Information processing system and method

A tree (tree) structure encryption key structure, a comprises a pressing block (EKB) to transmit the content key, a authentication key and program data is equal. EKB is wherein a tree the insulated device of teeth with a blade key and a defined node key, a specific invocation key block (EKB) and distributed a specific node the special device, and define device capable upgrading. No lower-stage the device for group it decryption, wherein the key distribution safety. . I.e, the structure encryption key structure executing the distribution of each key or data in tree (tree), and is in efficient and via the data sending information processing system and method.