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.

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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.

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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]

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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 ).

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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]

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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。

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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”.

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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

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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.

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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]

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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.

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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.

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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 :

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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]