A Uniform Approach to Modelling Timed Protection

P. Balbiani (France)


Access control, matrix model, temporal rea soning.


Most of access control mechanisms use the matrix model to represent protection states of computer systems as ternary relations between subjects, rights, and objects. We present in this paper a variant of the matrix model obtained by incorporating time-dependent access control requirements saying, e.g., that such-and-such right may only be given to those subjects who already possess specific rights for at least a certain period. This combination of the access con trol matrix model with temporal reasoning is called timed protection. It constitutes a new approach for the formal design of real-time protection systems where real numbers are used to model time.

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