Patent ID: 8286001

Claim:
A central processing unit for processing at least one encrypted software, wherein the encrypted software comprises at least one encrypted software section, the encrypted software section being encrypted with a particular management key MK and stored in a memory area, the MK being encrypted with a device key DK as an encrypted MK, the central processing unit comprising: a processing and cache unit; a cryptographic unit, comprising: a device key storage unit for storing the DK; a plurality of management key storage units for storing MKs, wherein each management key storage unit corresponds to a management key index MKI; a decryption unit for decrypting an encrypted MK with the DK to obtain a MK, storing the MK to a management key storage unit, and outputting a MKI corresponding to the management key storage unit, the MKI being used to identify a location of the encrypted software section in the memory area; the cryptographic unit outputting the MKIs to the processing and cache unit, and the processing and cache unit storing the MKIs; the processing and cache unit transferring software and one of the MKIs to the cryptographic unit, and the cryptographic unit using said one of the MKIs to obtain one of the MKs, and using said MKs to encrypt the software transferred from the processing and cache unit; wherein the MKI corresponding to said particular MK is used both to identify the location of the particular MK, and to identify the location in the memory area of the encrypted software section encrypted by the particular MK; and wherein, the decryption unit invokes the corresponding MK according to the MKI and decrypts the encrypted software section, and directly transfers the decrypted software from the decryption unit to the processing and cache unit.