Method for authenticating a terminal equipment, device, server equipment and related computer program

A device for authenticating a user of a terminal equipment for access from a client browser of the terminal equipment to a remote service hosted by a server equipment, said device comprising:

• a calculation machine dedicated or configured to:
• authenticate the user from user's credentials;
• in the event of a successful user authentication, authenticating the terminal equipment from credentials stored in a first memory of the server equipment in association with the user's credentials, comprising an execution command to render a first pattern whose values are randomly selected from a plurality of predetermined values, said execution command comprising parameters describing the first pattern, and rendering the first pattern received from the terminal equipment, called a reference rendering, said authentication comprising:
• sending to the terminal equipment the first pattern rendering execution command;
• upon receipt of a response including a rendering of the first pattern by the terminal equipment, comparing with the reference rendering and evaluating a match score;
• deciding on successful authentication when the match score is greater than a predetermined threshold;
• following the authentication decision-, the calculation machine is configured to update the credentials of the client browser of the terminal equipment, delete, following an unsuccessful authentication, the first pattern rendering execution command and the rendering of first pattern of the first memory and, upon successful authentication of the terminal equipment, to replace the first pattern rendering execution command and the reference rendering stored in the first memory, with a execution command of rendering of a second pattern, distinct from the first, and a rendering of the second pattern.

A non-transitory computer-readable medium comprising instructions stored thereon, which when executed by a processor of server equipment, configure the server equipment to perform a method of authenticating a user of terminal equipment connected to a communication network, for access from this terminal equipment to a remote service hosted by the server equipment connected to said network, said method comprising the following acts implemented by the server equipment:

• authenticating the user from user's credentials;
• in the event of successful user authentication, authenticating the terminal equipment from credentials stored in a first memory of the server equipment in association with the user's credentials, including an execution command to render a first pattern whose values are randomly selected from a plurality of predetermined values, said command comprising parameters describing the first pattern, whose values are selected randomly among a plurality of predetermined values, and rendering the first pattern received from the terminal equipment, called a rendering reference pattern, said authentication comprising the following substeps:
• sending to the terminal equipment the first pattern rendering execution command;
• upon receipt of a response comprising a rendering of the first pattern by the terminal equipment, comparing with the rendering reference pattern and evaluating a match score;
• deciding on authenticating the terminal equipment according to the evaluated match score, a successful authentication being decided when the match score is greater than a predetermined threshold;
• and
• following the authentication decision, updating the credentials of the terminal equipment, said updating comprising, following a failed authentication, deleting the execution command of rendering of the first pattern and the rendering of the first pattern of the first memory and, in the event of successful authentication of the terminal equipment, replacing the first pattern rendering execution command and the reference rendering stored in the first memory, with an execution command of rendering of a second pattern, distinct from the first pattern, and a rendering a second pattern.