CAPTCHA: using hard AI problems for security
Luis von Ahn,Manuel Blum,Nicholas Hopper,John Langford +3 more
- pp 294-311
Reads0
Chats0
TLDR
This work introduces captcha, an automated test that humans can pass, but current computer programs can't pass; any program that has high success over a captcha can be used to solve an unsolved Artificial Intelligence (AI) problem; and provides several novel constructions of captchas, which imply a win-win situation.Abstract:
We introduce captcha, an automated test that humans can pass, but current computer programs can't pass: any program that has high success over a captcha can be used to solve an unsolved Artificial Intelligence (AI) problem. We provide several novel constructions of captchas. Since captchas have many applications in practical security, our approach introduces a new class of hard problems that can be exploited for security purposes. Much like research in cryptography has had a positive impact on algorithms for factoring and discrete log, we hope that the use of hard AI problems for security purposes allows us to advance the field of Artificial Intelligence. We introduce two families of AI problems that can be used to construct captchas and we show that solutions to such problems can be used for steganographic communication. captchas based on these AI problem families, then, imply a win-win situation: either the problems remain unsolved and there is a way to differentiate humans from computers, or the problems are solved and there is a way to communicate covertly on some channels.read more
Citations
More filters
Proceedings Article
Aiding the detection of fake accounts in large scale social online services
TL;DR: A new tool in the hands of OSN operators, which relies on social graph properties to rank users according to their perceived likelihood of being fake (SybilRank), which is computationally efficient and can scale to graphs with hundreds of millions of nodes, as demonstrated by the Hadoop prototype.
Proceedings ArticleDOI
The socialbot network: when bots socialize for fame and money
TL;DR: This paper adopts a traditional web-based botnet design and built a Socialbot Network (SbN): a group of adaptive socialbots that are orchestrated in a command-and-control fashion that is evaluated how vulnerable OSNs are to a large-scale infiltration by socialbots.
Proceedings ArticleDOI
Robust defenses for cross-site request forgery
TL;DR: This paper presents a new variation on CSRF attacks, login CSRF, in which the attacker forges a cross-site request to the login form, logging the victim into the honest web site as the attacker.
Proceedings Article
SybilInfer: Detecting Sybil Nodes using Social Networks.
George Danezis,Prateek Mittal +1 more
TL;DR: This work proves that, given standard constraints on the adversary, SybilInfer is secure, in that it successfully distinguishes between honest and dishonest nodes and is not susceptible to manipulation by the adversary.
Journal ArticleDOI
The spread of low-credibility content by social bots
Chengcheng Shao,Giovanni Luca Ciampaglia,Onur Varol,Kai-Cheng Yang,Alessandro Flammini,Filippo Menczer +5 more
TL;DR: In this paper, the authors analyze 14 million messages spreading 400 thousand articles on Twitter during ten months in 2016 and 2017 and find evidence that social bots played a disproportionate role in spreading articles from low-credibility sources.
References
More filters
Journal ArticleDOI
Telling humans and computers apart automatically
TL;DR: In this paper, lazy cryptographers do AI and show how lazy they can be, and how they do it well, and why they do so poorly, and they are lazy.
Proceedings ArticleDOI
Securing passwords against dictionary attacks
Benny Pinkas,Tomas Sander +1 more
TL;DR: The key idea is to efficiently combine traditional password authentication with a challenge that is very easy to answer by human users, but is (almost) infeasible for automated programs attempting to run dictionary attacks.
Patent
Method for selectively restricting access to computer systems
TL;DR: In this paper, a computerized method selectively accepts access requests from a client computer connected to a server computer by a network is proposed, where the server computer receives an access request from the client computer and generates a predetermined number of random characters.
Journal ArticleDOI
Pessimal print: a reverse Turing test
TL;DR: This work proposes a variant of the Turing test using pessimal print: that is, low-quality images of machine-printed text synthesized pseudo-randomly over certain ranges of words, typefaces, and image degradations and shows experimentally that judicious choice of these ranges can ensure that the images are legible to human readers but illegible to several of the best present-day optical character recognition (OCR) machines.
Book ChapterDOI
Provably Secure Steganography
TL;DR: In this article, the authors introduce definitions based on computational indistinguishability and prove that the existence of one-way functions implies secure steganographic protocols, and they also prove that secure protocols can be constructed from a complexity-theoretic point of view.