Biblio

The contemporary IC supply chain depends heavily on third-party intellectual property (3PIP) that is integrated to in-house designs. As the correctness of such 3PIPs should be verified before integration, one important challenge for 3PIP vendors is proving the functionality of their designs while protecting the privacy of circuit implementations. In this work, we present Pythia that employs zero-knowledge proofs to enable vendors convince integrators about the functionality of a circuit without disclosing its netlist. Pythia automatically encodes netlists into zero knowledge-friendly format, evaluates them on different inputs, and proves correctness of outputs. We evaluate Pythia using the ISCAS'85 benchmark suite.

Sharding can significantly improve the blockchain scalability, by dividing nodes into small groups called shards that can handle transactions in parallel. However, all existing sharding systems adopt complete sharding, i.e., shards are isolated. It raises additional overhead to guarantee the atomicity and consistency of cross-shard transactions and seriously degrades the sharding performance. In this paper, we present Pyramid, the first layered sharding blockchain system, in which some shards can store the full records of multiple shards thus the cross-shard transactions can be processed and validated in these shards internally. When committing cross-shard transactions, to achieve consistency among the related shards, a layered sharding consensus based on the collaboration among several shards is presented. Compared with complete sharding in which each cross-shard transaction is split into multiple sub-transactions and cost multiple consensus rounds to commit, the layered sharding consensus can commit cross-shard transactions in one round. Furthermore, the security, scalability, and performance of layered sharding with different sharding structures are theoretically analyzed. Finally, we implement a prototype for Pyramid and its evaluation results illustrate that compared with the state-of-the-art complete sharding systems, Pyramid can improve the transaction throughput by 2.95 times in a system with 17 shards and 3500 nodes.

The vulnerability of islanded microgrids to voltage and frequency variations is due to the presence of low-inertia distributed generation (DG) units. Besides, the considerable difference between the inertia of synchronous-based and inverter-based DGs results in a power mismatch between generation and consumption during abnormal conditions. As a result, both voltage and frequency of microgrid ac-bus start oscillating which might lead to blackouts. This paper deploys the traditional controller of photovoltaic (PV) units to improve the dynamics of islanded microgrids by reducing the voltage and frequency deviations. To this end, an adaptive piecewise droop (APD) curve is presented and implemented in PV units to attain a faster balance between supply and demand during transients, leading to an enhanced frequency response. Besides, the reactive-power control loop is equipped with a droop characteristic which enables the PV units to inject/absorb reactive power during transients and participate in voltage-profile enhancement of the system. Case study results are presented using PSCAD/EMTDC to confirm the validity of proposed method in improving the dynamic behavior of islanded microgrids.

The goal of this work is to design cache coherence protocols with many cores that can be verified with state-of-the-art automated verification methodologies. In particular, we focus on flat (non-hierarchical) coherence protocols, and we use a mostly-automated methodology based on parametric verification (PV). We propose several design guidelines that architects should follow if they want to design protocols that can be parametrically verified. We experimentally evaluate performance, storage overhead, and scalability of a protocol verified with PV compared to a highly optimized protocol that cannot be verified with PV.

Routing security has a great importance to the security of Mobile Ad Hoc Networks (MANETs). There are various kinds of attacks when establishing routing path between source and destination. The adversaries attempt to deceive the source node and get the privilege of data transmission. Then they try to launch the malicious behaviors such as passive or active attacks. Due to the characteristics of the MANETs, e.g. dynamic topology, open medium, distributed cooperation, and constrained capability, it is difficult to verify the behavior of nodes and detect malicious nodes without revealing any privacy. In this paper, we present PVad, an approach conducting privacy-preserving verification in the routing discovery phase of MANETs. PVad tries to find the existing communication rules by association rules instead of making the rules. PVad consists of two phases, a reasoning phase deducing the expected log data of the peers, and a verification phase using Merkle Hash Tree to verify the correctness of derived information without revealing any privacy of nodes on expected routing paths. Without deploying any special nodes to assist the verification, PVad can detect multiple malicious nodes by itself. To show our approach can be used to guarantee the security of the MANETs, we conduct our experiments in NS3 as well as the real router environment, and we improved the detection accuracy by 4% on average compared to our former work.

