Biblio

The secure Internet of Things (loT) increasingly relies on digital cryptographic signatures which require a private signature and public verification key. By their intrinsic nature, public keys are meant to be accessible to any interested party willing to verify a given signature. Thus, the storing of such keys is of great concern, since an adversary shall not be able to tamper with the public keys, e.g., on a local filesystem. Commonly used public-key infrastructures (PKIs), which handle the key distribution and storage, are not feasible in most use-cases, due to their resource intensity and high complexity. Thus, the general storing of the public verification keys is of notable interest for low-resource loT networks. By using the Distributed Ledger Technology (DLT), this paper proposes a decentralized concept for storing public signature verification keys in a tamper-resistant, secure, and resilient manner. By combining lightweight public-key exchange protocols with the proposed approach, the storing of verification keys becomes scalable and especially suitable for low-resource loT devices. This paper provides a Proof-of-Concept implementation of the DLT public-key store by extending our previously proposed NFC-Key Exchange (NFC-KE) protocol with a decentralized Hyperledger Fabric public-key store. The provided performance analysis shows that by using the decentralized keystore, the NFC- KE protocol gains an increased tamper resistance and overall system resilience while also showing expected performance degradations with a low real-world impact.

A tamper-resistant logical operation method based on integrated nanophotonics is proposed focusing on electromagnetic side-channel attacks. In the proposed method, only the phase of each optical signal is modulated depending on its logical state, which keeps the power of optical signals in optical logic circuits constant. This provides logic-gate-level tamper resistance which is difficult to achieve with CMOS circuits. An optical implementation method based on electronically-controlled phase shifters is then proposed. The electrical part of proposed circuits achieves 300 times less instantaneous current change, which is proportional to intensity of the leaked electromagnetic wave, than a CMOS logic gate.

Fueled by the emergence of IoT-enabled medical sensors and big data analytics, nations all over the world are widely adopting digitalization of healthcare systems. This is certainly a positive trend for improving the entire spectrum of quality of care, but this convenience is also posing a huge challenge on the security of healthcare data. For ensuring privacy and protection of healthcare data, access control is regarded as one of the first-line-of-defense mechanisms. As none of the traditional enterprise access control models can completely cater to the need of the healthcare domain which includes a myriad of contexts, in this paper, we present a context-policy-based access control scheme. Our scheme relies on the eTRON cybersecurity architecture for tamper-resistance and cryptographic functions, and leverages a context-specific blend of classical discretionary and role-based access models for incorporation into legacy systems. Moreover, our scheme adheres to key recommendations of prominent statutory and technical guidelines including HIPAA and HL7. The protocols involved in the proposed access control system have been delineated, and a proof-of-concept implementation has been carried out - along with a comparison with other systems, which clearly suggests that our approach is more responsive to different contexts for protecting healthcare data.

The characteristics of decentralization, tamper-resistance and transaction anonymity of blockchain can resolve effectively the problems in traditional intellectual property such as the difficulty of electronic obtaining for evidence, the high cost and low compensation when safeguarding the copyrights. Blockchain records the information through encryption algorithm, removes the third party, and stores the information in all nodes to prevent the information from being tampered with, so as to realize the protection of intellectual property. Starting from the bottom layer of blockchain, this paper expounds in detail the characteristics and the technical framework of blockchain. At the same time, according to the existing problems in transaction throughput, time delay and resource consumption of blockchain system, optimization mechanisms such as cross-chain and proof of stake are analyzed. Finally, combined with the characteristics of blockchain technology and existing application framework, this paper summarizes the existing problems in the industry and forecasts the development trend of intellectual property based on blockchain technology.

Data leakage and disclosure to attackers is a significant problem in embedded systems, considering the ability of attackers to get physical access to the systems. We present methods to protect memory data leakage in tamper-proof embedded systems. We present methods that exploit memory supply voltage manipulation to change the memory contents, leading to an operational and reusable memory or to destroy memory cell circuitry. For the case of memory data change, we present scenaria for data change to a known state and to a random state. The data change scenaria are effective against attackers who cannot detect the existence of the protection circuitry; furthermore, original data can be calculated in the case of data change to a known state, if the attacker identifies the protection circuitry and its operation. The methods that change memory contents to a random state or destroy memory cell circuitry lead to irreversible loss of the original data. However, since the known state can be used to calculate the original data.

