Digital Watermarking Systems

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‫ﻣﻌﺮﻓﻲ ﻋﻨﺎﺻﺮ اﺻﻠﻲ‬

Digital Watermarking Systems y ‫ﺑﻬﻨﺎم دزﻓﻮﻟﻲ‬ Behnam Dezfouli

‫ﻋﻨﺎﺻﺮ ﺳﻴﺴﺘﻢ‪:‬‬ ‫‰ ﺷﺒﺎﻫﺖ ﺑﺎ ﻳﻚ ﺳﻴﺴﺘﻢ ارﺗﺒﺎﻃﻲ‬ ‫داراي ‪ 3‬ﻋﻨﺼﺮ اﺳﺎﺳﻲ‪:‬‬ ‫ƒ‬ ‫ƒ‬ ‫ƒ‬

‫ﻣﻌﺎدل آن در‪watermarking‬‬

‫ارﺳﺎل ﻛﻨﻨﺪه = ﻗﺮار دادن داده ﻫﺎي ﻣﺨﻔﻲ ﺷﻮﻧﺪه در ﺳﻴﮕﻨﺎل ﻣﻴﺰﺑﺎن‬ ‫ارﺗﺒﺎﻃﻲ = ﭘﺮدازش ﺑﺮ روي داده ﻫﺎي ﻣﻴﺰﺑﺎن‬ ‫ﻛﺎﻧﺎل ارﺗﺒﺎﻃ‬ ‫درﻳﺎﻓﺖ ﻛﻨﻨﺪه = ﺑﺎزﻳﺎﺑﻲ داده ﻫﺎي ﻣﺨﻔﻲ ﺷﺪه‬

:‫ﻫﺎ‬ ‫داده ﺎ‬ ‫ﺳﺎزي ا‬ ‫ﻳﻚ ﺳﻴﺴﺘﻢ ﻣﺨﻔﻲ ﺎ‬ ‫ﻛﻠﻲ ﻚ‬ ‫ﺗﺼﻮﻳﺮ ﻛﻠ‬

b= Watermark Code , W= Watermark Signal A= Host Asset (Still image, Video,…) , K= Secret Key Aw= Watermarked Asset , A’w= Aw A w Conversion of Aw to A’w A w due to possible attacks

:‫ را ﺑﻪ ﺳﻪ ﺑﺨﺶ دﻳﮕﺮ ﻣﻲ ﺗﻮان ﺗﻘﺴﻴﻢ ﺑﻨﺪي ﻛﺮد‬Data Embedding ‫ﺑﺨﺶ‬

(Information Coding) - ‫ ﻛﺪ ﻛﺮدن داده ﻫﺎ‬-1 (Watermark Embedding) - Watermark ‫ ﻛﺎرﮔﺬاري‬-2 ((Watermark Concealment)) - Watermark ‫زي‬ ‫ﻲ ﺳﺎزي‬ ‫ ﻣﺨﻔﻲ‬-3

‫‰‬

‫ﻛﺪ ﻛﺮدن داده ﻫﺎ‪:‬‬

‫ﺗﺒﺪﻳﻞ ﺳﻴﮕﻨﺎل ‪ B‬ﺑﻪ ﺳﻴﮕﻨﺎل ‪W‬‬

‫ﻣﺜﺎل در ﺳﻴﺴﺘﻢ ﻣﺨﺎﺑﺮاﺗﻲ‪ :‬ﻛﺪ ﻛﺮدن دو ﻗﻄﺒﻲ –‬ ‫‰‬

‫‪zero=+1, one=-1‬‬

‫ﻛﺎرﮔﺬاري ‪:Watermark‬‬

‫ﺗﺎﺑﻊ ‪Embedding Function :ε‬‬ ‫‪ A , K,‬ﺑﻪ ﻋﻨﻮان ورودي‬ ‫ﻣﻘﺎدﻳﺮ ‪K W‬‬

‫‪ε(A,W,K)=Aw‬‬

‫‪Watermark embedding via invertible feature extraction‬‬

‫‪watermark‬‬ ‫‪t‬‬ ‫‪ : ε‬اﻧﺘﺨﺎب ﻣﺠﻤﻮﻋﻪ اي از ﻣﺸﺨﺼﺎت ‪ assett‬ﻣﻴﺰﺑﺎن و ﺗﻐﻴﻴﺮ آآﻧﻬﺎ ﺑﺮ اﺳﺎس ﺳﻴﮕﻨﺎل ‪k‬‬ ‫‪Watermark Features‬‬