Our proposal aims to help solving a trust problem between licensors and licensees that occurs during the active life of license agreements. We particularly focus on licensing of proprietary intellectual property (IP) that is embedded in Internet of Things (IoT) devices and services (e.g. patented technologies). To achieve this we propose to encode the logic of license agreements into smart licenses (SL). We define a SL as a `digital twin' of a licensing contract, i.e. one or more smart contracts that represent the full or relevant parts of a licensing agreement in machine readable and executable code. As SL are self enforcing, the royalty computation and execution of payments can be fully automated in a tamper free and trustworthy way. This of course, requires to employ a Distributed Ledger Technology (DLT). Such an Automated Licensing Payment System (ALPS) can thus automate an established business process and solve a longstanding trust issue in licensing markets. It renders traditional costly audits obsolete, lowers entry barriers for those who want to participate in licensing markets, and enables novel business models too complex with traditional approaches.

Some IoT data are time-sensitive and cannot be processed in clouds, which are too far away from IoT devices. Fog computing, located as close as possible to data sources at the edge of IoT systems, deals with this problem. Some IoT data are sensitive and require privacy controls. The proposed Policy Enforcement Fog Module (PEFM), running within a single fog, operates close to data sources connected to their fog, and enforces privacy policies for all sensitive IoT data generated by these data sources. PEFM distinguishes two kinds of fog data processing. First, fog nodes process data for local IoT applications, running within the local fog. All real-time data processing must be local to satisfy real-time constraints. Second, fog nodes disseminate data to nodes beyond the local fog (including remote fogs and clouds) for remote (and non-real-time) IoT applications. PEFM has two components for these two kinds of fog data processing. First, Local Policy Enforcement Module (LPEM), performs direct privacy policy enforcement for sensitive data accessed by local IoT applications. Second, Remote Policy Enforcement Module (RPEM), sets up a mechanism for indirectly enforcing privacy policies for sensitive data sent to remote IoT applications. RPEM is based on creating and disseminating Active Data Bundles-software constructs bundling inseparably sensitive data, their privacy policies, and an execution engine able to enforce privacy policies. To prove effectiveness and efficiency of the solution, we developed a proof-of-concept scenario for a smart home IoT application. We investigate privacy threats for sensitive IoT data and show a framework for using PEFM to overcome these threats.

Generic multi-button controllers are the most common input devices used for video games. In contrast, dedicated game controllers and gestural interactions increase immersion and playability. Room-sized gaming has opened up possibilities to further enhance the immersive experience, and provides players with opportunities to use full-body movements as input. We present a purpose-centric approach to appropriating everyday objects as physical game controllers, for immersive room-sized gaming. Virtual manipulations supported by such physical controllers mimic real-world function and usage. Doing so opens up new possibilities for interactions that flow seamlessly from the physical into the virtual world. As a proof-of-concept, we present a 'Tower Defence' styled game, that uses four everyday household objects as game controllers, each of which serves as a weapon to defend the base of the players from enemy bots. Players can use 1) a mop (or a broom) to sweep away enemy bots directionally; 2) a fan to scatter them away; 3) a vacuum cleaner to suck them; 4) a mouse trap to destroy them. Each controller is tracked using a motion capture system. A physics engine is integrated in the game, and ensures virtual objects act as though they are manipulated by the actual physical controller, thus providing players with a highly-immersive gaming experience.

