Management of shared authentication credentials

A method for management and usage of authentication credentials, wherein usage information associated with an authentication credential is updated with a media access control (MAC) address for a computing device associated with using the authentication credential (e.g. by encrypting and storing the MAC address in the usage information). When a login request including the authentication credential is received 304 from a computing device, a MAC address of the computing device that sent the login request is fetched 306 and the authentication credentials and the MAC address are validated 308. If the authentication credentials and the MAC address pass the validation then the computer device may be authorised for access 312, and if they fail the validation access of the computing device may be restricted 314. In particular, the computing device may be blocked if the fetched MAC address does not match the MAC address in the usage information. The authentication credentials may be shared authentication credentials associated with a plurality of potential users. Secure Shell (SSH) protocols may be used to fetch the MAC address.