Patent ID: 8261063
Filing Date: 2012-09-04
Classification: G06F

Abstract:
1. A computing platform comprising: a secure key-handling unit arranged to store a storage root key that forms the root node of a tree-structured node hierarchy the non-leaf nodes of which, other than the root node, each comprise, in encrypted form, a key used to encrypt the or each of its child nodes, and insecure storage for storing the hierarchy nodes other than the root node; the key-handling unit comprising: a memory for storing the storage root key and a current decryption-root key; a decrypted-access arrangement arranged to restrict decrypted access to the hierarchy nodes to those nodes decryptable by a chain of decryption rooted in said current decryption-root key, wherein the decrypted-access arrangement is operable in a mode where the current decryption-root key corresponds to a node of said hierarchy other than the root node and one or more nodes higher up in said hierarchy than is the node corresponding to the current decryption-root key are not available; and a current-decryption-root setting arrangement for storing in said memory, the key of a selected non-leaf node of said hierarchy to serve as said current decryption-root key, the current-decryption-root setting arrangement enabling the selected non-leaf node to be changed.