SECURE ELECTRONIC ENTITY FOR TIME CERTIFICATION

摘要

The secured electronic entity (11) comprises the times measurement unit (18), a unit (21) for the certification of a datum with respect to a date or a duration, and the synchronization unit (18a). The certification unit (21) receives the information on the date or the duration from the times measurement unit (18) and produces the certification data of the datum with respect to a date or a duration destined to an external entity. The certification unit (21) is adapted to provide a certified date or duration, or to certify the authenticity of a date or a duration received from the exterior. The certification unit (21) is adapted to certify that an action has been carried out in a given time period or before a limiting date. The times measurement unit (18) is adapted to provide a measure of times when the electronic entity (11) is not supplied by an external energy source, nor electrically supplied, and independently of all external clock signals. The times measurement unit (18) comprises the means for comparing two dates. The electronic entity (11) comprises at least one subset which contains a capacitive component having a leakage through its dielectric spacing, means for coupling the capacitive component to an electric energy source for charging, and means for measuring the residual charge which at least partly represents the time lapsed since the capacitive component is decoupled form the electric energy source. The capacitive component is implemented according to the MOS technology, and the dielectric spacing is constituted of silicon dioxide. The means for measuring the residual charge comprise a field-effect transistor with an insulator layer whose thickness is greater than the thickness of the insulator layer of the capacitive component, which is in the range of 4-10 nm. The electronic entity comprises at least two subsets whose capacitive components have different leakages through respective dielectric spacings, and means for processing the residual charges independently of calorific contributions. The electronic entity is portable, and is in the form of a microcircuit card.