Telecommunications installation with secured downloading of prepayment means and method for the download

摘要

The installation comprises a downloading mode in which, in response to a downloading request word (R) for a predetermined number of value units originating from the independent station (PA), there is provision for: - active authentication of the independent station (PA) and of the access system (SAA); - calculation of a downloading key (KCH or (SCH,PCH)) within the authorisation centre (CA); - sending of the enciphered downloading key intended for the access system (SAA); - secured downloading of the prepayment means (MPAY) originating from the access system, with the aid of the downloading key thus transmitted.