Abstract: In the information age, the security of air defense information network is a new challenging problem to the air defense system. According to the frangibility of the hardware, operation system and the network protocol, there was a great danger hidden in the air defense information network, and both of the outside and inside threats were studied. For keeping the security of the air defense information network, the defense in depth strategy was proposed, and then the defense models were constructed both in length and depth. At last, the technology framework was analyzed, and the key technology was studied.

Key words: Air defense information network,Defense in depth,Suter project,Cyber attack