Abstract: To solve the problem of security handoff in near space,a new security handoff scheme based on context transfer was proposed．Firstly,a handoff destination estimate algorithm was designed,which is based on the Doppler shift mechanism that can estimate the handoff time and location．Secondly,the previous base-station sent authentication message to the next based-station in advance based on context transfer,which can increase handoff efficiency．Performance analysis and simulation results show that the communication and computation overhead of the scheme are small,and the forced termination probability is low．The scheme is suitable for the application of near space.

Key words: Near space,Security handoff,Context transfer,Doppler shift