著者

岩崎 敦 東藤 大樹 Atsushi Iwasaki Taiki Todo

雑誌

人工知能学会誌 = Journal of Japanese Society for Artificial Intelligence (ISSN:09128085)

巻号頁・発行日

vol.28, no.3, pp.389-396, 2013-05-01

著者

Atsushi Iwasaki Ken Umeno

出版者

一般社団法人 日本応用数理学会

雑誌

JSIAM Letters (ISSN:18830609)

巻号頁・発行日

vol.9, pp.5-8, 2015 (Released:2017-02-18)

参考文献数

8

被引用文献数

2

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Permutation polynomials over a ring of modulo $2^w$ are well adopted to digital computers and digital signal processors, and so they are in particular expected to be useful for cryptography and pseudo random number generator{s}. For a longer period of the polynomial is demanded in general, we derive a necessary and sufficient condition that polynomials are permutating and their periods are the longest over the ring. We call polynomials which satisfy the condition ``one-stroke polynomials over the ring''.

著者

Atsushi Iwasaki Ken Umeno

出版者

一般社団法人 電子情報通信学会

雑誌

Nonlinear Theory and Its Applications, IEICE (ISSN:21854106)

巻号頁・発行日

vol.8, no.3, pp.215-223, 2017 (Released:2017-07-01)

参考文献数

13

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Vector Stream Cipher (VSC) is a stream cipher which consists of permutation polynomial over a ring of modulo 2w. The algorithm for generating key stream is very simple and the encryption is very fast. Some theoretical attacks for VSC have been reported so far since the invention of VSC in 2004. Then, the authors proposed some improvements and developed “Vector Stream Cipher 2.0 (VSC 2.0)” to be immune against the theoretical attacks. In this paper, we propose further improvement of VSC 2.0 to publish as a new chaos cipher “Vector Stream Cipher 2.1 (VSC2.1)”. VSC 2.1 is faster and more secure than VSC 2.0. Our result suggests that permutation polynomials over a ring of modulo 2w are useful for cryptography.

著者

Atsushi Iwasaki Ken Umeno

出版者

一般社団法人 電子情報通信学会

雑誌

Nonlinear Theory and Its Applications, IEICE (ISSN:21854106)

巻号頁・発行日

vol.7, no.1, pp.30-37, 2016 (Released:2016-01-01)

参考文献数

7

被引用文献数

6

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Vector Stream Cipher (VSC) is a stream cipher based on the chaos theory. The algorithm for generating stream keys is very simple and the encryption speed is very fast. Some theoretical attacks for VSC have been reported so far since the invention of VSC in 2004. In this paper, we improve the security of VSC and design a new cipher system “Vector Stream Cipher 2.0” so that the theoretical attacks cannot work. We show that the encryption speed of VSC 2.0 keeps more than 85% of that of VSC, and key-stream of VSC 2.0 has good randomness. The main result of this paper is that our proposed VSC 2.0 is shown to have provable security for attacks with linear masking. Because there is few cryptography based on the chaos theory which has proven security, VSC 2.0 is a rare example.