US Patent 7333615 Encryption between multiple devices

A first device receives first information and second information, encrypts the first information with a first set of encryption keys, and encrypts a combination of the second information and the encrypted first information with a second set of encryption keys into a first message. The first device may send the first message to a second device that receives the first message, decrypts the first message with a third set of encryption keys to yield the second information and the encrypted first information, determines a third information based on the second information, and encrypts into a second message, a combination of the third information and the encrypted first information, with a fourth set of encryption keys. The second message may be sent to a third device for decryption.