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.
7929836
Security Analysis of Two Signcryption Schemes
Signcryption is a new cryptographic primitive that performs signing and encryption simultaneously, at a cost significantly lower than that required by the traditional signature-then-encryption approach. In this paper, we present a security analysis of two such schemes: the Huang-Chang convertible signcryption scheme [12], and the Kwak-Moon group signcryption scheme [13]. Our results show that both schemes are insecure. Specifically, the Huang-Chang scheme fails to provide confidentiality, while the Kwak-Moon scheme does not satisfy the properties of unforgeability, coalition-resistance, and traceability.
1447896
Universal forgery on a group signature scheme using self-certified public keys
A group signature scheme allows any group member to sign messages on behalf of the group in an anonymous and unlinkable fashion. In the event of a dispute, a designated group manager can reveal the identity of the signer. In 1999, Tseng and Jan proposed a group signature scheme using self-certified public keys. By attacking their signature verification equation, we demonstrate that their scheme is universally forgeable, i.e., anybody can forge a valid group signature on any message such that the group manager is unable to determine the identity of the signer.
10216231
On the Security of Two Threshold Signature Schemes with Traceable Signers
A (t,n) threshold signature scheme allows t or more group members to generate signatures on behalf of a group with n members, while any t-1 or less members cannot do the same thing. In 2001, based on a variant of ElGamal digital signature scheme, Li et al. proposed two (t,n) threshold signature schemes with traceable signers. One of their schemes needs the assistance of a mutually trusted center, while the other does not. In this paper, we present a security analysis on their schemes. We first point out that in fact signers in their schemes are untraceable, since anybody can convert a valid threshold signature into a new one such that another subset of group members will be wrongly considered as the signers of the new threshold signature for the same message. Furthermore, we demonstrate an attack to show that their second threshold signature scheme is insecure. In our attack, (n-t+1) colluding members can control the group secret key. Therefore, they can generate valid threshold signature for any message without the help of other members. Furthermore, honest members cannot detect this security flaw in the system, since any t members can generate threshold signatures according to the prescribed protocols.
5847473
Generic non-repudiation protocols supporting transparent off-line TTP
A non-repudiation protocol enables the fair exchange of an electronic message and an irrefutable digital receipt between two mistrusting parties over the Internet. That is, at the end of any execution instance of such a protocol, either both parties obtain their expected items or neither party does. In this paper, we first argue that it is really meaningful in practice to exploit generic fair non-repudiation protocols with transparent off-line trusted third party (TTP). Namely, in those protocols, each involved party could use any secure digital signature algorithm to produce non-repudiation evidences; and the issued evidences are the same regardless of whether the TTP is involved or not. Then, we present such a fair non-repudiation protocol to overcome some limitations and shortcomings in previous schemes. Technical discussions are provided to show that our protocol is not only secure but also the most efficient solution, compared with existing non-repudiation protocols. In addition, some potential extensions are also pointed out.
17370273
On the Security of a Certified E-Mail Scheme with Temporal Authentication
Certified e-mail is a value-added service for standard e-mail systems, in which the intended recipient gets the mail content if and only if the mail originator receives a non-repudiation evidence that the message has been received by the recipient. As far as security is concerned, fairness is one of the most important requirements. Recently, Galdi and Giordano (2004) presented an optimistic protocol for certified e-mail with temporal authentication. In this paper, we analyze their protocol and demonstrate that it cannot achieve true fairness and has some other weaknesses. We further propose the improvements to avoid those security problems.
9542759
Defect-Tolerant Nanocomputing Using Bloom Filters
The authors propose a novel defect-tolerant design methodology using Bloom filters for defect mapping for nanoscale computing devices. It is a general approach that can be used for any permanent defects incurred during the manufacturing process. The redundant design methodology does not rely on a voting strategy, thus it utilizes the device redundancy more effectively than existing approaches. Additionally, our method does not have false-positive in defect identification, i.e. it will not report a defective device as functional. Moreover, it is very space economic and can be programmed to fit different scales and characteristics of the underlying specific nanoscale devices used in the system
47051192
Measurement-based analysis, modeling, and synthesis of the internet delay space
1009884
Movement-assisted sensor deployment
Abstract-Adequate coverage is very important for sensor networks to fulfill the issued sensing tasks. In many working environments, it is necessary to make use of mobile sensors, which can move to the correct places to provide the required coverage. In this paper, we study the problem of placing mobile sensors to get high coverage. Based on Voronoi diagrams, we design two sets of distributed protocols for controlling the movement of sensors, one favoring communication and one favoring movement. In each set of protocols, we use Voronoi diagrams to detect coverage holes and use one of three algorithms to calculate the target locations of sensors it holes exist. Simulation results show the effectiveness of our protocols and give insight on choosing protocols and calculation algorithms under different application requirements and working conditions.
62533537
Movement-Assisted Sensor Deployment
Abstract-Adequate coverage is very important for sensor networks to fulfill the issued sensing tasks. In many working environments, it is necessary to make use of mobile sensors, which can move to the correct places to provide the required coverage. In this paper, we study the problem of placing mobile sensors to get high coverage. Based on Voronoi diagrams, we design two sets of distributed protocols for controlling the movement of sensors, one favoring communication and one favoring movement. In each set of protocols, we use Voronoi diagrams to detect coverage holes and use one of three algorithms to calculate the target locations of sensors it holes exist. Simulation results show the effectiveness of our protocols and give insight on choosing protocols and calculation algorithms under different application requirements and working conditions.
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.