Patent ID: 7596698
Filing Date: 2009-09-29
Classification: G06F,G11C,H04N

Abstract:
1. A semiconductor memory card comprising: a protected area; and an unprotected area, wherein the protected area (i) stores an encryption key sequence comprising a plurality of encryption keys arranged into a predetermined order, and (ii) is only accessible by a device that is 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 and a plurality of pieces of management information, wherein each encrypted audio object includes unique identification information, 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) accessible by the device 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 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) includes a corresponding time search map and corresponding attribute information, wherein the time search map of each respective piece of management information includes a plurality of pieces of entry information identifying internal positions of the respective encrypted audio object that is in one-to-one correspondence with the respective piece of management information, the pieces of entry information identifying the internal positions of the respective encrypted audio object at predetermined intervals of an equal duration, wherein the piece of 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, and wherein a length of each respective encrypted audio object is restricted such that a number of pieces of entry information of the respective piece of management information identifying the internal positions at intervals of a same duration does not exceed a predetermined number.