Affiliations: [a] School of Electronic Engineering, Beijing University
of Posts and Telecommunications, Beijing, China | [b] Beijing Key Laboratory of Work Safety Intelligent
Monitoring, Beijing University off Posts and Telecommunications, Beijing,
China | [c] State Key Laboratory of Information Security, Graduate
School of Chinese Academy of Sciences, Beijing, China
Correspondence:
[*]
Corresponding author: Hongxin Zhang, School of Electronic
Engineering, P.O. BOX 116, Beijing University of Posts and Telecommunications,
Beijing 100876, China. Tel.: +86 010 6228 2818; Fax: +86 010 6228 1958; E-mail:
hongxinzhang@263.net
Abstract: To quantitatively evaluate the strength of information leakage
arising from computer under shielding conditions, a mathematic model is
established for information leakage based on near-field measurement results by
using the equivalence principle. In order to study the leakage threshold and
the shielding performance for information leakage, the notions of Information
Identifying Degree, Information Resolution Threshold and Computer Security
Defence Distance are formalized respectively. Then, Information Identifying
Degree, Information Resolution Threshold and Computer Security Defence Distance
are analyzed. So, the strength of information leakage is quantitatively
assessed under different shielding levels and distance. The simulation results
show that FCC and MIL461C standards are not suitable for the evaluation of
information leakage and even strictly standard should be considered. At last,
new shielding levels of information leakage are marked off and the shielding
effects are assessed by using Information Resolution Threshold. This research
aptly provides a quantitative evaluation method for assessing the information
leakage strength and presents a means to evaluate information leakage shielding
effectiveness of computers.
Keywords: Electromagnetic emission, information leakage, information security
