Directional captcha: A novel approach to text based CAPTCHA
28 Sep 2015-pp 1278-1283
TL;DR: A new captcha based on digits and symbols based on the facts that it is difficult for the machine to interpret symbols and perform the tasks accordingly from two different datasets is proposed.
Abstract: In this Paper, we have proposed a new captcha based on digits and symbols. It is based on the facts that it is difficult for the machine to interpret symbols and perform the tasks accordingly from two different datasets. We have also pointed out the main anti-recognition and anti-segmentation features from previous works and implemented them on our proposed captcha. We have also presented here the pseudocode of it, have done a security analysis and usability survey to firm our claims regarding it.
Citations
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30 Dec 2020
TL;DR: In this paper, a systematic review of different types of CAPTCHAs is presented, focusing on the benefits of text-based CAPTCHA over other schemes and highlighting the major deficiencies of textbased CAPTs.
Abstract: With the massive growth of accessing Internet-based services by users, there is a need to limit services use to human beings only rather than intelligent bots. The biggest challenge in front of researchers is to determine incoming requests are from benign users or bots. A CAPTCHA (Completely Automated Public Turing Test to tell Computers and Humans Apart) is a basic tool for preventing access to Internet-based services by intelligent bots. It plays a vital role in numerous security applications for denying automatic registration conducted by bots. This paper presents a systematic review of different types of CAPTCHAs and primarily focuses on the benefits of "text-based CAPTCHAs" over other schemes. Further, this paper highlights the major deficiencies of the text-based CAPTCHA schemes.
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References
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TL;DR: Post-hoc analysis showed that Blot Mask and Line Mask were the hardest CAPTCHAs, while Thread Noise, Global Warp, and Geometry Noise were on a par with Normal Type (no distortion).
35 citations
"Directional captcha: A novel approa..." refers background in this paper
...Lee et al. (2011) [2] carried out a usability study on several age groups, distortion types of captcha and gave many concludary remark on the basis of task performance, objective visual fatigue, and subjective workload....
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TL;DR: A user study conducted to measure the usability of Adamas indicates that its solving accuracy is comparable to major CAPTCHAs in use today and offers insights into factors that affect CAPTCHA usability.
13 citations
"Directional captcha: A novel approa..." refers background in this paper
...Chellapilla et al. (2005) [6] has pointed out very important conclusion that it is possible to build segmentation based HIPs which are diffcult to break for machines yet very usable for humans....
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