Access control system allowing transfer of authorisation to write keys

摘要

The card (C) carries an input/output interface (100) and an electrically writable non-volatile memory (101) containing an electronic key (CL) which is provided by a microcomputer (LE). The key includes a user identification and a personalisation date which are recorded in the lock (L). Authorisation to write such keys is held by the computer in the form of an identification (ID), a period of validity and the public key (K). It can be transferred to another computer by means of a new public key (K') and its signature (CER').