A method for storing an event encrypted by control words guarantees access to this event at any moment, even if identities of these events are modified between storage and the moment of viewing. The method is performed in a reception and decryption unit connected to a security unit, the control words and the necessary rights being contained in control messages the method comprising the steps of storing the encrypted event and associated control messages in the storage unit; transmitting the control messages to the security unit; verifying if the access rights to this event are contained in the security unit and, if so, calculating a receipt of all or part of the control message using a secret unique key contained in the security unit; and storing the receipt in the storage unit.