‫‪: Host Features‬‬

‫ﺑﺮاي ﺗﺴﻬﻴﻞ ﻟﺰوم ﻣﻌﻜﻮس ﭘﺬﻳﺮي ‪:F‬‬ ‫‪Weak Invertibility:‬‬ ‫ﻣﺜﺎل‪ :‬ذﺧﻴﺮه ﻛﺮدن ‪ watermark‬در ﺿﺮاﻳﺐ ﺗﺒﺪﻳﻞ ﻓﻮرﻳﻪ ﮔﺴﺴﺘﻪ‬

‫‪Watermark embedding in the magnitude of DFT‬‬

‫ﺳﺎزي‪:‬‬ ‫ﻣﺨﻔﻲ ﺎ‬ ‫‰ ﻔ‬ ‫ﻫﺪف اﺻﻠﻲ ﺑﺨﺶ ‪ embedding‬ﻏﻴﺮ ﻗﺎﺑﻞ درك ﺑﻮدن داده ﻫﺎ ﻣﻲ ﺑﺎﺷﺪ‬ ‫روش‪::‬‬ ‫ﺑﻪ دو روش‬ ‫‪ -1‬روش ﺿﻤﻨﻲ‪ :‬ﺗﻮﺳﻂ اﻧﺘﺨﺎب ﻣﺠﻤﻮﻋﻪ اي درﺳﺖ از ‪Host feature‬ﻫﺎ و ‪embedding rule‬‬ ‫‪ -2‬روش ﺻﺮﻳﺢ‪ :‬ﻣﻌﺮﻓﻲ ﻛﺮدن ﻳﻚ ﻣﺮﺣﻠﻪ ي ﺟﺪاﮔﺎﻧﻪ ﭘﺲ از ‪watermark embedding‬‬

‫ﺷﻮد‬ ‫ﻲ ﻮ‬ ‫ﺗﻮﺟﻪ ﻣﻲ‬ ‫ن ﻮ‬ ‫ﻲ اﻧﺴﺎن‬ ‫ﻢ اﺣﺴﺎﺳﻲ‬ ‫ ﺑﻪ ﻣﺸﺨﺼﺎت ﺳﻴﺴﺘﻢ‬،‫ن داده ﻫﺎ‬ ‫ﺑﻮدن‬ ‫ي ﻏﻴﺮﺮ ﻗﺎﺑﻞ درك ﻮ‬ ‫ﺑﺮاي‬ ‫ﺮ‬ Imperceptibility relies on the imperfection of human senses: Still image and Video watermarking: Human Visual System (HVS) ‫اﻧﺴﺎن‬ ‫ﺳﻴﺴﺘﻢ ﺑﺼﺮي اﻧ ﺎ‬ Audio watermarking: Human Auditory System (HAS) ‫ﺳﻴﺴﺘﻢ ﺳﻤﻌﻲ اﻧﺴﺎن‬

:watermark ‫ﺧﺮاﺑﻲ‬ :watermark ‫دﺳﺘﻜﺎري ﺑﺮ روي‬ watermark ‫ﺑﻪ ﻋﻠﺖ ﺑﺮداﺷﺘﻦ‬ ‫اﻫﺪاف دﻳﮕﺮ ﻣﺎﻧﻨﺪ ﻓﺸﺮده ﺳﺎزي داده ﻫﺎ و ﻳﺎ وﻳﺮاﻳﺶ داده ﻫﺎ‬ Aw

