Top PDF Constructing perfect secret sharing schemes for general and uniform access structures

Shiuh-Pyng Shieh ( ) received the M.S. and Ph.D. degrees in electrical engineering from the University of Maryland, College Park, in 1986 and 1991, respectively. He is currently a professor with the Department of Computer Science and Informa- tion Engineering, National Chiao Tung University. From 1988 to 1991, he participated in the design and implementation of the B2 Secure XENIX for IBM, Federal Sector Division, Gaithersburg, Maryland, USA. He is also the designer of the SNP (Secure Net- work Protocols). Since 1994, he has been a consultant for the Com- puter and Communications Laboratory, Industrial Technology Re- search Institute, Taiwan, in the area of network security and dis- tributed operating systems. He is also a consultant for the National Security Bureau, Taiwan.

Brick- ell and Stinson studied a perfect secret sharing scheme for a graph-based structure where the monotone-increasing access structure F contains the pairs of p[r]

Abstract A perfect secret-sharing scheme is a method of distributing a secret among a set of participants such that only qualified subsets of participants can recover the secret and the joint shares of the participants in any unqualified subset is statistically independent of the secret. The set of all qualified subsets is called the access structure of the scheme. In a graph-based access structure, each vertex of a graph G represents a participant and each edge of G represents a minimal qualified subset. The information ratio of a perfect secret-sharing scheme is defined as the ratio between the maximum length of the share given to a participant and the length of the secret. The average information ratio is the ratio between the average length of the shares given to the participants and the length of the secret. The infimum of the (average) information ratios of all possible perfect secret-sharing schemes realizing a given access structure is called the (average) information ratio of the access structure. Very few exact values of the (average) information ratio of infinite families of access structures are known. Csirmaz and Tardos have found the information ratio of all trees. Based on their method, we develop our approach to determining the exact values of the average information ratio of access structures based on trees.

Brickell and Stinson [5] studied a perfect secret sharing scheme for graph-based access structure F where the monotone-increasing access structure F contains the pairs of partic[r]

Our next goal is to find the sum m k of the orders of all subgraphs in P k . Due to the complexity of the enumeration, we consider the reduced forms first. We call G 0 k ¼ Wð1; . . . ; 1; 1; . . . ; 1Þ the reduced form of a general k-weighted graph W(a 1 , - . . ., a k , c 1 , . . . , c k ). We also let B 0 l ; M 0 l 1 ;l 2 and H 0 j be the graphs defined in the same ways as B l , M l 1 ;l 2 and H j respectively, except that a i ’s and c j ’s involved are all set to be one. Then G 0 k and B 0 k have the complete multipartite covering P 0 k and P B k 0 reduced from P k and P B k respectively. Note here that G 0 k has 2k vertices. By applying suitable splitting and expanding operations men- tioned in Section 4.1 to the reduced form G 0 k accordingly, one can recover the general k-weighted graph W(a 1 , . . . , a k , c 1 , . . . , c k ).

Perfect Secret Sharing Schemes 89 In this paper, we propose some recursive constructions for perfect secret sharing schemes with access structures of constant rank.. Sti[r]

2 Email: lincy@iim.nctu.edu.tw; 4 Email: jjhwang@cc.nctu.edu.tw ABSTRACT The authors propose a novel generalized secret sharing scheme that realizes an ordered access structure, in which the participants of a qualified subset can reconstruct the shared secret only if they follow the sequence of share/

一、 、 、 、簡介 簡介 簡介 簡介 隨著網路的蓬勃發展，人們愈來愈依賴網路 來傳播資訊，但在傳遞機密資料的過程中，機密 資料若被惡意的攻擊者所擷取，則會導致企業嚴 重的損失或是國家安全遭受威脅。因此，資料傳 輸的安全性也愈來愈受重視。為了保護機密資料 洩漏的問題，機密資料的擁有者常事先將資料進 行加密，再傳送之。之後，即使傳送中的資料被 竊取，仍無法得知機密資料的任何相關資訊。在 1979 年， Blakley [2] 和 Shamir [7] 兩學者分別 以 不 同 的 方 法 提 出 秘 密 分 享 機 制 ( Secret sharing scheme )，使得機密資料能分散地保管。

Abstract The concept of visual secret sharing (VSS) scheme was first proposed by Noar and Shamir in 1994. This is a technique to divide a secret image into several meaningless images, called shadows, such that certain qualified subsets of shadows can recover the secret image by “eyes”. The main characteristic of VSS schemes is that its decoding process can be perceived directly by the human visual system without the knowledge of cryptography and cryptographic computations. It possesses a special meaning and effect that “the secret codes are visible”.

