He has a security clearance that allows him access to classifiedinformation.
他有安全许可，这准许他接触机密。
《柯林斯英汉双解大词典》
2
The Homeland Security Department still has problems handling classified top secret intelligence information, according to a new report from the department’s Office of the Inspector General.
根据美国国土安全部总监办公室的一份报告显示，国土安全部在处理机密级高度保密情报信息方面仍存在问题。
3
The category of the security of information system is classified. With each kind of attack principle analysed, the precaution measures and the solutions are brought up.