- 著者
- Toshihiro Ohigashi Shuya Kawaguchi Kai Kobayashi Hayato Kimura Tatsuya Suzuki Daichi Okabe Takuya Ishibashi Hiroshi Yamamoto Maki Inui Ryo Miyamoto Kazuyoshi Furukawa Tetsuya Izu
- 出版者
- Information Processing Society of Japan
- 雑誌
- Journal of Information Processing (ISSN:18826652)
- 巻号頁・発行日
- vol.29, pp.548-558, 2021 (Released:2021-09-15)
- 参考文献数
- 19
In 2018, Takita et al. proposed a construction method of a fake QR code by adding stains to a target QR code, that probabilistically leads users to a malicious website. The construction abused the error-correction of error-correcting code used in the QR code, namely, the added stains induce decoding errors in black and white detection by a camera, so that the decoded URL leads to the malicious website. Also, the same authors proposed a detection method against such fake QR codes by comparing decoded URLs among multiple QR code readings since the decoded URLs may differ because of its probabilistic property. However, the detection method cannot work well over a few readings. Moreover, the proposed detection method does not consider the environmental or accidental changes such as sudden sunshine or reflection, nor recognizes the fake QR code as non-fake when the probability is low. This paper proposes new detection methods for such fake QR codes by analyzing information obtained from the error-correcting process. This paper also reports results from implementing the new detection methods on an Android smartphone. Results show that a combination of these detection methods works very well compared to when using only a single detection method.
- 著者
- Naoyuki SHINOHARA Tetsuya IZU Noboru KUNIHIRO
- 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.E94-A, no.1, pp.19-27, 2011-01-01
CRT-RSA is a variant of RSA, which uses integers dp = d mod (p-1) and dq = d mod (q-1) (CRT-exponents), where d, p, q are the secret keys of RSA. May proposed a method to obtain the secret key in polynomial time if a CRT-exponent is small, moreover Bleichenbacher and May improved this method. On the other hand, Takagi's RSA is a variant of CRT-RSA, whose public key N is of the form prq for a given positive integer r. In this paper, we extend the May's method and the Bleichenbacher-May's method to Takagi's RSA, and we show that we obtain p in polynomial time if by the extended May's method, and if by the extended Bleichenbacher-May's method, when dq is arbitrary small. If r=1, these upper bounds conform to May's and Bleichenbacher-May's results respectively. Moreover, we also show that the upper bound of pr increase with an increase in r. Since these attacks are heuristic algorithms, we provide several experiments which show that we can obtain the secret key in practice.