Abstract
It’s ironic that these hard problems, such as character recognition, have been known to be hard for a long, long time, and yet almost as soon as people make crypto things out of them, they get solved. Actually it’s not quite the way you think because what’s happened is that for the examples that get automatically generated, there are special techniques which work just because they’ve been created deliberately. It’s not trivial to produce things that are really hard to solve, and some of the ideas for distorting characters have been quickly broken, but I believe there are some around which are quite robust.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2009 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Mitchell, C.J. (2009). Using Human Interactive Proofs to Secure Human-Machine Interactions via Untrusted Intermediaries. In: Christianson, B., Crispo, B., Malcolm, J.A., Roe, M. (eds) Security Protocols. Security Protocols 2006. Lecture Notes in Computer Science, vol 5087. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-04904-0_23
Download citation
DOI: https://doi.org/10.1007/978-3-642-04904-0_23
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-04903-3
Online ISBN: 978-3-642-04904-0
eBook Packages: Computer ScienceComputer Science (R0)