A Novel （n, n） Secret Image Sharing Scheme Based on Sudoku

Recently, Chang et al. proposed a Sudoku-based secret image sharing scheme. They utilized the Sudoku grid to generate meaningful shadow images, and their scheme satisfied all essential requirements. Based on Chang et al.'s scheme, we propose a novel (n, n) secret image sharing scheme based on Sudoku. In the proposed scheme, a secret image can be shared among n different cover images by generating n shadow images, and the secret image can be reconstructed without distortion using only these n shadow images. Also, the proposed scheme can solve the overflow and underflow problems. The experimental results show that the visual quality of the shadow images is satisfactory. Furthermore, the proposed scheme allows for a large embedding capacity.     

）istortion-Free Data Embedding Scheme for Hig Dynamic Range Images

Distortion-free data embedding is a technique which can assure that not only the secret data is correctly extracted but also the cover media is recovered without any distortion after secret data is extracted completely. Because of these advantages, this technique attracts the attention of many researchers. In this paper, a new distortion-free data embedding scheme for high dynamic range (HDR) images is proposed. By depending on Cartesian product, this scheme can obtain higher embedding capacity while maintaining the exactly identical cover image and stego image when using the tone mapping algorithms. In experimental results, the proposed scheme is superior to Yu et al.'s scheme in regard to the embedding rate-an average embedding rate of 0.1355 bpp compared with Yu et al.'s scheme (0.1270 bpp).     

新的基于变色龙的车载通信安全与隐私保护

在车载自组网（VANET）中许多服务和应用需要保护数据通信的安全,为提高驾驶的安全性和舒适性,一些与交通状况有关的信息就要被周期性地广播并分享给司机,如果用户的身份和信息没有隐私和安全的保证,攻击者就会通过收集和分析交通信息追踪他们感兴趣的车辆,因此,匿名消息身份验证是VANET中不可或缺的要求。另一方面,当车辆参与纠纷事件时,证书颁发机构能够恢复车辆的真实身份。为解决车载通信这一问题,郭等人在传统方案的基础上提出一种基于椭圆曲线的变色龙散列的隐私保护验证协议。虽然此方案较之前方案具有车辆身份可追踪性和高效率性,但分析表明此方案不满足匿名性。对郭等人的方案进行安全性分析并在此基础上做出改进。     

Lossless Data Hiding Scheme Based on VQ Index Coding

Lossless data hiding can restore the original status of cover media after embedded secret data are extracted. In 2010, Wang et al. proposed a lossless data hiding scheme which hides secret data in vector quantization (VQ) indices, but the encoding strategies adopted by their scheme expand the final codestream. This paper designs four embedding and encoding strategies to improve Wang et al.'s scheme. The experiment result of the proposed scheme compared with that of the Wang et al.'s scheme reduces the bit rates of the final codestream by 4.6% and raises the payload by 1.09% on average.     

Analysis and improvement on identity-based cloud data integrity verification scheme

Many individuals or businesses outsource their data to remote cloud.Cloud storage provides users the advantages of economic convenience,but data owners no longer physically control over the stored data,which introduces new security challenges,such as no security guarantees of integrity and privacy.The security of two identity-based cloud data integrity verification schemes by Zhang et al and Xu et al respectively are analysed.It shows that Zhang et al.’s scheme is subjected to secret key recovery attack for the cloud servers can recover user’s private key only utilizing stored data.And Xu et al.’s scheme cannot satisfy security requirements of soundness.Based on Xu et al.'s scheme,a modified identity-based cloud data integrity verification scheme is proposed.A comprehensive analysis shows the new scheme can provide the security requirements of soundness and privacy,and has the same communication overhead and computational cost as Xu et al.’s scheme.     

Hierarchical Threshold Secret Sharing

We consider the problem of threshold secret sharing in groups with hierarchical structure. In such settings, the secret is shared among a group of participants that is partitioned into levels. The access structure is then determined by a sequence of threshold requirements: a subset of participants is authorized if it has at least k₀ 0 members from the highest level, as well as at least k₁ > k₀ members from the two highest levels and so forth. Such problems may occur in settings where the participants differ in their authority or level of confidence and the presence of higher level participants is imperative to allow the recovery of the common secret. Even though secret sharing in hierarchical groups has been studied extensively in the past, none of the existing solutions addresses the simple setting where, say, a bank transfer should be signed by three employees, at least one of whom must be a department manager. We present a perfect secret sharing scheme for this problem that, unlike most secret sharing schemes that are suitable for hierarchical structures, is ideal. As in Shamir's scheme, the secret is represented as the free coefficient of some polynomial. The novelty of our scheme is the usage of polynomial derivatives in order to generate lesser shares for participants of lower levels. Consequently, our scheme uses Birkhoff interpolation, i.e., the construction of a polynomial according to an unstructured set of point and derivative values. A substantial part of our discussion is dedicated to the question of how to assign identities to the participants from the underlying finite field so that the resulting Birkhoff interpolation problem will be well posed. In addition, we devise an ideal and efficient secret sharing scheme for the closely related hierarchical threshold access structures that were studied by Simmons and Brickell.     

