Method and system for processing information on encryption basis

摘要

A data processing apparatus generates a random number key, and generates a first intermediate key in response to the random number key. The data processing apparatus memorizes the first intermediate key in connection with an identifier. A combination of the identifier and the random number key is transmitted from the data processing apparatus to a reproducing device. The reproducing device generates a second intermediate key in response to the random number key. A combination of the identifier and the second intermediate key is transmitted from the reproducing device to the data processing apparatus. The data processing apparatus retrieves the first intermediate key in response to the identifier transmitted from the reproducing device. The data processing apparatus decides whether or not the retrieved first intermediate key and the second intermediate key are equal to each other. The data processing apparatus and the reproducing device are disconnected from each other when the data processing apparatus decides that the retrieved first intermediate key and the second intermediate key are not equal to each other. The data processing apparatus generates a first bus key in response to the first intermediate key. The reproducing device generates a second bus key in response to the second intermediate key. Encryption and decryption of digital information transmitted between the reproducing device and the data processing apparatus are implemented in response to the first and second bus keys.