Masakatsu Nishigaki

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— We propose a cryptographic protocol for biomet-rics authentication without revealing personal biometrical data against malicious verifier. Our protocol uses a neural network and zero-knowledge interactive proof. In this paper, we developed a sample implementation system of our proposed protocol and we evaluate the performance and the accuracy of the(More)
The Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) has been widely used as a technique that will allow a machine to distinguish between input from a human and that of another machine. The security of current CAPTCHA methods is not sufficient to protect against advanced modern malware. This paper focuses on applying(More)
— CAPTCHA is a technique that is used to prevent automatic programs from being able to acquire free e-mail or online service accounts. However, as many researchers have already reported, conventional CAPTCHA could be overcome by state-of-the-art malware since the capabilities of computers are approaching those of humans. Therefore, CAPTCHA should be based(More)