How to make a private URL?

Question

I want to create a private url as

http://domain.com/content.php?secret_token=XXXXX

Then, only visitors who have the exact URL (e.g. received by email) can see the page. We check the $_GET['secret_token'] before displaying the content.

My problem is that if by any chance search bots find the URL, they will simply index it and the URL will be public. Is there a practical method to avoid bot visits and subsequent index?

Possible But Unfavorable Methods:

1. Login system (e.g. by php session): But I do not want to offer user login.

2. Password-protected folder: The problem is as above.

3. Using Robots.txt: Many search engine bots do not respect it.

Answer 1

What you are talking about is security through obscurity. Its never a good idea. If you must, I would offer these thoughts:

• Make the link expire
• Lock the link to the C or D class of IPs that it was accessed from the first time
• Have the page challenge the user with something like a logic question before forwarding to the real page with a time sensitive token (2 step process), and if the challenge fails send a 404 back so the crawler stops.