一个可验证的门限多秘密分享方案

基于离散对数计算和大整数分解的困难性,利用RSA加密体制提出了一个新的门限多秘密分享方案.该方案通过零知识证明等协议来防止秘密分发者和秘密分享者的欺诈行为,因而是一个可验证的门限多秘密分享方案.该方案还具有:秘密影子可重复使用;子秘密影子可离线验证;供分享的秘密不须事先作预计算等特点.该方案可用于会议密钥(秘密)分配、安全多方计算、门限数字签名等应用领域.     

签密的门限生成协议

本文首次探讨了签密的门限生成问题，利用可验证秘密分享（VSS）和安全多方计算（MPC）技术提出了一个签密的门限生成协议。在该协议中，发送方的任何至少t个成员可生成对给定消息的有效的签密密文，而能勾结至多t-1个成员的攻击者无法伪造有效的签密密文。文中还改进了由Gennaro R,Jarecki S,Krawczyk H和Rabin T提出的计算秘密值的倒数的协议，使其效率得到了提高。     

向量空间接入结构上信息论安全的可验证秘密分享

可验证秘密分享在诸如对机密信息的安全保存与合法利用、密钥托管、面向群体的密码学、多 方安全计算、接入控制及电子商务等许多方面都有着广泛的应用。该文对向量空间接入结构上的可验证秘密分享进行了研究。提出了这类接入结构上的一个信息论安全的高效可验证秘密分享协议。新提出的协议不仅具有较高的信息速率,而且计算和通信代价都远远的低于已有的广义可验证秘密分享协议。     

基于向量空间接入结构的分布式密钥生成

密钥生成是密码系统的一个重要组成部分,其安全性对整个密码系统的安全性起着至关重要的作用.在群体保密通信、电子商务和面向群体的密码学中,往往需要采用分布式的密钥生成方式.本文对基于向量空间接入结构的分布式密钥生成进行了研究.以向量空间接入结构上信息论安全的一个可验证秘密分享方案为基础,提出了适应于这类接入结构的一个安全高效的分布式密钥生成协议.该协议比常见的基于门限接入结构的分布式密钥生成协议具有更广泛的适用性.     

数据相等问题的安全多方计算方案研究

安全多方计算是国际密码学界近年来的研究热点.本文主要研究科学计算中多个数据相等问题的安全多方计算,目前关于这个问题的研究还很少.本文设计了一种新的编码方法,以新的编码方法与ElGamal同态加密算法为基础,分别利用秘密分享技术和门限密码体制构造了两个在半诚实模型下能够抵抗合谋攻击的保密判定协议,应用模拟范例证明了协议的安全性,效率分析表明所设计的保密计算协议是高效的协议.并进一步设计了恶意模型下的安全计算方案.     

广义(k,n)-门限方案

１９７９年，Ｓｈａｍｉｒ提出的（ｋ，ｎ）－门限密钥分散管理的概念使密钥管理更加安全灵活。但这一方案也有其不完善之处，因为在现实中参与密钥管理的人在系统中所处的地位不尽相同，有许多活动必须要求某些特定的人参与才能进行。本文考查了此类情形，将（ｋ，ｎ）－门限方案加以推广，提出了更为一般的（ｔ，ｋ，ｎ）－门限方案，给出（ｔ，ｋ，ｎ）－秘密分享矩阵的概念，并利用（ｔ，ｋ，ｎ）－秘密分享矩阵实现（ｔ，ｋ，ｎ）－门限方案。     

基于广义可验证秘密分享的分布式密钥生成

利用广义可验证秘密分享,提出了基于离散对数的公钥体制的密钥的分布式生成协议.该协议适用于任意的接入结构,具有需要各参与者保存的秘密信息的数据量小,能保证所生成的私钥的随机性和均匀分布性等特点.因而与通常的基于门限接入结构的分布式密钥生成协议相比能够更广泛的应用于群体密码学中的各种场合.     

