16568303
Designated-verifier proxy signatures for e-commerce
In a designated-verifier proxy signature scheme, a user delegates her/his signing capability to another user in such a way that the latter can sign messages on behalf of the former, but the validity of generated signatures can only be checked by the designated verifier. In this paper, we first point out that one such scheme proposed recently by Dai et al. is insecure. To overcome the weaknesses in their scheme, based on the two-party Schnorr signature by Nicolosi et al., we present a new designated-verifier proxy signature scheme which is efficient and secure. Finally, we suggest the use of our scheme in electronic commerce applications, such as sale of digital products (digital music, movies, and books etc.).
34096143
On the Security of a Certified E-Mail Scheme
As a value-added service for standard e-mail systems, a certified e-mail scheme allows a sender to deliver a message to a receiver in a fair way in the sense that either the sender obtains a receipt from the receiver and the receiver accesses the content of the e-mail simultaneously, or neither party gets the expected item. In 2000, Ferrer-Gomila et al. [11] proposed a novel certified e-mail protocol. Their scheme is both efficient and optimistic, since it has only three steps and a trusted third party is not involved in normal cases. Later, Monteiro and Dahab [16] identified an attack on Ferrer-Gomila et al.’s scheme, and further presented a modified scheme. In this paper, we show that their improvement is still insecure by successfully identifying several weaknesses and security flaws. Our attacks also apply to Ferrer-Gomila et al.’s original scheme.
7849675
On the Security of a Group Signature Scheme with Forward Security
A group signature scheme allows a group member of a given group to sign messages on behalf of the group in an anonymous and unlinkable way. In case of a dispute, however, a designated group manager can reveal the signer of a valid group signature. Based on Song’s forward-secure group signature schemes, Zhang, Wu, and Wang proposed a new group signature scheme with forward security at ICICS 2003. Their scheme is very efficient on both communication and computation aspects. Unfortunately, their scheme is insecure. In this paper we present a security analysis to show that their scheme is linkable, untraceable, and forgeable.
8581433
An Abuse-Free Fair Contract-Signing Protocol Based on the RSA Signature
A fair contract-signing protocol allows two potentially mistrusted parities to exchange their commitments (i.e., digital signatures) to an agreed contract over the Internet in a fair way, so that either each of them obtains the other's signature, or neither party does. Based on the RSA signature scheme, a new digital contract-signing protocol is proposed in this paper. Like the existing RSA-based solutions for the same problem, our protocol is not only fair, but also optimistic, since the trusted third party is involved only in the situations where one party is cheating or the communication channel is interrupted. Furthermore, the proposed protocol satisfies a new property- abuse-freeness. That is, if the protocol is executed unsuccessfully, none of the two parties can show the validity of intermediate results to others. Technical details are provided to analyze the security and performance of the proposed protocol. In summary, we present the first abuse-free fair contract-signing protocol based on the RSA signature, and show that it is both secure and efficient.
17200585
Designated Verifier Signature Schemes: Attacks, New Security Notions and a New Construction
We show that the signer can abuse the disavowal protocol in the Jakobsson-Sako-Impagliazzo designated-verifier signature scheme. In addition, we identify a new security property—non-delegatability—that is essential for designated-verifier signatures, and show that several previously proposed designated-verifier schemes are delegatable. We give a rigorous formalisation of the security for designated-verifier signature schemes, and propose a new and efficient designated-verifier signature scheme that is provably unforgeable under a tight reduction to the Decisional Diffie-Hellman problem in the non-programmable random oracle model, and non-delegatable under a loose reduction in the programmable random oracle model. As a direct corollary, we also get a new efficient conventional signature scheme that is provably unforgeable under a tight reduction to the Decisional Diffie-Hellman problem in the non-programmable random oracle plus common reference string model.
12290163
On the Security of the Lee-Hwang Group-Oriented Undeniable Signature Schemes
Undeniable signature is an intriguing concept introduced by Chaum and van Antwerpen at Crypto’89. In 1999, Lee and Hwang presented two group-oriented undeniable signature schemes with a trusted center. Their schemes are natural generalizations of Chaum’s zero knowledge undeniable signature scheme proposed in 1990. However, we find that the Lee-Hwang schemes are insecure. In this paper, we demonstrate five effective attacks on their schemes: four of them are insider universal forgeries, in which one dishonest member (maybe colluding with a verifier) can get a valid signature on any chosen massage, and another attack allows a dishonest member to prevent honest members from generating valid signatures. We also suggest heuristic improvements to overcome some of the problems involved in these attacks.
