发明名称 |
FREMGANGSMAATE TIL KODING OG DEKODING AV MELDINGER. |
摘要 |
Method of coding and decoding messages wherein a basic key and a random message key, which is transmitted prior to the message, are used. Using a plurality of basic keys entails the problem that the proper basic key must be set in the receiving station. In accordance with the present method, the sequence of a portion (II) of the message key and of a number of check characters derived therefrom are coded, prior to the actual message transmission, using the basic key and a different portion (I) of the message key. Decoding in the receiving station is done by using a basic key which is chosen from a group of basic keys, and the different portion (I) of the message key. A test circuit 21 examines whether the decoded check characters correspond to the check characters derived in the receiving station from the decoded portion (II) of the message key. A positive test result indicates that the desired basic key has been found.
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申请公布号 |
NO152920(C) |
申请公布日期 |
1985.12.11 |
申请号 |
NO19800000962 |
申请日期 |
1980.04.01 |
申请人 |
PHILIPS` GLOEILAMPENFABRIEKEN, N.V., |
发明人 |
PAS, ANDRIES JOANNES MARTINUS VAN DE,;ENDE, ANTONIUS CORNELIS JOHANNES VAN DEN, |
分类号 |
H04L9/18;(IPC1-7):H04K1/02;H04L9/02 |
主分类号 |
H04L9/18 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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