Remote Attestation ( RA) is a security service that enables a trusted verifier ( Vrf) to measure current memory state of an untrusted remote prover ( Prv). If correctly implemented, RA allows Vrf to remotely detect if Prv's memory reflects a compromised state. However, RA by itself offers no means of remedying the situation once P rv is determined to be compromised. In this work we show how a secure RA architecture can be extended to enable important and useful security services for low-end embedded devices. In particular, we extend the formally verified RA architecture, VRASED, to implement provably secure software update, erasure, and system-wide resets. When (serially) composed, these features guarantee to Vrf that a remote Prv has been updated to a functional and malware-free state, and was properly initialized after such process. These services are provably secure against an adversary (represented by malware) that compromises Prv and exerts full control of its software state. Our results demonstrate that such services incur minimal additional overhead (0.4% extra hardware footprint, and 100-s milliseconds to generate combined proofs of update, erasure, and reset), making them practical even for the lowest-end embedded devices, e.g., those based on MSP430 or AVR ATMega micro-controller units (MCUs). All changes introduced by our new services to VRASED trusted components are also formally verified.

While the Internet of Things (IoT) is embraced as important tools for efficiency and productivity, it is becoming an increasingly attractive target for cybercriminals. This work represents the first endeavor to develop practical Puncturable Attribute Based Encryption schemes that are light-weight and applicable in IoTs. In the proposed scheme, the attribute-based encryption is adopted for fine grained access control. The secret keys are puncturable to revoke the decryption capability for selected messages, recipients, or time periods, thus protecting selected important messages even if the current key is compromised. In contrast to conventional forward encryption, a distinguishing merit of the proposed approach is that the recipients can update their keys by themselves without key re-issuing from the key distributor. It does not require frequent communications between IoT devices and the key distribution center, neither does it need deleting components to expunge existing keys to produce a new key. Moreover, we devise a novel approach which efficiently integrates attribute-based key and punctured keys such that the key size is roughly the same as that of the original attribute-based encryption. We prove the correctness of the proposed scheme and its security under the Decisional Bilinear Diffie-Hellman (DBDH) assumption. We also implement the proposed scheme on Raspberry Pi and observe that the computation efficiency of the proposed approach is comparable to the original attribute-based encryption. Both encryption and decryption can be completed within tens of milliseconds.

We present attacks that use only the volume of responses to range queries to reconstruct databases. Our focus is on practical attacks that work for large-scale databases with many values and records, without requiring assumptions on the data or query distributions. Our work improves on the previous state-of-the-art due to Kellaris et al. (CCS 2016) in all of these dimensions. Our main attack targets reconstruction of database counts and involves a novel graph-theoretic approach. It generally succeeds when R , the number of records, exceeds \$N2/2\$, where N is the number of possible values in the database. For a uniform query distribution, we show that it requires volume leakage from only O(N2 łog N) queries (cf. O(N4łog N) in prior work). We present two ancillary attacks. The first identifies the value of a new item added to a database using the volume leakage from fresh queries, in the setting where the adversary knows or has previously recovered the database counts. The second shows how to efficiently recover the ranges involved in queries in an online fashion, given an auxiliary distribution describing the database. Our attacks are all backed with mathematical analyses and extensive simulations using real data.

The MagNIF team at LLNL is developing a pulsed power platform to enable magnetized inertial confinement fusion and high energy density experiments at the National Ignition Facility. A pulsed solenoidal driver capable of premagnetizing fusion fuel to 40T is predicted to increase performance of indirect drive implosions. We have written a specialized Python code suite to support the delivery of a practical design optimized for target magnetization and risk mitigation. The code simulates pulsed power in parameterized system designs and converges to high-performance candidates compliant with evolving engineering constraints, such as scale, mass, diagnostic access, mechanical displacement, thermal energy deposition, facility standards, and component-specific failure modes. The physics resolution and associated computational costs of our code are intermediate between those of 0D circuit codes and 3D magnetohydrodynamic codes, to be predictive and support fast, parallel simulations in parameter space. Development of a reduced-order, physics-based target model is driven by high-resolution simulations in ALE3D (an institutional multiphysics code) and multi-diagnostic data from a commissioned pulser platform. Results indicate system performance is sensitive to transient target response, which should include magnetohydrodynamic expansion, resistive heating, nonlinear magnetic diffusion, and phase change. Design optimization results for a conceptual NIF platform are reported.