Use of digital token - which certifies the bearer's rights to some kind of products or services - is quite common nowadays for its convenience, ease of use and cost-effectiveness. Many of such digital tokens, however, are produced with software alone, making them vulnerable to forgery, including alteration and duplication. For a more secure safeguard for both token owner's right and service provider's accountability, digital tokens should be tamper-resistant as much as possible in order for them to withstand physical attacks as well. In this paper, we present a rights management system that leverages tamper-resistant digital tokens created by hardware-software collaboration in our eTRON architecture. The system features the complete life cycle of a digital token from generation to storage and redemption. Additionally, it provides a secure mechanism for transfer of rights in a peer-to-peer manner over the Internet. The proposed system specifies protocols for permissible manipulation on digital tokens, and subsequently provides a set of APIs for seamless application development. Access privileges to the tokens are strictly defined and state-of-the-art asymmetric cryptography is used for ensuring their confidentiality. Apart from the digital tokens being physically tamper-resistant, the protocols involved in the system are proven to be secure against attacks. Furthermore, an authentication mechanism is implemented that invariably precedes any operation involving the digital token in question. The proposed system presents clear security gains compared to existing systems that do not take tamper-resistance into account, and schemes that use symmetric key cryptography.

This work deals with key generation based on Physically Obfuscated Keys (POKs), i.e., a certain type of tamper-evident Physical Unclonable Function (PUF) that can be used as protection against invasive physical attacks. To design a protected device, one must take attacks such as probing of data lines or penetration of the physical security boundary into consideration. For the implementation of a POK as a countermeasure, physical properties of a material – which covers all parts to be protected – are measured. After measuring these properties, i.e. analog values, they have to be quantized in order to derive a cryptographic key. This paper will present and discuss the impact of the quantization method with regard to three parameters: key quality, tamper-sensitivity, and reliability. Our contribution is the analysis of two different quantization schemes considering these parameters. Foremost, we propose a new approach to achieve improved tamper-sensitivity in the worst-case with no information leakage. We then analyze a previous solution and compare it to our scenario. Based on empirical data we demonstrate the advantages of our approach. This significantly improves the level of protection of a tamper-resistant cryptographic device compared to cases not benefiting from our scheme.

Although existing for decades, software tampering attack is still a main threat to systems, such as Android, and cyber physical systems. Many approaches have been proposed to thwart specific procedures of tampering, e.g., obfuscation and self-checksumming. However, none of them can achieve theoretically tamper-proof without the protection of hardware circuit. Rather than proposing new tricks against tampering attacks, we focus on impeding the replication of software tampering via program diversification, and thus pose a scalability barrier against the attacks. Our idea, namely N-version obfuscation (NVO), is to automatically generate and deliver same featured, but functionally nonequivalent software copies to different machines or users. In this paper, we investigate such an idea on Android platform. We carefully design a candidate NVO solution for networked apps, which leverages a Message Authentication Code (MAC) mechanism to generate the functionally nonequivalent diversities. Our evaluation result shows that the time required for breaking such a software system increases linearly with respect to the number of software versions. In this way, attackers would suffer great scalability issues, considering that an app can have millions of users. With minimal NVO costs, effective tamper-resistant security can therefore be established.

Intrusion detection has been an active field of research for more than 35 years. Numerous systems had been built based on the two fundamental detection principles, knowledge-based and behavior-based detection. Anyway, having a look at day-to-day news about data breaches and successful attacks, detection effectiveness is still limited. Even more, heavy-weight intrusion detection systems cannot be installed in every endangered environment. For example, Industrial Control Systems are typically utilized for decades, charging off huge investments of companies. Thus, some of these systems have been in operation for years, but were designed afore without security in mind. Even worse, as systems often have connections to other networks and even the Internet nowadays, an adequate protection is mandatory, but integrating intrusion detection can be extremely difficult - or even impossible to date. We propose a new lightweight current-based IDS which is using a difficult to manipulate measurement base and verifiable ground truth. Focus of our system is providing intrusion detection for ICS and SCADA on a low-priced base, easy to integrate. Dr. WATTson, a prototype implemented based on our concept provides high detection and low false alarm rates.