The present invention provides an apparatus for securely acquire a circuit configuration information set corresponding to a new cryptosystem without increasing the number of reconfigurable circuits. A content playback apparatus 100 includes an FPGA 122 that is reconfigurable. The content playback apparatus 100 stores a decryption circuit program that shows the structure of a decryption circuit that executes decryption in accordance with a prescribed cryptosystem. The FPGA is reconfigured in accordance with the program to configure the decryption circuit. The playback apparatus 100 acquires, from outside, an encrypted file that has been generated by encrypting a file including a decryption circuit program corresponding to the new cryptosystem in accordance with the prescribed cryptosystem, and decrypts the encrypted file by the decryption circuit.