A’w A w Manipulations

ƒ ƒ

:‫ﻲ ﺷﺪه‬ ‫ي ﻣﺨﻔﻲ‬ ‫داده ﻫﺎي‬ ‫ﺑﺎزﻳﺎﺑﻲ ا‬ ‫ﺑ زﻳ ﺑﻲ‬ :‫ﺑﺨﺶ درﻳﺎﻓﺖ ﻛﻨﻨﺪه ﻣﻲ ﺗﻮاﻧﺪ ﺑﻪ دوﻓﺮم ﻣﺨﺘﻠﻒ ﺑﺎﺷﺪ‬ g :Detectable Watermarking :A ‫ﺑﺴﺘﻪ ﺑﻪ وﺟﻮد ﻳﺎ ﻋﺪم وﺟﻮد‬ With A: non-blind Detector

Without A: Blind Detector

:Readable R d bl Watermarking W ki :A ‫ﺑﺴﺘﻪ ﺑﻪ وﺟﻮد ﻳﺎ ﻋﺪم وﺟﻮد‬ With A A: non non-blind blind Detector

Without A: Blind Detector

‫ﻲ‪:‬‬ ‫ﭘﺮوﺗﻜﻠﻲ‬ ‫ﻣﻼﺣﻈﺎت ﭘﺮو‬ ‫‪ Alice‬ﻣﻲ ﺧﻮاﻫﺪ ﺗﻮﺳﻂ ‪ watermarking‬از ﻛﺎر ﺧﻮد ﺣﻔﺎﻇﺖ ﻛﻨﺪ‬ ‫‪Alice watermark asset:‬‬ ‫‪Bob produces the asset:‬‬ ‫ازﻫﺮ ﻛﺪام ﺧﻮاﺳﺘﻪ ﻣﻲ ﺷﻮد ﻛﻪ ﻧﺴﺨﻪ اي را ﻧﺸﺎن دﻫﻨﺪ ﻛﻪ ﺗﻨﻬﺎ ﺷﺎﻣﻞ ‪ watermark‬ﺧﻮدش ﺑﺎﺷﺪ‪:‬‬ ‫در اﻳﻦ ﺣﺎﻟﺖ ‪ Alice‬ﻗﺎدر ﺑﻪ اﻧﺠﺎم اﻳﻦ ﻛﺎر اﺳﺖ در ﺻﻮرﺗﻲ ﻛﻪ ‪ Bob‬ﻧﻤﻲ ﺗﻮاﻧﺪ‪ .‬ﭼﺮا ﻛﻪ او ﺑﺎ اﺿﺎﻓﻪ ﻛﺮدن‬ ‫‪ watermark‬ﺧﻮد ﺑﻪ ‪ Alice asset‬اﻳﻦ ‪ asset‬را ﺑﻮﺟﻮد آورده اﺳﺖ‪.‬‬

‫ﻣﺸﻜﻞ‪ :‬ﺣﻤﻼت ﻧﻮع ‪SWICO‬‬ ‫‪IF :‬‬ ‫‪We have Non-Blind watermarking‬‬

‫‪Detection by: subtracting original asset from the watermarked one‬‬

‫در اﻳﻦ ﺣﺎﻟﺖ ﻣﺸﻜﻠﻲ ﻧﺪارﻳﻢ و ‪ Bob asset‬ﻗﺎﺑﻞ ﻗﺒﻮل ﻧﻤﻲ ﺑﺎﺷﺪ‬

‫ﻣﺸﻜﻞ زﻣﺎﻧﻲ رخ ﻣﻴﺪﻫﺪ ﻛﻪ ‪ Bob‬ﻳﻚ ‪ original asset‬ﺗﻘﻠﺒﻲ را ﻣﻲ ﺳﺎزد‬

‫‪The SWICO attack‬‬

‫در اﻳﻦ ﺣﺎﻟﺖ ﺑﻪ ﻧﻈﺮ ﻣﻲ رﺳﺪ ﻛﻪ ‪ Bob‬ﻳﻚ ﻧﺴﺨﻪ ي درﺳﺖ را اراﺋﻪ ﻛﺮده اﺳﺖ و ﻟﺬا او ﺗﺄﻳﻴﺪ ﺻﻼﺣﻴﺖ ﻣﻲ ﺷﻮد‬

