Patent ID: 6999948
Filing Date: 2006-02-14
Classification: G06F,G06Q,G11B,H04H,H04L

Abstract:
1. A memory card to receive and record content key to decrypt content data comprising: a first key hold unit storing a first private decryption key to decrypt data encrypted with a predetermined first public encryption key corresponding to said memory card, a first decryption processing unit receiving a first symmetric key updated and distributed for each communication of a content key, and encrypted with said first public encryption key to apply a decryption process, a second key hold unit to store a second public encryption key unique to each memory card, a first encryption processing unit encrypting said second public encryption key based on said first symmetric key, and providing the encrypted second public encryption key, a second decryption processing unit receiving said content key encrypted with said second public encryption key, and further encrypted with said first symmetric key to apply a decryption process based on said first symmetric key, a first storage unit receiving and storing an output of said second decryption processing unit, a third key hold unit storing a second private decryption key to decrypt data encrypted with said second public encryption key, a third decryption processing unit to decrypt said content key using said second private decryption key, based on data stored in said first storage unit, and a control unit controlling operation of said memory card according to an operation mode designate from an external source, wherein said first storage unit receives and stores said encrypted content data that can be decrypted based on said content key, wherein said first encryption processing unit under control of said control unit receives and encrypts using said first symmetric key said content key from said third decryption processing unit in a response to designation of a reproduction operation of said content data for output, wherein said first storage unit under control of said control unit outputs said encrypted content data in response to designation of reproduction operation of said content data.