Biblio

We continue to tackle the problem of poorly defined security metrics by building on and improving our previous work on designing sound security metrics. We reformulate the previous method into a set of conditions that are clearer and more widely applicable for deriving sound security metrics. We also modify and enhance some concepts that led to an unforeseen weakness in the previous method that was subsequently found by users, thereby eliminating this weakness from the conditions. We present examples showing how the conditions can be used to obtain sound security metrics. To demonstrate the conditions' versatility, we apply them to show that an aggregate security metric made up of sound security metrics is also sound. This is useful where the use of an aggregate measure may be preferred, to more easily understand the security of a system.

Purpose: Determine the main theoretical aspects of managing the resilience of an industrial enterprise in conditions of uncertainty. Method: The static control methods include the technology of the matrix aggregate computer (MAC) and the R-lenses, and the dynamic control methods - the technology based on the 4x6 matrix model. All these methods are based on the results of the theory of fuzzy sets and soft computing. Result: A comparative analysis of the resilience of 82 largest industrial enterprises in five industry classes was carried out, R-lenses were constructed for these classes, and the main factors affecting the resilience of industrial companies were evaluated. Conclusions: The central problem points in assessing and ensuring the resilience of enterprises are: a) correct modeling of external disturbances; b) ensuring the statistical homogeneity of the source data array.

We propose an ideal functionality FCD and a construction ΠCD for oblivious and updatable committed databases. FCD allows a prover P to read, write, and update values in a database and to prove to a verifier V in zero-knowledge (ZK) that a value is read from or written into a certain position. The following properties must hold: (1) values stored in the database remain hidden from V; (2) a value read from a certain position is equal to the value previously written into that position; (3) (obliviousness) both the value read or written and its position remain hidden from V.ΠCD is based on vector commitments. After the initialization phase, the cost of read and write operations is independent of the database size, outperforming other techniques that achieve cost sublinear in the dataset size for prover and/or verifier. Therefore, our construction is especially appealing for large datasets. In existing “commit-and-prove” two-party protocols, the task of maintaining a committed database between P and V and reading and writing values into it is not separated from the task of proving statements about the values read or written. FCD allows us to improve modularity in protocol design by separating those tasks. In comparison to simply using a commitment scheme to maintain a committed database, FCD allows P to hide efficiently the positions read or written from V. Thanks to this property, we design protocols for e.g. privacy-preserving e-commerce and location-based services where V gathers aggregate statistics about the statements that P proves in ZK.

Recently, federated learning (FL), as an advanced and practical solution, has been applied to deal with privacy-preserving issues in distributed multi-party federated modeling. However, most existing FL methods focus on the same privacy-preserving budget while ignoring various privacy requirements of participants. In this paper, we for the first time propose an algorithm (PLU-FedOA) to optimize the deep neural network of horizontal FL with personalized local differential privacy. For such considerations, we design two approaches: PLU, which allows clients to upload local updates under differential privacy-preserving of personally selected privacy level, and FedOA, which helps the server aggregates local parameters with optimized weight in mixed privacy-preserving scenarios. Moreover, we theoretically analyze the effect on privacy and optimization of our approaches. Finally, we verify PLU-FedOA on real-world datasets.

Anomalous users detection in social network is an imperative task for security problems. Motivated by the great power of Graph Neural Networks(GNNs), many current researches adopt GNN-based detectors to reveal the anomalous users. However, the increasing scale of social activities, explosive growth of users and manifold technical disguise render the user detection a difficult task. In this paper, we propose an innovate Relevance-aware Anomalous Users Detection model (RAU-GNN) to obtain a fine-grained detection result. RAU-GNN first extracts multiple relations of all types of users in social network, including both benign and anomalous users, and accordingly constructs the multiple user relation graph. Secondly, we employ relevance-aware GNN framework to learn the hidden features of users, and discriminate the anomalous users after discriminating. Concretely, by integrating Graph Convolution Network(GCN) and Graph Attention Network(GAT), we design a GCN-based relation fusion layer to aggregate initial information from different relations, and a GAT-based embedding layer to obtain the high-level embeddings. Lastly, we feed the learned representations to the following GNN layer in order to consolidate the node embedding by aggregating the final users' embeddings. We conduct extensive experiment on real-world datasets. The experimental results show that our approach can achieve high accuracy for anomalous users detection.

