Patent ID: 6859535
Filing Date: 2005-02-22
Classification: G06F,G11B

Abstract:
1. A digital content protection system that enables a digital content to be used and includes a recording medium apparatus having a storage area for holding digital content information and an access apparatus that reads information from and writes information into the storage area, the digital content protection system operating according to the following phases: an authentication phase where the recording medium apparatus secretly transmits an inherent key to the access apparatus, and the recording medium apparatus and the access apparatus perform mutual authentication using the inherent key, the inherent key being information that is unique to the recording medium apparatus; and a content transfer phase, performed only when the recording medium apparatus and the access apparatus have successfully authenticated each other, where the access apparatus either (a) encrypts a digital content using the secretly transmitted inherent key and sends the encrypted digital content to the recording medium apparatus or (b) receives an encrypted digital content from the recording medium apparatus and decrypts the encrypted digital content using the secretly transmitted inherent key, wherein the recording medium apparatus includes a first calculation means, and the access apparatus includes a first authentication information generating means and a first authentication means, wherein while the access apparatus judges whether the recording medium apparatus is legitimate in the authentication phase, the first authentication information generating means generates first authentication information and outputs the first authentication information to the recording medium apparatus, the first calculation means receives the first authentication information, generates first calculated authentication information by performing a first calculation on the received first authentication information using the inherent key, and outputs the first calculated authentication information to the access apparatus, and the first authentication means judges whether the recording medium apparatus is legitimate from the first authentication information and the first calculated authentication information using the secretly transmitted inherent key, wherein the access apparatus includes a second calculation means, and the recording medium apparatus includes a second authentication information generating means and a second authentication means, wherein while the recording medium apparatus judges whether the access apparatus is legitimate in the authentication phase, the second authentication information generating means generates second authentication information and outputs the second authentication information to the access medium apparatus, the second calculation means receives the second authentication information, generates second calculated authentication information by performing a second calculation on the received second authentication information using the secretly transmitted inherent key, and outputs the second calculated authentication information to the recording medium apparatus, and the second authentication means judges whether the access apparatus is legitimate from the second authentication information and the second calculated authentication information using the inherent key, wherein the recording medium apparatus further includes a first encryption means and an inherent key storing means for prestoring the inherent key, and the access apparatus further includes a first decryption means, wherein while the recording medium apparatus secretly transmits the inherent key to the access apparatus in the authentication phase, the first encryption means generates an encrypted inherent key by applying a first encryption algorithm to the inherent key and outputs the encrypted inherent key to the access apparatus, and the first decryption means receives the encrypted inherent key and generates a decrypted inherent key by applying a first decryption algorithm to the encrypted inherent key, the first decryption algorithm being used to decrypt cipher text generated with the first encryption algorithm, wherein the recording medium apparatus further includes a first key storing means for prestoring a first key, and the access apparatus further includes a second key storing means for prestoring a second key that corresponds to the first key, wherein the first encryption means encrypts the inherent key using the first key, and the first decryption means decrypts the encrypted inherent key using the second key, wherein the first key and the second key are the same master key, and the first decryption means decrypts the encrypted inherent key using the second key that is the same as the first key.