Abstract: A method of authenticating a user, implemented when the user accesses an online service, which is accessible in a server through an access terminal. The method includes: dissemination, by the access terminal, of a first piece of authentication data; obtaining by an authentication terminal, the first piece of authentication data; connection, by the authentication terminal, to the server at a resource-location address derived from the first piece of authentication data; obtaining, by the server, of at least one piece of identification data for identifying the authentication terminal; and when the at least one piece of identification data for identifying the authentication terminal corresponds to piece of data pre-recorded in the server: transmission, to the access terminal, of a piece of data representing a page for entering a personal identification code of the user; and displaying, by the access terminal, the page for entering a personal identification code.