There is provided a method performed by a first entity of a network. Contextual information for the first entity and a timestamp for the contextual information is acquired (102). An authentication token is generated (104) using the acquired contextual information. Transmission of an authentication request message is initiated (106) towards a second entity of the network requesting authentication of the first entity with the second entity. The authentication request message comprises the generated authentication token and the timestamp for use in the authentication. An authentication response message indicative of whether authentication of the first entity with the second entity is successful or unsuccessful received (108).