Abstract: Authentication management of software (22) in a product (28) encompasses trust anchor assignment (66) and trust anchor verification (68). A root public key (40) of a root trust anchor (32) is stored (80) in non-changeable memory (54) in the product (28). A signed operational public key (86) is formed by attaching a root signature (84) to an operational public key (44) of an operational trust anchor (34) using a root private key (38). An operational signature (96) is appended to the software (22) using an operational private key. (42) to form signed software (98). The signed operational public key (86) and the signed software (98) are saved in changeable memory (56) in the product (28). Upon verification of the root signature (84) utilizing the root public key (40) and validation of the operational signature (96) using the operational public key (44), the software (22) is authenticated and enabled to execute.

Abstract: Methods for applying coverings to surfaces by casting at least a portion of the covering in a mould from a solidifiable liquid mix. The mould may be applied directly to the surface or to an already cast layer of the covering. In another embodiment an outer portion of the covering is cast in a mould and is affixed to the surface, or to an already cast layer of the covering, so as to define a void between the outer portion and the surface or already cast layer. The void is filled with solidifiable liquid mix.

Abstract: Coverings are applied to a surface by means of a member capable of temporarily holding the covering and urging it against the surface with adhesive interposed between the covering and the surface. The covering may be held by the member by means of suction and be urged against the surface by air pressure. The member may be mounted on a first articulated arm whose movement can be controlled by an operator who may be situated on a working platform mounted on a second articulated arm. The covering may be an acoustic tile for application to the surface of a submarine hull.