Patent ID: 8275990

Claim:
A method for receiving/sending a multimedia message, comprising steps of: receiving/sending the multimedia message between a multimedia messaging service (MMS) user device and a MMS gateway via a wireless LAN; and encrypting the multimedia message by: using the MMS gateway to perform: issuing a certificate to the MMS user device; sending a session ID and a master key encrypted by the MMS gateway's private key to the MMS user device in response to a request of said MMS user device having the certificate; generating a shared secret key using an algorithm combining the master key with the MMS user device's phone number and the session ID; and encrypting the multimedia message using the shared secret key; using the MMS user device to perform: decoding the master key received from the MMS gateway; and generating the shared secret key using the algorithm combining the decoded master key with the MMS user device's phone number and the session ID.