公开(公告)号：JPH0334641A

公开(公告)日：1991-02-14

申请号：JP5977190

申请日：1990-03-09

Applicant: TANDEM COMPUTERS INC

Inventor： MAACHIN EMU ATARA ,  UEBUSUTAA DEE HOPUKINSU ,  RARUFU AARU BESUTOTSUKU ,  JIEE YANGU KIMU

IPC: G09C1/00 ,  G07F7/10 ,  H04L9/08 ,  H04L9/06 ,  H04L9/14

Abstract: PURPOSE: To make it impossible to discover an encryption key by monitoring a transaction with time by using a cryptography for generating a unique key. CONSTITUTION: A unique dynamic encryption key is periodically generated related with each of plural remote terminals by using the seed key of a system which is present only in a host computer. The generated dynamic encryption key is used at the time of enciphering data transferred to a host computer by a terminal, and also used for decoding data received from the host computer. This method includes the storage of the dynamic key preliminarily generated by the host computer related with a terminal in the terminal. Thus, it is impossible to discover the encipherment key by monitoring a transaction with time.