CRYPTOGRAPHIC KEY MANAGEMENT SYSTEM

摘要

This invention relates to a cryptographic key management system that finds particular application as a key management system in a cash in transit system. The key management system of this invention comprises a controlled device equipped with a key derivation algorithm (KDA) which allows it to derive a new key (a controlled device key derivation algorithm (CDKDA)) from a current key (K_n+i = CDKDA(K_n)). The key derivation algorithm may conveniently allow the controlled device to derive a block of new keys from at least one current key or from a block of current keys. The preferred method for key derivation is triple DES DUKPT (Derived Unique Key Per Transaction).