‫ﻧﺘﻴﺠﻪ‪:‬‬ ‫‪ watermarking‬ﺑﻪ ﺗﻨﻬﺎﻳﻲ ﻛﺎراﻳﻲ ﻧﺨﻮاﻫﺪ داﺷﺖ‬ ‫‪t‬‬ ‫‪ki‬‬ ‫ﺗﺎ زﻣﺎﻧﻲ ﻛﻪ ﻳﻚ ﭘﺮوﺗﻜﻞ ﺣﻔﺎﻇﺘﻲ ﺻﺤﻴﺢ ﺑﻴﺎن ﻧﺸﺪه ﺑﺎﺷﺪ‪،‬‬

‫ﻇﺮﻓﻴﺖ ﺗﻜﻨﻴﻚ ﻫﺎي ‪:watermarking‬‬ ‫اﻧﺘﻘﺎل ﺑﺪﻫﺪ‬ ‫داده ااي ﻛﻛﻪ ﻗﺎﻗﺎدر ااﺳﺖ اﻧ ﻘﺎل‬ ‫ﺑﻴﺘﻬﺎي ا‬ ‫ﻣﻘﺪار ﺎ‬ ‫ﻘ ا‬ ‫ƒ ﻣﺸﺨﺼﺎت ﺳﻴﮕﻨﺎل ﻣﻴﺰﺑﺎن‬ ‫ƒ اﻋﻮﺟﺎج ﺟﺎﺳﺎزي )‪(embedding distortion‬‬ ‫ﺣﻤﻼت‬ ‫ƒ ﻗﻗﺪرت ﻼ‬ ‫ﺑﺪون در ﻧﻈﺮ ﮔﺮﻓﺘﻦ ﻛﺎرﺑﺮدي ﻛﻪ ﻣﻲ ﺧﻮاﻫﺪ در آن اﺳﺘﻔﺎده ﺑﺸﻮد ﻧﻤﻲ ﺗﻮان ﻧﻴﺎز واﻗﻌﻲ را ﺗﻌﺮﻳﻒ ﻛﺮد‬ ‫ﻋﻨﻮان دﻫﻲ‬ ‫ﻫﺰار ﺑﻴﺖ‪ :‬ﻨ ا‬ ‫ﭼﻨﺪﻳﻦ ا‬ ‫ﻨ‬ ‫اﻣﻨﻴﺖ و‬ ‫واﺑﺴﺘﻪ ﺑﻪ ا ﻨ‬ ‫ﻛﺎرﺑﺮدﻫﺎي ا‬ ‫ﺎ‬ ‫ﭼﻨﺪ ﺻﺪ ﺑﻴﺖ‪ :‬ﻛﺎ‬ ‫ﻨ‬ ‫ﻇﺮﻓﻴﺖ در ﻣﻘﺎﺑﻞ دو ﺧﺼﻴﺼﻪ ﻣﻬﻢ ﻣﻮرد ﻧﻴﺎز ﻣﻘﺎوﻣﺖ ﻣﻲ ﻛﻨﺪ‪:‬‬ ‫ƒ ﻏﻴﺮ ﻗﺎﺑﻞ درك ﺑﻮدن ‪Imperceptibility‬‬ ‫ƒ اﺳﺘﺤﻜﺎم و ﻗﺪرت ‪Robustness‬‬ ‫ﺑﺎﻳﺪ ﺑﻴﻦ اﻳﻦ ﻣﻮارد ﻣﺼﺎﻟﺤﻪ اي ﺑﺮﻗﺮار ﺑﺸﻮد‬

