A protection key for hardware includes a first storage area configured to
store a key data used for permission to use software installed in a
information processor, a second storage area configured to store a data
table including a plurality of random numbers, a receiver configured to
receive a cryptography key from the information processor, a
coder/decoder configured to encrypt the key data based on the
cryptography key by picking one random number from the data table, and a
transmitter configured to transmit the encrypted key data to the
information processor.