An Accessible CAPTCHA System for People with Visual Disability – Generation of Human/Computer Distinguish Test with Documents on the Net

  • Michitomo Yamaguchi
  • Toru Nakata
  • Takeshi Okamoto
  • Hiroaki Kikuchi
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8516)


We propose a new scheme of CAPTCHA that does not become a perceptual barrier for disable people. Our CAPTCHA system generates the tests in verbal style, so its use is not limited in specific perceptual channels. The tests are composed of several phrases and there are two kinds of tests: Human users try to (1) distinguish a phrase of strange meaning from others, and (2) identify the common topic among them.In our test we utilize open documents for material. Note that there is quite a large amount of documents on the net, so we can generate brand-new tests every time. One may say that adversaries can look for the phrases over the Internet and get several hints. Our system hides the sources by substituting the consonants of the phrases against such an attack.The mechanism is designed to imitate the phenomenon called “consonant gradation” of natural languages.


universal design aid for the visually-impaired verbal interaction information security 


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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Michitomo Yamaguchi
    • 1
    • 3
  • Toru Nakata
    • 2
  • Takeshi Okamoto
    • 3
  • Hiroaki Kikuchi
    • 1
  1. 1.Department of Mathematical Modeling, Analysis and Simulation, Graduate School of Advanced Mathematical SciencesMeiji UniversityTokyoJapan
  2. 2.Research Institute for Secure SystemsNational Institute of Advanced Industrial Science and Technology (AIST)IbarakiJapan
  3. 3.Graduate School of Technology and SciencesTsukuba University of TechnologyIbarakiJapan

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