introduction to watermark advisor :杭學鳴 教授 student :朱育成
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Introduction to WatermarkIntroduction to Watermark
AdvisorAdvisor :杭學鳴 教授:杭學鳴 教授StudentStudent :朱育成:朱育成
OutlineOutline
Review of watermarkingReview of watermarking Applications and examples of watermarkingApplications and examples of watermarking Some architectures of watermarking combined Some architectures of watermarking combined
with other techniqueswith other techniques
Motive of watermarkingMotive of watermarking
Recent advancements in computer technologies Recent advancements in computer technologies offer many facilities for duplication, distribution, offer many facilities for duplication, distribution, creation, and manipulation of digital contents.creation, and manipulation of digital contents.
Encryption is useful for transmission but does Encryption is useful for transmission but does not provide a way to examine the original data in not provide a way to examine the original data in its protected form.its protected form.
Watermarking processWatermarking process
1)1) Embedding stageEmbedding stage– Spatial domainSpatial domain
flipping the low-order bit of each pixelsflipping the low-order bit of each pixels
– Frequency domainFrequency domain embedding the watermark in mid-frequency componentsembedding the watermark in mid-frequency components relatively robust to noise, image processing and compressionrelatively robust to noise, image processing and compression the quality of the host image will be distorted significantly if too the quality of the host image will be distorted significantly if too
much data is embedded much data is embedded
2)2) Distribution stageDistribution stage– Compression, transmission error, and common image Compression, transmission error, and common image
processing are seen as an attack on the embedded processing are seen as an attack on the embedded informationinformation
Watermarking processWatermarking process
3)3) Extraction stageExtraction stage– Blind – extraction without original imageBlind – extraction without original image
– Semi-blind – rely on some data or featuresSemi-blind – rely on some data or features
– Non-blind – need original imageNon-blind – need original image
4)4) Detection stageDetection stage– Evaluate the similarity between the original and detected wEvaluate the similarity between the original and detected w
atermarkatermark False positiveFalse positive :: watermark is detected although there is nonewatermark is detected although there is none False negativeFalse negative :: no watermark is detected while there is oneno watermark is detected while there is one
Watermarking propertiesWatermarking properties
Perceptual transparencyPerceptual transparency RobustnessRobustness
– The mark should resist to The mark should resist to Common signal processing like lossy compressionCommon signal processing like lossy compression Geometric transformation like image rotation, scaling, and croppingGeometric transformation like image rotation, scaling, and cropping
SecuritySecurity– How easy it is to intentionally remove a watermarkHow easy it is to intentionally remove a watermark
Data capacityData capacity– Amount of information that can be stored within the contentAmount of information that can be stored within the content
Categories of digital watermarkCategories of digital watermark
PerceptiblePerceptible ImperceptibleImperceptible Robust Robust
– ownership assertionownership assertion FragileFragile
– indicate modifications of the contentindicate modifications of the content Semi-fragileSemi-fragile
– differentiate between lossy transformation that are “info. presdifferentiate between lossy transformation that are “info. preserving” and lossy transformation which are “info. altering”erving” and lossy transformation which are “info. altering”
ApplicationsApplications
Copyright ProtectionCopyright Protection– Invisible watermark which can tolerate malicious and Invisible watermark which can tolerate malicious and
unintentional attacksunintentional attacks
– It does not prevent people from copying the digital dataIt does not prevent people from copying the digital data
Data HidingData Hiding– It tries to invisibly embed the maximum amount of data into a It tries to invisibly embed the maximum amount of data into a
host signal => this allows communication using enciphered host signal => this allows communication using enciphered messages without attracting the attention of a third partymessages without attracting the attention of a third party
– Robustness is not important while invisibility and capacity Robustness is not important while invisibility and capacity are requiredare required
ApplicationsApplications
Authentication and Data IntegrityAuthentication and Data Integrity– Verification watermarks are required to be fragile, so that any Verification watermarks are required to be fragile, so that any
