I-D Action:draft-tschofenig-sipping-captcha-01.txt

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title           : Completely Automated Public Turing Test to Tell Computers and Humans Apart (CAPTCHA) based Robot Challenges for SIP
	Author(s)       : H. Tschofenig, et al.
	Filename        : draft-tschofenig-sipping-captcha-01.txt
	Pages           : 24
	Date            : 2008-02-25

A common approach to deal with unwanted communication attempts is to
rely on some form of authorization policies, typically whitelists.
In order to populate the entries in such an access control list it is
helpful to have a way to challenge the entity willing to engage in a
conversation (unless they are already pre-authorized).  One reason
why this is desired is to deal with robots that are aggressively
distributing messages.

This document describes how "Completely Automated Public Turing Test
to Tell Computers and Humans Apart" (CAPTCHA) tests, which require
human interaction, are applied to SIP.

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