A method of authenticating a user to a service provider by means of an authentication provision unit, the method comprising: in a first stage of the method: receiving credentials from a user; determining whether the credentials received from the user represent a valid logon; and if that determination is positive: generating at least one network address comprising a domain address and at least one instance parameter, the instance parameter uniquely identifying the user and the instance of generation of the network address; and providing the network address to the user; and in a second stage of the method: receiving a parameter from a service provider; determining whether the received parameter indicates a valid attempt to log on to the service provider by checking that the received parameter matches an instance parameter that has previously been issued to a user and that has not previously been received from a service provider; and if that determination is positive: signalling to the service provider over a secure channel a message indicating that the received parameter represents a valid logon attempt, the message including credentials of the user to whom the instance parameter that matches the received parameter had been issued.
展开▼
