Abstract: The disclosure concerns memory cards and, more particularly, cards that are used as means of prepayment in installations for the dispensing of products and services. It is proposed to make the memory rechargeable by means of a credit counter, incrementable from outside the card, and a comparator which compares the content of this counter with that of a page counter. The page counter records the number of pages of P accounting units already used up. A no more credit signal is emitted on an external terminal when the content of the page counter reaches the content of the credit counter. A security system against the fraudulent recharging of the card is set up by an algorithm bringing into play the content of the credit counter and an identification number contained in the card.

Abstract: The microcircuit card is such that at least one strain-indicating sensor is placed on the microcircuit, in a known state of strain, and is maintained in this state by a protection layer deposited on the microcircuit for as long as this layer is not affected. The microcircuit has means for measuring an electrical value that is characteristic of the strain, and a logic circuit connected to the measuring means to detect the changes in the condition of strain indicating an intrusion into the card.