‫ﺟﺎﺳﺎزي ﭼﻨﺪﺗﺎﻳﻲ )‪:(multiple embedding‬‬ ‫ƒ‬ ‫ƒ‬

‫ﺑﺎﻳﺪ ﻗﺎﺑﻠﻴﺖ ﺧﻮاﻧﺪن ﺗﻤﺎم ‪watermark‬ﻫﺎ را ﺑﻄﻮر ﺻﺤﻴﺢ داﺷﺘﻪ ﺑﺎﺷﺪ‬ ‫‪Watermark‬ﺟﺪﻳﺪ ﻧﺒﺎﻳﺪ ﻣﻮﺟﺐ ﻋﺪم ﺗﻮاﻧﺎﻳﻲ ﺧﻮاﻧﺪن ‪ watermark‬ﻗﺒﻠﻲ ﺑﺸﻮد – ﻣﺜﺎل ﻣﺎﻟﻚ و ﻣﺼﺮف‬ ‫ﻛﻨﻨﺪه – اﺿﺎﻓﻪ ﻛﺮدن ﻣﺼﺮف ﻛﻨﻨﺪﮔﺎن – ﻋﺪم ﺧﺮاﺑﻲ ﻧﺎم ﺗﻮﻟﻴﺪ ﻛﻨﻨﺪه‬

‫ﻣﻘﺎوﻣﺖ و اﺳﺘﺤﻜﺎم‪:‬‬ ‫ﺗﻮاﻧﺎﻳﻲ زﻧﺪه ﻣﺎﻧﺪن داده ﻫﺎي ﻣﺨﻔﻲ ﺷﺪه از دﺳﺘﻜﺎرﻳﻬﺎي آﻟﻮده ﻳﺎ ﻏﻴﺮ آﻟﻮده ﺳﻴﮕﻨﺎل ﻣﻴﺰﺑﺎن‬ ‫ﻣﻌﺮﻓﻲ ﭼﻬﺎر ﺳﻄﺢ اﺳﺘﺤﻜﺎم ﻛﻴﻔﻲ ﻛﻪ اﻏﻠﺐ ﻛﺎرﺑﺮدﻫﺎ را در ﺑﺮ ﻣﻲ ﮔﻴﺮد‪:‬‬

‫‪ Watermarking‬اﻣﻦ )‪:(secure watermarking‬‬ ‫ƒ‬ ‫ƒ‬ ‫ƒ‬

‫ﺑﺮاي ﻛﺎرﺑﺮدﻫﺎي واﺑﺴﺘﻪ ﺑﻪ اﻣﻨﻴﺖ‬ ‫ﺷﺪﻳﺪ ﮕﻨﺎل‬ ‫ﺳﻴﮕﻨﺎل‬ ‫اﻓﺖ ﺷ‬ ‫ﺗﻨﻬﺎﺎ در ﺻﻮرت اﻓ‬ ‫ﻣﺨﻔﻲ ﺗﻨ‬ ‫ﻫﺎي ﺨﻔ‬ ‫داده ﺎ‬ ‫دادن ا‬ ‫اﻣﻜﺎن ااز دﺳﺖ ا‬ ‫ا ﻜﺎ‬ ‫ﻟﺰوم ﻣﻘﺎوﻣﺖ در ﺑﺮاﺑﺮ دﺳﺘﻜﺎري ﻫﺎي آﻟﻮده و ﻏﻴﺮ آﻟﻮده )ﻣﺎﻧﻨﺪ ﻓﺸﺮده ﺳﺎزي ﭘﺮ ﺗﻼف‪ ،‬ﻓﻴﻠﺘﺮﻳﻨﮓ و ‪(...‬‬ ‫‪Examples of Non-malicious manipulations:‬‬ ‫‪Z‬‬ ‫‪Zooming,‬‬ ‫‪i‬‬ ‫‪contrast‬‬ ‫‪t t enhancement,‬‬ ‫‪h‬‬ ‫‪t frame‬‬ ‫‪f‬‬ ‫‪removal,‬‬ ‫‪l frame‬‬ ‫‪f‬‬ ‫‪exchange,‬‬ ‫‪h‬‬ ‫‪echo‬‬ ‫‪h addition‬‬ ‫‪dditi‬‬

