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Research Collection School Of Computing and Information Systems

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(Deterministic) Hierarchical Identity-Based Encryption From Learning With Rounding Over Small Modulus, Fuyang Fang, Bao Li, Xianhui Lu, Yamin Liu, Dingding Jia, Haiyang Xue Jun 2016

(Deterministic) Hierarchical Identity-Based Encryption From Learning With Rounding Over Small Modulus, Fuyang Fang, Bao Li, Xianhui Lu, Yamin Liu, Dingding Jia, Haiyang Xue

Research Collection School Of Computing and Information Systems

In this paper, we propose a hierarchical identity-based encryption (HIBE) scheme in the random oracle (RO) model based on the learning with rounding (LWR) problem over small modulus $q$. Compared with the previous HIBE schemes based on the learning with errors (LWE) problem, the ciphertext expansion ratio of our scheme can be decreased to 1/2. Then, we utilize the HIBE scheme to construct a deterministic hierarchical identity-based encryption (D-HIBE) scheme based on the LWR problem over small modulus. Finally, with the technique of binary tree encryption (BTE) we can construct HIBE and D-HIBE schemes in the standard model based on …


Anonymous Identity-Based Broadcast Encryption With Chosen-Ciphertext Security, Kai He, Jian Weng, Jia-Nan Liu, Joseph K. Liu, Wei Liu, Deng, Robert H. May 2016

Anonymous Identity-Based Broadcast Encryption With Chosen-Ciphertext Security, Kai He, Jian Weng, Jia-Nan Liu, Joseph K. Liu, Wei Liu, Deng, Robert H.

Research Collection School Of Computing and Information Systems

In this paper, we propose the first identity-based broadcast encryption scheme, which can simultaneously achieves confidentiality and full anonymity against adaptive chosen-ciphertext attacks under a standard assumption. In addition, two further desirable features are also provided: one is fully-collusion resistant which means that even if all users outside of receivers S collude they cannot obtain any information about the plaintext. The other one is stateless which means that the users in the system do not need to update their private keys when the other users join or leave our system. In particular, our scheme is highly efficient, where the public …


Stabilized Annotations For Mobile Remote Assistance, Omid Fakourfar, Kevin Ta, Richard Tang, Scott Bateman, Anthony Tang May 2016

Stabilized Annotations For Mobile Remote Assistance, Omid Fakourfar, Kevin Ta, Richard Tang, Scott Bateman, Anthony Tang

Research Collection School Of Computing and Information Systems

Recent mobile technology has provided new opportunities for creating remote assistance systems. However, mobile support systems present a particular challenge: both the camera and display are held by the user, leading to shaky video. When pointing or drawing annotations, this means that the desired target often moves, causing the gesture to lose its intended meaning. To address this problem, we investigate annotation stabilization techniques, which allow annotations to stick to their intended location. We studied two annotation systems, using three different forms of annotations, with both tablets and head-mounted displays. Our analysis suggests that stabilized annotations and head-mounted displays are …


Efficient Verifiable Computation Of Linear And Quadratic Functions Over Encrypted Data, Ngoc Hieu Tran, Hwee Hwa Pang, Robert H. Deng May 2016

Efficient Verifiable Computation Of Linear And Quadratic Functions Over Encrypted Data, Ngoc Hieu Tran, Hwee Hwa Pang, Robert H. Deng

Research Collection School Of Computing and Information Systems

In data outsourcing, a client stores a large amount of data on an untrusted server; subsequently, the client can request the server to compute a function on any subset of the data. This setting naturally leads to two security requirements: confidentiality of input data, and authenticity of computations. Existing approaches that satisfy both requirements simultaneously are built on fully homomorphic encryption, which involves expensive computation on the server and client and hence is impractical. In this paper, we propose two verifiable homomorphic encryption schemes that do not rely on fully homomorphic encryption. The first is a simple and efficient scheme …


Graph-Aided Directed Testing Of Android Applications For Checking Runtime Privacy Behaviours, Joseph Joo Keng Chan, Lingxiao Jiang, Kiat Wee Tan, Rajesh Krishna Balan May 2016

