1. A method for opening a session of a first machine using session checking means for a machine set of machines comprising at least said first machine and a second machine, said second machine comprising security means, the method comprising: receiving, by the session checking means, a request to open a session on said first machine, said request comprising at least one item of identification information of a user; verifying, by the session checking means, that the at least one item of identification information of said user is associated with an item of identification data of said second machine in a repository; checking by the session checking means that the user has the right to open a session on the first machine; if said verification and check are positive, sending by the session checking means a session status modification request of said second machine to said security means of said second machine; and if the session status of the second machine is modified, sending a request to authorize opening of a session to the first machine by the session checking means; and storing said at least one identification information item for said user that is associated with an item of identifying data of said first machine in said repository by the session checking means.