Patent ID: 7818258

Claim:
An electronic musical apparatus for reproducing encrypted music contents received from any one of plural types of music content sources, the electronic musical apparatus comprising: a storage device for storing a secret key and a plurality of source IDs each unique to one of the plurality types of music content sources; a memory for storing computer executable instructions; and a processor coupled to the memory for executing the computer executable instructions for causing the electronic musical apparatus to reproduce encrypted music contents by: loading an encrypted music content from one of the music content sources, wherein the encrypted music content includes encrypted common key information, encrypted security information, and encrypted music piece information, wherein the encrypted common key information is encrypted with a secret key, and wherein the encrypted security information includes copyright information and content ID; determining a type of the one of the music content sources; retrieving a source ID for the determined type of the one of the music content sources and the secret key from the storage device; retrieving the encrypted common key information, decrypting the encrypted common key information using the retrieved secret key, and retrieving the common key from the decrypted common key information; generating a first key using the retrieved common key and the retrieved source ID; retrieving the encrypted security information, decrypting the encrypted security information using the first key, and retrieving the content ID from the decrypted security information; and decrypting the encrypted music piece information using the retrieved content ID and reproducing the decrypted music piece information.