Graph-Aided Directed Testing Of Android Applications For Checking Runtime Privacy Behaviours, Joseph Joo Keng Chan, Lingxiao Jiang, Kiat Wee Tan, Rajesh Krishna Balan

Research Collection School Of Computing and Information Systems

While automated testing of mobile applications is very useful for checking run-time behaviours and specifications, its capability in discovering issues in apps is often limited in practice due to long testing time. A common practice is to randomly and exhaustively explore the whole app test space, which takes a lot of time and resource to achieve good coverage and reach targeted parts of the apps. In this paper, we present MAMBA, a directed testing system for checking privacy in Android apps. MAMBA performs path searches of user events in control-flow graphs of callbacks generated from static analysis of app bytecode. …


Leveraging Automated Privacy Checking For Design Of Mobile Privacy Protection Mechanisms, Joseph Joo Keng Chan, Lingxiao Jiang, Kiat Wee Tan, Rajesh Balan May 2016

Leveraging Automated Privacy Checking For Design Of Mobile Privacy Protection Mechanisms, Joseph Joo Keng Chan, Lingxiao Jiang, Kiat Wee Tan, Rajesh Balan

Research Collection School Of Computing and Information Systems

While mobile platforms rely on developers to follow good practices in privacy design, developers might not always adhere. In addition, it is often difficult for users to understand the privacy behaviour of their applications without some prolonged usage. To aid in these issues, we describe on-going research to improve privacy protection by utilizing techniques that mine privacy information from application binaries as a grey-box (Automated Privacy Checking). The outputs can then be utilized to improve the users' ability to exercise privacy-motivated discretion. We conducted a user study to observe the effects of presenting information on leak-causing triggers within applications in …


A Key-Insulated Cp-Abe With Key Exposure Accountability For Secure Data Sharing In The Cloud, Hanshu Hong, Zhixin Sun, Ximeng Liu May 2016

A Key-Insulated Cp-Abe With Key Exposure Accountability For Secure Data Sharing In The Cloud, Hanshu Hong, Zhixin Sun, Ximeng Liu

Research Collection School Of Computing and Information Systems

ABE has become an effective tool for data protection in cloud computing. However, since users possessing the same attributes share the same private keys, there exist some malicious users exposing their private keys deliberately for illegal data sharing without being detected, which will threaten the security of the cloud system. Such issues remain in many current ABE schemes since the private keys are rarely associated with any user specific identifiers. In order to achieve user accountability as well as provide key exposure protection, in this paper, we propose a key-insulated ciphertext policy attribute based encryption with key exposure accountability (KI-CPABE-KEA). …


Dual-Server Public-Key Encryption With Keyword Search For Secure Cloud Storage, Rongmao Chen, Yi Mu, Guomin Yang, Fuchun Guo, Xiaofen Wang Apr 2016

Dual-Server Public-Key Encryption With Keyword Search For Secure Cloud Storage, Rongmao Chen, Yi Mu, Guomin Yang, Fuchun Guo, Xiaofen Wang

Research Collection School Of Computing and Information Systems

Searchable encryption is of increasing interest for protecting the data privacy in secure searchable cloud storage. In this paper, we investigate the security of a well-known cryptographic primitive, namely, public key encryption with keyword search (PEKS) which is very useful in many applications of cloud storage. Unfortunately, it has been shown that the traditional PEKS framework suffers from an inherent insecurity called inside keyword guessing attack (KGA) launched by the malicious server. To address this security vulnerability, we propose a new PEKS framework named dual-server PEKS (DS-PEKS). As another main contribution, we define a new variant of the smooth projective …


Anonymous Proxy Signature With Hierarchical Traceability, Jiannan Wei, Guomin Yang, Yi Mu, Kaitai Liang Apr 2016

Anonymous Proxy Signature With Hierarchical Traceability, Jiannan Wei, Guomin Yang, Yi Mu, Kaitai Liang

