Abstract: The objective of the present invention is to propose a method that allows preventing the use of more than one identical security module for the identification and use of resources administered by an operating centre. This objective is achieved by an anti-cloning method based on the memorization of the identification numbers of the user units connected to said security module. During a connection with an operating centre these numbers are transmitted and compared with the numbers of a previous transmission. Differences are accepted as long as new numbers are added to a list previously transmitted. The security module is declared invalid if the numbers previously memorized are not included in the transmitted numbers.

Abstract: The objective of the present invention is to propose a method that allows preventing the use of more than one identical security module for the identification and use of resources administered by an operating centre. This objective is achieved by an anti-cloning method based on the memorisation of the identification numbers of the user units connected to said security module.

Abstract: The objective of the present invention is to propose a method that guarantees the encryption of the exchanged data a security module and a user unit by a pairing key specific to the couple user unit/security module, and at the same time leaving the possibility for the security module to be paired with other user units.

Abstract: A process for spraying concrete or mortar, by a dry route or by a wet route, in order to produce on a surface a layer of concrete or of mortar. Just before or at the time of spraying, an aqueous suspension (A) of silica and of an aluminum compound chosen from aluminum sulphate, basic aluminum sulphates, alums and mixtures thereof is added to the concrete or mortar. The aqueous suspension (A) has a pH lower than 4, a solids content of between 10 and 50% by weight, and, after a period at rest of 48 hours, is in the form of a gel which is reversible under low shear. The aqueous suspension (A) is effective for increasing the thickness of the sprayed layer and reducing rebound of the concrete or mortar sprayed onto the surface.