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1.
The concept of multisignature, in which multiple signers can cooperate to sign the same message and any verifier can verify the validity of the multi-signature, was first introduced by Itakura and Nakamura. Several multisignature schemes have been proposed since. Chen et al. proposed a new digital multi-signature scheme based on the elliptic curve cryptosystem recently. In this paper, we show that their scheme is insecure, for it is vulnerable to the so-called active attacks, such as the substitution of a "false" public key to a "true" one in a key directory or during transmission. And then the attacker can sign a legal signature which other users have signed and forge a signature himself which can be accepted by the verifier.  相似文献   

2.
In this paper,a beamforming (BF) based cooperation scheme with decode-and-forward (DF) protocol is proposed and its performance analysis is provided.Firstly,to solve the issue of carrier synchronization in distributed networks,a backward synchronization (B-Sync) method is introduced,where participating relays synchronize to the reference carrier broadcast by the destination and make signals superimposed coherently at the destination without any phase feedback.Then,based on B-sync,a cooperation scheme with DF protocol is proposed to carry out BF forwarding among relays.The outage probability of this scheme is derived and analyzed,which shows that the full diversity order can be achieved by the proposed scheme.Furthermore,symbol error probability (SEP) analysis is presented to evaluate the practical performance.Simulation results validate the analysis,and show that the proposed scheme outperforms other existing ones in terms of outage probability and SEP.  相似文献   

3.
In this paper,a composite control scheme for macro-micro dual-drive positioning stage with high acceleration and high precision is proposed.The objective of control is to improve the precision by reducing the influence of system vibration and external noise.The positioning stage is composed of voice coil motor(VCM) as macro driver and piezoelectric actuator(PEA) as micro driver.The precision of the macro drive positioning stage is improved by the combined PID control with adaptive Kalman filter(AKF).AKF is used to compensate VCM vibration(as the virtual noise) and the external noise.The control scheme of the micro drive positioning stage is presented as the integrated one with PID and intelligent adaptive inverse control approach to compensate the positioning error caused by macro drive positioning stage.A dynamic recurrent neural networks(DRNN) based inverse control approach is proposed to offset the hysteresis nonlinearity of PEA.Simulations show the positioning precision of macro-micro dual-drive stage is clearly improved via the proposed control scheme.  相似文献   

4.
Packet combining based on cross-packet coding   总被引:1,自引:0,他引:1  
We propose a packet combining scheme of using cross-packet coding. With the coding scheme, one redundant packet can be used to ensure the error-correction of multiple source packets. Thus, the proposed scheme can increase the code rate. Moreover, the proposed coding scheme has also advantages of decoding complexity, reducing undetectable errors (by the proposed low-complexity decoder) and flexibility (applicable to channels with and without feedback). Theoretical analysis under the proposed low-complexity decoding algorithm is given to maximize the code rate by optimizing the number of source packets. Finally, we give numerical results to demonstrate the advantages of the proposed scheme in terms of code rates compared to the traditional packet combining without coding or ARQ (automatic repeat-request) techniques.  相似文献   

5.
白涛  吴智铭 《自动化学报》2007,33(9):963-967
A hybrid bandwidth scheduling scheme is proposed to improve the quality of service and the bandwidth utilization for the CAN-based networked control systems. It combines rate monotonic and improved round-robin scheme for both the real-time and non-real-time data. Moreover, considering the constraints of control performance and network schedulability, a heuristic branch and bound genetic algorithm (GA) algorithm is presented for the control data to minimize their bandwidth occupancy and the jitter caused by improper scheduling. The residual bandwidth is allocated to non-real-time data by the proposed scale round-robin scheme such that their network loads are balanced.  相似文献   

6.
IEEE 802.11 Medium Access Control (MAC) is proposed to support asynchronous and time bounded delivery of radio packets. Distributed Coordination b-kmction (DCF), which uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) and binary slotted exponen-tial backoff, is the basis of the 802.11 MAC. This paper proposes a throughput enhancement for DCF by adjusting the Contention Window (CW) setting scheme. Moreover, an analytical model based on Markov chain is introduced to compute the enhanced throughput. The accuracy of the model and the enhancement of the proposed scheme are verified by elaborate simulations.  相似文献   

