There is an Open Access version for this licensed article that can be read free of charge and without license restrictions. The content of the Open Access version may differ from that of the licensed version.
Pricing information
Please choose your delivery country and your customer group
One of the reasons why information systems have been used widely is the highly-improved reliability of the systems. The reliability have been steadily improved without causing too much increase in cost. However, a fairly large cost increase is expected today for security improvement. The Ministry of Trade and Industry established 'the Standards of Safety Measures for Electronic Computer Systems' and the Ministry of Postal Services and Telecommunications established 'the Standards for Safety and Reliability of Data Communication Networks'. Security of the information network is not completed by only improving its components but requires general considerations of the whole network.