Integrated circuit device and a data transmission system

An integrated circuit device includes: a reception control unit that receives data from an information processing terminal over a network; a main control unit having a route selection determining unit that controls selection of data to be transmitted to a subsequent system based on information whether data received by the reception control unit is encrypted; a decrypting unit that decrypts the encrypted data outputted from the main control unit; and a route selector that selects whether to acquire undecrypted data outputted from the main control unit or to acquire decrypted data outputted from the decrypting unit based on control by the route selection determining unit.