modification to the image will destroy the markmodification to the image will destroy the mark
Copy ProtectionCopy Protection– RequirementsRequirements
Robustness against removalRobustness against removal Ability of blind detectionAbility of blind detection Capability of conveying non-trivial number of bitsCapability of conveying non-trivial number of bits
ApplicationsApplications
FingerprintingFingerprinting– Trace the source of illegal copiesTrace the source of illegal copies
Different watermarks are embedded by the owner in the copies of the Different watermarks are embedded by the owner in the copies of the data that are supplied to different customersdata that are supplied to different customers
Transparency and robustness are requiredTransparency and robustness are required
Examples of watermarkingExamples of watermarking
Image WatermarkingImage Watermarking Document WatermarkingDocument Watermarking Graphics watermarkingGraphics watermarking Video watermarkingVideo watermarking
Image WatermarkingImage Watermarking
Robust and imperceptible Robust and imperceptible – The watermark may be scaled appropriately to minimize noticThe watermark may be scaled appropriately to minimize notic
eable distortion to the hosteable distortion to the host
ExamplesExamples– Texture-based watermarkTexture-based watermark
Embed it into a portion of the image with similar textureEmbed it into a portion of the image with similar texture
– Insert a watermark into the phase componentsInsert a watermark into the phase components The phase information is perceptually more inportant than the magnituThe phase information is perceptually more inportant than the magnitu
de datade data
Document WatermarkingDocument Watermarking
Line-shiftsLine-shifts Word-shiftsWord-shifts
Document WatermarkingDocument Watermarking
Slight modifications to charactersSlight modifications to characters
Graphics WatermarkingGraphics Watermarking
Embedding in facial animation parameter (FAP) dataEmbedding in facial animation parameter (FAP) data– The amount of deviation the watermark signal has on FAP is The amount of deviation the watermark signal has on FAP is
limited to minimize visible distortionlimited to minimize visible distortion 1% for head rotation1% for head rotation 3% for lip motion3% for lip motion
Video WatermarkingVideo Watermarking
Copy generation managementCopy generation management– Minimum information that must conveyMinimum information that must convey
Copy neverCopy never Copy onceCopy once Copy no moreCopy no more Copy freelyCopy freely
For DVD, real-time decoding is requiredFor DVD, real-time decoding is required Detector placementDetector placement
– Detection in the driveDetection in the drive
– Detection within the application (within MPEG decoder)Detection within the application (within MPEG decoder)
Video WatermarkingVideo Watermarking
ExamplesExamples– For video coding like MPEG or H.26x, we embed the For video coding like MPEG or H.26x, we embed the
watermark into DCT coefficients watermark into DCT coefficients Only partial decoding of block DCT is necessary for watermark Only partial decoding of block DCT is necessary for watermark
embeddingembedding If constant bit rate is required, only nonzero DCT coefficients are If constant bit rate is required, only nonzero DCT coefficients are
markedmarked
Layered Access Control Schemes on Layered Access Control Schemes on Watermarked Scalable MediaWatermarked Scalable Media
Scalability – spatial, temporal and SNR scalabilityScalability – spatial, temporal and SNR scalability A typical MPEG-2 conditional access receiverA typical MPEG-2 conditional access receiver
Layered Access Control Schemes on Layered Access Control Schemes on Watermarked Scalable MediaWatermarked Scalable Media
A typical MPEG-2 conditional access receiverA typical MPEG-2 conditional access receiver– Control Word – change very often so that fast (simple) Control Word – change very often so that fast (simple)
decryption algorithm would not be broken easilydecryption algorithm would not be broken easily
– EMM (Entitlement Management Message) – with the aid of EMM (Entitlement Management Message) – with the aid of EMM, the broadcaster can change the status of the user EMM, the broadcaster can change the status of the user accessibility of contentsaccessibility of contents
– ECM (Entitlement Control Message)ECM (Entitlement Control Message)
Layered Access Control Schemes on Layered Access Control Schemes on Watermarked Scalable MediaWatermarked Scalable Media
A typical MPEG-2 conditional access receiverA typical MPEG-2 conditional access receiver– ProblemProblem
We send the key to user via reliable channel, while the content goes We send the key to user via reliable channel, while the content goes through an unreliable channel.through an unreliable channel.
