Re: CAPTCHA image validation in web form

Joe,

<<new symbolic link in the IFS to the image for each request, and then
send that symbolic link name. >>

yes, a good idea, maybe added to the routine in each two months adding and
removing some images, not too complex at all.
also is important don't allow more than one select error (even none) in each
transaction.

Guillermo.


On Wed, Sep 3, 2008 at 6:54 AM, Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx>wrote:

Nathan Andelin wrote:

But there's a 1/7 chance that a bot could pick the right image the first
time, and over a large enough number of iterations a smart bot could
learn which radio button descriptions were paired with which image
files. Over a large enough number of iterations a bot could esentially
download & duplicate your entire image library and cross-reference
table.

In this case, you would never use a static name for the image. There
are a number of ways to handle it, but one simple way would be to 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.

Joe