Research Collection School Of Computing and Information Systems

Anonymous proxy signatures are very useful in the construction of anonymous credential systems such as anonymous voting and anonymous authentication protocols. As a basic requirement, we should ensure an honest proxy signer is anonymous. However, in order to prevent the proxy signer from abusing the signing right, we should also allow dishonest signers to be traced. In this paper, we present three novel anonymous proxy signature schemes with different levels of (namely, public, internal and original signer) traceability. We define the formal definitions and security models for these three different settings, and prove the security of our proposed schemes under …


Strongly Leakage-Resilient Authenticated Key Exchange, Rongmao Chen, Yi Mu, Guomin Yang, Willy Susilo, Fuchun Guo Mar 2016

Strongly Leakage-Resilient Authenticated Key Exchange, Rongmao Chen, Yi Mu, Guomin Yang, Willy Susilo, Fuchun Guo

Research Collection School Of Computing and Information Systems

Authenticated Key Exchange (AKE) protocols have been widely deployed in many real-world applications for securing communication channels. In this paper, we make the following contributions. First, we revisit the security modelling of leakage-resilient AKE protocols, and show that the existing models either impose some unnatural restrictions or do not sufficiently capture leakage attacks in reality. We then introduce a new strong yet meaningful security model, named challenge-dependent leakage-resilient eCK (CLR- eCKCLR- eCK) model, to capture challenge-dependent leakage attacks on both long-term secret key and ephemeral secret key (i.e., randomness). Second, we propose a general framework for constructing one-round CLR- eCKCLR- …


Cca-Secure Keyed-Fully Homomorphic Encryption, Junzuo Lai, Deng, Robert H., Changshe Ma, Kouichi Sakurai, Jian Weng Mar 2016

Cca-Secure Keyed-Fully Homomorphic Encryption, Junzuo Lai, Deng, Robert H., Changshe Ma, Kouichi Sakurai, Jian Weng

Research Collection School Of Computing and Information Systems

To simultaneously achieve CCA security and homomorphic property for encryption, Emura et al. introduced a new cryptographic primitive named keyed-homomorphic encryption, in which homomorphic ciphertext manipulations can only be performed by someone holding a devoted evaluation key which, by itself, does not enable decryption. A keyed-homomorphic encryption scheme should provide CCA2 security when the evaluation key is unavailable to the adversary and remain CCA1-secure when the evaluation key is exposed. While existing keyed-homomorphic encryption schemes only allow simple computations on encrypted data, our goal is to construct CCA-secure keyed-fully homomorphic encryption (keyed-FHE) capable of evaluating any functions on encrypted data …


One Size Does Not Fit All: A Game-Theoretic Approach For Dynamically And Effectively Screening For Threats, Matthew Brown, Arunesh Sinha, Aaron Schlenker, Milind Tambe Feb 2016

One Size Does Not Fit All: A Game-Theoretic Approach For Dynamically And Effectively Screening For Threats, Matthew Brown, Arunesh Sinha, Aaron Schlenker, Milind Tambe

Research Collection School Of Computing and Information Systems

An effective way of preventing attacks in secure areas is to screen for threats (people, objects) before entry, e.g., screening of airport passengers. However, screening every entity at the same level may be both ineffective and undesirable. The challenge then is to find a dynamic approach for randomized screening, allowing for more effective use of limited screening resources, leading to improved security. We address this challenge with the following contributions: (1) a threat screening game (TSG) model for general screening domains; (2) an NP-hardness proof for computing the optimal strategy of TSGs; (3) a scheme for decomposing TSGs into subgames …


Privacy-Preserving And Verifiable Data Aggregation, Ngoc Hieu Tran, Robert H. Deng, Hwee Hwa Pang Jan 2016

Privacy-Preserving And Verifiable Data Aggregation, Ngoc Hieu Tran, Robert H. Deng, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

