A proxy server is implemented between a user computer and the Web. The user accesses an IAM service and selects a cloud service. The proxy server intercepts the login form from the user, stores the identifier and password, and replaces the identifier and password. The proxy server allows the form to continue to the IAM service which registers the cloud service. Later, the user accesses the IAM service and selects the cloud service. The IAM service returns a login form for the cloud service with the identifier and password and redirects the user's computer to the cloud service. The proxy server intercepts the form and replaces the identifier and password with the correct identifier and password. The proxy server then allows the form to continue to the cloud service. The user is then authenticated by the cloud service and receives a Web page from the cloud service indicating logged in.