Patent ID: 7839999

Claim:
An encryption device that receives a request for information, the encryption device comprising: a processing unit; a first unit that acquires, in response to receiving the request, value information denoting a value of the information to be encrypted, wherein the first unit acquires the value information using the processing unit; and a second unit that determines a strength parameter denoting an encryption strength for the information, based on the value information, wherein the second unit has a fifth unit and a sixth unit, the fifth unit calculating an estimate calculation amount corresponding to a unit price, wherein the estimated calculation amount is an estimate value of a calculation amount in the unit price and in a period, based on a computational power in the unit price varying dependent on a price and a performance of a processing device that decrypts or decodes encrypted information maliciously or without authorization, and the sixth unit calculating the strength parameter satisfying a condition, based on the estimate calculation amount corresponding to the unit price, a value of the value information, and an estimate formula for calculating an amount necessary for decrypting or decoding the encrypted information maliciously or without authorization, wherein the estimate calculation amount corresponding to the unit price is f(Y), which is given by a following expression, f ( Y )= F ·(2^( Y/ 1.5)), where F denotes the computational power in the unit price and Y denotes the period.