OpenID is another one of those "cool technologies you've never heard of" type of deals. OpenID is an open source initiative that provides a way for Web users to register their identity in one place and then use that identity anywhere on the Web that supports OpenID. [...] Before getting an OpenID, though, I should point out that it's not required that you run an OpenID provider to OpenID-enable your application. In fact, no special software or service is required in your Web application. The only requirement is that your Web server programming language be able to make HTTP requests of the OpenID provider, which is something all of them can do.

Once you have your OpenID account set up, his simple script, making use of the ability that any version of PHP has to open URLs, can authenticate off of a remote OpenID service - that has the cURL extension compiled in.

OpenID, a free, open-source framework for "single sign-on" across different Web sites and applications. The even better news? There already exist a bunch of PHP widgets that allow developers to easily integrate OpenID into a PHP application, and this article is going to show you how to use them. So what are you waiting for? Flip the page, and let's get going!

For those not familiar with the authentication method, he defines OpenID and shows how it can help with the "too many passwords, too many accounts" problem many users face. He uses the PHP OpenID Library and the Authentication::OpenID_Consumer PEAR package (as well as several other PEAR packages to help with the connections and message formatting). He builds two simple forms to use the service - one to authenticate a user and another to create a new account.

Since there have been numerous tutorials written regarding Zend_Auth, I won't attempt to make a full tutorial on it. If you are curious, google around, you'll find them. Today though, I'd like to show you a cool new piece that has been added to Auth in Zend Framework 1.5, the new Zend_Auth_Adapter_OpenId.

Cal explains what the OpenID system is all about before getting into the code that uses it. He suggests MyOpenID as a provider to register at and includes the code to make a request to them to authenticate a username/password combo. The actual authentication check is only about three or four lines of code.