Biblio
We introduce FairSwap – an efficient protocol for fair exchange of digital goods using smart contracts. A fair exchange protocol allows a sender S to sell a digital commodity x for a fixed price p to a receiver R. The protocol is said to be secure if R only pays if he receives the correct x. Our solution guarantees fairness by relying on smart contracts executed over decentralized cryptocurrencies, where the contract takes the role of an external judge that completes the exchange in case of disagreement. While in the past there have been several proposals for building fair exchange protocols over cryptocurrencies, our solution has two distinctive features that makes it particular attractive when users deal with large commodities. These advantages are: (1) minimizing the cost for running the smart contract on the blockchain, and (2) avoiding expensive cryptographic tools such as zero-knowledge proofs. In addition to our new protocols, we provide formal security definitions for smart contract based fair exchange, and prove security of our construction. Finally, we illustrate several applications of our basic protocol and evaluate practicality of our approach via a prototype implementation for fairly selling large files over the cryptocurrency Ethereum. This article is summarized in: the morning paper an interesting/influential/important paper from the world of CS every weekday morning, as selected by Adrian Colyer
Security against hardware trojans is currently becoming an essential ingredient to ensure trust in information systems. A variety of solutions have been introduced to reach this goal, ranging from reactive (i.e., detection-based) to preventive (i.e., trying to make the insertion of a trojan more difficult for the adversary). In this paper, we show how testing (which is a typical detection tool) can be used to state concrete security guarantees for preventive approaches to trojan-resilience. For this purpose, we build on and formalize two important previous works which introduced ``input scrambling" and ``split manufacturing" as countermeasures to hardware trojans. Using these ingredients, we present a generic compiler that can transform any circuit into a trojan-resilient one, for which we can state quantitative security guarantees on the number of correct executions of the circuit thanks to a new tool denoted as ``testing amplification". Compared to previous works, our threat model covers an extended range of hardware trojans while we stick with the goal of minimizing the number of honest elements in our transformed circuits. Since transformed circuits essentially correspond to redundant multiparty computations of the target functionality, they also allow reasonably efficient implementations, which can be further optimized if specialized to certain cryptographic primitives and security goals.
The most popular CAPTCHA service in use today is Google reCAPTCHA v2, whose main offering is an image-based CAPTCHA challenge. This paper looks into the security measures used in reCAPTCHA v2's image challenges and proposes a deep learning-based solution that can be used to automatically solve them. The proposed method is tested with both a custom object- detection deep learning model as well as Google's own Cloud Vision API, in conjunction with human mimicking mouse movements to bypass the challenges. The paper also suggests some potential defense measures to increase overall security and other additional attack directions for reCAPTCHA v2.
If you’re involved in cybersecurity as a software developer, forensic investigator, or network administrator, this practical guide shows you how to apply the scientific method when assessing techniques for protecting your information systems. You’ll learn how to conduct scientific experiments on everyday tools and procedures, whether you’re evaluating corporate security systems, testing your own security product, or looking for bugs in a mobile game.
Once author Josiah Dykstra gets you up to speed on the scientific method, he helps you focus on standalone, domain-specific topics, such as cryptography, malware analysis, and system security engineering. The latter chapters include practical case studies that demonstrate how to use available tools to conduct domain-specific scientific experiments.
- Learn the steps necessary to conduct scientific experiments in cybersecurity
- Explore fuzzing to test how your software handles various inputs
- Measure the performance of the Snort intrusion detection system
- Locate malicious “needles in a haystack” in your network and IT environment
- Evaluate cryptography design and application in IoT products
- Conduct an experiment to identify relationships between similar malware binaries
- Understand system-level security requirements for enterprise networks and web services
We consider the setting of HTTP traffic over encrypted tunnels, as used to conceal the identity of websites visited by a user. It is well known that traffic analysis (TA) attacks can accurately identify the website a user visits despite the use of encryption, and previous work has looked at specific attack/countermeasure pairings. We provide the first comprehensive analysis of general-purpose TA countermeasures. We show that nine known countermeasures are vulnerable to simple attacks that exploit coarse features of traffic (e.g., total time and bandwidth). The considered countermeasures include ones like those standardized by TLS, SSH, and IPsec, and even more complex ones like the traffic morphing scheme of Wright et al. As just one of our results, we show that despite the use of traffic morphing, one can use only total upstream and downstream bandwidth to identify – with 98% accuracy - which of two websites was visited. One implication of what we find is that, in the context of website identification, it is unlikely that bandwidth-efficient, general-purpose TA countermeasures can ever provide the type of security targeted in prior work.