Blockchain technology has gradually replaced traditional centralized data storage methods, and provided people reliable data storage services with its decentralized and non-tamperable features. However, the current blockchain data supervision is insufficient and the data cannot be modified once it is on the blockchain, which will cause the blockchain system to face various problems such as illegal information cannot be deleted and breach of smart contract cannot be fixed in time. To address these issues, we propose an anonymous editable blockchain scheme based on the reconstruction of the blockchain structure of the SpaceMint combining with the certificateless aggregate signature algorithm. Users register with their real identities and use pseudonyms in the system to achieve their anonymity. If the number of users who agree to edit meets the threshold, the data on the blockchain can be modified or deleted, and our scheme has the function of accountability for malicious behavior. The security analysis show that the proposed certificateless aggregate signature algorithm enjoys the unforgeability under the adaptive selected message attack. Moreover, the method of setting the threshold of related users is adopted to guarantee the effectiveness and security of editing blockchain data. At last, we evaluate the performance of our certificateless aggregate signature algorithm and related schemes in theoretical analysis and experimental simulation, which demonstrates our scheme is feasible and efficient in storage, bandwidth and computational cost.

Federated learning is a privacy-preserving learning system where participants locally update a shared model with their own training data. Despite the advantage that training data are not sent to a server, there is still a risk that a state-of-the-art model inversion attack, which may be conducted by the server, infers training data from the models updated by the participants, referred to as individual models. A solution to prevent such attacks is differential privacy, where each participant adds noise to the individual model before sending it to the server. Differential privacy, however, sacrifices the quality of the shared model in compensation for the fact that participants' training data are not leaked. This paper proposes a federated learning system that is resistant to model inversion attacks without sacrificing the quality of the shared model. The core idea is that each participant divides the individual model into model fragments, shuffles, and aggregates them to prevent adversaries from inferring training data. The other benefit of the proposed system is that the resulting shared model is identical to the shared model generated with the naive federated learning.

Smart substation and Vehicular Ad-Hoc Network (VANET) are two important applications of aggregate signature scheme. Due to the large number of data collection equipment in substation, it needs security authentication and integrity protection to transmit data. Similarly, in VANET, due to limited resources, it has the needs of privacy protection and improving computing efficiency. Aggregate signature scheme can satisfy the above these needs and realize one-time verification of signature for multi-terminal data collection which can improve the performance. Aggregate signature scheme is an important technology to solve network security problem. Recently, many aggregate signature schemes are proposed which can be applied in smart grid or VANET. In this paper, we present two security analyses on two aggregate signature schemes proposed recently. By analysis, it shows that the two aggregate signature schemes do not satisfy the security property of unforgeability. A malicious user can forge a signature on any message. We also present some improved methods to solve these security problems with better performance. From security analysis to improvement of aggregate signature scheme, it is very suitable to be an instance to exhibit the students on designing of security aggregate signature scheme for network security education or course.

The Internet of Things (IoT) is an evolving network of billions of interconnected physical objects, such as, numerous sensors, smartphones, wearables, and embedded devices. These physical objects, generally referred to as the smart objects, when deployed in real-world aggregates useful information from their surrounding environment. As-of-late, this notion of IoT has been extended to incorporate the social networking facets which have led to the promising paradigm of the `Social Internet of Things' (SIoT). In SIoT, the devices operate as an autonomous agent and provide an exchange of information and services discovery in an intelligent manner by establishing social relationships among them with respect to their owners. Trust plays an important role in establishing trustworthy relationships among the physical objects and reduces probable risks in the decision making process. In this paper, a trust computational model is proposed to extract individual trust features in a SIoT environment. Furthermore, a machine learning-based heuristic is used to aggregate all the trust features in order to ascertain an aggregate trust score. Simulation results illustrate that the proposed trust-based model isolates the trustworthy and untrustworthy nodes within the network in an efficient manner.

