标签: 数据加密例程

ThisApplicationNotecoversfourencryptionalgorithms:AES,XTEA,SKIPJACK®andasimpleencryptionalgorithmusingapseudo-randombinarysequencegenerator.ThescienceofcryptographydatesbacktoancientEgypt.Intoday’seraofinforma-tiontechnologywheredataiswidelyaccessible,sensitivematerial,especiallyelectronicdata,needstobeencryptedfortheuser’sprotection.Forexample,anetwork-basedcardentrydoorsystemthatlogsthepersonswhohaveenteredthebuildingmaybesuscep-tibletoanattackwheretheuserinformationcanbestolenormanipulatedbysniffingorspoofingthelinkbetweentheprocessorandthememorystoragedevice.Iftheinformationisencryptedfirst,ithasabetterchanceofremainingsecure.Manyencryptionalgorithmsprovideprotectionagainstsomeonereadingthehiddendata,aswellasprovidingprotectionagainsttampering.Inmostalgorithms,thedecryptionprocesswillcausetheentireblockofinformationtobedestroyedifthereisasinglebiterrorintheblockpriortodecryption.AN953DataEncryptionRoutinesforthePIC18Author:DavidFlowersENCRYPTIONMODULEOVERVIEWMicrochipTechnologyInc.Fouralgorithmstochoosefrom,eachwiththeirownbenefitsINTRODUCTIONAdvancedEncryptionStandard(AES)ThisApplicationNotecoversfourencryption-ModulesavailableinC,Assemblyandalgorithms:AES,XTEA,SKIPJACKandasimpleAssemblywrittenforCencryptionalgorithmusingapseudo-random……