7.
Multi-path routing in the optical burst switching(OBS) networks can reduce the burst loss probability(BLP) by distributing the data burst traffic to multiple paths, compared with single path routing. Unlike the other multi-path routing schemes without considering the carrying capability of the routes, a new multi-path routing scheme based on effective voids(MPEV) is proposed to balance the load of multi-path and reduce the BLP in the paper. MPEV scheme first obtains the information on effective voids of the bottleneck link of multipath by sending a probe packet periodically. The effective voids can accommodate data bursts and accurately represent the available channel resource that is the main determinant of the BLP for OBS networks without optical random access memory. Then MPEV scheme distributes the burst traffic between an ingress node and an egress node to multiple link-disjoint paths by the ratio of the effective voids. More traffic is distributed to the path that has more effective voids, and vice versa. And the distributed amount is proportional to the effective voids of the bottleneck link. So MPEV scheme can balance the load of multi-path routes and can effectively reduce the BLP by avoiding the high load of a single path. And it is easy to implement and agilely adapt to dynamic network traffic. The performance of MPEV scheme is analyzed by queuing theory and is evaluated by simulation. The numerical results show that the proposed scheme can effectively reduce the BLP and balance the traffic load over multiple paths at the same time.  相似文献   

8.
Image registration is fundamental and crucial to remote sensing. However getting highly accurate registration performance automatically and fast for large-field images consistently is a challenge. As a work around to this problem, we propose a new image registration concept based on visual attention in this paper. This concept employs the advantages of feature-based or area-based methods to improve the precision and efficiency of image registration. The key concept of proposed integrated scheme is to make optimum use of the highly prominent details in the full scene by means of visual attention computational mechanism. To testify the validation, comparisons with other classical methods are carried out on real-world images. The experimental results show that the proposed method can effectively perform on multi-view/multi-temporal remote sensing images with outstanding precision and time saving performance.  相似文献   

9.
This paper introduces a practical algorithm for super-resolution,the process of reconstructing a high-resolution image from low-resolution input ones.The emphasis of the work is to super-resolve frames from real-world image/video sequences which may contain significant object occlusion or scene changes.As the quality of super-resolved images highly relies on the correctness of image alignment between consecutive frames,the robust optical flow method is used to accurately estimate motion between the image pair.An efficient and reliable scheme is devised to detect and discard incorrect matchings which may degrade the output quality.The usage of elliptical weighted average (EWA) filter is also introduced to model the point spread function (PSF) of acquisition system in order to improve accuracy of the model.A number of complex video sequences are tested to demonstrate the applicability and reliability of the proposed algorithm.  相似文献   

10.
A novel networked data-fusion method is developed for the target tracking in wireless sensor networks (WSNs). Specifically, this paper investigates data fusion scheme under the communication constraint between the fusion center and each sensor. Such a message constraint is motivated by the bandwidth limitation of the communication links, fusion center, and by the limited power budget of local sensors. In the proposed scheme, each sensor collects one noise-corrupted sample, performs a quantizing operation, and transmits quantized message to the fusion center. Then the fusion center combines the received quantized messages to produce a final estimate. The novel data-fusion method is based on the quantized measurement innovations and decentralized Kalman filtering (DKF) with feedback. For the proposed algorithm, the performance analysis of the estimation precision is provided. Finally, Monte Carlo simulations show the effectiveness of the proposed scheme.  相似文献   

11.
王璐  亢保元 《计算机与数字工程》2012,40(10):102-104,165
盲签名和代理多重签名在电子商务和电子现金系统中有着广泛的应用.结合这两种签名的特点,人们提出了代理盲多重签名方案.在代理盲多重签名中,一个原始签名组将签名权委托给代理签名人,由其对签名请求者发送来的盲化消息进行代理签名.通过分别对秦艳琳等人和周立章提出的代理盲多重签名方案的安全性分析,发现秦的方案中一个恶意的原始签名人可以伪造出代理签名密钥,从而生成代理盲多重签名;并同时指出周的方案无法抵挡代理签名伪造攻击,不满足不可伪造性.针对上述两种攻击,在秦方案的基础上提出了一种新的方案,证明及分析了新方案的正确性和安全性.该方案有效地克服了原方案的缺陷,并满足代理盲多重签名的各种要求,提高了系统的安全性.  相似文献   

