Passing Authentication Credentials From Webapplication A to Webapplication B?

I have got a Web application say A which v开发者_JS百科ia url needs to communicate with application B and get the response from B. Application B uses a HTTP authentication mechanism. What I need to do is pass the authentication credentials from Application A to Application B through url request. I dont want to use _GET or _POST method due to security issues

Attach an encrypted string to the URL request from A to B. B should know the decryption method and parameters, it decrypt the encrypted string which received from A and check it is correct or not.