The configurable Ring oscillator Physical unclonable function (CRO PUF) is the newly proposed strong PUF based on classic RO PUF, which can generate exponential Challenge-Response Pairs (CRPs) and has good uniqueness and reliability. However, existing proposals have low hardware utilization and vulnerability to modeling attacks. In this paper, we propose a Novel Configurable Dual State (CDS) PUF with lower overhead and higher resistance to modeling attacks. This structure can be flexibly transformed into RO PUF and TERO PUF in the same topology according to the parity of the Hamming Weight (HW) of the challenge, which can achieve 100% utilization of the inverters and improve the efficiency of hardware utilization. A feedback obfuscation mechanism (FOM) is also proposed, which uses the stable count value of the ring oscillator in the PUF as the updated mask to confuse and hide the original challenge, significantly improving the effect of resisting modeling attacks. The proposed FOM-CDS PUF is analyzed by building a mathematical model and finally implemented on Xilinx Artix-7 FPGA, the test results show that the FOM-CDS PUF can effectively resist several popular modeling attack methods and the prediction accuracy is below 60%. Meanwhile it shows that the FOM-CDS PUF has good performance with uniformity, Bit Error Rate at different temperatures, Bit Error Rate at different voltages and uniqueness of 53.68%, 7.91%, 5.64% and 50.33% respectively.

Nowadays the computing technology is going through a major paradigm shift. Local processing platforms are being replaced by physically out of reach yet more powerful and scalable environments such as the cloud computing platforms. Previously, we introduced the OJIT system as a novel approach for obfuscating remotely executed programs, making them difficult for adversaries to reverse-engineer. The system exploited the JIT compilation technology to randomly and dynamically transform the code, making it constantly changing, thereby complicating the execution state. This work aims to propose the new design iOJIT, as an enhanced approach that patches the old systems shortcomings, and potentially provides more effective obfuscation. Here, we present an analytic study of the obfuscation techniques on the generated code and the cost of applying such transformations in terms of execution time and performance overhead. Based upon this profiling study, we implemented a new algorithm to choose which obfuscation techniques would be better chosen for “efficient” obfuscation according to our metrics, i.e., less prone to security attacks. Another goal was to study the system performance with different applications. Therefore, we applied our system on a cloud platform running different standard benchmarks from SPEC suite.

The concept of witness hiding was proposed by Feige and Shamir as a natural relaxation of zero-knowledge. Prior constructions of witness hiding protocol for general hard distribution on NP language consist of at least three rounds. In this paper we construct a two-round witness hiding protocol for all hard distributions on NP language. Our construction is based on two primitives: point obfuscation and adaptive witness encryption scheme.

This paper addresses the issue of text matching for plagiarism detection. This task aims at identifying the matching plagiarism segments in a pair of suspicious document and its plagiarism source document. All the time, heuristic-based methods are mainly utilized to resolve this problem. But the heuristics rely on the experts' experiences and fail to integrate more features to detect the high obfuscation plagiarism matches. In this paper, a statistical machine learning approach, named the Ranking-based Text Matching Approach for Plagiarism Detection, is proposed to deal with the issues of high obfuscation plagiarism detection. The plagiarism text matching is formalized as a ranking problem, and a pairwise learning to rank algorithm is exploited to identify the most probable plagiarism matches for a given suspicious segment. Especially, the Meteor evaluation metrics of machine translation are subsumed by the proposed method to capture the lexical and semantic text similarity. The proposed method is evaluated on PAN12 and PAN13 text alignment corpus of plagiarism detection and compared to the methods achieved the best performance in PAN12, PAN13 and PAN14. Experimental results demonstrate that the proposed method achieves statistically significantly better performance than the baseline methods in all twelve document collections belonging to five different plagiarism categories. Especially at the PAN12 Artificial-high Obfuscation sub-corpus and PAN13 Summary Obfuscation plagiarism sub-corpus, the main evaluation metrics PlagDet of the proposed method are even 22% and 43% relative improvements than the baselines. Moreover, the efficiency of the proposed method is also better than that of baseline methods.

Multilinear maps have lots of cryptographic applications including multipartite key exchange and indistinguishability obfuscations. Since the concept of multilinear map was suggested, three kinds of candidate multilinear maps are constructed. However, the security of multilinear maps suffers from various attacks. In this paper, we overview suggested multilinear maps and cryptanalysis of them in diverse cases.

