Time sensitive passcodes in PHP

[thecubed]

Hello, all!
I would like to know if there was a way to make time sensitive passcodes in PHP.
For example, this passcode would be generated by another PHP script, then given out to the customer to access protected areas of a website.
I am going to use this for a remote support feature for my clients, so that I don't have a bunch of people abusing my support program and network.

I know that I could probably just use a mysql database/PHP script that generates a key, saves it to the database, then when user logs in, it verifies it against the passcodes in the database by time and stuff...
But, if it's possible to make a time sensitive passcode in PHP, could someone lead me in the right direction

Thank you very much!

[thecubed]

A clarification to what I mean is like this:

* A PHP script generates a password using some algorhythm that encodes
the time into the password, and an example output would be
something like 7703938 which would be the time encoded with a secret
value.
* then another PHP script decodes the password using the reverse algorhythm
and compares the encoded time with the current time and then allows the
user to see the protected resource.

I guess this falls more under the category of cryptography, because what I really need is an algorhythm to encode the time and a key into a password, and another algorhythm that extracts the encoded time from the password and compares it with the current time and expiration time.
An example of this would be a SecurID card, which generates random PINs based on the time and a secret key.
What I'm looking for is something like that, because I need some kind of time sensitive login application to protect my support network from being abused.

Sorry if none of this makes sense, my head is never not jumbled

Thanks for your time.