[lists] Re: [wp-hackers] Anti spam idea

[John Watson]

This is the hashcash idea.  I implemented this a few weeks ago (the
sample code is in the list archives and
http://flagrantdisregard.com/index.php?p=267).  It's not practical
because Javascript is so slow computing the hashes.  A 16-bit
collision takes a fraction of a second to compute in C but could take
30-60 seconds in Javascript.  Spammers are using apps that post
directly to the page which could compute the hashes very quickly. 
Another problem is that hashcash isn't really effective in stemming
the tide overall unless a significant portion of the community uses
it.

It would still slow them down a little.  Actually, since none of them
have code in their apps to compute the hashes, even a really simple
hash prevents the spam for now.

--
John
http://flagrantdisregard.com/

On Thu, 18 Nov 2004 06:01:15 -0500, Elliott Bäck <ecb29 at cornell.edu> wrote:
> Why not just make comment spammers pay in CPU time for each comment?
> Put a buffer page in between when the user submits his comment and the
> final submission.  In between, have him calculate an expensive hash in
> javascript.  If you played with the constants, you could make a 10s