Patent ID: 7747538
Filing Date: 2010-06-29
Classification: G06F,G06Q,G11B,H04H,H04L

Abstract:
1. A memory card to receive and record encrypted data and decryption information data to decrypt said encrypted data, comprising: a first storage unit storing said encrypted data, a first key hold unit storing a predetermined first public encryption key corresponding to said memory card and its own authentication data, said memory card being a first party, encrypted so as to be decryptable with a public authentication key, the encrypted predetermined first public encryption key and its own authentication data being stored in the first key hold unit allowing output to an external source, a second key hold unit storing a first private decryption key to decrypt data encrypted with the first public encryption key, a first decryption processing unit receiving a first symmetric key that is encrypted with the first public encryption key, and configured to apply a decryption process on the received first symmetric key, the received first symmetric key being updated and transmitted for each communication of said decryption information data, a third key hold unit to store a second public encryption key unique to each said memory card, a session key generation unit generating a second symmetric key updated for each communication of said decryption information data, a first encryption processing unit encrypting said second public encryption key and said second symmetric key based on said first symmetric key for output, a second decryption processing unit to decrypt using said second symmetric key said decryption information data encrypted by said second public encryption key at an external source, and further encrypted by the second symmetric key, a second storage unit storing said decryption information data encrypted with said second public encryption key that is an output of said second decryption processing unit, a fourth key hold unit storing a second private decryption key to decrypt data encrypted by said second public encryption key, a third decryption processing unit decrypting data stored in said second storage unit based on said second private decryption key to extract said decryption information data, a fifth key hold unit storing said public authentication key, a fourth decryption processing unit decrypting and extracting an externally applied third public encryption key of another party, said another party being a second party, encrypted so as to be decryptable with said public authentication key, and a second authentication data of another party, a control unit conducting an authentication process based on said second authentication data extracted by said fourth decryption processing unit, and inhibiting output of said decryption information data when the authenticity is not verified, a third encryption processing unit extracting a second symmetric key updated for each communication by said session key generation unit based on said third public encryption key for output, and a third encryption processing unit to apply encryption based on an externally applied unique fourth public encryption key of another party, wherein i) said second decryption processing unit is configured to decrypt and output said first symmetric key encrypted with the second symmetric key, or the fourth public encryption key and first symmetric key, ii) when said fourth public encryption key is extracted by said second decryption processing unit, said third decryption processing unit is configured to extract decryption information data from data recorded in said first storage unit, said third encryption processing unit encrypts an output of said third decryption processing unit using a fourth public encryption key output by said second decryption processing unit, and said first encryption processing unit encrypts an output of said third encryption processing unit based on the second symmetric key extracted by said second decryption processing unit for output, iii) when only said second symmetric key is extracted by said second decryption processing unit, said second decryption processing unit extracts decryption information data from data stored in said first storage unit, and said third encryption processing unit encrypts an output of said second decryption processing unit based on the second symmetric key extracted by said second decryption processing unit for output, in the case where there is an output request for decryption information data from an external source, and said control unit does not inhibit output of decryption information data.