| Project/Area Number |
09650418
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
情報通信工学
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
KOHDA Tohru Kyushu Univ., Dept. of Comp. Sci. & Eng., Professor, 大学院・システム情報科学研究科, 教授 (20038102)
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| Co-Investigator(Kenkyū-buntansha) |
TSUNEDA Koichi Kyushu Univ., Dept. of Comp. Sci. & Eng., Associate Professor, 大学院・システム情報科学研究科, 助教授 (60264066)
OOHAMA Yasutada Kyushu Univ., Dept. of Comp. Sci. & Eng., Associate Professor, 大学院・システム情報科学研究科, 助教授 (20243892)
NISHI Testuo Kyushu Univ., Dept. of Comp. Sci. & Eng., Professor, 大学院・システム情報科学研究科, 教授 (40037908)
FUJISAKI Hiroshi Kyushu Univ., Dept. of Comp. Sci. & Eng., Research Associate, 大学院・システム情報科学研究科, 助手 (80304757)
柏木 雅英 九州大学, 大学院・システム情報科学研究科, 助教授 (00257247)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 1999: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Chaotic Binary Sequence / Stream Cipher System / I.I.D. / 独立同分布(I.I.D.) / i.i.d. |
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| Research Abstract |
Stream ciphers provide probably the most important method of modern encipherment. The central problem in stream cipher cryptography is the difficulty of efficiently generating long unpredictable sequencers of binary signals form a short and random key. Although such an unpredictable sequence can be generated in various ways, linear feedback shift register (LFSR) sequences are employed in nearly all the methods. In this study, not using such sequences, we give a simple method to obtain a running key sequence of stream cipher system in which chaotic orbits of nonlinear maps are used. Two type of sequences of balanced I. I. D. (dependent and identically distributed) binary random variables have been defined, referred to as a chaotic binary sequence and a chaotic bit sequence, each of which is obtained from chaotic real-valued orbits generated by nonlinear maps. The stream cipher system proposed in this study has the following characteristics : 1) There are several parameters as short secret key : 2) The linear complexity of the running-key sequence of period N is nearly equal to N/2 : 3) The correlation property of ciphertexts is as good as those of the DES and FEAL.
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