There are several recent research studies on privacy-preserving aggregation of time series data, where an aggregator computes an aggregation of multiple users' data without learning each individual's private input value. However, none of the existing schemes allows the aggregation result to be verified for integrity. In this paper, we present a new data aggregation scheme that protects user privacy as well as integrity of the aggregation. Towards this end, we first propose an aggregate signature scheme in a multi-user setting without using bilinear maps. We then extend the aggregate signature scheme into a solution for privacy-preserving and verifiable data aggregation. …


Hidden Ciphertext Policy Attribute-Based Encryption Under Standard Assumptions, Tran Viet Xuan Phuong, Guomin Yang, Willy Susilo Jan 2016

Hidden Ciphertext Policy Attribute-Based Encryption Under Standard Assumptions, Tran Viet Xuan Phuong, Guomin Yang, Willy Susilo

Research Collection School Of Computing and Information Systems

We propose two new ciphertext policy attributebased encryption (CP-ABE) schemes where the access policy is defined by AND-gate with wildcard. In the first scheme, we present a new technique that uses only one group element to represent an attribute, while the existing ABE schemes of the same type need to use three different group elements to represent an attribute for the three possible values (namely, positive, negative, and wildcard). Our new technique leads to a new CP-ABE scheme with constant ciphertext size, which, however, cannot hide the access policy used for encryption. The main contribution of this paper is to …


On The Unreliability Of Bug Severity Data, Yuan Tian, Nasir Ali, David Lo, Ahmed E. Hassan Dec 2015

On The Unreliability Of Bug Severity Data, Yuan Tian, Nasir Ali, David Lo, Ahmed E. Hassan

Research Collection School Of Computing and Information Systems

Severity levels, e.g., critical and minor, of bugs are often used to prioritize development efforts. Prior research efforts have proposed approaches to automatically assign the severity label to a bug report. All prior efforts verify the accuracy of their approaches using human-assigned bug reports data that is stored in software repositories. However, all prior efforts assume that such human-assigned data is reliable. Hence a perfect automated approach should be able to assign the same severity label as in the repository – achieving a 100% accuracy. Looking at duplicate bug reports (i.e., reports referring to the same problem) from three open-source …


Bl-Mle: Block-Level Message-Locked Encryption For Secure Large File Deduplication, Rongmao Chen, Yi Mu, Guomin Yang, Fuchun Guo Dec 2015

Bl-Mle: Block-Level Message-Locked Encryption For Secure Large File Deduplication, Rongmao Chen, Yi Mu, Guomin Yang, Fuchun Guo

Research Collection School Of Computing and Information Systems

Deduplication is a popular technique widely used to save storage spaces in the cloud. To achieve secure deduplication of encrypted files, Bellare et al. formalized a new cryptographic primitive named message-locked encryption (MLE) in Eurocrypt 2013. Although an MLE scheme can be extended to obtain secure deduplication for large files, it requires a lot of metadata maintained by the end user and the cloud server. In this paper, we propose a new approach to achieve more efficient deduplication for (encrypted) large files. Our approach, named block-level message-locked encryption (BL-MLE), can achieve file-level and block-level deduplication, block key management, and proof …


Lossy Projective Hashing And Its Applications, Haiyang Xue, Yamin Liu, Xianhui Lu, Bao Li Dec 2015

Lossy Projective Hashing And Its Applications, Haiyang Xue, Yamin Liu, Xianhui Lu, Bao Li

Research Collection School Of Computing and Information Systems

In this paper, we introduce a primitive called lossy projective hashing. It is unknown before whether smooth projective hashing (Cramer-Shoup, Eurocrypt’02) can be constructed from dual projective hashing (Wee, Eurocrypt’12). The lossy projective hashing builds a bridge between dual projective hashing and smooth projective hashing. We give instantiations of lossy projective hashing from DDH, DCR, QR and general subgroup membership assumptions (including 2k-th residue, p-subgroup and higher residue assumptions). We also show how to construct lossy encryption and fully IND secure deterministic public key encryption from lossy projective hashing. – We give a construction of lossy projective hashing via dual …