12.
指出了文献[1]方案中存在的安全性问题,随后利用椭圆曲线密码算法设计了一个新的有序多重数字签名方案,且不使用哈希函数和消息冗余函数,减少了这方面所带来的安全威胁;取消了施方案里的签名中心,避免了该签名中心的参与导致计算瓶颈的产生;所有消息均公开,签名者可以共同通过验证来发现伪签名和成员内部的欺诈行为.此方案能够克服施方案的安全问题,并且计算量小,结构简单,具有一定的实用价值.  相似文献   

13.
多重代理多重签名体制中,原始签名群可以将签名权利委托给代理签名群,再由这些代理签名人联合生成一个代表所有原始签名人的数字签名。通过对ECC签名方案和多重代理多重签名的分析,提出了一个基于ECC的多重代理多重签名方案,该方案有较好的安全性和实用性。  相似文献   

14.
多重代理多重签名体制中,原始签名群可以将签名权利委托给代理签名群,再由这些代理签名人联合生成一个代表所有原始签名人的数字签名。通过对ECC签名方案和多重代理多重签名的分析,提出了一个基于ECC的多重代理多重签名方案,该方案有较好的安全性和实用性。  相似文献   

15.
在研究代理多重签名和椭圆曲线数字签名的基础上,提出了一种基于椭圆曲线的多重代理多重签名方案。一组原签名人可以共同授权给一组代理签名人,授权代理签名组的所有成员一起可以代替原签名组成员行使签名权利。其安全性基于求解椭圆曲线离散对数的困难性,比已有的方案更加安全、高效;最后讨论了其正确性和有效性。  相似文献   

16.
秦艳琳  吴晓平 《计算机工程》2010,36(11):134-136,139
在讨论代理多重签名方案、多重代理签名方案、多重代理多重签名方案及盲签名方案设计原理的基础上,将多重代理多重签名方案与盲签名方案相结合,提出基于椭圆曲线密码的广播多重代理多重盲签名方案和有序多重代理多重盲签名方案,并对其进行安全性分析,分析结果表明,2类方案均满足多重代理多重签名的安全特性及盲签名的盲性和不可追踪性。  相似文献   

17.
椭圆曲线密码体制(ECC)以椭圆曲线离散对数问题的难解性为基础,相比其他密码体制,其安全性更高、操作数更短,针对该特点,设计基于ECC的自认证盲签密方案。该方案对签密消息进行盲化处理,非法用户在未知盲因子的情况下很难分析出明消息,可有效防止非法用户对消息进行抵赖、伪造和篡改,满足盲签密的正确性、匿名性、不可伪造性和不可跟踪性。  相似文献   

18.
一个基于超椭圆曲线的单向数字签名   总被引:1,自引:0,他引:1  
蔡庆华  程一飞 《微机发展》2006,16(1):221-222
超椭圆曲线密码体制(HECC)是椭圆曲线密码体制(ECC)的自然推广,但不仅仅是一种简单的推广。HECC与ECC相比有速度快、基域小的优点。而单向签名是一种只有特定的用户才能验证的数字签名方案。该文基于超椭圆曲线密码体制提出了一个单向签名方案,并分析了其安全性。与现有方案相比,本方案有一定的优势。  相似文献   

19.
分布式PKI在移动Ad Hoc网中的应用   总被引:1,自引:0,他引:1  
介绍了一种基于椭圆曲线和门限算法的数字签名算法,并提出了一个基于分布式PKI的移动Ad Hoc网络安全体系结构。该体系结构中主要采用了分布式PKI安全机制、门限密钥管理、椭圆曲线算法和动态网络分簇思想。分布式PKI和门限密钥管理的应用增加了系统的安全性、容错性,椭圆曲线算法的应用减少了对移动节点的性能的要求,分簇算法的应用减少了对节点容量的要求。  相似文献   

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