7098845
Security Analysis of Several Group Signature Schemes
At Eurocrypt’91, Chaum and van Heyst introduced the concept of group signature. In such a scheme, each group member is allowed to sign messages on behalf of a group anonymously. However, in case of later disputes, a designated group manager can open a group signature and identify the signer. In recent years, researchers have proposed a number of new group signature schemes and improvements with different levels of security. In this paper, we present a security analysis of several group signature schemes proposed in [25, 27, 18, 31]. By using the same method, we successfully identify several universally forging attacks on these schemes. In our attacks, anyone (not necessarily a group member) can forge valid group signatures on any messages such that the forged signatures cannot be opened by the group manager. We also discuss the linkability of these schemes, and further explain why and how we find the attacks.
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.
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.
15430810
HARP: hard-wired routing pattern FPGAs
Modern FPGA architectures provide ample routing resources so that designs can be routed successfully. The routing architecture is designed to handle versatile connection configurations. However, providing such great flexibility comes at a high cost in terms of area, delay and power. We propose a new FPGA routing architecture\footnoteThis work was supported in part by a grant from NSF under contract CAREER CCF-0347891 that utilizes a mixture of hardwired and traditional flexible switches. The result is 24% reduction in leakage power consumption, 7% smaller area and 24% shorter delays, which translates to 30% increase in clock frequency. Despite the increase in clock speeds, the overall power consumption is %, including dynamic power, reduced by 8%.
40285763
Critical Points for Interactive Schema Matching
Experience suggests that fully automated schema matching is infeasible, especially for n-to-m matches involving semantic functions. It is therefore advisable for a matching algorithm not only to do as much as possible automatically, but also to accurately identify the critical points where user input is maximally useful. Our matching algorithm combines several existing approaches, with a new emphasis on using the context provided by the way elements are embedded in paths. A prototype tested on biological data (gene sequence, DNA, RNA, etc.) and on bibliographic data, shows significant performance improvements from user feedback and context checking. In non-interactive mode on the purchase order schemas, it compares favorably with COMA, the most mature schema matching system in literature, and also correctly identifies critical points for user input.
36826410
Web search with personalization and knowledge
Although many search engines provide relevantly good search results to the user, they do not consider personal, domain-specific preferences in their searching or ranking algorithms. In an intranet environment we could collect background information about users such as their expertise. If we can accumulate, categorize and personalize Web usage information, it can be used to help the user search Web pages efficiently and effectively. Data analysis and mining can further facilitate Web searching in an intelligent way. This paper describes Internet Search Advisor (ISA), a personalized, knowledge-driven search system that helps the user find informative Web sites. The ISA supports multi-dimensional data analysis and data mining based on association rules and sequential patterns.
11895032
A Signal-Dependent Quadratic Time Frequency Distribution for Neural Source Estimation
A novel method for kernel design of a quadratic time frequency distribution (TFD) as the initial step for neural source estimation is proposed. The kernel is constructed based on the product ambiguity function (AF), which efficiently suppresses cross terms and noise in the ambiguity domain. In order to reduce the influence from the strong signal to the weak signal, an iterative approach is implemented. Simulation results validate the method and demonstrate suppression of cross terms and noise, and high resolution in the time frequency domain.
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.