Patent ID: 7894603

Claim:
A recording system in which a host device and a recording drive are connected via a bus, said host device comprising a determination module configured to determine whether input content is to be protected by an encryption process when transferred over the bus, said recording drive comprising a recording module configured to record user data interspersed with user control data in a unit of physical cluster on a recording medium, wherein the content is recorded in the user data, and protection information is recorded in the user control data, the protection information consisting of a one-bit flag indicating whether the content is to be protected by the encryption process when being transmitted on the bus based on a determination result obtained by said determination module, said host device further comprises a first encryption module configured to encrypt the content using a recording medium key of the recording medium regardless of whether said determination module determines that the content is to be protected, and said host device further comprises a second encryption module configured to encrypt the content using a key common to both the host device and the recording drive before being sent to the bus when said determination module determines that the content is to be protected.