There is described a method for enabling a user of a client computer to securely access a remote server via a network, which is preferably the Internet, by authenticating the user. The method comprises providing a portable apparatus to the user which may communicate with the client computer. It further involves storing on the portable apparatus user credentials required to enable the user to be authenticated at the server and performing an authentication protocol between the client and the server. The authentication protocol includes the transmission to the server of a digest based at least partially on the user credentials; and the user credentials are stored on the portable apparatus in the form of a digest.