SteganographyWhat is SteganographyUsage of Steganography vs CryptographySteganographic AlgorithmsAttacks on Steganography, SteganalysisSteganalysis AttacksAttacks Against Steganography Vs Attacks Against CryptographyEzStegoAttacking EzStegoPoV FrequencySimilarity to Monoalphabetic CrackShared Key SteganographyF5 AlgorithmAttacking F5Ideal Steganographic AlgorithmWatermarkingWatermarking vs Digital SignatureDefending Against SteganographyConclusionQuestions ?SteganographySteganographyBrent McClainBrent McClainRob CareyRob CareyWhat is SteganographyWhat is SteganographyGreek Origin Greek Origin ““SteganosSteganos” means covered” means covered“Graph” means writing“Graph” means writingHiding information in plain sightHiding information in plain sightCover ImageAnother image hidden in the pictureCreated with InfoStegUsage of Steganography Usage of Steganography vsvsCryptographyCryptographySteganographySteganographyCovert ChannelCovert ChannelOnly useful for low Only useful for low volume of datavolume of dataWatermarking is used Watermarking is used for verificationfor verificationCryptographyCryptographyCovert MessageCovert MessageUseful for any given Useful for any given volume of datavolume of dataDigital Signatures are Digital Signatures are used for verificationused for verificationSteganographicSteganographicAlgorithmsAlgorithmsNo published standardNo published standardAlgorithms are hidden until cracked Algorithms are hidden until cracked Security through obscurity Security through obscurity Types of AlgorithmsTypes of AlgorithmsLSBLSBDCTDCTAttacks on Steganography, Attacks on Steganography, SteganalysisSteganalysisSteganalysisSteganalysisis the detection and analysis is the detection and analysis of data that has been hidden using of data that has been hidden using Steganography. Steganography. SteganalyisSteganalyisprimarily uses statistics to primarily uses statistics to detect and attack Steganographydetect and attack SteganographySteganalysisSteganalysisAttacksAttacksStegoStegoonly attackonly attack––StegoStegoObject availableObject availableKnown cover attackKnown cover attack--Original Cover and Original Cover and StegoStegoObjects Objects are availableare availableKnown message attackKnown message attack--Hidden Message and Hidden Message and StegoStegoObject are availableObject are availableChosen Chosen stegostegoattackattack--The The StegoStegoAlgorithm and Algorithm and StegoStegoObject are availableObject are availableChosen message attackChosen message attack--Takes a chosen message Takes a chosen message and generates a and generates a StegoStegoObject for comparisonObject for comparisonKnown Known stegostegoattackattack--the the StegoStegoAlgorithm, the Cover Algorithm, the Cover Object and the Object and the StegoStegoObject are availableObject are availableAttacks Against Attacks Against Steganography Vs Attacks Steganography Vs Attacks Against CryptographyAgainst CryptographySteganalyisSteganalyisCryptanalysisCryptanalysisStegoStegoonly attackonly attackCiphertextCiphertextonly attackonly attackKnown message attackKnown message attackKnown plaintext attackKnown plaintext attackChosen message attackChosen message attackChosen plaintext attackChosen plaintext attackChosen Chosen stegostegoattackattackChosen Chosen ciphertextciphertextattackattackEzStegoEzStegoHides data in the LSBHides data in the LSBSorts the color palette of a GIFSorts the color palette of a GIFChanges pixel color based on data being Changes pixel color based on data being hiddenhiddenBefore EzStego Before EzStego SortingSortingAfter EzStego SortingAfter EzStego SortingOriginal Image50% EmbeddedOriginal Image Filtered 50% Embedded FilteredAttacking EzStegoAttacking EzStegoFrequency Based DeterminationFrequency Based Determinationχχ² (Chi² (Chi--Squared) AttackSquared) AttackUses Pairs of Values Uses Pairs of Values Values which only differ by the LSBValues which only differ by the LSBNormal ImageNormal ImageEzStego ImageEzStego ImagePoVPoVFrequencyFrequencySimilarity to Similarity to MonoalphabeticMonoalphabeticCrack Crack Character Frequency in a long English plain textCharacter Frequency in the corresponding cipher text for a shift cipherShared Key Shared Key SteganographySteganographyAdvanced Advanced SteganographicSteganographicAlgorithmsAlgorithmsDistribution Behaviors changes base on Distribution Behaviors changes base on the private keythe private keyLack of preordained distribution set Lack of preordained distribution set decreases probability of detectiondecreases probability of detectionF5 AlgorithmF5 AlgorithmThe private key acts as seed for the pseudo The private key acts as seed for the pseudo random number generation schemerandom number generation schemePseudoPseudo--Random walk through image to Random walk through image to randomize distribution signaturerandomize distribution signatureMatrixMatrix--based embedding schemebased embedding schemeDecrements DCT coefficient instead of just Decrements DCT coefficient instead of just setting LSBsetting LSBImmune to Immune to χχ² Attack² AttackAttacking F5Attacking F5Still a Frequency Based attackStill a Frequency Based attackEstimated cover image is recreated by Estimated cover image is recreated by decompressing, manipulating, and decompressing, manipulating, and recompressingrecompressingDeviation of the Deviation of the DCT’sDCT’sfrom the value 0 from the value 0 are compared in the histograms of the are compared in the histograms of the observed image and the estimated cover observed image and the estimated cover imageimageIdeal Ideal SteganographicSteganographicAlgorithmAlgorithmAvoids detection when Avoids detection when SteganographicSteganographicAlgorithm is knownAlgorithm is knownGood ratio between Cover Object and Good ratio between Cover Object and Hidden Object sizeHidden Object sizeWatermarkingWatermarkingWatermarking is a subset of Watermarking is a subset of SteganographySteganographyUsed for document tracking and rights Used for document tracking and rights managementmanagementMovies distributed for review carry Movies distributed for review carry watermarks to identify who they were sent watermarks to identify who they were sent
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