Visual CAPTCHAs for Document Authentication

Fischer, Igor; Herfet, Thorsten

doi:10.1109/mmsp.2006.285353

Cited by 17 publications

(10 citation statements)

References 9 publications

(8 reference statements)

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“…They have proposed an animated CAPTCHA scheme containing moving letters on a noisy background. Fischer and Herfet proposed an idea of presenting the text on a deforming surface [13]. Chow and Susilo proposed an animated CAPTCHA scheme based on motion parallax [14].…”

Section: Cui Et Al Termed It As Zero Knowledge Per Framementioning

confidence: 99%

Reading the Moving Text in Animated Text-Based CAPTCHAs

Shah¹,

Shaikh²,

Arain³

2018

ijacsa

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Having based on hard AI problems, CAPTCHA (Completely Automated Public Turing test to tell the Computers and Humans Apart) is a hot research topic in the field of computer vision and artificial intelligence. CAPTCHA is a challenge-response test conducted to single out humans and bots. It is ubiquitously implemented on the web since its introduction. As text-based CAPTCHAs are successfully broken by various researchers therefore several design variants have been proposed and implemented in order to further strengthen it. Animated Text-based CAPTCHAs are one of the design variant of it and are based on the difficulty of reading the moving text. They are based on zero knowledge per frame principle. Although it's still easy for humans to read animated text but it's a challenge for machines. As proposals for animated CAPTCHAs are on the rise so there is a strong need to scrutinize their strength against automated attacks. In this research, such CAPTCHAs are investigated to verify their robustness against automated attacks. The proposed methods proved that these CAPTCHAs are vulnerable and they do not guarantee the robustness against automated attacks. The proposed frame selection, noise removal, segmentation and recognition methods have successfully decoded these CAPTCHAs with an overall precision, segmentation accuracy and recognition rate of up to 53.8%, 92.9% and 93.5% respectively.

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Section: Cui Et Al Termed It As Zero Knowledge Per Framementioning

confidence: 99%

Reading the Moving Text in Animated Text-Based CAPTCHAs

Shah¹,

Shaikh²,

Arain³

2018

ijacsa

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“…Examples of animated CAPTCHAs include a method based on moving letters amid a noisy background [21], the use of animation technology to provide better security over static images with distorted text [22], and an approach based on the idea of presenting distorted text on the face of a deforming surface [23]. Chow and Susilo [24] devised an animated 3D CAPTCHA named AniCAP, which was designed with the segmentation-resistant principle in mind.…”

Section: Animatedmentioning

confidence: 99%

Text-based CAPTCHAs over the years

Chow

Susilo

2017

IOP Conf. Ser.: Mater. Sci. Eng.

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“…Needless to say, solutions of this kind require the use of smart phones as trusted hardware devices. Solutions based on CAPTCHAs: In some solutions, CAPTCHA images are used as trusted channels for transmitting transaction data from U to S [61, Solution 2] or from S to U [27,60,64]. The security is based on the assumption that a CAPTCHA image cannot be manipulated by the untrusted computer C in a real-time manner.…”

Section: Existing Solutionsmentioning

confidence: 99%

hPIN/hTAN: A Lightweight and Low-Cost E-Banking Solution against Untrusted Computers

Sadeghi

Heisrath

et al. 2012

Lecture Notes in Computer Science

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Abstract. In this paper, we propose hPIN/hTAN, a low-cost hardware token based PIN/TAN system for protecting e-banking systems against the strong threat model where the adversary has full control over the user's computer. This threat model covers various kinds of attacks related to untrusted terminal computers, such as keyloggers, screen scrapers, session hijackers, Trojan horses and transaction generators. The core of hPIN/hTAN is a secure and easy user-computer-token interface. The security is guaranteed by the user-computer-token interface and two underlying security protocols for user/server/transaction authentication. The hPIN/hTAN system is designed as an open framework so that the underlying authentication protocols can be easily reconfigured. To minimize the costs and maximize usability, we chose two security protocols dependent on simple cryptography (a cryptographic hash function). In contrast to other hardware-based solutions, hPIN/hTAN depends on neither a second trusted channel nor a secure keypad nor external trusted center. Our prototype implementation does not involve cryptography beyond a cryptographic hash function. The minimalistic design can also help increase security because more complicated systems tend to have more security holes. As an important feature, hPIN/hTAN exploits human users' active involvement in the whole process to compensate security weaknesses caused by careless human behavior.

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Visual CAPTCHAs for Document Authentication

Cited by 17 publications

References 9 publications

Reading the Moving Text in Animated Text-Based CAPTCHAs

Reading the Moving Text in Animated Text-Based CAPTCHAs

Text-based CAPTCHAs over the years

hPIN/hTAN: A Lightweight and Low-Cost E-Banking Solution against Untrusted Computers

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