Patent ID: 7643635

Claim:
A method for decrypting re-encrypted digital content at a target device, the method comprising: receiving the re-encrypted digital content without a source encryption key from a source device connected to the target device; wherein the re-encrypted digital content is generated at the source device by: 1) decrypting an encrypted digital content which is previously encrypted in an external device, and 2) re-encrypting the decrypted digital content with the source encryption key; performing an addition operation by using a first target internal key and an identifier (ID), the first target internal key being associated with the target device, and the ID being associated with at least one of the target device and a storage medium of the target device; generating a target encryption key based on an output of the addition operation and a second target internal key by using a predetermined encryption algorithm, the second target internal key being generated at the target device; and decrypting, the re-encrypted digital content using the target encryption key.