In this paper, we consider a stochastic model to evaluate the system availability of an intrusion tolerant system (ITS), where the system undergoes the patch management with a periodic vulnerability checking strategy, i.e., a pull-type patch management. Based on the model, this paper discusses the appropriate timing for patch applying. In particular, the paper models the attack behavior of adversary and the system behaviors under reactive defense strategies by a composite stochastic reward net (SRN). Furthermore, we formulate the interval availability by applying the phase-type (PH) approximation to solve the Markov regenerative process (MRGP) models derived from the SRNs. Numerical experiments are conducted to study the sensitivity of the system availability with respect to the number of checking.

This paper aims to address the security challenges on physical unclonable functions (PUFs) raised by modeling attacks and denial of service (DoS) attacks. We develop a hardware isolation-based secure architecture extension, namely PUFSec, to protect the target PUF from security compromises without modifying the internal PUF design. PUFSec achieves the security protection by physically isolating the PUF hardware and data from the attack surfaces accessible by the adversaries. Furthermore, we deploy strictly enforced security policies within PUFSec, which authenticate the incoming PUF challenges and prevent attackers from collecting sufficient PUF responses to issue modeling attacks or interfering with the PUF workflow to launch DoS attacks. We implement our PUFSec framework on a Xilinx SoC equipped with ARM processor. Our experimental results on the real hardware prove the enhanced security and the low performance and power overhead brought by PUFSec.

In the era of edge computing and Artificial Intelligence (AI), securing billions of edge devices within a network against intelligent attacks is crucial. We propose PUFGAN, an innovative machine learning attack-proof security architecture, by embedding a self-adversarial agent within a device fingerprint- based security primitive, public PUF (PPUF) known for its strong fingerprint-driven cryptography. The self-adversarial agent is implemented using Generative Adversarial Networks (GANs). The agent attempts to self-attack the system based on two GAN variants, vanilla GAN and conditional GAN. By turning the attacking quality through generating realistic secret keys used in the PPUF primitive into system vulnerability, the security architecture is able to monitor its internal vulnerability. If the vulnerability level reaches at a specific value, PUFGAN allows the system to restructure its underlying security primitive via feedback to the PPUF hardware, maintaining security entropy at as high a level as possible. We evaluated PUFGAN on three different machine environments: Google Colab, a desktop PC, and a Raspberry Pi 2, using a real-world PPUF dataset. Extensive experiments demonstrated that even a strong device fingerprint security primitive can become vulnerable, necessitating active restructuring of the current primitive, making the system resilient against extreme attacking environments.

Recently, it is predicted that interworking between heterogeneous devices will be accelerated due to the openness of the IoT (Internet of Things) platform, but various security threats are also expected to increase. However, most IoT open platforms remain at the level that utilizes existing security technologies. Therefore, a more secure security technology is required to prevent illegal copying and leakage of important data through stealing, theft, and hacking of IoT devices. In addition, a technique capable of ensuring interoperability with existing standard technologies is required. This paper proposes an IoT device authentication method based on PUF (Physical Unclonable Function) that operates on an IoT open platform. By utilizing PUF technology, the proposed method can effectively respond to the threat of exposure of the authentication key of the existing IoT open platform. Above all, the proposed method can contribute to compatibility and interoperability with existing technologies by providing a device authentication method that can be effectively applied to the OCF Iotivity standard specification, which is a representative IoT open platform.

