Block encrypting device for fast session switching and method of operating the same

PURPOSE: A block coding apparatus capable of changing a high-speed session and a method for driving the same are provided to reduce a delay time due to a session change by performing a series of operations for a session change at high speed using hardware of the block coding apparatus. CONSTITUTION: A host matching unit(200) performs a standard matching function of a host. A local bus arbitrator(201) transmits instruction data and coding/decoding processing data inputted from the host and transfers coding/decoding result data and response data to the host. An instruction interpreter(207) analyzes the instruction data from the host. If the instruction data is coding/decoding processing instruction, the instruction interpreter(207) generates response data to transmit it to the host matching unit(200), and otherwise, it transmits variables required to the instruction data and a coding/decoding processing to instruct the start of a coding/decoding processing operation. A CPU(Central Processing Unit) generates response data corresponding to the instruction performance result. A code chip receives the variables from the instruction interpreter(207) to realize a block code algorithm and to perform a block coding or decoding operation. A session data memory stores data of a session key, an initialization vector, an operation mode, a condition of a session. Input/output buffer memories temporarily stores the coding/decoding processing data from the host and the coding/decoding processing result data of the code chip.