Security Slicing For Auditing Xml, Xpath, And Sql Injection Vulnerabilities, Julian Thome, Lwin Khin Shar, Lionel Briand Nov 2015

Security Slicing For Auditing Xml, Xpath, And Sql Injection Vulnerabilities, Julian Thome, Lwin Khin Shar, Lionel Briand

Research Collection School Of Computing and Information Systems

XML, XPath, and SQL injection vulnerabilities are among the most common and serious security issues for Web applications and Web services. Thus, it is important for security auditors to ensure that the implemented code is, to the extent possible, free from these vulnerabilities before deployment. Although existing taint analysis approaches could automatically detect potential vulnerabilities in source code, they tend to generate many false warnings. Furthermore, the produced traces, i.e. dataflow paths from input sources to security-sensitive operations, tend to be incomplete or to contain a great deal of irrelevant information. Therefore, it is difficult to identify real vulnerabilities and …


Stack Layout Randomization With Minimal Rewriting Of Android Binaries, Yu Liang, Xinjie Ma, Daoyuan Wu, Xiaoxiao Tang, Debin Gao, Guojun Peng, Chunfu Jia, Huanguo Zhang Nov 2015

Stack Layout Randomization With Minimal Rewriting Of Android Binaries, Yu Liang, Xinjie Ma, Daoyuan Wu, Xiaoxiao Tang, Debin Gao, Guojun Peng, Chunfu Jia, Huanguo Zhang

Research Collection School Of Computing and Information Systems

Stack-based attacks typically require that attackers have a good understanding of the stack layout of the victim program. In this paper, we leverage specific features on ARM architecture and propose a practical technique that introduces randomness to the stack layout when an Android application executes. We employ minimal binary rewriting on the Android app that produces randomized executable of the same size which can be executed on an unmodified Android operating system. Our experiments on applying this randomization on the most popular 20 free Android apps on Google Play show that the randomization coverage of functions increases from 65% (by …


Security And Privacy Of Electronic Health Information Systems: Editorial, Elisa Bertino, Robert H. Deng, Xinyi Huang, Jianying Zhou Nov 2015

Security And Privacy Of Electronic Health Information Systems: Editorial, Elisa Bertino, Robert H. Deng, Xinyi Huang, Jianying Zhou

Research Collection School Of Computing and Information Systems

Digital technologies have dramatically transformed our daily lives by bringing countless conveniences and benefits. As an evolving concept, electronic health information has become the focus of attention in both academia and industry. By leveraging modern digital technologies like the internet and the cloud, electronic health information systems will be a key enabling technology in improving the quality and convenience of patient care, encouraging patient participation in their care, reducing medical errors, improving practice efficiencies, and saving time and cost. The complexity of electronic health information systems, however, raises several new security and privacy issues. It is thus critical to investigate …


Towards Automatic Generation Of Security-Centric Descriptions For Android Apps, Mu Zhang, Yue Duan, Qian Feng, Heng Yin Oct 2015

Towards Automatic Generation Of Security-Centric Descriptions For Android Apps, Mu Zhang, Yue Duan, Qian Feng, Heng Yin

Research Collection School Of Computing and Information Systems

To improve the security awareness of end users, Android markets directly present two classes of literal app information: 1) permission requests and 2) textual descriptions. Unfortunately, neither can serve the needs. A permission list is not only hard to understand but also inadequate; textual descriptions provided by developers are not security-centric and are significantly deviated from the permissions. To fill in this gap, we propose a novel technique to automatically generate security-centric app descriptions, based on program analysis. We implement a prototype system, DESCRIBEME, and evaluate our system using both DroidBench and real-world Android apps. Experimental results demonstrate that DESCRIBEME …


A Note On The Security Of Khl Scheme, Jian Weng, Yunlei Zhao, Deng, Robert H., Shengli Liu, Yanjiang Yang, Kouichi Sakurai Oct 2015

A Note On The Security Of Khl Scheme, Jian Weng, Yunlei Zhao, Deng, Robert H., Shengli Liu, Yanjiang Yang, Kouichi Sakurai

