Patent ID: 8533492

Claim:
An electronic device that executes a key-using process indicating a process using a key, the electronic device comprising: a physical quantity generator that generates a physical quantity intrinsic to the electronic device and having a value which is different from one electronic device to another and different each time the physical quantity is generated; a key generator that generates the same key, based on the physical quantity generated by the physical quantity generator, each time the key-using process is to be executed, immediately before the key-using process is started; a key-using process executor that executes the key-using process using the key generated by the key generator; and a key deletor that deletes the key generated by the key generator, each time the key-using process is ended, wherein the key-using process executor includes a keyed hash value generator that executes, as the key-using process, a keyed hash value generation process of generating a keyed hash value of information which is to be used for a predetermined process and specified in advance, by using the key generated by the key generator, a check code storage that stores a keyed hash value generated in the past by the keyed hash value generator, as a check code, and a comparer that checks, by comparison, whether the check code stored in the check code storage coincides with a keyed hash value which is generated in a current keyed hash value generation process of the keyed hash value generator, the electronic device further comprising a coincidence information executor that executes the predetermined process using the information which is to be used for the predetermined process and specified in advance, only when the comparer judges that coincidence is established.