Single Sign-On (SSO) describes the one-time authentication of a user, whereby he or she is authorized to use all associated services without having to authenticate again. SSO is often implemented in companies. If the user changes the device (e.g. from computer to tablet), the authentication is of course no longer necessary. SSO has the advantage that it saves time and is user-friendly. The user only has to authenticate himself once, which means that the password only has to be transmitted once. One password is easier to remember than several, even if password managers can be used. If the SSO system fails, the connected services may not be available. The sign-out is often implemented on a time basis.