| 摘要 |
PROBLEM TO BE SOLVED: To realize share of an encryption key between an encoder and a decoder in a little memory area and in a short calculation time. SOLUTION: In a system constituted by connecting the encoder 1 with the decoder 2 by an open channel 3, the encryption key is generated by multiplying a first random number system by a first linear matrix and outputted, a code word is generated by multiplying the first random number system by a second linear matrix in a second multiplier and the code word is transmitted to the receiving side via the open channel 3 in the encoder 1. The first random number system is estimated by receiving the code word via the open channel 3, using the second random number system having correlation with the first random number system in the encoder 1 and the received code word and performing maximum likelihood decoding using the second linear matrix which is the same as that on the side of the encoder 1 in the decoder 2. Then, the encryption key is generated by multiplying the first estimated random number system to the first linear matrix which is the same as that on the side of the encoder 1 and the encryption key is outputted. COPYRIGHT: (C)2004,JPO&NCIPI
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