Abstract: A key holding system comprises one or more locks responsive to key codes stored by a programmable key to enable the selective operation of that lock. The key is programmed by a key programmer carried by the key holder or installed in a vehicle. A database of key codes related to individual locks is maintained at a remote station and the code required by the key to operate a particular lock is communicated, subject to any required validation, e.g., as to the identity of the key holder, to the key programmer. Various methods of increasing security of the system are disclosed.