Re: CAPTCHA image validation in web form

[Nathan Andelin <nandelin@xxxxxxxxxxxx>]

> Joe Pluta wrote:
> create a new symbolic link in the IFS to the image for each
> request, and then send that symbolic link name.  You'd run
> a regular job to clear out old links.

That's a pretty good idea, but every file has a "signature", so to 
speak.  A clever bot author wouldn't need to rely on a file name.  And 
remember that a learning bot would be downloading and duplicating your 
entire image library and description cross-reference table, and could be 
assigning its own name to the image.  It would just need to match up the 
signature.  A signature might consist of a combination of factors such 
as total # of bytes, plus various byte comparisons interspersed 
throughout the stream.

It's not that I have a better idea.  I don't, but wish I did.  The 
TicketMaster case kind of jarred me into the reality that a bot author 
may have a strong financial interest in overcoming a captcha.

Nathan.