摘要: Hashing schemes are widely used to improve the performance of data mining association rules, as in the DHP algorithm that utilizes the hash table in identifying the validity of candidate itemsets according to the number of the table's bucket accesses. However, since the hash table used in DHP is plagued by the collision problem, the process of

Hashing schemes are a common technique to improve the performance in mining not only association rules but also sequential patterns or traversal patters. However, the collision problem in hash schemes may result in severe performance degradation. In this paper, we propose perfect hashing schemes for mining traversal patterns to avoid collisions in the hash table. The main idea is to transform each large itemsets into one large 2-itemset by employing a delicate encoding scheme.

building blocks in the filter. In this paper, we present testable design and built-in self-test schemes for FIR filters. The characteristic of a bijective cell function is used to make the filter array easily testable. According to this approach, pseudoexhaustive test patterns can be applied to each module in the filter and faulty effects can be propagated to the primary outputs. The test pattern generator can be implemented with a simple binary counter and the output response analyzer is implemented with a checksum accumulator. In order to make the filter easily testable, some Design-for- testability techniques should be made. Our approach is also suitable for diagnosis of a faulty module. In order to verify our approach, a cell-based design of the BISTed filter has been implemented. Experimental results show that 100% fault coverage is achieved. The hardware overhead is 7.12% and 5.53% for wordlength

題名: Secret image sharing with steganography and authentication 作者: C. C. Lin;W. H. Tsai 貢獻者: Department of Information Communication 關鍵詞: Secret image sharing;Steganography;Authentication;Camouflage image;Data hiding;Stego-image;Fragile watermarking;Least significant bit replacement 日期: 2004

Available online 5 December 2003 Abstract A novel approach to secret image sharing based on a ðk; nÞ-threshold scheme with the additional capabilities of steganography and authentication is proposed. A secret image is first processed into n shares which are then hidden in n user-selected camouflage images. It is suggested to select these camouflage images to contain well-known contents, like famous character images, well-known scene pictures, etc., to increase the steganographic effect for the security protection purpose. Furthermore, an image watermarking technique is employed to embed fragile watermark signals into the camouflage images by the use of parity-bit checking, thus providing the capability of authenticating the fidelity of each processed camouflage image, called a stego-image. During the secret image recovery process, each stego-image brought by a participant is first verified for its fidelity by checking the consistency of the parity conditions found in the image pixels. This helps to prevent the participant from incidental or intentional provision of a false or tampered stego-image. The recovery process is stopped if any abnormal stego-image is found. Otherwise, the secret image is recovered from k or more authenticated stego-images. Some effective techniques for handling large images as well as for enhancing security protection are employed, including pixelwise processing of the secret image in secret sharing, use of parts of camouflage images as share components, adoption of prime-number modular arithmetic, truncation of large image pixel values, randomization of parity check policies, etc. Consequently, the proposed scheme as a whole offers a high secure and effective mechanism for secret image sharing that is not found in existing secret image sharing methods. Good experimental results proving the feasibility of the proposed approach are also included.

scheme was first proposed by Naor and Shamir in 1994; many secret sharing schemes were published afterward; one of them, the color images of hierarchical multiple visual secret shari[r]

名: A Scheme for Threshold Multi-Secret Sharing 作者: Chan, C. W.;Chang, C. C 關鍵詞: Access structure;Basis of access structure;The Chinese remainder theorem;Distinctness;Entropy;Idealness;Multi-secret sharing scheme;Perfectness;The Shamir (t, n)-threshold secret sharing scheme;(t, n)-threshold access structure;Threshold multi-secret sharing scheme

6. CONCLUSION Because the important parts of a secret HTML document are the components that can be displayed or be accessed on browsers, it is proposed in this study to share these components among participants of the secret HTML document by the cooperative sharing operation with data magnitude control by the modulus operation. In order to create steganographic effects on the shares of the components, two steganographic techniques for the text component and the non-text components of secret HTML documents are proposed. For a share of a text component, the proposed technique substitutes the original text component by an article with the share hidden into between-word spaces. For a share of a non-text component, the proposed technique uses a dynamic link with the share as the parameter of the link to create steganographic effects. After applying the two steganographic techniques to the shares of the components in the secret HTML document, HTML-type shares with styles identical to that of the secret HTML document are generated. Experimental results show the applicability of the proposed methods to real HTML documents.

E-mail address: jclin@cis.nctu.edu.tw (J.-C. Lin). Accordingly, the size of each stego image was 2=t or 4=t of that of the secret image. To solve the problem of size ex- pansion, we present in this work a new method in which the size of the stego image (which contains the hidden shadow) is still about 1=t of that of the secret image. This requirement is met by shrinking the range of shadow values (which are the output values of the sharing phase in Ref. [1]); hence, the input values (which are the gray values of the secret image) must also be quantized. Therefore, a pre-processing quantization procedure is developed for narrowing the range of gray values of the secret image. The pre-processing pro- cedure /rstly quantizes the secret image using two types of blocks, producing a record of block types, namely, an S–E table. The S–E table is then embedded in the quan- tized image to prevent size expansion. After it has been pre-processed, the image is shared among n participants. Fi- nally, a simple hiding procedure is proposed for hiding each shadow image in an ordinary image. The rest of this paper is organized as follows. Section 2 describes the proposed method. Section 3 presents the experimental results and compares them with those obtained by reported methods.

DEFINITION 2. A (k, n) NEVSS scheme can be shown as two collections C 0 and C 1 consisting of n λ and n γ n × 1 matrices, respectively. When sharing a white (resp. black) pixel, the dealer first randomly chooses one column matrix in C 0 (resp. C 1 ), and then randomly selects one row of this column matrix to a relative shadow. The chosen matrix defines the gray level of one sub pixel in every one of the n shadows. A NEVSS Scheme is considered valid if the following conditions are met :

M: folding mirror; L1, L2: mode-matching lenses; PL: pump lens; DC: dichroic curve mirror (R=10 cm); DCM1, DCM3: flat double chirped mirrors; DCM2, DCM4: curved double chirped mirrors (R[r]