Hiding Text in Sequence Number Field of TCP/IP

 The exchanging process inside Local Area Network (LAN) or through Internet may be exposed to be stolen, altered or damaged by baleful person who was represented as real threats to transport process and also to information especially if this information was sensitive, important and must be accessed by only authorized person. Wherefore this data must be secured against such threats. Many ideas was
suggested under security concept for protecting data from this threats such as hiding content of the message sent which was named cryptography or concealment the existence of such message which was named steganography. Two ways were suggested to hide this data. One of them used the source port and destination port fields of the Transmission Control Protocol (TCP) header as the Stego key. And the other use the combination of source and source port fields of the Transmission Control Protocol (TCP) header with the protocol and version fields of the Internet Protocol (IP) header. The process is summarized by the implementation of the exclusive OR (XOR) between those data required to be hidden with the STEGO key. A sequence number field was selected from the Transmitter Control Protocol (TCP) to be the carrier for hidden data. Four characters are included in thisfield and sent in one connection. The suggested methods differ from the existing methods. One of them was sentone character through one connection while in the proposed methods four charactersare sent.  In addition to this difference, the stego key that was used also differed.Because the constant value will be collected with the ASCII character code. While inthe proposed methods are variable and the collection process is not used but XOR is used. Although in the other methods four characters have been sent, but they usedmany resources for execution because the characters have been compressed andencrypted.