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Fighting Spambots with .NET and AI - Cont'd By Adnan Masood email this article to a colleague suggest an article Conclusion CAPTCHA, short for "Completely Automated Public Turing Test to Tell Computers and Humans Apart", are tests to protect the digital assets from automated bots and illegitimate agents pretending to be human beings. This battle between good and bad will go on. Breaking CAPTCHAs is opening new venues for machine visions, and therefore providing sophisticated applications and better optical character recognizers. CAPTCHAs are unfriendly for the disabled and visually impaired; therefore, w3c accessibility guidelines should be followed. This article is the first in a series of three articles focusing on scientific solutions for eliminating spam, the plague of messaging. The second article in this series is about writing a Bayesian text classifier API library in C#.NET. The third and final one will use the Bayesian text classification library to implement a spam filter using Web services. Thanks for reading and happy .NETTING! References and Further Readings CAPTCHA home http://www.captcha.net/ Breaking a visual CAPTCHA http://www.cs.berkeley.edu/~mori/gimpy/gimpy.html Greg Mori and Jitendra Malik, UC Berkeley Computer Vision Group Telling Humans & Computers apart (to appear in CACM) http://www.cs.cmu.edu/~biglou/captcha.pdf CAPTCHA: Using Hard AI Problems for Security (Eurocrypt) http://www.cs.cmu.edu/~biglou/captcha_crypt.pdf Protect Your Online Forms By John Clyman http://www.pcmag.com/article2/0,4149,1401422,00.asp CAPTCHA-ing the Spammer By Cade Metz http://www.pcmag.com/article2/0,4149,1306805,00.asp News Human or Computer? Take This Test, The New York Times, December 10, 2002. Up to the Challenge: Computer Scientists Crack a Set of AI-Based Puzzles, SIAM News, November 2002. Robot solves Internet robot problem By Byron Spice, Pittsburgh Post-Gazette, October 21, 2001 Computer or Human? New Programs can tell By Matt O'Brien, University of Miami Newspaper, November 20, 2001 Can Hard AI Problems Foil Internet Interlopers? By Sara Robinson, SIAM News, April 2002 Researchers battle e-mail stealing Web bots with identity checks By Mike Crissey, The Associated Press, December, 2002 Computer Pioneer Aids Spam Fight The BBC News, January, 2003 Recognizing Objects in Adversarial Clutter: Breaking a Visual CAPTCHA (2003) Greg Mori, Jitendra Malik Turing Test A. M. Turing (1950) Computing Machinery and Intelligence. Mind 49: 433-460. http://cogprints.ecs.soton.ac.uk/archive/00000499/00/turing.html The Turing test page http://cogsci.ucsd.edu/~asaygin/tt/ttest.html Alan Turing Homepage http://www.turing.org.uk/turing/ AI Glossary - Syracuse University http://physics.syr.edu/courses/modules/MM/gloss/ai_glossary.html Technical Solutions for Controlling Spam http://citeseer.nj.nec.com/541678.html BaffleText: a Human Interactive Proof http://www.cs.berkeley.edu Gimpy High Level Description http://www.cs.berkeley.edu/~mori/gimpy/high_level.html Gimpy Paper http://www.cs.berkeley.edu/~mori/gimpy/gimpy.pdf Telling Humans and Computers apart OR How Lazy Cryptographers do AI Luis von Ahn_ Manuel Blum_ John Langford_ http://www-2.cs.cmu.edu/~biglou/captcha.pdf SIG (Special Interests Group) Computer Science Dept., Carnegie Mellon University, Pittsburgh The UC Berkeley Computer Vision Group Shape Matching and Object Recognition Detecting Natural Image Boundaries British Computing Society Artificial Intelligence Group EZGimpy in Action with yahoo http://edit.yahoo.com/config/eval_register?.intl=us&new=1&.done=&.src=ym&.partner=&.p=&promo=&.last= Practical A.I. - Introduction - Ben Garcia http://www.15seconds.com/Issue/030508.htm Web Methods returning something else than XML? http://www.dotnet247.com/247reference/msgs/6/31078.aspx Sapience Validation is an XML RPC based service. http://kokochi.com:8080/sapience/index.jsp The heart of Sapience is the validation image generator, which was created by Paul Tremblett and published in the October 2003 issue of Dr Dobb's Journal. Dav Coleman turned it into an XML RPC service, creating the Sapience system View the Real World in Your Application, with TerraServer, by Karl Moore http://www.developer.com/net/print.php/10916_2222811_2 CityView App: Build Web Service Clients Quickly and Easily with C#, MSDN Magazine http://msdn.microsoft.com/msdnmag/issues/01/04/wicked/ Demonstration of using Base64 encoding, in a Web Service using the .NET Framework, by Robert Chartier http://authors.aspalliance.com/nothingmn/default.aspx?whichpoll=nothingmn_121&aid=121 Baffling the Bots, by Lee Bruno http://www.sciam.com/article.cfm?chanID=sa006&colID=6&articleID=00053EA7-B6E8-1F80-B57583414B7F0103 Bot Related Websites http://www.runabot.com/ http://www.activebuddy.com/ http://members.aol.com/adamkb/aol/imbots http://www.pandorabots.com/pandora Botspot http://www.donbarker.com/Botspot/best_of_the_bots/ How to build a Bot Trap and keep bad bots away from a web site http://www.kloth.net/internet/bottrap.php Robot Exclusion