Patent ID: 8156347
Filing Date: 2012-04-10
Classification: G06F,G11C,H04N

Abstract:
1. A semiconductor memory card comprising: a protected area; and an unprotected area, wherein the protected area stores an encryption key sequence composed of a plurality of encryption keys arranged into a predetermined order, and is only accessible by a device connected to the semiconductor memory card if a mutual authentication between the device and the semiconductor memory card is successful, wherein the unprotected area stores a plurality of encrypted audio objects, a plurality of pieces of management information, and a playlist, such that the plurality of pieces of management information are in one-to-one correspondence with the plurality of encrypted audio objects, wherein the plurality of encrypted audio objects each includes unique identification information, wherein the plurality of encrypted audio objects includes: wherein each respective encryption key of the plurality of encryption keys is (i) in one-to-one correspondence with a respective encrypted audio object of the plurality of encrypted audio objects based on the unique identification information of the respective encrypted audio object, and (ii) used to decrypt the respective encrypted audio object that is in one-to-one correspondence with the respective encryption key, wherein each respective piece of management information of the plurality of pieces of management information includes attribute information, block information, and link information, wherein the attribute information of each respective piece of management information shows that the respective encrypted audio object that is in one-to-one correspondence with the respective piece of management information is one of (a) an entire audio track, (b) a first part of an audio track, (c) a middle part of an audio track, and (d) an end part of an audio track, wherein the block information of each respective piece of management information includes (i) an offset from a start position of the valid data of the respective encrypted audio object that is in one-to-one correspondence with the respective piece of management information and (ii) a length of the valid data, of the respective encrypted audio object that is in one-to-one correspondence with the respective piece of management information, that starts at the position indicated by the offset, such that the block information of each respective piece of management information specifies a position of the valid data in the respective encrypted audio object without decrypting the respective encrypted audio object, wherein the link information, of a respective piece of management information of the plurality of pieces of management information that is in one-to-one correspondence with a respective encrypted audio object of the plurality of encrypted audio objects that is the first part of the audio track or the middle part of the audio track, identifies an encrypted audio object of the plurality of encrypted audio objects that is the middle part of the audio track or the end part of the audio track that follows the first part of the audio track or the middle part of the audio track of the encrypted audio object that is the first part of the audio track or the middle part of the audio track, and wherein the playlist shows a playback order of audio tracks and a playback order of respective encrypted audio objects, of the plurality of encrypted audio objects, included in each audio track of the audio tracks.