDs. Custom-tailored schemes have been proposed instead which, however, fail to cover the full spectrum of security features that modern IMDs and their ecosystems so critically require. In this paper we propose IMDfence, a security protocol for IMD ecosystems that provides a comprehensive yet practical security portfolio, which includes availability, non-repudiation, access control, entity authentication, remote monitoring and system scalability. The protocol also allows emergency access that results in the graceful degradation of offered services without compromising security and patient safety. The performance of the security protocol as well as its feasibility and impact on modern IMDs are extensively analyzed and evaluated. We find that IMDfence achieves the above security requirements at a mere less than 7% increase in total IMD energy consumption, and less than 14 ms and 9 kB increase in system delay and memory footprint, respectively.

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Implantable Medical Devices (IMDs) such as pacemakers and neurostimulators are highly constrained in terms of energy. In addition, the wireless-communication facilities of these devices also impose security requirements considering their life-critical nature. However, security solutions that provide considerable coverage are generally considered to be too taxing on an IMD battery. Consequently, there has been a tendency to adopt ultra-lightweight security primitives for IMDs in literature. In this work, we demonstrate that the recent advances in embedded computing in fact enable the IMDs to use more mainstream security primitives, which do not need to compromise significantly on security for fear of impacting IMD autonomy.

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Modern Implantable Medical Devices (IMDs) feature wireless connectivity, which makes them vulnerable to security attacks. Particular to IMDs is the battery Denial-of-Service attack whereby attackers aim to fully deplete the battery by occupying the IMD with continuous authentication requests. Zero-Power Defense (ZPD) based on energy harvesting is known to be an excellent protection against these attacks. This paper establishes essential design specifications for employing ZPD techniques in IMDs, offers a critical review of ZPD techniques found in literature and, subsequently, gives crucial recommendations for developing comprehensive ZPD solutions.

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