Anti-spamming email harvesting

harvesting, stylesheets, backwards, unicode-bidi, bidi-override, browsers, hex, anti-harvesting, spammers, regular expressions, regular expression

26^th of February 2004

Stu's Site has a nice example of a way of preventing email harvesting by writing the email in reverse and then letting stylesheets reverse it when rendering. The HTML source looks like this:

And the result is: stu@s7u.co.uk. It works on in my web browsers (win, linux), but the nasty effect is that if you select the text, copy and paste; when you paste it pastes it as ku.oc.u7s@uts. Pretty annoying.

My site uses hex encoding so the HTML looks like this:

The result is as if no anti-harvesting effect had been applied.

Sadly I bet that spammers have tricks to get around both but what matters is how few spammers have yet to come up with the solution. I'm thinking of keeping my method and adding something that scrambles up the encoded string to break spammers regular expressions. But the effect mustn't be as bad as the example on Stu's site.

Comment

	Name: Email: hide my email address. Your email address will be encoded to prevent email-extraction spiders from reading it so you won't get spammed if you decide to show your email address.
	What number is this?

Dear all people entering comments,
Due to an increase in comment spam I've had to make it mandatory to recognize the imagenumbers. If you're unable to post comments, please contact me as soon as possible.