Title
CAPTCHA: using hard AI problems for security
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.
Year
DOI
Venue
2003
10.1007/3-540-39200-9_18
EUROCRYPT
Keywords
Field
DocType
current computer program,hard problem,unsolved artificial intelligence,artificial intelligence,ai problem family,ai problem,automated test,security purpose,practical security,hard ai problem,captcha
Cryptographic protocol,Computer science,Cryptography,Computer security,AI-complete,Optical character recognition,Theoretical computer science,CAPTCHA,Reverse Turing test,Discrete logarithm,Applications of artificial intelligence
Conference
Volume
ISSN
ISBN
2656
0302-9743
3-540-14039-5
Citations 
PageRank 
References 
511
33.97
6
Authors
4
Search Limit
100511
Name
Order
Citations
PageRank
Luis von Ahn13461346.66
manuel blum247951351.57
Nicholas Hopper3146995.76
John Langford45392353.60