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.
Abstract A perfectsecret-sharing scheme is a method of distributing a secret among a set of participants such that only qualified subsets of participants can recover the secretand 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 perfectsecret-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 perfectsecret-sharingschemes 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 accessstructures 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 accessstructures based on trees.
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 ).
2 Email: firstname.lastname@example.org; 4 Email: email@example.com
The authors propose a novel generalized secretsharing 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/
The concept of visual secretsharing (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 schemesfor 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 schemesfor 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
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 secretsharing, 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 forsecret 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.
名: A Scheme for Threshold Multi-SecretSharing 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-secretsharing scheme;Perfectness;The Shamir (t, n)-threshold secretsharing scheme;(t, n)-threshold access structure;Threshold multi-secretsharing scheme
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: firstname.lastname@example.org (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. ); 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 :