20110158405 | KEY MANAGEMENT METHOD FOR SCADA SYSTEM - Disclosed is a shared key management method for SCADA system in which a master terminal unit (MTU), a plurality of sub-master terminal units (sub-MTUs), and a plurality of remote terminal units (RTUs) are sequentially and hierarchically structured, comprising the steps of: generating shared keys of a group key in a tree structure by the MTU, the tree structure including a binary tree ranging from a root node corresponding to the MTU to intermediate nodes corresponding to the sub-MTUs; storing shared keys of descendant nodes and ancestor nodes of an intermediate node of a sub-MTU by the sub-MTU; and updating, upon updating of a shared key of an intermediate node, all shared keys of on-path nodes from the updated intermediate node to the root node, the shared keys of the on-path nodes being updated using their own shared keys and shared keys of off-path child nodes. | 06-30-2011 |