Distributed Denial of Service (DDoS) attacks aim at bringing down or decreasing the availability of services for their legitimate users, by exhausting network or server resources. It is difficult to differentiate attack traffic from legitimate traffic as the attack can come from distributed nodes that additionally might spoof their IP addresses. Traditional DoS mitigation solutions fail to defend all kinds of DoS attacks and huge DoS attacks might exceed the processing capacity of routers and firewalls easily. The advent of Software-defined Networking (SDN) and Network Function Virtualization (NFV) has brought a new perspective for network defense. Key features of such technologies like global network view and flexibly positionable security functionality can be used for mitigating DDoS attacks. In this paper, we propose a collaborative DDoS attack mitigation scheme that uses SDN and NFV. We adopt a machine learning algorithm from related work to derive accurate patterns describing DDoS attacks. Our experimental results indicate that our framework is able to differentiate attack and legitimate traffic with high accuracy and in near-realtime. Furthermore, the derived patterns can be used to create OpenFlow (OF) or Firewall rules that can be pushed back into the direction of the attack origin for more efficient and distributed filtering.

The usage of K-anonymity to preserve location privacy for wireless sensor network (WSN) monitoring systems, where sensor nodes operate together to notify a server with anonymous shared positions. That k-anonymous position is a coated region with at least k people. However, we identify an attack model to show that overlapping aggregate locations remain privacy-risk because the enemy can infer certain overlapping areas with persons under k who violate the privacy requirement for anonymity. Within this paper we suggest a mutual WSN privacy protocol (REAL). Actual needs sensor nodes to arrange their sensing areas separately into a variety of non-overlapping, extremely precise anonymous aggregate positions. We also developed a state transfer framework, a locking mechanism and a time delay mechanism to address the three main REAL challenges, namely self-organisation, shared assets and high precision. We equate REAL's output with current protocols through virtual experiments. The findings demonstrate that REAL preserves the privacy of sites, offers more precise question answers and decreases connectivity and device expense.

Future intelligent transportation systems necessitate a fine-grained and accurate estimation of vehicular traffic flows across critical paths of the underlying road network. This task is relatively trivial if we are able to collect detailed trajectories from every moving vehicle throughout the day. Nevertheless, this approach compromises the location privacy of the vehicles and may be used to build accurate profiles of the corresponding individuals. To this end, this work introduces a privacy-preserving protocol that leverages roadside units (RSUs) to communicate with the passing vehicles, in order to construct encrypted Bloom filters stemming from the vehicle IDs. The aggregate Bloom filters are encrypted with a threshold cryptosystem and can only be decrypted by the transportation authority in collaboration with multiple trusted entities. As a result, the individual communications between the vehicles and the RSUs remain secret. The decrypted Bloom filters reveal the aggregate traffic information at each RSU, but may also serve as a means to compute an approximation of the traffic flow between any pair of RSUs, by simply estimating the number of common vehicles in their respective Bloom filters. We performed extensive simulation experiments with various configuration parameters and demonstrate that our protocol reduces the estimation error considerably when compared to the current state-of-the-art approaches. Furthermore, our implementation of the underlying cryptographic primitives illustrates the feasibility, practicality, and scalability of the system.

In order to realize the security authentication of information transmission between vehicle nodes in the vehicular ad hoc network, based on the certificateless public key cryptosystem and aggregate signature, a privacy-protected certificateless aggregate signature scheme is proposed, which eliminates the complicated certificate maintenance cost. This solution also solves the key escrow problem. By Communicating with surrounding nodes through the pseudonym of the vehicle, the privacy protection of vehicle users is realized. The signature scheme satisfies the unforgeability of an adaptive selective message attack under a random prophetic machine. The scheme meets message authentication, identity privacy protection, resistance to reply attacks.

