- 著者
- SeongHan SHIN Shota YAMADA Goichiro HANAOKA Yusuke ISHIDA Atsushi KUNII Junichi OKETANI Shimpei KUNII Kiyoshi TOMOMURA
- 出版者
- The Institute of Electronics, Information and Communication Engineers
- 雑誌
- IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)
- 巻号頁・発行日
- vol.E105-A, no.8, pp.1121-1133, 2022-08-01
- 被引用文献数
- 1
AONT (All-or-Nothing Transform) is a kind of (n, n)-threshold secret sharing scheme that distributes a message m into a set of n shares such that the message m can be reconstructed if and only if n shares are collected. At CRYPTO 2000, Desai proposed a simple and faster AONT based on the CTR mode of encryption (called CTRT) and proved its security in the ideal cipher model. Though AES-128, whose key length k = 128 and block length l = 128, can be used in CTRT as a block cipher, AES-256 and AES-192 cannot be used due to its intrinsic restriction of k ≤ l. In this paper, we propose an extended CTRT (for short, XCTRT) suitable for AES-256. By thoroughly evaluating all the tricky cases, we prove that XCTRT is secure in the ideal cipher model under the same CTRT security definition. Also, we discuss the security result of XCTRT in concrete parameter settings. For more flexibility of key length, we propose a variant of XCTRT dealing with l<k ≤ 2l by slightly modifying the construction of the last block. After showing implementation details and performance evaluation of CTRT, XCTRT, and the variant, we can say that our XCTRT and its variant have high-speed encoding and decoding performance and are quite practical enough to be deployed in real-world applications.
- 著者
- Takeshi Ebara Ryohei Azuma Naoto Shoji Tsuyoshi Matsukawa Yasuyuki Yamada Tomohiro Akiyama Takahiro Kurihara Shota Yamada
- 出版者
- (公社)日本産業衛生学会
- 雑誌
- Journal of Occupational Health (ISSN:13419145)
- 巻号頁・発行日
- pp.17-0101-OA, (Released:2017-08-24)
- 被引用文献数
- 12
Objectives: Objective measurements using built-in smartphone sensors that can measure physical activity/inactivity in daily working life have the potential to provide a new approach to assessing workers' health effects. The aim of this study was to elucidate the characteristics and reliability of built-in step counting sensors on smartphones for development of an easy-to-use objective measurement tool that can be applied in ergonomics or epidemiological research.Methods: To evaluate the reliability of step counting sensors embedded in seven major smartphone models, the 6-minute walk test was conducted and the following analyses of sensor precision and accuracy were performed: 1) relationship between actual step count and step count detected by sensors, 2) reliability between smartphones of the same model, and 3) false detection rates when sitting during office work, while riding the subway, and driving.Results: On five of the seven models, the inter-class correlations coefficient (ICC (3,1)) showed high reliability with a range of 0.956–0.993. The other two models, however, had ranges of 0.443–0.504 and the relative error ratios of the sensor-detected step count to the actual step count were ±48.7%–49.4%. The level of agreement between the same models was ICC (3,1): 0.992–0.998. The false detection rates differed between the sitting conditions.Conclusions: These results suggest the need for appropriate regulation of step counts measured by sensors, through means such as correction or calibration with a predictive model formula, in order to obtain the highly reliable measurement results that are sought in scientific investigation.