Research Collection School Of Computing and Information Systems

A public key trace and revoke scheme combines the functionality of broadcast encryption with the capability of traitor tracing. In Asiacrypt 2003, Kim, Hwang and Lee proposed a public key trace and revoke scheme (referred to as KHL scheme), and gave the security proof to support that their scheme is z-resilient against adaptive chosen-ciphertext attacks, in which the adversary is allowed to adaptively issue decryption queries as well as adaptively corrupt up to z users. In the passed ten years, KHL scheme has been believed as one of the most efficient public key trace and revoke schemes with z-resilience against …


On Robust Image Spam Filtering Via Comprehensive Visual Modeling, Jialie Shen, Deng, Robert H., Zhiyong Cheng, Liqiang Nie, Shuicheng Yan Oct 2015

On Robust Image Spam Filtering Via Comprehensive Visual Modeling, Jialie Shen, Deng, Robert H., Zhiyong Cheng, Liqiang Nie, Shuicheng Yan

Research Collection School Of Computing and Information Systems

The Internet has brought about fundamental changes in the way peoples generate and exchange media information. Over the last decade, unsolicited message images (image spams) have become one of the most serious problems for Internet service providers (ISPs), business firms and general end users. In this paper, we report a novel system called RoBoTs (Robust BoosTrap based spam detector) to support accurate and robust image spam filtering. The system is developed based on multiple visual properties extracted from different levels of granularity, aiming to capture more discriminative contents for effective spam image identification. In addition, a resampling based learning framework …


Seeing Your Face Is Not Enough: An Inertial Sensor-Based Liveness Detection For Face Authentication, Yan Li, Yingjiu Li, Qiang Yan, Hancong Kong, Robert H. Deng Oct 2015

Seeing Your Face Is Not Enough: An Inertial Sensor-Based Liveness Detection For Face Authentication, Yan Li, Yingjiu Li, Qiang Yan, Hancong Kong, Robert H. Deng

Research Collection School Of Computing and Information Systems

Leveraging built-in cameras on smartphones and tablets, face authentication provides an attractive alternative of legacy passwords due to its memory-less authentication process. However, it has an intrinsic vulnerability against the media-based facial forgery (MFF) where adversaries use photos/videos containing victims' faces to circumvent face authentication systems. In this paper, we propose FaceLive, a practical and robust liveness detection mechanism to strengthen the face authentication on mobile devices in fighting the MFF-based attacks. FaceLive detects the MFF-based attacks by measuring the consistency between device movement data from the inertial sensors and the head pose changes from the facial video captured by …


Enhancing Wifi-Based Localization With Visual Clues, Han Xu, Zheng Yang, Zimu Zhou, Longfei Shangguan, Yunhao Liu, Ke Yi Sep 2015

Enhancing Wifi-Based Localization With Visual Clues, Han Xu, Zheng Yang, Zimu Zhou, Longfei Shangguan, Yunhao Liu, Ke Yi

Research Collection School Of Computing and Information Systems

Indoor localization is of great importance to a wide range of applications in the era of mobile computing. Current mainstream solutions rely on Received Signal Strength (RSS) of wireless signals as fingerprints to distinguish and infer locations. However, those methods suffer from fingerprint ambiguity that roots in multipath fading and temporal dynamics of wireless signals. Though pioneer efforts have resorted to motion-assisted or peer-assisted localization, they neither work in real time nor work without the help of peer users, which introduces extra costs and constraints, and thus degrades their practicality. To get over these limitations, we propose Argus, an image-assisted …


Attribute Based Broadcast Encryption With Short Ciphertext And Decryption Key, Tran Viet Xuan Phuong, Guomin Yang, Willy Susilo, Xiaofeng Chen Sep 2015

Attribute Based Broadcast Encryption With Short Ciphertext And Decryption Key, Tran Viet Xuan Phuong, Guomin Yang, Willy Susilo, Xiaofeng Chen