In order to solve the problem of data leakage and tampering in end-to-end power data security management, this paper proposes a Blockchain-based power terminal data security management model, which includes power terminals and Blockchain nodes. Among them, the power terminal is responsible for the collection of front-end substation data; the Blockchain node is responsible for data verification and data storage. Secondly, the data security management mechanism of power terminal based on Blockchain is proposed, including data aggregation, data encryption and transmission, signature verification for single Blockchain, aggregation signature for main Blockchain nodes, and intelligent contract storage. Finally, by applying the mechanism to the data storage process and data request process analysis, the data management mechanism proposed in this paper has a good application effect.

The article deals with the development and implementation of a method for synthesizing structures of threats and risks to information security based on a fuzzy approach. We consider a method for modeling threat structures based on structural abstractions: aggregation, generalization, and Association. It is shown that the considered forms of structural abstractions allow implementing the processes of Ascending and Descending inheritance. characteristics of the threats. A database of fuzzy rules based on procedural abstractions has been developed and implemented in the fuzzy logic tool environment Fussy Logic.

We present ctrlTCP, a method to combine the congestion controls of multiple TCP connections. In contrast to the previous methods such as the Congestion Manager, ctrlTCP can couple all TCP flows that leave one sender, traverse a common bottleneck (e.g., a home user's thin uplink) and arrive at different destinations. Using ns-2 simulations and an implementation in the FreeBSD kernel, we show that our mechanism reduces queuing delay, packet loss, and short flow completion times while enabling precise allocation of the share of the available bandwidth between the connections according to the needs of the applications.

Communication between two Internet hosts using parallel connections may result in unwanted interference between the connections. In this dissertation, we propose a sender-side solution to address this problem by letting the congestion controllers of the different connections collaborate, correctly taking congestion control logic into account. Real-life experiments and simulations show that our solution works for a wide variety of congestion control mechanisms, provides great flexibility when allocating application traffic to the connections, and results in lower queuing delay and less packet loss.

A country drives by their people and the electricity energy, the availability of the electricity power reflects the strength of that country. All most everything depends on the electricity energy, So it is become very important that we use the available energy very efficiently, and here the energy management come in the picture and Non Intrusive appliance Load monitoring (NIALM) is the part of energy management, in which the energy consumption by the particular load is monitored without any intrusion of wire/circuit. In literature, NIALM has been discussed as a monitoring process for conservation of energy using single point sensing (SPS) for extraction of aggregate signal of the appliances' features, ignoring the second function of demand response (DR) assuming that it would be manual or sensor-based. This assumption is not implementable in developing countries like India, because of requirement of extra cost of sensors, and privacy concerns. Surprisingly, despite decades of research on NIALM, none of the suggested procedures has resulted in commercial application. This paper highlights the causes behind non- commercialization, and proposes a viable and easy solution worthy of commercial exploitation both for monitoring and DR management for outage reduction in respect of Indian domestic consumers. Using a approach of multi point sensing (MPS), combined with Independent Component Analysis (ICA), experiments has been done in laboratory environment and CPWD specification has been followed.

Two-phase I/O is a well-known strategy for implementing collective MPI-IO functions. It redistributes I/O requests among the calling processes into a form that minimizes the file access costs. As modern parallel computers continue to grow into the exascale era, the communication cost of such request redistribution can quickly overwhelm collective I/O performance. This effect has been observed from parallel jobs that run on multiple compute nodes with a high count of MPI processes on each node. To reduce the communication cost, we present a new design for collective I/O by adding an extra communication layer that performs request aggregation among processes within the same compute nodes. This approach can significantly reduce inter-node communication contention when redistributing the I/O requests. We evaluate the performance and compare it with the original two-phase I/O on Cray XC40 parallel computers (Theta and Cori) with Intel KNL and Haswell processors. Using I/O patterns from two large-scale production applications and an I/O benchmark, we show our proposed method effectively reduces the communication cost and hence maintains the scalability for a large number of processes.