Key and contents won’t arrive at the same timeKey and contents won’t arrive at the same time=> Synchronization problem=> Synchronization problem
– SolutionSolution Using robust watermark to embed the ECM and EMM information Using robust watermark to embed the ECM and EMM information
into the contentinto the content
Layered Access Control Schemes on Layered Access Control Schemes on Watermarked Scalable MediaWatermarked Scalable Media
Receiver architecture of the proposed methodReceiver architecture of the proposed method
Layered Access Control Schemes on Layered Access Control Schemes on Watermarked Scalable MediaWatermarked Scalable Media
Receiver architecture of the proposed methodReceiver architecture of the proposed method– Current layer is decrypt by the key Ki extracted from past layCurrent layer is decrypt by the key Ki extracted from past lay
erer– The user key Gi should be obtained before receiving media daThe user key Gi should be obtained before receiving media da
ta, for instance, by manually or automatically update after subta, for instance, by manually or automatically update after subscriptionscription
ConclusionConclusion– Cryptography does not provide error tolerance. By combining Cryptography does not provide error tolerance. By combining
cryptography and robust watermarking techniques, the key recryptography and robust watermarking techniques, the key receives stronger error-protection since the robust watermark caceives stronger error-protection since the robust watermark can tolerate transmission errors/attacksn tolerate transmission errors/attacks
– The key is implicitly synchronized to the contentThe key is implicitly synchronized to the content
A Novel Public Watermarking System A Novel Public Watermarking System based on Advanced Encryption Systembased on Advanced Encryption System
MotiveMotive– Almost proposed watermarking methods keep the Almost proposed watermarking methods keep the
watermarking algorithm private to ensure the embedded watermarking algorithm private to ensure the embedded watermark secretwatermark secret
Proposed watermark embedding algorithmProposed watermark embedding algorithm– 2 different watermarks for the spatial and frequency domain 2 different watermarks for the spatial and frequency domain
separatelyseparately Robust watermark for frequency domainRobust watermark for frequency domain Fragile watermark is embedded into the LSB plane in spatial domainFragile watermark is embedded into the LSB plane in spatial domain
A Novel Public Watermarking System bA Novel Public Watermarking System based on Advanced Encryption Systemased on Advanced Encryption System
Robust watermark embedding algorithmRobust watermark embedding algorithm1.1. WWRSRS = RS_Encode(Wo) = RS_Encode(Wo)
2.2. IIZZ = Set_LSB_Zero(Io) = Set_LSB_Zero(Io)
3.3. CSCS00 = DWT(I = DWT(IZZ))
4.4. MSCPS = Order_of_Significant_Coefficients(CSMSCPS = Order_of_Significant_Coefficients(CS00, k, ||W, k, ||WRSRS||)||)
C-MSCPS = Rijndael_Encrypt(MSCPS, K)C-MSCPS = Rijndael_Encrypt(MSCPS, K)WMPS = Select_Watermark_Positions(C-MSCPS, ||WWMPS = Select_Watermark_Positions(C-MSCPS, ||WRR
SS||)||)
5.5. CSCSww = Embed_Robust_Watermark(CS = Embed_Robust_Watermark(CS00, WMPS, W, WMPS, WRSRS))
6.6. IIwfwf = IDWT(CS = IDWT(CSww))
A Novel Public Watermarking System bA Novel Public Watermarking System based on Advanced Encryption Systemased on Advanced Encryption System
Robust watermark embedding algorithmRobust watermark embedding algorithm– Details in step 4Details in step 4