With the increasing prevalent of digital devices and their abuse for digital content creation, forgeries of digital images and video footage are more rampant than ever. Digital forensics is challenged into seeking advanced technologies for forgery content detection and acquisition device identification. Unfortunately, existing solutions that address image tampering problems fail to identify the device that produces the images or footage while techniques that can identify the camera is incapable of locating the tampered content of its captured images. In this paper, a new perceptual data-device hash is proposed to locate maliciously tampered image regions and identify the source camera of the received image data as a non-repudiable attestation in digital forensics. The presented image may have been either tampered or gone through benign content preserving geometric transforms or image processing operations. The proposed image hash is generated by projecting the invariant image features into a physical unclonable function (PUF)-defined Bernoulli random space. The tamper-resistant random PUF response is unique for each camera and can only be generated upon triggered by a challenge, which is provided by the image acquisition timestamp. The proposed hash is evaluated on the modified CASIA database and CMOS image sensor-based PUF simulated using 180 nm TSMC technology. It achieves a high tamper detection rate of 95.42% with the regions of tampered content successfully located, a good authentication performance of above 98.5% against standard content-preserving manipulations, and 96.25% and 90.42%, respectively, for the more challenging geometric transformations of rotation (0 360°) and scaling (scale factor in each dimension: 0.5). It is demonstrated to be able to identify the source camera with 100% accuracy and is secure against attacks on PUF.

Along with the rapid development of hardware security techniques, the revolutionary growth of countermeasures or attacking methods developed by intelligent and adaptive adversaries have significantly complicated the ability to create secure hardware systems. Thus, there is a critical need to (re)evaluate existing or new hardware security techniques against these state-of-the-art attacking methods. With this in mind, this paper presents a novel framework for incorporating active learning techniques into hardware security field. We demonstrate that active learning can significantly improve the learning efficiency of physical unclonable function (PUF) modeling attack, which samples the least confident and the most informative challenge-response pair (CRP) for training in each iteration. For example, our experimental results show that in order to obtain a prediction error below 4%, 2790 CRPs are required in passive learning, while only 811 CRPs are required in active learning. The sampling strategies and detailed applications of PUF modeling attack under various environmental conditions are also discussed. When the environment is very noisy, active learning may sample a large number of mislabeled CRPs and hence result in high prediction error. We present two methods to mitigate the contradiction between informative and noisy CRPs.

Graph data publishing under node-differential privacy (node-DP) is challenging due to the huge sensitivity of queries. However, since a node in graph data oftentimes represents a person, node-DP is necessary to achieve personal data protection. In this paper, we investigate the problem of publishing the degree distribution of a graph under node-DP by exploring the projection approach to reduce the sensitivity. We propose two approaches based on aggregation and cumulative histogram to publish the degree distribution. The experiments demonstrate that our approaches greatly reduce the error of approximating the true degree distribution and have significant improvement over existing works. We also present the introspective analysis for understanding the factors of publishing the degree distribution with node-DP.

Cloud service providers offer storage outsourcing facility to their clients. In a secure cloud storage (SCS) protocol, the integrity of the client's data is maintained. In this work, we construct a publicly verifiable secure cloud storage protocol based on a secure network coding (SNC) protocol where the client can update the outsourced data as needed. To the best of our knowledge, our scheme is the first SNC-based SCS protocol for dynamic data that is secure in the standard model and provides privacy-preserving audits in a publicly verifiable setting. Furthermore, we discuss, in details, about the (im)possibility of providing a general construction of an efficient SCS protocol for dynamic data (DSCS protocol) from an arbitrary SNC protocol. In addition, we modify an existing DSCS scheme (DPDP I) in order to support privacy-preserving audits. We also compare our DSCS protocol with other SCS schemes (including the modified DPDP I scheme). Finally, we figure out some limitations of an SCS scheme constructed using an SNC protocol.

In public video surveillance, there is an inherent conflict between public safety goals and privacy needs of citizens. Generally, societies tend to decide on middleground solutions that sacrifice neither safety nor privacy goals completely. In this paper, we propose an alternative to existing approaches that rely on cloud-based video analysis. Our approach leverages the inherent geo-distribution of fog computing to preserve privacy of citizens while still supporting camera-based digital manhunts of law enforcement agencies.

