| 摘要 |
PURPOSE:To prevent intermission of communication even when a key or an initial vector is changed and to improve the transmission speed by providing a memory circuit storing a random pattern required for ciphering and decoding and an exclusive OR circuit ciphering and decoding an information bit based on the random pattern read. CONSTITUTION:A ciphering key from a key register 2 and a ciphering initial vector from an initial vector (IV) register 3 are acted on a ciphering arithmetic unit 1. A ciphered output is obtained by feeding back an output ciphered from the ciphering arithmetic unit 1 to the input via a changeover switch 9. The random pattern for ciphering obtained in this way is stored in a memory circuit 4 via a changeover switch 10. In case of transmission, the random pattern for ciphering read from the memory circuit 4 and the information bit to be sent are ORed exclusively by an exclusive OR circuit 7 to cipher the information bit and the result is sent as a transmission data. |