k||Wk||WRSRS|| most significant coefficients (MSC) of the LL ban|| most significant coefficients (MSC) of the LL band of CSd of CS00 are selected first are selected first
The order of these MSC is reordered in the descending ordThe order of these MSC is reordered in the descending order of magnitude to be MSCPSer of magnitude to be MSCPS
Cipher-MSCPS (C-MSCPS) is obtained by encrypting MSCipher-MSCPS (C-MSCPS) is obtained by encrypting MSCPS with a key K using the Rijndael block cipherCPS with a key K using the Rijndael block cipher
Finally, ||WFinally, ||WRSRS|| most significant bytes of C-MSCPS are sel|| most significant bytes of C-MSCPS are selected as the embedding positions => We embed the first biected as the embedding positions => We embed the first bit of Wt of WRSRS into the position corresponds to the most significa into the position corresponds to the most significant byte of the C-MSCPSnt byte of the C-MSCPS
A Novel Public Watermarking System bA Novel Public Watermarking System based on Advanced Encryption Systemased on Advanced Encryption System
Robust watermark embedding algorithmRobust watermark embedding algorithm– Examples of step 4Examples of step 4
A Novel Public Watermarking System bA Novel Public Watermarking System based on Advanced Encryption Systemased on Advanced Encryption System
Robust watermark embedding algorithmRobust watermark embedding algorithm– The watermarking method in step 5The watermarking method in step 5
If WIf WRSRS(i) = 0, then v(i) = 0, then vii’ = v’ = vi i (1 –α)(1 –α)
If WIf WRSRS(i) = 1, then v(i) = 1, then vii’ = v’ = vi i (1 +α)(1 +α)
– In sum, the watermark is added to the significant coeIn sum, the watermark is added to the significant coefficients of the LL band of the original image to ensufficients of the LL band of the original image to ensure its robustnessre its robustness
A Novel Public Watermarking System bA Novel Public Watermarking System based on Advanced Encryption Systemased on Advanced Encryption System
Fragile watermark embedding algorithmFragile watermark embedding algorithm7.7. IIwfzwfz = Set_LSB_Zero(I = Set_LSB_Zero(Iwfwf))
8.8. RS-ECC = Generate_RS_ECC(IRS-ECC = Generate_RS_ECC(Iwfzwfz)) RS-ECC contains all the parity check bits of Encoded Reed-SolomoRS-ECC contains all the parity check bits of Encoded Reed-Solomo
n coden code
9.9. C-RS-ECC = Rijndael_Encrypt(RS-ECC, K)C-RS-ECC = Rijndael_Encrypt(RS-ECC, K)
10.10. IIww = Embed_Fragile_Watermark(I = Embed_Fragile_Watermark(Iwfzwfz, C-RS-ECC), C-RS-ECC) All the LSB of IAll the LSB of Iwfwf are replaced with C-RS-ECC in a raster scan orde are replaced with C-RS-ECC in a raster scan orde
rr
A Novel Public Watermarking System bA Novel Public Watermarking System based on Advanced Encryption Systemased on Advanced Encryption System
ConclusionConclusion– The robust watermark WThe robust watermark WRSRS is used to carry the copyright infor is used to carry the copyright infor
mation while the fragile watermark C-RS-ECC is used to verimation while the fragile watermark C-RS-ECC is used to verify the image integrity and capable of providing the ability to rfy the image integrity and capable of providing the ability to recover altered imageecover altered image
A Novel Public Watermarking System bA Novel Public Watermarking System based on Advanced Encryption Systemased on Advanced Encryption System
Watermark Extraction ProcedureWatermark Extraction Procedure– Inspection phaseInspection phase
