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.