• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.565-573
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• 2022

Current mobile communication system is in the mid-process of conversion from 4G LTE to 5G network. According to the generalization of mobile communication services, personal information such as user's identifiers and location information is transmitted through a mobile communication network. The importance of security technology is growing according to the characteristics of wireless mobile communication networks, the use of wireless shared channels is inevitable, and security technology cannot be applied to all network system elements in order to satisfy the bandwidth and speed requirements. In particular, for security threat analysis, researches are being conducted on various attack types and vulnerability analysis through rogue base stations or attacker UE to make user services impossible in the case of 5G networks. In this paper, we established a 5G network testbed using open sources. And we analyzed three security vulnerabilities related to NAS COUNT and confirmed the validity of two vulnerabilities based on the testbed or analyzing the 3GPP standard.

• Journal of Drive and Control
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• v.9 no.2
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• pp.39-45
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• 2012

The NAS 1638 cleanliness classification system was originally developed in 1966 by the US Aircraft Industries of America to both simplify reporting of particle count data and to control the introduction of dirt during the assembly of aircraft fluid systems. The numbers of particles at stated sizes are represented by broad bands where the interval was generally a doubling of contamination. A number of systems have been introduced since this to suit differing requirements. NAS 1638 and AS4059 are used in other industrial sectors such as the Off-shore & Sub-Sea and the Primary Metal Industries. The changes to ISO contamination measurement standards controlled by ISO/TC131/SC6 in 1999 meant that a revision of most of these classification systems was necessary. The body responsible for NAS 1638 decided to withdraw it for new installations and replace it with an update of an existing standard, SAE AS 4059. This paper details the philosophy behind the contamination coding systems, the reasons for the changes to the ISO contamination standards and explains the workings of AS 4059, the replacement for NAS 1638. It goes on to detail the latest changes to this standard.