The problem of privacy-preserving data analysis has a long history spanning multiple disciplines. As electronic data about individuals becomes increasingly detailed, and as technology enables ever more powerful collection and curation of these data, the need increases for a robust, meaningful, and mathematically rigorous definition of privacy, together with a computationally rich class of algorithms that satisfy this definition. Differential Privacy is such a definition.After motivating and discussing the meaning of differential privacy, the preponderance of this monograph is devoted to fundamental techniques for achieving differential privacy, and application of these techniques in creative combinations, using the query-release problem as an ongoing example. A key point is that, by rethinking the computational goal, one can often obtain far better results than would be achieved by methodically replacing each step of a non-private computation with a differentially private implementation. Despite some astonishingly powerful computational results, there are still fundamental limitations — not just on what can be achieved with differential privacy but on what can be achieved with any method that protects against a complete breakdown in privacy. Virtually all the algorithms discussed herein maintain differential privacy against adversaries of arbitrary computational power. Certain algorithms are computationally intensive, others are efficient. Computational complexity for the adversary and the algorithm are both discussed.We then turn from fundamentals to applications other than queryrelease, discussing differentially private methods for mechanism design and machine learning. The vast majority of the literature on differentially private algorithms considers a single, static, database that is subject to many analyses. Differential privacy in other models, including distributed databases and computations on data streams is discussed.Finally, we note that this work is meant as a thorough introduction to the problems and techniques of differential privacy, but is not intended to be an exhaustive survey — there is by now a vast amount of work in differential privacy, and we can cover only a small portion of it.
Despite bringing many benefits of global network configuration and control, Software Defined Networking (SDN) also presents potential challenges for both digital forensics and cybersecurity. In fact, there are various attacks targeting a range of vulnerabilities on vital elements of this paradigm such as controller, Northbound and Southbound interfaces. In addition to solutions of security enhancement, it is important to build mechanisms for digital forensics in SDN which provide the ability to investigate and evaluate the security of the whole network system. It should provide features of identifying, collecting and analyzing log files and detailed information about network devices and their traffic. However, upon penetrating a machine or device, hackers can edit, even delete log files to remove the evidences about their presence and actions in the system. In this case, securing log files with fine-grained access control in proper storage without any modification plays a crucial role in digital forensics and cybersecurity. This work proposes a blockchain-based approach to improve the security of log management in SDN for network forensics, called SDNLog-Foren. This model is also evaluated with different experiments to prove that it can help organizations keep sensitive log data of their network system in a secure way regardless of being compromised at some different components of SDN.
The outsourcing of portions of the integrated circuit design chain, mainly fabrication, to untrusted parties has led to an increasing concern regarding the security of fabricated ICs. To mitigate these concerns a number of approaches have been developed, including logic locking. The development of different logic locking methods has influenced research looking at different security evaluations, typically aimed at uncovering a secret key. In this paper, we make the case that corruptibility for incorrect keys is an important metric of logic locking. To measure corruptibility for circuits too large to exhaustively simulate, we describe an ATPG-based method to measure the corruptibility of incorrect keys. Results from applying the method to various circuits demonstrate that this method is effective at measuring the corruptibility for different locks.
Automotive systems have always been designed with safety in mind. In this regard, the functional safety standard, ISO 26262, was drafted with the intention of minimizing risk due to random hardware faults or systematic failure in design of electrical and electronic components of an automobile. However, growing complexity of a modern car has added another potential point of failure in the form of cyber or sensor attacks. Recently, researchers have demonstrated that vulnerability in vehicle's software or sensing units could enable them to remotely alter the intended operation of the vehicle. As such, in addition to safety, security should be considered as an important design goal. However, designing security solutions without the consideration of safety objectives could result in potential hazards. Consequently, in this paper we propose the notion of security for safety and show that by integrating safety conditions with our system-level security solution, which comprises of a modified Kalman filter and a Chi-squared detector, we can prevent potential hazards that could occur due to violation of safety objectives during an attack. Furthermore, with the help of a car-following case study, where the follower car is equipped with an adaptive-cruise control unit, we show that our proposed system-level security solution preserves the safety constraints and prevent collision between vehicle while under sensor attack.