The test IThe test Iww’ image is inspected whether I’ image is inspected whether Iww’ is altered or not’ is altered or not
– Extraction phaseExtraction phase Inspection phaseInspection phase
1.1. (I(Iwzwz’, C-RS-ECC’) = Extract_Fragile_Watermark_and_Set_’, C-RS-ECC’) = Extract_Fragile_Watermark_and_Set_LSB_Zero(ILSB_Zero(Iww’)’)
2.2. RS-ECC’ = Rijndael_Decrypt(C-RS-ECC’, K)RS-ECC’ = Rijndael_Decrypt(C-RS-ECC’, K)RS-ECC = Generate_RS_ECC (IRS-ECC = Generate_RS_ECC (Iwzwz’)’)
3.3. If RS-ECC’ == RS-ECC, jump to Extraction phaseIf RS-ECC’ == RS-ECC, jump to Extraction phase
4.4. Fix_Image(IFix_Image(Iwzwz’, RS-ECC’)’, RS-ECC’)
A Novel Public Watermarking System bA Novel Public Watermarking System based on Advanced Encryption Systemased on Advanced Encryption System
Extraction phaseExtraction phase1.1. CSCSWW’ = DWT(I’ = DWT(Iwzwz’)’)
2.2. CSCS00 = DWT(I = DWT(IZZ))
3.3. MSCPS = Order_of_Significant_Coefficients(CSMSCPS = Order_of_Significant_Coefficients(CS00, k, ||W, k, ||WRSRS||)||)
C-MSCPS = Rijndael_Encrypt(MSCPS, K)C-MSCPS = Rijndael_Encrypt(MSCPS, K)WMPS = Select_Watermark_Positions(C-MSCPS, ||WWMPS = Select_Watermark_Positions(C-MSCPS, ||WRSRS||
|)|)
4.4. WWRSRS’ = Extract_Robust_Watermark(CS’ = Extract_Robust_Watermark(CSWW’, CS’, CS00, WMPS), WMPS) WWRSRS’(i) = 1, if v’(i) = 1, if vii’ > v’ > vii
WWRSRS’(i) = 0, if v’(i) = 0, if vii’ < v’ < vii
5.5. W’ = RS_Decode(WW’ = RS_Decode(WRSRS’)’)
A Novel Public Watermarking System bA Novel Public Watermarking System based on Advanced Encryption Systemased on Advanced Encryption System
Flow chart of watermark extractionFlow chart of watermark extraction
ReferenceReference
1.1. W.A. Wan Adnan, S. Hitam, S. Abdul-Karim, M.R.Tamjis, “A W.A. Wan Adnan, S. Hitam, S. Abdul-Karim, M.R.Tamjis, “A Review of Image Watermarking,” in Proceedings, Student ConReview of Image Watermarking,” in Proceedings, Student Conference on Research and Development, Aug. 2003, pp.381-384ference on Research and Development, Aug. 2003, pp.381-384
2.2. C.I. Podilchuk, E.J. Delp, “Digital WatermarkingC.I. Podilchuk, E.J. Delp, “Digital Watermarking :: AlgorithmAlgorithms and Applications,” IEEE Signal Processing Magazine, Vol. 1s and Applications,” IEEE Signal Processing Magazine, Vol. 18 Issue 4, July 2001, pp. 33-468 Issue 4, July 2001, pp. 33-46
3.3. S.H. Kwok, C.C. Yang, K.Y. Tam, “Watermark Design Pattern S.H. Kwok, C.C. Yang, K.Y. Tam, “Watermark Design Pattern for Intellectual Property Protection in Electronic Commerce Afor Intellectual Property Protection in Electronic Commerce Applications,” in Proceedings of the 33rd Annual Hawaii Internapplications,” in Proceedings of the 33rd Annual Hawaii International Conference on System Sciences, Vol. 2, Jan 4-7 2000. tional Conference on System Sciences, Vol. 2, Jan 4-7 2000.
ReferenceReference
4.4. F.C. Chang, H.C. Huang, H.M. Hang, “Layered access control F.C. Chang, H.C. Huang, H.M. Hang, “Layered access control schemes on watermarked scalable media,” IEEE International schemes on watermarked scalable media,” IEEE International Symposium on Circuits and Systems, Vol. 5, May 2005, pp. 49Symposium on Circuits and Systems, Vol. 5, May 2005, pp. 4983-498683-4986
5.5. K.M. Chan, L.W. Chang, “A novel public watermarking systeK.M. Chan, L.W. Chang, “A novel public watermarking system based on advanced encryption system,” International Conferm based on advanced encryption system,” International Conference on Advanced Information Networking and Applications, ence on Advanced Information Networking and Applications, Vol. 1, 2004, pp. 48-52Vol. 1, 2004, pp. 48-52