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http://dx.doi.org/10.13089/JKIISC.2009.19.6.105

Breaking character-based CAPTCHA using color information  

Kim, Sung-Ho (Information Security Research Laboratory, INHA University)
Nyang, Dae-Hun (Information Security Research Laboratory, INHA University)
Lee, Kyung-Hee (The University of Suwon)
Publication Information
Journal of the Korea Institute of Information Security & Cryptology / v.19, no.6, 2009 , pp. 105-112 More about this Journal
Abstract
Nowadays, completely automated public turing tests to tell computers and humans apart(CAPTCHAs) are widely used to prevent various attacks by automated software agents such as creating accounts, advertising, sending spam mails, and so on. In early CAPTCHAs, the characters were simply distorted, so that users could easily recognize the characters. From that reason, using various techniques such as image processing, artificial intelligence, etc., one could easily break many CAPTCHAs, either. As an alternative, By adding noise to CAPTCHAs and distorting the characters in CAPTCHAs, it made the attacks to CAPTCHA more difficult. Naturally, it also made users more difficult to read the characters in CAPTCHAs. To improve the readability of CAPTCHAs, some CAPTCHAs used different colors for the characters. However, the usage of the different colors gives advantages to the adversary who wants to break CAPTCHAs. In this paper, we suggest a method of increasing the recognition ratio of CAPTCHAs based on colors.
Keywords
CAPTCHA; Support Vector Machine; RGB Color;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
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