The invention is directed to a source device and a method for encrypting digital content at the source device. According to an embodiment, the method includes authenticating a target device connected to the source device using an identifier (ID) associated with at least one of the target device and a storage medium of the target device; performing an addition operation by using a source internal key and the ID, the source internal key being associated with the source device; generating a source encryption key based on an output of the addition operation; encrypting the digital content using the source encryption key; and transmitting the encrypted digital content without the source encryption key to the target device.