‫‰‬

‫‪ Watermarking‬ﻣﻘﺎوم )‪:(robust watermarking‬‬

‫ƒ‬

‫آﻟﻮده‬ ‫دﺳﺘﻜﺎرﻳﻬﺎي ﻏﻏﻴﺮ آﻟ د‬ ‫ﺑﺮاﺑﺮ د ﺘﻜﺎ ﺎ‬ ‫ﺗﻨﻬﺎﺎ ددر ا‬ ‫ﺖ ﺗﻨ‬ ‫ﻣﻘﺎوﻣﺖ‬ ‫ﻟﺰوم ﻘﺎ‬ ‫ﻟﺰ‬ ‫در ﻛﺎرﺑﺮدﻫﺎﻳﻲ ﻛﻪ اﺣﺘﻤﺎل دﺳﺘﻜﺎري داده ﻫﺎ ﺑﺨﺎﻃﺮ ﺣﺬف ‪ Watermark‬ﺑﻌﻴﺪ ﻣﻲ ﺑﺎﺷﺪ‬ ‫ﻣﺎﻧﻨﺪ ﻧﺴﺨﻪ ﻫﺎﻳﻲ ﻛﻪ در دﺳﺖ ﺑﺎزﻳﮕﺮان ﻗﺮار ﻣﻲ ﮔﻴﺮد‬ ‫ﺷﻮد‬ ‫ﺧﺮاب ﻣﻲ ﺷ‬ ‫ﺳﻨﺪ ﺧ ا‬ ‫ﺗﻘﻠﺒﻲ‪ ،‬ﻨ‬ ‫در ﺻﻮرت درج ‪ watermark‬ﺗﻘﻠ‬

‫ƒ‬ ‫ƒ‬ ‫ƒ‬

‫‰‬

‫‪ Watermarking‬ﻧﻴﻤﻪ آﺳﻴﺐ ﭘﺬﻳﺮ )‪:(Semi-fragile watermarking‬‬

‫ƒ‬

‫‪ watermarking‬از اﻳﻦ ﻧﻮع ﻣﻲ ﺑﺎﺷﺪ ﻛﻪ در ﻣﻘﺎﺑﻞ ﻳﻜﺴﺮي دﺳﺘﻜﺎرﻳﻬﺎي ﻣﺤﺪود و از‬ ‫‪t‬‬ ‫در ﺻﻮرﺗﻲ ﻳﻚ ‪ki‬‬ ‫ﻗﺒﻞ ﺗﻌﺮﻳﻒ ﺷﺪه اي ﻣﻘﺎوﻣﺖ داﺷﺘﻪ ﺑﺎﺷﺪ‬ ‫ﻣﺜﺎل‪ lossy compression :‬و اﻓﺰاﻳﺶ ﻛﻴﻔﻴﺖ‬

‫ƒ‬

‫‰‬ ‫ƒ‬ ‫ƒ‬

‫‪Watermarking‬آﺳﻴﺐ ﭘﺬﻳﺮ )‪:(fragile watermarking‬‬ ‫داده ﻫﺎي ﻣﺨﻔﻲ ﺷﺪه در ﺻﻮرت اﻋﻤﺎل ﻫﺮ ﻧﻮع دﺳﺘﻜﺎري از ﺑﻴﻦ ﻣﻲ روﻧﺪ‬ ‫)‪ – (Authentication‬از دﺳﺖ دادن داده ﻫﺎ ﺑﻪ ﻣﻌﻨﻲ دﺳﺘﻜﺎري ﺷﺪن اﺳﺖ‬ ‫در ﺗﺸﺨﻴﺺ ﻫﻮﻳﺖ ) ‪(A th ti ti‬‬

