（1）is the science of hiding information.Where as the goal of cryp to graphy is to make data unreadable by a third party.the goal of steganography is to hide the data from a third party.In this article,I will discuss what steganography is,what purposes it serves,and will provide an example using available software. There are a large number of steganographic（2）that most of us are familiar with(especially if you watch a lot of spymovies),ranging from invisible inkandmicrodotstosecretingahiddenmessageinthesecondletterofeachwordofalargebodyoftextandspreadspectrumradiocommunication.With computersandnetworks,there arem any other ways of hiding informations,suchas: Covertchannels(c,g,Lokiandsomedistributeddenial-of-servicetoolsusetheInternetControl（3）Protocol,orICMP,asthecommunicationchannelbetweenthe“badguy”andacompromicyedsystem) HiddentextwithinWebpages Hidingfilesin“plainsight”(c,g.whatbetterplaceto“hide”afilethanwithanimportantsoundingnameinthec:\winntsystem32directory) Nullciphers(c,g,usingthefirstletterofeachwordtoformahiddenmessageinanotherwiseinnocuoustext) steganographytoday,however,issignificantlymore（4）than the example about suggest,allowing ausertohidelargeamountsofinformationwithinimageandaudio.Theseformsofsteganographyoftenareusedinconjunctionwith cryptographysothe information is double protected;firstitisencryptedandthenhiddensothatanadvertisementfirst.find the information(an often difficult task inandofitself)and the decryptedit. The simple stapproachtohidingdatawithinanimagefileiscalled（5）signatureinsertion.In this method,we can take the binaryrepresentationofthehiddendataandthebitofeachbytewithinthecovertimage.If weareusing 24-bitcolor the amount and will be minimum and indiscriminate to the human eye.
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