In a proxy re-signatures (PRS) scheme, a semi-trusted proxy is given some information which allows it to translate a user i's signature on a message m into another user j's signature on the same message m. However, the proxy cannot, on it own, compute signatures for either i or j. This notion introduced by Blaze et a. at EUROCRYPT 1998, and then revisited by Ateniese and Hohenberger at CCS 2005. The existence of multi-use unidirectional PRS scheme is an open problem left by AH05. Whereafter, at CCS 2008, Libert and Vergnaud constructed the first multi-use unidirectional PRS scheme. However, there is a major drawback in the LV08 scheme that the size of the signatures is linear in the number of translations. Hence, Libert and Vergnaud said that a more challenging task would be to find out implementations of such primitives where the size of signatures and the verification cost do not grow linearly with the number of translations. In this work we resolve this task by constructing a such PRS scheme in the standard model by using indistinguishability obfuscation. A shortcoming of our construction is that the security is selective but not full.

Modern web applications incorporate many programmatic frameworks and APIs that are often pushed to the client-side with most of the application logic while contents are the result of mashing up several resources from different origins. Such applications are threatened by attackers that often attempts to inject directly, or by leveraging a stepstone website, script codes that perform malicious operations. Web scripting based malware proliferation is being more and more industrialized with the drawbacks and advantages that characterize such approach: on one hand, we are witnessing a lot of samples that exhibit the same characteristics which make these easy to detect, while on the other hand, professional developers are continuously developing new attack techniques. While obfuscation is still a debated issue within the community, it becomes clear that, with new schemes being designed, this issue cannot be ignored anymore. Because many proposed countermeasures confess that they perform better on unobfuscated contents, we propose a 2-stage technique that first relieve the burden of obfuscation by emulating the deobfuscation stage before performing a static abstraction of the analyzed sample's functionalities in order to reveal its intent. We support our proposal with evidence from applying our technique to real-life examples and provide discussion on performance in terms of time, as well as possible other applications of proposed techniques in the areas of web crawling and script classification. Additionally, we claim that such approach can be generalized to other scripting languages similar to JavaScript.

Program analysis techniques have improved steadily over the past several decades, and software obfuscation schemes have come to be used in many commercial programs. A software obfuscation scheme transforms an original program or a binary file into an obfuscated program that is more complicated and difficult to analyze, while preserving its functionality. However, the security of obfuscation schemes has not been properly evaluated. In this paper, we analyze obfuscation schemes in order to clarify the advantages of our scheme, the XOR-encoding scheme. First, we more clearly define five types of attack models that we defined previously, and define quantitative resistance to these attacks. Then, we compare the security, functionality and efficiency of three obfuscation schemes with encoding variables: (1) Sato et al.'s scheme with linear transformation, (2) our previous scheme with affine transformation, and (3) the XOR-encoding scheme. We show that the XOR-encoding scheme is superior with regard to the following two points: (1) the XOR-encoding scheme is more secure against a data-dependency attack and a brute force attack than our previous scheme, and is as secure against an information-collecting attack and an inverse transformation attack as our previous scheme, (2) the XOR-encoding scheme does not restrict the calculable ranges of programs and the loss of efficiency is less than in our previous scheme.

This paper reports on an evaluation result of current obfuscation techniques for Java byte code, such as Collberg's techniques in terms of mutational capability, real-time applicability, and program size increase. We suggest effective obfuscation techniques for random and real-time obfuscation (RR obfuscation). In the evaluation results, the combination of some obfuscation techniques was found to be useful for RR obfuscation, and some obfuscation techniques makes little or no difference after a certain threshold.

Many computer systems are designed to make it easy for end-users to install and update software. An undesirable side effect, from the perspective of many software producers, is that hostile end-users may analyze or tamper with the software being installed or updated. This paper proposes a way to avoid the side effect without affecting the ease of installation and updating. We construct a computer system M with the following properties: 1) the end-user may install a program P in any conveniently accessible area of M; 2) the program P contains encoded instructions whose semantics are obscure and difficult to understand; and 3) an internal interpreter W, embedded in a non-accessible area of M, interprets the obfuscated instructions without revealing their semantics. Our W is a finite state machine (FSM) which gives context-dependent semantics and operand syntax to the encoded instructions in P; thus, attempts to statically analyze the relation between instructions and their semantics will not succeed. We present a systematic method for constructing a P whose instruction stream is always interpreted correctly regardless of its input, even though changes in input will (in general) affect the execution sequence of instructions in P. Our framework is easily applied to conventional computer systems by adding a FSM unit to a virtual machine or a reconfigurable processor.

Software obfuscation is a promising approach to protect intellectual property rights and secret information of software in untrusted environments. Unfortunately previous software obfuscation techniques share a major drawback that they do not have a theoretical basis and thus it is unclear how effective they are. Therefore we propose new software obfuscation techniques in this paper. The techniques are based on the difficulty of interprocedural analysis of software programs. The essence of our obfuscation techniques is a new complexity problem to precisely determine the address a function pointer points to in the presence of arrays of function pointers. We show that the problem is NP-hard and the fact provides a theoretical basis for our obfuscation techniques. Furthermore, we have already implemented a prototype tool that obfuscates C programs according to our proposed techniques and in this paper we describe the implementation and discuss the experiments results.