Yin Lihua

Utility-based cooperative decision in cooperative authentication

In mobile networks, cooperative authentication is an efficient way to recognize false identities and messages. However, an attacker can track the location of cooperative mobile nodes by monitoring their communications. Moreover, mobile nodes consume their own resources when cooperating with other nodes in the process of authentication. These two factors cause selfish mobile nodes not to actively participate in authentication. In this paper, a bargaining-based game for cooperative authentication is proposed to help nodes decide whether to participate in authentication or not, and our strategy guarantees that mobile nodes participating in cooperative authentication can obtain the maximum utility, all at an acceptable cost. We obtain Nash equilibrium in static complete information games. To address the problem of nodes not knowing the utility of other nodes, incomplete information games for cooperative authentication are established. We also develop an algorithm based on incomplete information games to maximize every nodes utility. The simulation results demonstrate that our strategy has the ability to guarantee authentication probability and increase the number of successful authentications.

A Mandatory Access Control Model Based on Concept Lattice

Confidentiality and integrity of information are basic attributes of information security, but the existing access control models cannot unify the both well. A mandatory access control model based on access control concept lattice is proposed in this paper. This model integrates many safe sensitivity labels such as integrity, confidentiality, security category. Thus, mandatory constraints of the access of subject to the object can be realized, and Hasse diagram of lattice can be created automatically, such that security levels of the subject and object in the system can be displayed clearly.

Automatically verifying STRAC policy

In the IoT (Internet of Things), inconsistent ACP (Access Control Policies) would cause disastrous consequences, for example, fire disasters and failures of cardiac pacemakers, as a result, ACP should be verified before they are applied. Tediousness and error-proneness of manual verifications make automatic and formal verification necessary. In this paper, timed automata is presented to formally model the STRAC (Spatio-Temporal Access Control based on Reputation, one policy for the IoT) policies and CTL (Computation Tree Logic) is adopted to describe the properties that should be satisfied by these policies. Then model checker UPPAAL is proposed to automatically verify whether STRAC policies conform to security properties. Experiment results show that our approach is effective.

Quantifying Information Leakage for Fully Probabilistic Systems

Quantifying the improper leakage of confidential information is a great challenge. In this paper, we propose a method to quantify the information leakage for a fully probabilistic system. Our approach relies on αmutual information (αMI). In our analysis, system is modeled as a fully probabilistic automata; information leakage is identified by means of the weak probabilistic trace equivalence, and then measured via αMI. The accuracy of our approach is demonstrated by experiments.

Botnet spoofing: fighting botnet with itself

A botnet consists of a network of compromised computers connected to the Internet that is controlled by a remote attacker (botmaster) via command and control (C&C) channels. Botnets are the root cause of many Internet attacks such as Email spam, extortion through DDoS, seeding malware, and online identity theft etc. Recently, the arms race between botmasters and defenders has become increasingly common. Defenders have successfully shut down many well-known botnets such as Rustock, Mariposa, Waledac, Stuxnet, Coreflood, and Kelihos by exploiting their C&C design flaws. However, these countermeasures also stimulate the botnets to be more resilient. For security-conscious Internet users, the hostbased security software (i.e., anti-virus and firewall) could provide effective protection against the botnet attacks; however, the remaining security-unconscious users will suffer from the botnet attacks and be compromised easily. Consequently, how to protect both security-conscious and security-unconscious users against advanced botnets (without any C&C vulnerability) has posed a great challenge to this day. In this paper, we propose the idea of botnet spoofing which aims at addressing the above challenge to some degree. We define botnet spoofing as a technique which could trick a malicious bot to spread BotSpoofer instead of spreading itself. BotSpoofer is defined as a computer program which implements botnet spoofing technique.

Analyzing asking/bidding price in dynamic game for cooperative authentication

With the problem that the non-cooperation of selfish nodes causes by location privacy leakage and resource consumption, some researchers proposed a bargaining-based game for cooperative authentication in MANETs. In this game, a fundamental issue is to study how the asking/bidding price affects the cooperative willingness of nodes. To address the problem that the improvement of cooperative willingness in dynamic decision-making, a bargaining-based dynamic game is proposed to analyze the dynamic behavior of the asking/bidding price of nodes. Further, the Subgame Perfect Nash Equilibriums and Perfect Bayesian Equilibrium are obtained to guide the player chooses its optimal strategy under complete and incomplete information, respectively. Finally, factors affect cooperative willingness have been analyzed and the simulation results indicate all positive factors, which cause a lower asking price and a higher bidding price, imply a higher cooperative willingness and a higher probability of successful cooperative authentication.

Balancing authentication and location privacy in cooperative authentication

In MANET, the cooperative authentication mechanism requires the cooperation of the neighbor nodes and significantly enhances the authentication probability. However, it exposes location privacy of neighbor nodes and is costly. How to balance the authentication and location privacy is a key issue. In this paper, we use game theory to analyze the behavior of neighbor nodes in cooperative authentication and gain the optimal strategy. Every node seeks to obtain most reward at least location privacy loss and cost. We first build the static game with complete information and obtain two pure-strategy and one mixed-strategy Nash equilibria. These equilibria can be used efficiently to balance authentication and location privacy. Then, we build the static game with incomplete information and obtain the Bayesian Nash equilibria.

Network security analysis method taking into account the usage information (poster abstract)

Existing network security analysis methods such as using tools like attack graphs or attack trees to compute risk probabilities did not consider the concrete running environment of the target network, which may make the obtained results deviate from the true situation. In this paper, we propose a network security analysis method taking into account the usage information of the target network. We design usage sensors in each host to get the usage information in the network. Combining with attack graph generation tool which gets all the vulnerabilities in the network in the graph form, we evaluation the network using the usage information and the vulnerabilities information, and get more accurate evaluation results.

Approach of Security Policy Expression and Verification Based on Well-Founded Semantic

This study proposes a logic-based security policy framework. First, the study proposes the security policy syntax and semantic. Next, four algoritms are proposed to transfer first-order logic based security policies into extended logic programs to evaluate queries with simple goals, to transfer complex queries into simple ones, and to verify security policies against complex security properties. Under well-founded semantics, all the algorithms are sound and completed, and their computational complexities are polynomial. In this framework, security policy declaration, evaluation and verification are executed under the same semantics, which is significant for security policy management. Furthmore, the framework can manage the security policies with advanced features, such as non-monotony and recursion, which is not supported in many existent security policy management frameworks.

A Novel Dynamic Self-adaptive Framework for Network Security Evaluation

Evaluating network security is vital step in risk management. However, existing evaluating methods such as using tools like attack graphs or attack trees to compute risk probabilities did not consider the concrete running environment of the target network, which may make the obtained results deviate from the true situation. In this paper, we propose a novel dynamic self-adaptive framework for network security evaluation. In addition to using Scan Tool and Attack Graph Generator to generate attack graphs, we design Audit Processor and Property Evaluator to get key information in the running environment of the target network. The major evaluation computing will be performed in Security Evaluator. We show how to use our framework to the real network. Experiment results show that our framework which capture the concrete running environment information of the network get closer result to the true situation and can dynamically adapt to changing environment.