1647421
Generic, Optimistic, and Efficient Schemes for Fair Certified Email Delivery
As a value-added service for standard email systems, a certified email 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 email simultaneously, or neither party gets the expected item. In this paper, we first point out some weaknesses in several existing schemes. Then, we present two generic optimistic certified email schemes with transparent TTP. Our schemes are not only fair, but also support timeliness in two flavors: one scheme supports weak timeliness but with stateless TTP, while the other guarantees (strong) timeliness though only supports weak stateless TTP. Technical discussion and comparison are provide to show that our schemes are both secure and efficient, compared with the-state-of-art in this field.
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.
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.
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.
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.
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.
52293772
Optimizing sensor movement planning for energy efficiency
Conserving the energy for motion is an important yet not-well-addressed problem in mobile sensor networks. In this paper, we study the problem of optimizing sensor movement for energy efficiency. We adopt a complete energy model to characterize the entire energy consumption in movement. Based on the model, we propose an optimal velocity schedule for minimizing energy consumption when the road condition is uniform; and a near optimal velocity schedule for the variable road condition by using continuous-state dynamic programming. Considering the variety in motion hardware, we also design one velocity schedule for simple microcontrollers, and one velocity schedule for relatively complex microcontrollers, respectively. Simulation results show that our velocity planning may have significant impact on energy conservation
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.
12571017
A Metadata Integration Assistant Generator for Heterogeneous Distributed Databases
This paper describes a metadata interchange approach for semi-automatedin tegration of heterogeneous distributedd atabases. Our system prototype uses distributed metadata to generate a GUI tool for a meta-user (who does the metadata integration) to describe mappings between master and source databases by assigning index number and specifying conversion function names; the system uses Quilt as its XML query language. The queries for the local databases being transparent for users are generated, which is based on the metadata built semi-automatically. An experiment testing feasibility is reportedin which 3 different publishers' databases are integrated.
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.