（2，2）贝叶斯理性秘密共享方案

在理性秘密共享协议中,自利性目标可能会驱使理性参与者偏离协议,从而影响协议的公平性。在（t, n）门限理性秘密共享方案中,其特殊情形（2,2）理性秘密共享方案的公平性较难实现。在同时考虑理性参与者的眼前利益和长远利益的基础上,基于不完全信息动态博弈模型,通过分析理性参与者在（2,2）秘密重构阶段可能采取的策略和信念系统,引入理性参与者的期望收益,研究了（2,2）理性秘密共享重构阶段的完美贝叶斯均衡问题。进一步结合机制设计理论中的VCG（Vickrey-Clarke-Groves）机制,设计激励相容的交互记录机制来约束理性参与者的行为,在不需要秘密分发者保持在线的情形下,提出一个适用于异步通信的公平的（2,2）理性秘密共享方案。     

一种基于可验证秘密分享的密钥管理方案

介绍了一种应用于PKI系统中安全的密钥管理方案。利用秘密分享的方法来备份和恢复私钥,有效维护私钥的安全性,防止由一方单方面独享私钥。该方案采用可验证的秘密分享协议有效地解决了分享者欺骗的问题。     

门限多重秘密共享方案

本文提出了一个门限多重秘密共享方案,其安全性依赖于RSA数字签名的安全性,即大数分解的困难性.该方案具有如下特点:参与者的子秘密可反复使用,可用来共享任意多个秘密;能有效预防管理员欺诈及参与者之间的互相欺骗;此外,在验证是否有欺诈行为存在的过程中,不需要执行交互协议.     

Multipartite Secret Sharing Based on CRT

Secure communication has become more and more important for system security. Since avoiding the use of encryption one by one can introduce less computation complexity, secret sharing scheme (SSS) has been used to design many security protocols. In SSSs, several authors have studied multipartite access structures, in which the set of participants is divided into several parts and all participants in the same part play an equivalent role. Access structures realized by threshold secret sharing are the simplest multipartite access structures, i.e., unipartite access structures. Since Asmuth–Bloom scheme based on Chinese remainder theorem (CRT) was presented for threshold secret sharing, recently, threshold cryptography based on Asmuth–Bloom secret sharing were firstly proposed by Kaya et al. In this paper, we extend Asmuth–Bloom and Kaya schemes to bipartite access structures and further investigate how SSSs realizing multipartite access structures can be conducted with the CRT. Actually, every access structure is multipartite and, hence, the results in this paper can be seen as a new construction of general SSS based on the CRT. Asmuth–Bloom and Kaya schemes become the special cases of our scheme.     

没有SDC的(t，n)门限秘密共享方案

利用椭圆曲线离散问题对数问题的难解性,给出了基于椭圆曲线密码体制的(t,n)门限秘密共享方案。基于门限秘密共享方案一般分为需要SDC和不需要SDC两类,在分布式环境下,一个被所有成员信任的SDC并不存在,不需要SDC的门限秘密共享方案的安全性得到很大的提高,该方案中由组成员共同生成群公钥和私有密钥。并给出了当新成员加入时,无SDC下的周期密钥分片的更新方案。还给出了一个本方案数据实例,最后对本方案的安全性进行了分析。     

一种共享份分块构造的异或区域递增式视觉密码方案

该文依据授权子集的个数将共享份划分若干块,按照共享份分块构造的设计思路,结合(n, n)异或单秘密视觉密码的加密矩阵,构造了异或区域递增式视觉密码的秘密分享与恢复流程。与现有方案相比,该方案可以实现解密区域图像的完全恢复,且明显减小了共享份的大小。     

视觉密码方案概述

视觉密码(VC)是一种用于分享秘密图像的加密方案,与传统的密码技术相比具有简单性、安全性、隐蔽性等优点。其加密是将图像编码为分享,将分享打印在透明胶片上或以数字形式存储;其解密过程是对分享进行叠加,然后通过人类的视觉能力来实现。本文介绍了视觉密码的基本概念和各种不同的视觉密码方案,以及每种方案中使用的技术。此外,对视觉密码在不同领域上的应用做出了说明。     

