★★★ ＜知的財産翻訳検定＞答案用紙 ★★★
==================================================================科目：電気・電子工学

氏

名：杉浦まゆみ==================================================================
WHAT IS CLAIMED IS:
1.

A cipher communication device comprising:a cipher recording unit including
an error correction encoder for adding a redundancy to input data toperform error correction encoding,an interleaving device for rearranging output data from the error
correction encoder in accordance with a predetermined rule every predetermined fixed
bit number for output, andan encrypting device for encrypting output data from the interleaving
device to keep secrecy of contents of the output data from the interleaving device; anda cipher reproducing unit including
a decrypting device for decrypting input data, the input data being
output data from a recording medium recorded by the cipher recording unit,
a de-interleaving device for rearranging output data from thedecrypting device in accordance with a predetermined rule every predetermined fixed
bit number to restore the order of the output data from the decrypting device, which has
been rearranged by the interleaving device, into an original order, andan error correction decoder for performing correction decoding of anerror in input data based on the redundancy added thereto by the error correction
encoder, the input data being output data from the de-interleaving device.
2.

The cipher communication device according to claim 1, further

comprising a key information generator each adapted for the cipher recording unit andthe cipher reproducing unit to operate the error correction encoder, the interleavingdevice, and the encrypting device of the cipher recording unit, and the decrypting device,
the de-interleaving device, and the error correction decoder of the cipher reproducingunit.
Upon receiving data from the cipher recording unit, the decrypting device 5 inthe cipher reproducing unit is operated to decrypt the encrypted data.

After thedecryption, the de-interleaving device 6 performs a pseudo random conversion withrespect to a consecutive error, which has occurred during reproduction of the data fromthe recording medium by the decrypting device 5.

FIGS. 3A, 3B, and 3C are

illustrations showing the operations of the cipher reproducing unit. Assuming that-1-

input/output data of the ciphering device 3 and the deciphering device 5 are blockciphers, if an error occurs during reproduction of the data from the recording medium,and the error is included in the output data from the deciphering device 5, as shown in
FIG. 3A, Bi block in a data string indicated by the reference numeral 13 carries theerror consecutively.

In a matrix memory configuration indicated by the reference

numeral 14 in FIG. 3B, the de-interleaving device 6 is operated in such a manner thatdata is sequentially written in a column direction in one row, and the data writing is
executed one row after another, and that the data is sequentially read in a row direction
in one column, and the data reading is executed one column after another. Under thecondition, the block Bi carrying the error is written in the i-th row in the memory of thede-interleaving device 6, and is read in a distributive manner in the i-th bit of eachcolumn (see Pj in data string 15, and (Pj, i) in data string 16 in FIG. 3C). In this way,
the consecutive error in the block in the output data from the decrypting device 5 isdistributed by the de-interleaving device 6, which may be outputted in a pseudo randommanner from the de-interleaving device 6.

-2-