Research Collection School Of Computing and Information Systems

Attribute Based Broadcast Encryption (ABBE) is a combination of Attribute Based Encryption (ABE) and Broadcast Encryption (BE). It allows a broadcaster (or encrypter) to broadcast an encrypted message that can only be decrypted by the receivers who are within a predefined user set and satisfy the access policy specified by the broadcaster. Compared with normal ABE, ABBE allows direct revocation, which is important in many real-time broadcasting applications such as Pay TV. In this paper, we propose two novel ABBE schemes that have distinguishing features: the first scheme is key-policy based and has short ciphertext and constant size decryption key; …


On Indistinguishability In Remote Data Integrity Checking, Xinyu Fan, Guomin Yang, Yi Mu, Yong Yu Sep 2015

On Indistinguishability In Remote Data Integrity Checking, Xinyu Fan, Guomin Yang, Yi Mu, Yong Yu

Research Collection School Of Computing and Information Systems

With a rapid growth of data storage in the cloud, data integrity checking in a remote data storage system has become an important issue. A number of protocols, which allow remote integrity checking by a third party, have been proposed. Although those protocols are provably secure, the data privacy issues in those protocols have not been considered. We believe that these issues are equally important since the communication flows of integrity proofs from the cloud server should not reveal any useful information of the stored data. In this paper, we introduce a new definition of data privacy called ‘INDPrivacy’ by …


From Physical Security To Cybersecurity, Arunesh Sinha, Thanh H. Nguyen, Debarun Kar, Matthew Brown, Milind Tambe, Albert Xin Jiang Sep 2015

From Physical Security To Cybersecurity, Arunesh Sinha, Thanh H. Nguyen, Debarun Kar, Matthew Brown, Milind Tambe, Albert Xin Jiang

Research Collection School Of Computing and Information Systems

Security is a critical concern around the world. In many domains from cybersecurity to sustainability, limited security resources prevent complete security coverage at all times. Instead, these limited resources must be scheduled (or allocated or deployed), while simultaneously taking into account the importance of different targets, the responses of the adversaries to the security posture, and the potential uncertainties in adversary payoffs and observations, etc. Computational game theory can help generate such security schedules. Indeed, casting the problem as a Stackelberg game, we have developed new algorithms that are now deployed over multiple years in multiple applications for scheduling of …


On Security Of Content-Based Video Stream Authentication, Swee Won Lo, Zhou Wei, Deng, Robert H., Xuhua Ding Sep 2015

On Security Of Content-Based Video Stream Authentication, Swee Won Lo, Zhou Wei, Deng, Robert H., Xuhua Ding

Research Collection School Of Computing and Information Systems

Content-based authentication (CBA) schemes are used to authenticate multimedia streams while allowing content-preserving manipulations such as bit-rate transcoding. In this paper, we survey and classify existing transform-domain CBA schemes for videos into two categories, and point out that in contrary to CBA for images, there exists a common design flaw in these schemes. We present the principles (based on video coding concept) on how the flaw can be exploited to mount semantic-changing attacks in the transform domain that cannot be detected by existing CBA schemes. We show attack examples including content removal, modification and insertion attacks. Noting that these CBA …


Server-Aided Revocable Identity-Based Encryption, Baodong Qin, Deng, Robert H., Yingjiu Li, Shengli Liu Sep 2015

Server-Aided Revocable Identity-Based Encryption, Baodong Qin, Deng, Robert H., Yingjiu Li, Shengli Liu

Research Collection School Of Computing and Information Systems

Efficient user revocation in Identity-Based Encryption (IBE) has been a challenging problem and has been the subject of several research efforts in the literature. Among them, the tree-based revocation approach, due to Boldyreva, Goyal and Kumar, is probably the most efficient one. In this approach, a trusted Key Generation Center (KGC) periodically broadcasts a set of key updates to all (non-revoked) users through public channels, where the size of key updates is only O(r log N/r), with N being the number of users and r the number of revoked users, respectively; however, every user needs to keep at least O(logN) …