Patent ID: 8804961

Claim:
A method for clear session and scrambled session communication switch between mobile terminals comprising: after a first terminal and a second terminal have established clear session communication, the first terminal initiating a scrambled session request to the second terminal, if a scrambled session request response of the second terminal indicating the scrambled session request being accepted by the second terminal is received in a preset time, then the first terminal starting the key negotiation process with the second terminal; after the key negotiation process is completed, the first terminal initiating a scrambled session transferring request to the second terminal, the second terminal returning a scrambled session transferring response after receiving the scrambled session transferring request while starting the scrambled session; and the first terminal starting the scrambled session after receiving the scrambled session transferring response, and the first terminal and the second terminal entering into the scrambled session communication; wherein the scrambled session request, the scrambled session request response, the scrambled session transferring request, and the scrambled session transferring response are transmitted by using end-to-end signaling messages; and wherein the end-to-end signaling message includes a user information message, and carries a command type and/or parameter through a user-user field of the user information message in 3GPP protocol, wherein the command type comprises one of the scrambled session request, the scrambled session request response, the scrambled session transferring request, and the scrambled session transferring response.