17th CSEC Group Meeting

May 23, 2002

Information Processing Society of Japan (IPSJ) Meeting Room
Shibaura-Maekawa Bldg. 7F, 3-16-20, Shibaura, Minato-ku, Tokyo 108-0023, JAPAN

JR Tokyo - (8 minutes JR Yamanote Line) - JR Tamachi

17th CSEC Group Meeting Program
(1) Secure Gateway System Design for Home Teleworking
Kenji Rikitake (KDDI R&D Laboratories, Inc.)
Takahiro Kikuchi (KDDI R&D Laboratories, Inc.)
Hiroshi Nagata (KDDI R&D Laboratories, Inc.)
Tatsuaki Hamai (KDDI R&D Laboratories, Inc.)
Tohru Asami (KDDI R&D Laboratories, Inc.)

Home Teleworking has become a major workstyle for corporate and part-time workers. As high-speed access methods to Internet become popular, workers can utilize sufficient bandwidth to perform their tasks from home. On the other hand, home equipments are not well-protected as those of the corporate networks, and have been major victims of security attacks. In this paper, we first analyze the technical weakness of common system configurations for home teleworking. We then address the basic requirements to enforce network security of home teleworking systems, and propose the configuration examples using the gateway system at the border of the home and the external networks.

(2) Deploying User-based Extranet without Global Addresses
Koichi Okada (NTT Information Sharing Platform Laboratories)
Eric Y. Chen (NTT Information Sharing Platform Laboratories)
Teruyuki Komiya (NTT Information Sharing Platform Laboratories)
Hitoshi Fuji (NTT Information Sharing Platform Laboratories)

Extranet is known to pose a number of threats to the confidential data exchanged among partner sites. End-to-end VPN network solutions are sometimes deployed to cope with both the external threats from the Internet and the internal threats within the mutual sites. However, because existing end-to-end VPN technologies require all participating hosts to have a global address, it is often speculated that the limited address space of IPv4 would eventually thwart their acceptance. Although we can wait for the arrival of IPv6 to alleviate this problem, in this paper we propose a method for deploying an end-to-end VPN using only private addresses by incorporating the Twice-NAT into our VPN-Exchange System (a star-type end-to-end VPN that we have proposed).

(3) Note on Voting Schemes Suitable for Multiple Ballots per Voter - To Construct Electronic Decision Systems at Stockholder's Meetings -
Tetsuro SAISHO (Chuo University, FNT)
Taiichi SAITO (NTT Labs)
Hiroshi DOI (RDI, Chuo University)
Shigeo TSUJII (RDI, Chuo University)

Since any stockholder has ballots the number of which is proportional to his amount of stocks, the voting procedure in the annual stockholder's meeting can be seen as a modification of usual voting in democratic meetings. However the computerization of the procedures in stockholder's meetings and its security technologies have not been developed enough. We have studied the computerization in stockholder's meetings, in which the proposal of electronic decision systems at stockholder's meetings is one of our main purposes. In this paper, we focus on the property that one stockholder can vote several ballots in a stockholder's meeting, and consider related issues. Moreover we propose electronic voting schemes for stockholder's meetings through which that property holds, and clarify their benefits.

(4) Overview of Comparisons and Future Work of Electronic Voting Scheme
Hiroshi Yamaguchi (NEC Soft, Ltd)
Miyako Ohkubo (NTT EAST)
Atsushi Kitazawa (NEC Soft, Ltd)
Shigeo Tsujii (Chuo University)

Many papers have been written on the electronic voting schemes discussing the required properties of elections, among which are privacy, universal verifiability and various forms of robustness, Recent advancements have also been concerned with performance aspect. We will compare different features of three schemes using blind signatures, mix-net anonymous channel, and partially compatible homomorphisms. We also discuss the new properties particularly concerned with the computation and communication capabilities, reliability of computer and communication systems and operationability.

(5) Type-based Verification of Authenticity in Protocols with Public Key Encryption using Spi-Calculus
Ken Hatayama (Government & Public Corporation Information Systems Division, Hitachi Ltd.)
Shigeki Hagihara (Department of Computer Science, Graduate School of Information Science and Engineering, Tokyo Institute of Technology.)
Naoki Yonezaki (Department of Computer Science, Graduate School of Information Science and Engineering, Tokyo Institute of Technology.)

M.Abadi and A.D.Gordon invented the "Spi-Calculus" and constructed a verification method of secrecy and authenticity in protocols using symmetric-keys by typing. However, the method of verifying authenticity in protocols using public-keys and private-keys cannot be done by a simple extension of the method of symmetric-keys. The purpose of this paper is to construct the verification method of authenticity in such protocols. In order to achieve this, we introduced types and constructed typing rules. And we proved that the typing system we defined is sound and justified.

(6) Classification of Time Stamping Schemes from the Viewpoint of Availability of Verification Procedures
Masashi Une (Institute for Monetary and Economic Studies,Bank of Japan)
Tsutomu Matsumoto (Graduate School of Environment and Information Sciences, Yokohama National University)

This paper discusses the classification of time stamping schemes by the availability of verification procedures. First, we discuss what criterion is suitable to classify schemes by the availability. After considerable discussion, we choose, as the criterion, the number of feasible verification operations under situations in which a verifier cannot obtain data for the verification from other entities. Next, we classify schemes into ten categories by the number of the feasible operations. Finally, we apply our results to seven existing schemes and clarify their characteristics on the availability of verification procedures.

(7) A Study on Digital Watermarking Based on Process of Speech Production
Mitsuhiro HATADA (Dept. of Electronics, Information and Communication Eng., WASEDA Univ.)
Toshiyuki SAKAI (Dept. of Electronics, Information and Communication Eng., WASEDA Univ.)
Naohisa KOMATSU (Dept. of Electronics, Information and Communication Eng., WASEDA Univ.)
Yasushi YAMAZAKI (Dept. of Information and Media Sciences, The Univ. of Kitakyushu)

A speech production model can be divided into three parts, which are glottal source, ar-ticulation and radiation respectively. Some digital watermarks for speech that have been proposed are based on changing quantized values or parameters of a coding scheme. In this paper, we propose a new watermarking method for speech by manipulating articulation in process of speech production. That is, we realize the proposed method by applying watermarked vocal tract model. In the proposed method, the watermarked vocal tract model is expressed by codebook made by LSP(Line Spectrum Pair) pa-rameters. The procedures of watermark for speech are as follows; 1) LSPs are extracted from speech. 2) Some of the extracted LSPs are replaced with the codebook vectors. 3) Speech is synthesized using replaced LSPs. In above process, watermark are embedded indirectly to speech. Evaluation tests on speech quality and accuracy of the proposed method will be discussed with simulation results.

(8) Multi-lateral Security and implementation in MPEG-21/IPMP
Itaru Kaneko (Research Institute for Science and Engineering Waseda University)
Katsuhiko Shirai (Waseda University)

Authors are proposing Multi-Lateral Security Model(MLSM) which may analyze more variety of security issues those need to be considered in large scale audio visual services such as broadband multimedia services which is rapidly evolving and must be considered as a social infrastructure. In this report, we will show the formal representation of the model, and also describe implementations using MPEG-21/IPMP based on the latest specification.


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