In one embodiment, messages are encrypted with encrypted transformations
that commute with one another. In another embodiment, a message is
divided into message segments, and with each encrypted message segment
one or more encrypted keys are sent. The encrypted keys may be used to
decrypt a message segment that is sent at another time, such as the next
message segment to be sent. In another embodiment, a sender encrypts a
message with a first encryption, which may be unknown to the receiver.
Then a receiver encrypts the message with a second encryption. Next the
sender removes the first encryption, thereby allowing the receiver to
reconstitute the original message by removing the second encryption.