5632600
"On-the-fly Programming: Using Code as an Expressive Musical Instrument"
On-the-fly programming is a style of programming in which the programmer/performer/composer augments and modifies the program while it is running, without stopping or restarting, in order to assert expressive, programmable control at runtime. Because of the fundamental powers of programming languages, we believe the technical and aesthetic aspects of on-the-fly programming are worth exploring.In this paper, we present a formalized framework for on-the-fly programming, based on the ChucK synthesis language, which supports a truly concurrent audio programming model with sample-synchronous timing, and a highly on-the-fly style of programming. We first provide a well-defined notion of on-the-fly programming. We then address four fundamental issues that confront the on-the-fly programmer: timing, modularity, conciseness, and flexibility. Using the features and properties of ChucK, we show how it solves many of these issues. In this new model, we show that (1) concurrency provides natural modularity for on-the-fly programming, (2) the timing mechanism in ChucK guarantees on-the-fly precision and consistency, (3) the Chuck syntax improves conciseness, and (4) the overall system is a useful framework for exploring on-the-fly programming. Finally, we discuss the aesthetics of on-the-fly performance.
12983199
Design space exploration using time and resource duality with the ant colony optimization
Design space exploration during high level synthesis is often conducted through ad-hoc probing of the solution space using some scheduling algorithm. This is not only time consuming but also very dependent on designer's experience. We propose a novel design exploration method that exploits the duality between the time and resource constrained scheduling problems. Our exploration automatically constructs a high quality time/area tradeoff curve in a fast, effective manner. It uses the max-min ant colony optimization to solve both the time and resource constrained scheduling problems. We switch between the time and resource constrained algorithms to quickly traverse the design space. Our algorithm provides a significant solution quality savings (average 17.3% reduction of resource counts) with similar run time on a comprehensive benchmark suite constructed with classic and real-life samples, compared to using force directed scheduling exhaustively at every time step. Our algorithms scale well over different applications and problem sizes
8431943
GPU-friendly warped display for scope-maintained video surveillance
In this paper, we propose an efficient technique for warped display of surveillance video signal. Usually, there are regions of interest (ROIs) in video surveillance, such as entrance or exit, and moving objects or persons. The surveillant has two or more conflicting goals in mind. He/She wants to blow up the ROIs, but also wants to have an overview of the whole surveillance scope. The proposed method solves this conflict by warping the input video signal in real time fashion. First, multiple ROIs are detected. Then, the mesh for texture mapping is deformed, according to the position and shape of the ROIs. The original video frame is mapped as a texture on the deformed mesh to produce the warped effect. Mesh deformation and texture mapping are accelerated by modern graphics processing units (GPU). By allocating more display space for ROIs, the proposed technique highlights such important regions and assists the surveillant to locate them effectively. By experiments, we show that the proposed method is effective and efficient.
7629821
Sensor relocation in mobile sensor networks
Recently there has been a great deal of research on using mobility in sensor networks to assist in the initial deployment of nodes. Mobile sensors are useful in this environment because they can move to locations that meet sensing coverage requirements. This paper explores the motion capability to relocate sensors to deal with sensor failure or respond to new events. We define the problem of sensor relocation and propose a two-phase sensor relocation solution: redundant sensors are first identified and then relocated to the target location. We propose a Grid-Quorum solution to quickly locate the closest redundant sensor with low message complexity, and propose to use cascaded movement to relocate the redundant sensor in a timely, efficient and balanced way. Simulation results verify that the proposed solution outperforms others in terms of relocation time, total energy consumption, and minimum remaining energy.
12450638
A High Performance Application Representation for Reconfigurable Systems
Modern reconfigurable computing systems feature powerful hybrid architectures with multiple microprocessor cores, large reconfigurable logic arrays and distributed memory hierarchies. Mapping applications to these complex systems requires a representation that allows both hardware and software synthesis. Additionally, this representation must enable optimizations that exploit fine and coarse grained parallelism in order to effectively utilize the performance of the underlying reconfigurable architecture. Our work explores a representation based on the program dependence graph (PDG) incorporated with the static single-assignment (SSA) for synthesis to high performance reconfigurable devices. The PDG effectively describes control dependencies, while SSA yields precise data dependencies. When used together, these two representations provide a powerful, synthesizable form that exploits both fine and coarse grained parallelism. Compared to other commonly used representations for reconfigurable systems, the PDG+SSA form creates faster execution time, while using similar area.