A device and method for decrypting digital contents are discussed. According to an embodiment, a method for decrypting digital content at a target device, includes receiving the digital content without a source encryption key from a source device connected to the target device, the digital content having been encrypted with the source encryption key in the source device; 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 associated with the target device; and decrypting the encrypted digital content using the target encryption key.