A method and apparatus are disclosed for communicating state information
in an electronic message. First data representing a state of an
electronic transaction is encoded, to result in creating an encoded
message element that is impractical for a recipient to decode. For
example, steganographic invisibility encoding may be used. The encoded
message element is sent as part of a first message associated with the
transaction. A second message associated with the transaction is
received, and the third message includes the encoded message element. The
encoded message element is decoded, to result in recovering the state of
the transaction, which is used in processing the second message. As a
result, large volumes of state information are sent to clients for local,
transitory storage, precluding the need for a large state data store on
the server side.