基于ECC的可公开验证的非交互式密钥共享方案

提出一种基于椭圆曲线加密的非交互式零知识证明协议,并基于该证明协议提出一个可公开验证的密钥共享方案.在该方案中,密钥和密钥份额被嵌入椭圆曲线的点上,任何人均可对密钥和密钥份额进行验证,只有合法参与者集合可恢复出密钥,但无法知道密钥的具体内容;这样有效阻止了攻击者窃取密钥,也防止了数据的误发和成员之间的欺诈,更有利于密钥的复制与更新.     

The Size of a Share Must Be Large

A secret sharing scheme permits a secret to be shared among participants of an n-element group in such a way that only qualified subsets of participants can recover the secret. If any nonqualified subset has absolutely no information on the secret, then the scheme is called perfect. The share in a scheme is the information that a participant must remember. In [3] it was proved that for a certain access structure any perfect secret sharing scheme must give some participant a share which is at least 50\percent larger than the secret size. We prove that for each n there exists an access structure on n participants so that any perfect sharing scheme must give some participant a share which is at least about times the secret size.^1 We also show that the best possible result achievable by the information-theoretic method used here is n times the secret size. ^1 All logarithms in this paper are of base 2. Received 24 November 1993 and revised 15 September 1995     

多重门限的图像秘密共享方案

 针对传统的基于视觉密码的图像秘密共享方案存在像素扩张导致其只能共享小尺寸的秘密图像、信息隐藏效率较低的问题,提出一种能够提高信息隐藏容量的(t,k,n)多重门限图像秘密共享方案.该方案利用秘密图像信息控制视觉密码方案中共享矩阵的选取,从而实现秘密图像在视觉密码方案中的隐藏.在秘密图像恢复的第一阶段,任意t个参与者直接叠加其影子图像后可以视觉解密出低质量的秘密图像信息;在第二阶段,任意k个参与者可以从影子图像中提取出隐藏的信息,并通过计算恢复出精确的灰度秘密图像.相对于传统的视觉密码方案,本文方案在不影响视觉密码恢复图像的视觉质量前提下,可以隐藏更多的秘密图像信息,而像素扩张尺寸较小.     

对安全有效的(t,n)多秘密共享认证方案的改进

最近,谢琪等人(2005)基于双密钥思想提出了一种多秘密共享认证方案。在他们方案的秘密重构阶段,每个成员必须同时使用两个子密钥来证实自己没有欺骗。本文给出了一种攻击方法表明他们的方案并不能有效抵制成员的欺骗。同时给出了一种改进方案,不仅弥补了谢琪等人方案的安全缺陷,而且在秘密重构时采用并行算法来降低运算复杂度。     

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.     

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.     

WSN中基于乱序多项式对偶密钥的攻击方案

针对Guo等的WSN中基于乱序对称多项式的对偶密钥方案提出一种攻击方案。通过构造黑盒的方式,对多项式进行攻击,通过整体求解多项式集合,而不是求解单个多项式的方式,使多项式的排列顺序在多项式的破解中失去作用,从而实现乱序多项式的破解。定理证明和实例分析表明Guo等的方案不能抵御大规模节点俘获攻击,未能突破多项式的容忍门限,是一种不安全的方案。     

Dual Image Reversible Data Hiding by Modifying Least-Significant-Bit Matching Revisited Rules

The concept of dual image reversible data hiding (DIRDH) is the technique that can produce two camouflage images after embedding secret data into one original image. Moreover, not only can the secret data be extracted from two camouflage images but also the original image can be recovered. To achieve high image quality, Lu et al.'s method applied least-significant-bit (LSB) matching revisited to DIRDH. In order to further improve the image quality, the proposed method modifies LSB matching revisited rules and applies them to DIRDH. According to the experimental results, the image quality of the proposed method is better than that of Lu et al.'s method.     