In recent years, service providers, such as mobile operators providing wireless services, collected location data in enormous extent with the increase of the usages of mobile phones. Vertical businesses, such as banks, may want to use this location information for their own scenarios. However, service providers cannot directly provide these private data to the vertical businesses because of the privacy and legal issues. In this demo, we show how privacy preserving solutions can be utilized using such location-based queries without revealing each organization's sensitive data. In our demonstration, we used partially homomorphic cryptosystem in our protocols and showed practicality and feasibility of our proposed solution.

Due to the increased diversity and complexity of cyberattacks, innovative and effective analytics are needed in order to identify critical cyber incidents on a corporate network even if no ground truth data is available. This paper develops an automated system which processes a set of intrusion alerts to create behavior aggregates and then classifies these aggregates into empirical attack models through a dynamic Bayesian approach with innovative feature engineering methods. Each attack model represents a unique collective attack behavior that helps to identify critical activities on the network. Using 2017 National Collegiate Penetration Testing Competition data, it is demonstrated that the developed system is capable of generating and refining unique attack models that make sense to human, without a priori knowledge.

A key question for characterising a system's vulnerability against timing attacks is whether or not it allows an adversary to aggregate information about a secret over multiple timing measurements. Existing approaches for reasoning about this aggregate information rely on strong assumptions about the capabilities of the adversary in terms of measurement and computation, which is why they fall short in modelling, explaining, or synthesising real-world attacks against cryptosystems such as RSA or AES. In this paper we present a novel model for reasoning about information aggregation in timing attacks. The model is based on a novel abstraction of timing measurements that better captures the capabilities of real-world adversaries, and a notion of compositionality of programs that explains attacks by divide-and-conquer. Our model thus lifts important limiting assumptions made in prior work and enables us to give the first uniform explanation of high-profile timing attacks in the language of information-flow analysis.

The behavior of a differentially private system is governed by a parameter epsilon which sets a balance between protecting the privacy of individuals and returning accurate results. While a system owner may use a number of heuristics to select epsilon, existing techniques may be unresponsive to the needs of the users who's data is at risk. A promising alternative is to allow users to express their preferences for epsilon. In a system we call epsilon voting, users report the parameter values they want to a chooser mechanism, which aggregates them into a single value. We apply techniques from mechanism design to ask whether such a chooser mechanism can itself be truthful, private, anonymous, and also responsive to users. Without imposing restrictions on user preferences, the only feasible mechanisms belong to a class we call randomized dictatorships with phantoms. This is a restrictive class in which at most one user has any effect on the chosen epsilon. On the other hand, when users exhibit single-peaked preferences, a broader class of mechanisms - ones that generalize the median and other order statistics - becomes possible.

Vehicle ad-hoc network (VANET) is the main driving force to alleviate traffic congestion and accelerate the construction of intelligent transportation. However, the rapid growth of the number of vehicles makes the construction of the safety system of the vehicle network facing multiple tests. This paper proposes an identity-based aggregate signature scheme to protect the privacy of vehicle identity, receive messages in time and authenticate quickly in VANET. The scheme uses aggregate signature algorithm to aggregate the signatures of multiple users into one signature, and joins the idea of batch authentication to complete the authentication of multiple vehicular units, thereby improving the verification efficiency. In addition, the pseudoidentity of vehicles is used to achieve the purpose of vehicle anonymity and privacy protection. Finally, the secure storage of message signatures is effectively realized by using reliable cloud storage technology. Compared with similar schemes, this paper improves authentication efficiency while ensuring security, and has lower storage overhead.

Identity management is an essential cornerstone of securing online services. Service provisioning relies on correct and valid attributes of a digital identity. Therefore, the identity provider is a trusted third party with a specific trust requirement towards a verified attribute supply. This trust demand implies a significant dependency on users and service providers. We propose a novel attribute aggregation method to reduce the reliance on one identity provider. Trust in an attribute is modelled as a combined assurance of several identity providers based on probability distributions. We formally describe the proposed aggregation model. The resulting trust model is implemented in a gateway that is used for authentication with self-sovereign identity solutions. Thereby, we devise a service provider specific web of trust that constitutes an intermediate approach bridging a global hierarchical model and a locally decentralized peer to peer scheme.