Resilient Control for Networked Control Systems Subject to Cyber/Physical Attacks

In this paper, we investigate a resilient control strategy for networked control systems（NCSs） subject to zero dynamic attacks which are stealthy false-data injection attacks that are designed so that they cannot be detected based on control input and measurement data. Cyber resilience represents the ability of systems or network architectures to continue providing their intended behavior during attack and recovery. When a cyber attack on the control signal of a networked control system is computed to remain undetectable from passive model-based fault detection and isolation schemes, we show that the consequence of a zero dynamic attack on the state variable of the plant is undetectable during attack but it becomes apparent after the end of the attack. A resilient linear quadratic Gaussian controller, having the ability to quickly recover the nominal behavior of the closed-loop system after the attack end, is designed by updating online the Kalman filter from information given by an active version of the generalized likelihood ratio detector.

Security strategy of powered-off SRAM for resisting physical attack to data remanence

This paper presents a security strategy for resisting a physical attack utilizing data remanence in powered- off static random access memory （SRAM）. Based on the mechanism of physical attack to data remanence, the strategy intends to erase data remanence in memory cells once the power supply is removed, which disturbs attackers trying to steal the right information. Novel on-chip secure circuits including secure power supply and erase transistor are integrated into conventional SRAM to realize erase operation. Implemented in 0.25μm Huahong-NEC CMOS technology, an SRAM exploiting the proposed security strategy shows the erase operation is accomplished within 0.2 μs and data remanence is successfully eliminated. Compared with conventional SRAM, the retentive time of data remanence is reduced by 82% while the operation power consumption only increases by 7%.

A Lightweight Certificate-Based Aggregate Signature Scheme Providing Key Insulation

Recently,with the advancement of Information and Communications Technology(ICT),Internet of Things(IoT)has been connected to the cloud and used in industrial sectors,medical environments,and smart grids.However,if data is transmitted in plain text when collecting data in an IoTcloud environment,it can be exposed to various security threats such as replay attacks and data forgery.Thus,digital signatures are required.Data integrity is ensured when a user(or a device)transmits data using a signature.In addition,the concept of data aggregation is important to efficiently collect data transmitted from multiple users(or a devices)in an industrial IoT environment.However,signatures based on pairing during aggregation compromise efficiency as the number of signatories increases.Aggregate signature methods(e.g.,identity-based and certificateless cryptography)have been studied.Both methods pose key escrow and key distribution problems.In order to solve these problems,the use of aggregate signatures in certificate-based cryptography is being studied,and studies to satisfy the prevention of forgery of signatures and other security problems are being conducted.In this paper,we propose a new lightweight signature scheme that uses a certificate-based aggregate signature and can generate and verify signed messages from IoT devices in an IoT-cloud environment.In this proposed method,by providing key insulation,security threats that occur when keys are exposed due to physical attacks such as side channels can be solved.This can be applied to create an environment in which data is collected safely and efficiently in IoT-cloud is environments.