无线传感器网络层簇式密钥管理方案的研究

密钥管理是无线传感器网络安全机制最关键的技术之一。该文分析比较了各种密钥管理方案,认为组密钥管理更适合于无线传感器网络。并在集中式和分布式两种组密钥管理方案的基础上,提出了新的层簇式密钥管理架构,并解决了这两种方案存在的安全缺陷。而组间通信则采用基于(t, n)门限方案的密钥分割机制来实现。该新方案能保证无线传感器网络安全需求的同时改善执行效能。     

Friendly progressive random-grid-based visual secret sharing with adaptive contrast

Visual secret sharing (VSS) schemes providing secret communication services are classified into two categories depending on the method of encoding the secret: visual cryptography (VC)-based and random grid (RG)-based schemes. A friendly progressive version of the VC-based VSS scheme was presented in 2008; however, it is marred by pixel expansion, which is the innate deficiency of conventional VC-based VSS schemes. This paper proposes a suitable user-friendly RG-based VSS scheme with progressive secret reconstruction and without pixel expansion. The experimental results of the developed scheme validated its feasibility, and a theoretical analysis demonstrated its visual quality and security.     

A new authentication based cheating prevention scheme in Naor–Shamir’s visual cryptography

Visual cryptography (VC), first presented by Naor and Shamir, is a variant of secret sharing, thus it also called visual secret sharing. It can be widely used in many applications such as encrypting large data efficiently. In the literature, the problem of cheating is under consideration in secret sharing. Recently, Horng et al. pointed out that cheating is possible in k-out-of-n VC schemes, and presented two kinds of the cheating prevention schemes for protecting honest participants. One of them is the authentication based cheating prevention scheme. In this paper, we analyze the definition of cheating prevention and propose a new authentication based cheating prevention scheme. This scheme is constructed with Naor–Shamir’s VC scheme. Finally, we give the security analysis to prove that the proposed scheme is immune to cheating.     

Distributed node selection for threshold key management with intrusion detection in mobile ad hoc networks

In mobile ad hoc networks (MANETs), identity (ID)-based cryptography with threshold secret sharing is a popular approach for the security design. Most previous work for key management in this framework concentrates on the protocols and structures. Consequently, how to optimally conduct node selection in ID-based cryptography with threshold secret sharing is largely ignored. In this paper, we propose a distributed scheme to dynamically select nodes with master key shares to do the private key generation service. The proposed scheme can minimize the overall threat posed to the MANET while simultaneously taking into account of the cost (e.g., energy consumption) of using these nodes. Intrusion detection systems are modeled as noisy sensors to derive the system security situations. We use stochastic system to formulate the MANET to obtain the optimal policy. Simulation results are presented to illustrate the effectiveness of the proposed scheme.     

基于多项式秘密共享的前摄性门限RSA签名方案

现有可证明安全的前摄性门限RSA签名方案均依赖加性秘密共享方法,存在每次签名均需所有成员参与,易暴露合法成员的秘密份额,签名效率低下等问题。该文以Shoup门限签名为基础,提出一种基于多项式秘密共享的前摄性门限RSA签名方案,并对其进行了详细的安全性及实用性分析。结果表明,在静态移动攻击者模型中,该方案是不可伪造的和稳健的,与现有同类方案相比,其通信开销更低,运算效率更高。     

Mutually Trusted Authority-Free Secret Sharing Schemes

Traditional secret sharing schemes involve the use of a mutually trusted authority to assist in the generation and distribution of shares that will allow a secret to be protected among a set of participants. In contrast, this paper addresses the problem of establishing secret sharing schemes for a given access structure without the use of a mutually trusted authority. A general protocol is discussed and several implementations of this protocol are presented. Several efficiency measures are proposed and we consider how to refine the general protocol in order to improve the efficiency with respect to each of the proposed measures. Special attention is given to mutually trusted authority-free threshold schemes. Constructions are presented for such threshold schemes that are shown to be optimal with respect to each of the proposed efficiency measures. Received 13 September 1995 and revised 10 April 1996