多分存彩色图像秘密共享（2，n）方案

文献[2]中提出了一种基于异或（XOR）操作的彩色图像秘密共享（2,n）方案,简单易于实现,但恢复密图的效果较差。通过分析此方案,文章提出一个多分存的彩色图像秘密共享（2,n）方案,通过给用户增加分存图像的方法改善了恢复密图的质量。实验分析表明所提方案不仅取得了很好的恢复效果,而且保持了安全性和算法的简单性。     

Encrypted signal-based reversible data hiding with public key cryptosystem

Encrypted image-based reversible data hiding (EIRDH) is a well-known method allowing that (1) the image provider gives the data hider an encrypted image, (2) the data hider embeds the secret message into it to generate the encrypted image with the embedded secret message to the receiver, and (3) finally the receiver can extract the message and recover the original image without encryption. In the literature, the data hider and image provider must be specific parties who know the shared key with the receiver in traditional encrypted image-based reversible data hiding. In this paper, we propose an encrypted signal-based reversible data hiding (ESRDH) with public key cryptosystem, not only for images. The proposed scheme is secure based on Paillier homomorphic encryption. Finally, the experimental results show that the proposed scheme has much payload and high signal quality.     

GOMSS: A Simple Group Oriented (t,m, n) Multi-secret Sharing Scheme

In most (t,n)-Multi-secret sharing ((t,n)-MSS) schemes, an illegal participant, even without any valid share, may recover secrets when there are over t participants in secret reconstructions. To address this problem, the paper presents the notion of Group ori-ented (t,m,n)-multi-secret sharing (or (t,m,n)-GOMSS), in which recovering each secret requires all m (n ≥ m ≥ t) participants to have valid shares and actually participate in secret reconstruction. As an example, the paper then pro-poses a simple (t,m,n)-GOMSS scheme. In the scheme, every shareholder has only one share; to recover a secret, m shareholders construct a Polynomial-based randomized component (PRC) each with the share to form a tightly coupled group, which forces the secret to be recovered only with all m valid PRCs. As a result, the scheme can thwart the above illegal participant attack. The scheme is simple as well as flexible and does not depend on conventional hard problems or one way functions.     

On the size of shares for secret sharing schemes

A secret sharing scheme permits a secret to be shared among participants in such a way that only qualified subsets of participants can recover the secret, but any nonqualified subset has absolutely no information on the secret. The set of all qualified subsets defines the access structure to the secret. Sharing schemes are useful in the management of cryptographic keys and in multiparty secure protocols.We analyze the relationships among the entropies of the sample spaces from which the shares and the secret are chosen. We show that there are access structures with four participants for which any secret sharing scheme must give to a participant a share at least 50% greater than the secret size. This is the first proof that there exist access structures for which the best achievable information rate (i.e., the ratio between the size of the secret and that of the largest share) is bounded away from 1. The bound is the best possible, as we construct a secret sharing scheme for the above access structures that meets the bound with equality.This work was partially supported by Algoritmi, Modelli di Calcolo e Sistemi Informativi of M.U.R.S.T. and by Progetto Finalizzato Sistemi Informatici e Calcolo Parallelo of C.N.R. under Grant Number 91.00939.PF69.     

Improvements of a two-in-one image secret sharing scheme based on gray mixing model

Yang and Ciou recently proposed a two-in-one image secret sharing scheme (TiOISSS), which can easily preview a vague image by human eyes, but also provide a perfect reconstruction of the original image by computation. However, their scheme cannot recover the lossless image by computation as they claimed. In this paper, we resolve the problem of lossless reconstruction. In addition, we improve the visual quality of the previewed image. Also, we introduce a new definition of contrast to evaluate the visual quality of the previewed image. Compared with Yang and Ciou’s TiOISSS, our scheme can gain the lossless secret image and meantime enhance the contrast of previewed image.     

An authenticated group key distribution mechanism using theory of numbers

A group key distribution protocol can enable members of a group to share a secret group key and use it for secret communications. In 2010, Harn and Lin proposed an authenticated group key distribution protocol using polynomial‐based secret sharing scheme. Recently, Guo and Chang proposed a similar protocol based on the generalized Chinese remainder theorem. In this paper, we point out that there are some security problems of Guo and Chang's protocol and propose a simpler authenticated group key distribution protocol based on the Chinese remainder theorem. The confidentiality of our proposed protocol is unconditionally secure. Copyright © 2013 John Wiley & Sons, Ltd.