A CAPTCHA in the Text Domain

Ximenes, Pablo; Santos, André dos; Fernández, Marcial Delgado; Celestino, Joaquim

doi:10.1007/11915034_84

Cited by 15 publications

(3 citation statements)

References 6 publications

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“…CAPTCHA in text domain was desired from the beginning, but there are few new works done in this field including [22] and [23]. As the authors of these papers said, designing a Text Domain CAPTCHA is very difficult and currently there is no text based CAPTCHA that can be used practically in real world websites.…”

Section: Non Visual Methodsmentioning

confidence: 99%

Multilingual Highlighting CAPTCHA

Shirali-Shahreza

2011

2011 Eighth International Conference on Information Technology: New Generations

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There are many websites specially designed for mobile phones. Some hackers write automated programs to abuse these website services and waste the website resources. Therefore, it is necessary to distinguish between human users and computer programs. Methods known for achieving this are known as CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart). CAPTCHA methods are mainly based on the weaknesses of OCR (Optical Character Recognition) systems and ask the user to type a word. So using them is difficult in tools such as PDAs (Personal Digital Assistant) or mobile phones that lack a complete keyboard.In this paper, a new CAPTCHA system is proposed for touchscreen devices such as PDAs and mobile phones. In this system, a word is drawn in a random place on the screen and a number of arcs are drawn on the screen. Then the user is asked to highlight the word by the stylus. Due to the limitations of the PDA and mobile phone, OCR programs on these devices cannot recognize the shown word, while a human user can easily highlight the word. The proposed method is implemented by the JavaME (Java Platform Micro Edition) language and tested on a SonyEricsson P990i mobile phone.

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Section: Non Visual Methodsmentioning

confidence: 99%

Multilingual Highlighting CAPTCHA

Shirali-Shahreza

2011

2011 Eighth International Conference on Information Technology: New Generations

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“…Ximenes et al [8] utilized phonetic punning riddles based on "knock knock" jokes (KK jokes). Their system challenges a user to differentiate real KK jokes from fake KK jokes.…”

Section: Related Work On Verbal Captchasmentioning

confidence: 99%

Vulnerability of the conventional accessible CAPTCHA used by the White House and an alternative approach for visually impaired people

Yamaguchi

Nakata

Watanabe

et al. 2014

2014 IEEE International Conference on Systems, Man, and Cybernetics (SMC)

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Many people with visual impairments complain about the poor accessibility of conventional CAPTCHA systems because the audio-style test is too difficult for humans. Even a U.S. governmental site, the "We the People" public website, was criticized for the same reason, and thus it implemented a more accessible quiz-based CAPTCHA system. However, this system is vulnerable to simple heuristics. In this study, we demonstrate the insecurity of this type of CAPTCHA system. We demonstrate that our solver program can beat the CAPTCHA with a success rate of over 99%. In addition, we propose a new verbal-style system to replace the quiz-based CAPTCHA. Our system synthesizes several sentences, which have different degrees of naturalness in terms of their contextual meaning, from a set of source documents using a flexible-order Markov chain. Only human users can perceive the difference in the semantics and select the most (or the least) meaningful option correctly. This test is implemented in a verbal style, which means that it is universally suitable for any type of perceptual channel. We implemented our proposed scheme and analyzed its security based on experiments.

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“…Other researchers proposed semantic audio, which requires users to solve the CAPTCHA by suggesting a title for a given sound [21] [22]. Ximenes et al developed a CAPTCHA method using "Knock Knock Jokes" by making puns on words that are presented on CAPTCHA question [23]. In addition, a researcher used "Phonemic Restoration" concept by distorting sounds using white noise [24].…”

Section: Related Workmentioning

confidence: 99%

A Novel Design of Audio CAPTCHA for Visually Impaired Users

Alnfiai

2022

Int. j. commun. netw. inf. secur.

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CAPTCHAs are widely used by web applications for the purpose of security and privacy. However, traditional text-based CAPTCHAs are not suitable for sighted users much less users with visual impairments. To address the issue, this paper proposes a new mechanism for CAPTCHA called HearAct, which is a real-time audio-based CAPTCHA that enables easy access for users with visual impairments. The user listens to the sound of something (the “sound-maker”), and he/she must identify what the sound-maker is. After that, HearAct identifies a word and requires the user to analyze a word and determine whether it has the stated letter or not. If the word has the letter, the user must tap and if not, they swipe. This paper presents our HearAct pilot study conducted with thirteen blind users. The preliminary user study results suggest the new form of CAPTCHA has a lot of potential for both blind and visual users. The results also show that the HearAct CAPTCHA can be solved in a shorter time than the text-based CAPTCHAs because HearAct allows users to solve the CAPTCHA using gestures instead of typing. Thus, participants preferred HearAct over audio-based CAPTCHAs. The results of the study also show that the success rate of solving the HearAct CAPTCHA is 82.05% and 43.58% for audio CAPTCHA. A significant usability differences between the System Usability score for HearAct CAPTCHA method was 88.07 compared to audio CAPTCHA was 52.11%. Using gestures to solve the CAPTCHA challenge is the most preferable feature in the HearAct solution. To increase the security of HearAct, it is necessary to increase the number of sounds in the CAPTCHA. There is also a need to improve the CAPTCHA solution to cover wide range of users by adding corresponding image with each sound to meet deaf users’ needs; they then need to identify the spelling of the sound maker’s word.

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A CAPTCHA in the Text Domain

Cited by 15 publications

References 6 publications

Multilingual Highlighting CAPTCHA

Multilingual Highlighting CAPTCHA

Vulnerability of the conventional accessible CAPTCHA used by the White House and an alternative approach for visually impaired people

A Novel Design of Audio CAPTCHA for Visually Impaired Users

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