The Research On Application Of VPN Based On IPSec In Civil Aircraft Air To Ground Communication

The civil aircraft system cannot use the public communication network,which will affect the security of the airborne network.IPSec VPN is a virtual private network that runs on the IP layer and meets the IP protocol.IPSec VPN can create an exclusive IPSec tunnel between communication ends through end's authentication and data transmission encryption.Then it provides security services to ensure airborne network security of the air-to-ground wireless communication network based on IP network communication.This thesis analyzes the using and security requirements of civil aircraft wireless broadband communication,and use the experience of the key techniques of IPSec VPN tunnels,authentication,data encryption,authentication head,encapsulating security payload,key exchange.Then this thesis presents design of the IPSec VPN top-level model on airborne system to provide a secure communication link for data interaction between the airborne system and the ground support system.The mode includes logical architecture,IP message stream processing,internal data,inter-device authentication,etc.The key technologies and objectives to be considered in the model are: IKE negotiation component supports the pre-shared key,the authentication mode which based on the modified public key and digital signature;includes ESP or AH + ESP package and unpack format;the algorithm of encryption algorithm such as AES128,3DES and MD5 and sha-1 are designed;core component supports the completion of SA and SP additions,deletions,updates,and so on in trigger mode.The test results shows that the key negotiation function of the airborne IPSec VPN gateway is compliant with the IKE protocol,the tunnel which successfully built can provide the upper service communication and protect IP packet.The VPN can disconnect the upper service after the tunnel is stopped.Next research will be carried out on the security and robustness of the keys,the compatibility of new IPSec versions,the gateway across of network address port translation,etc.