Background: Bug datasets have been created and used by many researchers to build bug prediction models. Aims: In this work we collected existing public bug datasets and unified their contents. Method: We considered 5 public datasets which adhered to all of our criteria. We also downloaded the corresponding source code for each system in the datasets and performed their source code analysis to obtain a common set of source code metrics. This way we produced a unified bug dataset at class and file level that is suitable for further research (e.g. to be used in the building of new bug prediction models). Furthermore, we compared the metric definitions and values of the different bug datasets. Results: We found that (i) the same metric abbreviation can have different definitions or metrics calculated in the same way can have different names, (ii) in some cases different tools give different values even if the metric definitions coincide because (iii) one tool works on source code while the other calculates metrics on bytecode, or (iv) in several cases the downloaded source code contained more files which influenced the afferent metric values significantly. Conclusions: Apart from all these imprecisions, we think that having a common metric set can help in building better bug prediction models and deducing more general conclusions. We made the unified dataset publicly available for everyone. By using a public dataset as an input for different bug prediction related investigations, researchers can make their studies reproducible, thus able to be validated and verified.

Communication is an essential part of everyday life, both as a social interaction and collaboration to achieve goals. Wireless technology has effectively release the users to roam more freely to achieving collaboration and communication. The principle attraction of mobile ad hoc networks (MANET) are their set-up less and decentralized action. However, mobile ad hoc networks are seen as relatively easy targets for attackers. Security in mobile ad hoc network is provided by encrypting the data when exchanging messages and key management. Cryptography is therefore vital to ensure privacy of message and robustness against disruption. The proposed scheme public string based threshold cryptography (PSTC) describes the new scheme based on threshold cryptography that provides reasonably secure and robust cryptography scheme for mobile ad hoc networks. The scheme is implemented and simulated in ns-2. The scheme is based on trust value and analyze against Denial of Service attack as node found the attacker, the node reject all packet from that attacker. In proposed scheme whole network is compromised only when all nodes of network is compromised because threshold nodes only sharing public string not the master private key. The scheme provides confidentiality and integrity. The default threshold value selected is 2 according to time and space analysis.

A physical unclonable function (PUF) is an integrated circuit (IC) that serves as a hardware security primitive due to its complexity and the unpredictability between its outputs and the applied inputs. PUFs have received a great deal of research interest and significant commercial activity. Public PUFs (PPUFs) address the crucial PUF limitation of being a secret-key technology. To some extent, the first generation of PPUFs are similar to SIMulation Possible, but Laborious (SIMPL) systems and one-time hardware pads, and employ the time gap between direct execution and simulation. The second PPUF generation employs both process variation and device aging which results in matched devices that are excessively difficult to replicate. The third generation leaves the analog domain and employs reconfigurability and device aging to produce digital PPUFs. We survey representative PPUF architectures, related public protocols and trusted information flows, and related testing issues. We conclude by identifying the most important, challenging, and open PPUF-related problems.

The use of image data in multimedia communication based applications like military applications and medical images security applications are increasing every day and the secrecy of the image data is extremely important for such applications. A number of methods and techniques for securely transmitting images are proposed in the literature based on image encryption and steganography approaches. A novel mechanism for transmitting color images securely is proposed in this paper mainly based on public key cryptography mechanism also by combining the advantage of simplicity of symmetric schemes. The technique combines the strengths of Elliptic Curve Cryptography and the classical symmetric cryptographic mechanism called Hill Cipher encryption method. The technique also includes the concept of Magic Square for jumbling the pixels yielding maximum diffusion in the image pixels. In the performance evaluation, the proposed method proved that the new system works pretty well. The method is proved to be effective in maintaining the confidentiality of the image in transit and also for resisting security attacks.