Abstract: A method is provided to improve authentication of a user to login with a client device to a computer system. A mobile device stores a list of Uniform Resource Locators (URLs), user names and passwords. The mobile device reads an authentication code displayed on a display of the client device to extract a URL and a session identifier (ID), searches a user name and a password associated with the URL in the list of URLs, user names and passwords, transmits the user name, the password, and the session ID to a gateway server when the user name and the password associated with the URL are found in the list, and authenticates the user to login to the computer system with the client device when the client device retrieves from the gateway server the user name and the password.