Method for authenticating a user by user identifier and associated graphical password, characterized in that: > the graphical password comprises two parts: o a first part obtained by a first selection of a group of images (1 - 5) from several groups of images, o a second part obtained by a second selection of a sequence of several images (A-Y) in the selected group of images, ➢ the user gives his or her user identifier to an application, and graphically performs: o a first selection of a group of images in a set of several groups of images, the order of the groups of images in this set of groups of images being randomly displayed by the application with each new authentication of said user, ∘ a second selection of a sequence of several images (A-Y) in this group of images, the order of the images (A-Y) in this group of images being randomly displayed by the application with each new authentication of said user, > the application: o identifies the position of the selected group of images in said set of groups of images and identifies the position of each selected image (A-Y) in said sequence, ∘ establishes the correspondence between the position of the selected group of images and the identifier of the selected group of images, and between the sequence of the positions of the selected images (A-Y) and the sequence of the identifiers of the selected images (A-Y), ∘ compares the identifier of the group of selected images with the identifier of the group of images of the password registered for said user identifier, and compares the sequence of the identifiers of the selected images (A-Y) with the sequence of the identifiers of the images (A-Y) of the password registered for said user identifier, ∘ the application being the only entity able to establish this correspondence and/or the application being the only entity able to make this comparison, ∘ authenticates said user if said comparison is positive but refuses to authenticate said user if said comparison is negative. > the graphical password comprises two parts: o a first part obtained by a first selection of a group of images (1 - 5) from several groups of images, o a second part obtained by a second selection of a sequence of several images (A-Y) in the selected group of images, o a first part obtained by a first selection of a group of images (1 - 5) from several groups of images, o a second part obtained by a second selection of a sequence of several images (A-Y) in the selected group of images, ➢ the user gives his or her user identifier to an application, and graphically performs: o a first selection of a group of images in a set of several groups of images, the order of the groups of images in this set of groups of images being randomly displayed by the application with each new authentication of said user, ∘ a second selection of a sequence of several images (A-Y) in this group of images, the order of the images (A-Y) in this group of images being randomly displayed by the application with each new authentication of said user, o a first selection of a group of images in a set of several groups of images, the order of the groups of images in this set of groups of images being randomly displayed by the application with each new authentication of said user, ∘ a second selection of a sequence of several images (A-Y) in this group of images, the order of the images (A-Y) in this group of images being randomly displayed by the application with each new authentication of said user, > the application: o identifies the position of the selected group of images in said set of groups of images and identifies the position of each selected image (A-Y) in said sequence, ∘ establishes the correspondence between the position of the selected group of images and the identifier of the selected group of images, and between the sequence of the positions of the selected images (A-Y) and the sequence of the identifiers of the selected images (A-Y), ∘ compares the identifier of the group of selected images with the identifier of the group of images of the password registered for said user identifier, and compares the sequence of the identifiers of the selected images (A-Y) with the sequence of the identifiers of the images (A-Y) of the password registered for said user identifier, ∘ the application being the only entity able to establish this correspondence and/or the application being the only entity able to make this comparison, ∘ authenticates said user if said comparison is positive but refuses to authenticate said user if said comparison is negative. o identifies the position of the selected group of images in said set of groups of images and identifies the position of each selected image (A-Y) in said sequence, ∘ establishes the correspondence between the position of the selected group of images and the identifier of the selected group of images, and between the sequence of the positions of the selected images (A-Y) and the sequence of the identifiers of the selected images (A-Y), ∘ compares the identifier of the group of selected images with the identifier of the group of images of the password registered for said user identifier, and compares the sequence of the identifiers of the selected images (A-Y) with the sequence of the identifiers of the images (A-Y) of the password registered for said user identifier, ∘ the application being the only entity able to establish this correspondence and/or the application being the only entity able to make this comparison, ∘ authenticates said user if said comparison is positive but refuses to authenticate said user if said comparison is negative.