Patent ID: 7225339

Claim:
An information recorder for recording information onto a recording medium, said recorder comprising: cryptography means for generating an encryption key based on encryption key generating data built within said information recorder and for encrypting, using the generated encryption key, data that is to be stored on the recording medium; and memory means for storing a corresponding leaf key and at least a portion of a plurality of node keys, the plurality of node keys being associated with a plurality of nodes whereby a given one of the plurality of node keys is associated with a particular one of the plurality of nodes, the plurality of nodes being arranged according to a hierarchical tree structure having a root node and having one or more leaves, a specific leaf of the one or more leaves being associated with said information recorder and with its corresponding leaf key, the portion of the plurality of node keys being the node keys associated with the nodes disposed along a particular path from the root node to the specific leaf, the encryption key generating data being renewable using a key renewal block and at least one key selected from the group consisting of the corresponding leaf key and the portion of the plurality of node keys, the key renewal block including encrypted data and tag data, the encrypted data being derived from encryption of renewed encryption key generating data and the selected at least one key, and the tag data indicating locations in the hierarchical tree structure whose associated keys are encrypted within the encrypted data, the encryption key being a first encryption key and the encryption key generating data being first encryption key generating data when playback of the recording medium is to be restricted to only a player storing a specific identifier, the first encryption key generating data being stored on the recording medium, and the encryption key being a second encryption key and the encryption key generating data being second encryption key generating data when playback of the recording medium is not to be restricted.