http://www.robotstxt.org/wc/exclusion.html Computer Vision and Image Understanding Palo Alto Research Center http://www.parc.xerox.com http://www2.parc.com/istl/members/baird/ Stopping Spambots: A Spambot Trap Using Linux, Apache, mod_perl, Perl, MySQL, ipchains and Embperl, By Neil Gunton http://neilgunton.com/spambot_trap/ SECURITY and CRYPTOGRAPHY 15-827 Lecture #17 http://www-2.cs.cmu.edu/~hopper/cs827-f01/lec17.txt OGDEN's BASIC ENGLISH http://ogden.basic-english.org/basiceng.html Base64 content-Transfer-encoding http://www.freesoft.org/CIE/RFC/1521/7.htm The 1st referred Published paper on CAPTCHAs: L. Coates, H. S. Baird, R. Fateman, "Pessimal Print: a Reverse Turing Test," Proc., 6th IAPR Int'l Conf. On Document Analysis & Recognition, Seattle, WA, Sept. 10-13, 2001. Hosted first professional event: 1st NSF Int'l Workshop on HIPs, Jan. 9-11, 2002, Palo Alto, CA. ImageMagik:Image Manipulation API http://www.imagemagick.com/ Securing passwords against dictionary attacks http://portal.acm.org/citation.cfm?id=586133&jmp=cit&dl=GUIDE&dl=ACM About the Author Adnan Masood is a software developer for UKIM in London and is getting his Msc in software engineering from UNW Stratford London campus. With a broad hybrid development vision on multiple software development technologies, Adnan's main expertise is in server-side programming on Microsoft and Sun Platforms. He's been an active ASP and Java developer for the past five years and holds a Bachelors of Science degree in Computer Science and a Sun Java-II Certification (SCJP-II). You can read his blog at www.axisebusiness.com/adnano. He can be reached via e-mail at amasood@bcs.org.uk . <-- Delivering and Invoking CAPTCHA from Web Services   <<-- Introduction Rate this Article Supporting Products/Tools AspEncrypt Built around the Microsoft CryptoAPI, AspEncrypt helps you harness all major encryption and hashing algorithms such as DES, Triple-DES, RC2, RC4, RSA, MD5 and SHA1 in just a few lines of code. The component can be used in tandem with AspEmail to send encrypted and signed mail in the industry-standard S/MIME format, or with AspUpload to encrypt files as they are being uploaded. AspEncrypt can also be used to issue and manage X.509 digital certificates. [Top] AspPDF AspPDF is an ASP/ASP.NET component which enables generation and management of documents in PDF format. Features include advanced text formatting, font embedding, form fill-in, images, tables, content and page extraction, document stitching, encryption, digital signatures, and more. [Top] Other Articles Feb 3, 2005 - ASP.NET Mixed Mode Authentication In many web applications it is desirable for both intranet users and external parties to be able to seamlessly log onto the system. The problem this raises is that it is not easy to allow intranet users to log in via Windows integrated authentication while also allowing external parties to log in to the same application using standard forms authentication. This article will show you one way to achieve the best of both worlds when it comes to authentication. [Read This Article]  [Top] Dec 8, 2004 - Designing Role-Based Security Models for .NET In this article, Michele Leroux Bustamante discusses authentication, authorization and role-based security in .NET. Along the way, he provides some best practices for implementing role-based security in some typical .NET application scenarios including rich clients, Web applications, and Web services. [Read This Article]  [Top] May 11, 2004 - SharePoint Security and .NET Impersonation When implementing custom components that require access to restricted resources, implicit impersonation must be used. Jay Nathan shows how to create a class that makes using .NET Impersonation a snap. [Read This Article]  [Top] Mar 10, 2004 - Intellectual Property Protection and Code Obfuscation Learn about the execution process of CLR-based programs and how to protect your applications from being easily disassembled back into source code. [Read This Article]  [Top] Feb 24, 2004 - How to Send Secure Mail in ASP-Based E-Commerce Applications - Part II Businesses that utilize encrypted e-mail may find Secure Multipurpose Internet Mail Extensions (S/MIME) to be somewhat restrictive. This article shows how to use security features in PDF as an alternative to S/MIME. [Read This Article]  [Top] Feb 2, 2004 - Fighting Spambots with .NET and AI Bill Gates, in a recent interview, predicted the end of spam by 2006. One of the methods he mentioned involved a challenge only a real live person could handle. Adnan Masood shows how to use AI and .NET to create a user verification scheme that incorporates similar concepts Gates alluded to. [Read This Article]  [Top] Jan 21, 2004 - Configuring .NET Code Access Security Code Access Security (CAS) is the .NET Framework security model that grants code permission to resources based on "evidence" pertaining to the encapsulating assembly. In this article, David Myers examines CAS and explains different configuration methods. 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