Embedded systems must address a multitude of potentially conflicting design constraints such as resiliency, energy, heat, cost, performance, security, etc., all in the face of highly dynamic operational behaviors and environmental conditions. By incorporating elements of intelligence, the hope is that the resulting “smart” embedded systems will function correctly and within desired constraints in spite of highly dynamic changes in the applications and the environment, as well as in the underlying software/hardware platforms. Since terms related to “smartness” (e.g., self-awareness, self-adaptivity, and autonomy) have been used loosely in many software and hardware computing contexts, we first present a taxonomy of “self-x” terms and use this taxonomy to relate major “smart” software and hardware computing efforts. A major attribute for smart embedded systems is the notion of self-awareness that enables an embedded system to monitor its own state and behavior, as well as the external environment, so as to adapt intelligently. Toward this end, we use a System-on-Chip perspective to show how the CyberPhysical System-on-Chip (CPSoC) exemplar platform achieves self-awareness through a combination of cross-layer sensing, actuation, self-aware adaptations, and online learning. We conclude with some thoughts on open challenges and research directions.
For an action recognition system a decisive component is represented by the feature encoding part which builds the final representation that serves as input to a classifier. One of the shortcomings of the existing encoding approaches is the fact that they are built around hand-crafted features and they are not also highly competitive on encoding the current deep features, necessary in many practical scenarios. In this work we propose two solutions specifically designed for encoding local deep features, taking advantage of the nature of deep networks, focusing on capturing the highest feature response of the convolutional maps. The proposed approaches for deep feature encoding provide a solution to encapsulate the features extracted with a convolutional neural network over the entire video. In terms of accuracy our encodings outperform by a large margin the current most widely used and powerful encoding approaches, while being extremely efficient for the computational cost. Evaluated in the context of action recognition tasks, our pipeline obtains state-of-the-art results on three challenging datasets: HMDB51, UCF50 and UCF101.
Biometric authentication schemes are frequently used to establish the identity of a user. Often, a trusted hardware device is used to decide if a provided biometric feature is sufficiently close to the features stored by the legitimate user during enrollment. In this paper, we address the question whether the stored features can be extracted with side-channel attacks. We consider several models for types of leakage that are relevant specifically for fingerprint verification, and show results for attacks against the Bozorth3 and a custom matching algorithm. This work shows an interesting path for future research on the susceptibility of biometric algorithms towards side-channel attacks.
With the proliferation of WiFi-enabled devices, people expect to be able to use them everywhere, be it at work, while commuting, or when visiting friends. In the latter case, home owners are confronted with the burden of controlling the access to their WiFi router, and usually resort to simply sharing the password. Although convenient, this solution breaches basic security principles, and puts the burden on the friends who have to enter the password in each and every of their devices. The use of social networks, specifying the trust relations between people and devices, provides for a more secure and more friendly authentication mechanism. In this paper, we progress the state-of-the-art by abandoning the centralized solution to embed social networks in WiFi authentication; we introduce EAP-SocTLS, a decentralized approach for authentication and authorization of WiFi access points and other devices, exploiting the embedded trust relations. In particular, we address the (quadratic) search complexity when indirect trust relations, like the smartphone of a friend's kid, are involved. We show that the simple heuristic of limiting the search to friends and devices in physical proximity makes for a scalable solution. Our prototype implementation, which is based on WebID and EAP-TLS, uses WiFi probe requests to determine the pool of neighboring devices and was shown to reduce the search time from 1 minute for the naive policy down to 11 seconds in the case of granting access over an indirect friend.
Multimedia transmission in wireless multimedia sensor networks is often energy constraints. In practice the bit rate resulting from all the multimedia digitization formats are substantially larger than the bit rates of transmission channels that are available with the networks associated with these applications. For the purpose of efficient of storage and transmission of the content, the popular compression technique MPEG4/H.264 has been made used. To achieve better coding efficiency video streaming protocols MPEG4/H.264 uses several techniques which is increasing the complexity involved in computation at the encoder prominently for wireless sensor network devices having lesser power abilities. In this paper we propose energy consumption reduction framework for transmission in wireless networks so that well-balanced quality of service (QoS) in multimedia network can be maintained. The experiment result demonstrate that the effectiveness of the proposed approach in energy efficiency in wireless sensor network where the energy is the critical parameter.