CISSPEssentials:MasteringtheCommonBodyofKnowledgeClass3:CryptographyLecturerShonHarris,CISSP,MCSEPresident,LogicalSecurityCISSPEssentialsLibrary:www.searchsecurity.com/CISSPessentialsClass3Quiz:www.searchsecurity.com/Class3quizClass3Spotlight:www.searchsecurity.com/Class3spotlightCISSPEssentials:MasteringtheCommonBodyofKnowledgeCryptographyobjectivesHistoricalusesofcryptographyFoundationalpiecesofcryptographySymmetricandAsymmetricAlgorithmsPublicKeyInfrastructureE-mailclientencryptionproceduresProtocolsthatusecryptographyAttacksoncryptographyCryptographyusesyesterdayandtodayInthepast•Cryptographywasmainlyusedforprovidingconfidentiality•Itprotectedsensitiveinformation,mainlyduringtransmissionToday•Stillusedforconfidentiality•Alsousedfor:•Dataintegrity•Sourceauthentication•Non-repudiationKeyandalgorithmrelationshipKey•LongstringofrandomvaluesAlgorithm•GroupofmathematicalequationsthatcanbeusedfortheencryptionanddecryptionprocessesUsedtogether•Keyvaluesareusedbythealgorithmstoindicatewhichequationstouse,inwhatorderandwithwhatvaluesWhydoesa128-bitkeyprovidemoreprotectionthana64-bitkey?Keyspace•Allpossiblevaluesthatcanbeusedtogenerateakey•Thelargerthekeysize,thelargerthekeyspace•264<2128•Thelargerthekeyspace,themorevaluesanattackerhastobruteforceStrengthofacryptosystemDeterminingstrengthincryptography•Strengthofacryptosystemdependsupon•Properdevelopmentofthealgorithm•Secrecyandprotectionofkey•Lengthofthekey•Initializationvectors•Howallofthesepiecesareimplementedandworktogether•Todaythemostsuccessfulattacksareagainstthehumanfactorofcryptography•ImproperimplementationandkeymanagementTypesofciphersusedtodayModerncryptography•Substitutionmethods•Transpositionmethods•Symmetricciphers•Blockciphers•Streamciphers•AsymmetricciphersSymmetrickeycryptographyCharacteristics•Senderandreceiverusethesamekeytoencryptanddecryptamessage•Protectiondependsuponuserskeepingthesymmetrickeysecret•Requires“out-of-band”exchangeofkeys•Securecourierorsneakernet•C...
