A method for operating a locking system comprising an electronic key and an electronic lock and a central unit which in locking operation is used locally separately from the electronic key and the electronic lock, wherein in the method an external authorization code is generated by the central unit by means of an authorization code determination program, the external authorization code is transferred to the electronic key and the external authorization code is saved in a memory by the electronic key, wherein, on interaction of the electronic key with the electronic lock, the external authorization code is read out from the memory by the electronic lock and is checked by a processor of the electronic lock in that, using an internal authorization code determination program, the processor itself determines an internal authorization code and compares it with the external authorization code received by the electronic key and wherein, in the event of the determined internal authorization code being identical to the transferred external authorization code, the processor permits an opening process.