Patent ID: 7099474

Claim:
A key and lock device having a key and a lock, comprising: a plurality of first devices belonging to a group of first devices, each first device comprising: a first electronic processor, a first memory connected to said first electronic processor, and a first connector connected to said first electronic processor, a second device comprising: a second electronic processor, a second memory connected to said second electronic processor, and a second connector connected to said second electronic processor and adapted to mechanically co-operate with said first connector when said key is inserted in the lock so as to transfer information between said key and lock, and a power source connectable to said first and second processors, a mechanically operated blocking mechanism operated by a mechanically coded device, and an electrically operated blocking mechanism adapted to block operation of the lock when an unauthorized key is inserted in the lock, wherein said first memory is adapted for storing a public identity and a single secret identity, wherein said secret identity is the same for the first devices belonging to the group of first devices, said second memory is adapted for storing the public identity and a secret identity for authorized first devices, said first electronic processor is arranged to identify itself to said second electronic processor by said public identity, and said first and second electronic processors are arranged to exchange a random number and to calculate a respective code word using at least a part of said secret identity and at least a part of said random number, and wherein said electrically operated blocking mechanism is brought to a non-blocking position if said code words calculated in said first and second electronic circuits, respectively, are identical.