Abstract: A block processing section divides message data into a plurality of blocks, so as to obtain a plurality of data blocks. A plurality of data encryption processing sections are provided in correspondence to the data blocks. The first one of the data encryption processing sections selects one of pre-stored data conversion algorithms in response to an initial selection control signal. Each of the remaining data encryption processing sections selects one of the data conversion algorithms in response to a selection control signal supplied from a preceding data encryption processing section. Each of the data encryption processing sections performs data encryption processing with respect to the corresponding data block on the basis of the selected data conversion algorithm, and generates a selection control signal to be supplied to the succeeding data encryption processing section, on the basis of the data obtained by the data encryption processing.

Abstract: A block processing section divides message data into a plurality of blocks, so as to obtain a plurality of data blocks. A plurality of data encryption processing sections are provided in correspondence to the data blocks. The first one of the data encryption processing sections selects one of pre-stored data conversion algorithms in response to an initial selection control signal. Each of the remaining data encryption processing sections selects one of the data conversion algorithms in response to a selection control signal supplied from a preceding data encryption processing section. Each of the data encryption processing sections performs data encryption processing with respect to the corresponding data block on the basis of the selected data conversion algorithm, and generates a selection control signal to be supplied to the succeeding data encryption processing section, on the basis of the data obtained by the data encryption processing.

Abstract: A block processing section divides message data into a plurality of blocks, so as to obtain a plurality of data blocks. A plurality of data encryption processing sections are provided in correspondence to the data blocks. The first one of the data encryption processing sections selects one of pre-stored data conversion algorithms in response to an initial selection control signal. Each of the remaining data encryption processing sections selects one of the data conversion algorithms in response to a selection control signal supplied from a preceding data encryption processing section. Each of the data encryption processing sections performs data encryption processing with respect to the corresponding data block on the basis of the selected data conversion algorithm, and generates a selection control signal to be supplied to the succeeding data encryption processing section, on the basis of the data obtained by the data encryption processing.

Abstract: A path memory control method in a Viterbi decoder outputs, when a plurality of decoding steps are required to trace back to a final stage of a surviving path, the same number of decoded data as that of the decoding steps required for trace-back, thereby determining the decoded data. During trace-back, state transition information throughout a plurality of times can be combined with each other, and the final stage of the surviving path can be traced back by jumping back a plurality of stages, at a time, by reducing the number of memory access, thereby realizing high-speed decoding.