US Patent 7549044 Block-level storage device with content security

A block-level storage device is provided that implements a digital rights management (DRM) system. In response to receiving a public key from an associated host system, the storage device challenges the host system to prove it has the corresponding private key to establish trust. This trust is established by encrypting a secure session key using the public key. The host system uses its private key to recover the secure session key. The storage device may store content that has been encrypted according to a content key. In addition, the storage device may encrypt the content key using the secure session key.