‫ﻣﻘﺎوﻣﺖ در ﺑﺮاﺑﺮ اﻋﻮﺟﺎج ﺳﻴﮕﻨﺎل ﺗﻮﺳﻂ ﻗﺮار دادن داده ﻫﺎ در ﺑﺨﺸﻬﺎي ادراﻛﻲ ﻣﻬﻢ ﺑﻬﺘﺮ ﺣﺎﺻﻞ ﺧﻮاﻫﺪ ﺷﺪ‬ ‫ﻛﻴﻔﻴﺖ‬ ‫ﺗﻐﻴﻴﺮ ﻛ ﻔ‬ ‫ادراﻛﻲ‪ ،‬ﺑﺪون ﺗﻐ‬ ‫ﺑﺨﺸﻬﺎي ﻏﻏﻴﺮ ﻣﻬﻢ ا اﻛ‬ ‫ﺣﺬف ﻛﻛﺮدن ﺨﺸ ﺎ‬ ‫ﺗﻮﺳﻂ ﺬف‬ ‫ﻣﺜﺎل‪ :‬در ‪ lossy compression‬ﺗ ﻂ‬ ‫ﺜﺎل‬ ‫‪ Watermark‬ﺑﻬﺘﺮ اﺳﺖ در ﺑﺨﺸﻬﺎي ﻣﻬﻢ ﺑﺎﺷﺪ‬

‫‪:Blind Recovery‬‬ ‫ﻋﺪم ﻧﻴﺎز ﺑﻪ ﺳﻴﮕﻨﺎل اﺻﻠﻲ ﺑﺮاي ﺑﺎزﻳﺎﺑﻲ ‪) – watermark‬روش ‪(oblivious‬‬

‫‪:Non-Blind Recovery‬‬ ‫ﺑﺎزﻳﺎﺑﻲ ﻧﻴﺎزﻣﻨﺪ دﺳﺘﺮﺳﻲ ﺑﻪ ﺳﻴﮕﻨﺎل اﺻﻠﻲ اﺳﺖ )‪(more robust‬‬

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‫‪:Private Watermarking‬‬

‫ƒ‬

‫ﺗﻨﻬﺎ ﻛﺎرﺑﺮان واﺟﺪ ﺻﻼﺣﻴﺖ ﻗﺎدر ﺑﻪ ﺑﺎزﻳﺎﺑﻲ داده ﻫﺎ ﻣﻲ ﺑﺎﺷﻨﺪ‬ ‫روش ‪ non-blind‬ﻳﻚ روش ‪ private‬ﻣﻲ ﺑﺎﺷﺪ‬ ‫ﻣﺜﺎل‪ :‬اﻧﺘﺴﺎب ﻛﻠﻴﺪﻫﺎي اﻣﻨﻴﺘﻲ ﻣﺨﺘﻠﻒ ﺑﻪ اﻓﺮاد‬

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‫‪:Public Watermarking‬‬

‫ƒ‬

‫ﺗﻜﻨﻴﻜﻲ ﻛﻪ در آن ﻫﺮ ﻛﺴﻲ اﺟﺎزه ﺧﻮاﻧﺪن ‪ Watermark‬را دارد‬

‫‪9‬‬

‫روش ‪ private‬از روش ‪ public‬ﺑﻬﺘﺮ و داراي اﺳﺘﺤﻜﺎم ﺑﻴﺸﺘﺮي اﺳﺖ )‪(more robust‬‬

‫‰‬

‫‪:Detectable Watermarking‬‬ ‫ﺗﻨﻬﺎ ﺗﺸﺨﻴﺺ وﺟﻮد ﻳﺎ ﻋﺪم وﺟﻮد ﻳﻚ ‪ watermark‬ﺧﺎص در ﻳﻚ ﺳﻨﺪ‬ ‫ﻳﻚ روش ‪ private‬ﻣﻲ ﺑﺎﺷﺪ – ﻓﺮد داراي ﺻﻼﺣﻴﺖ‬ ‫‪More robust‬‬

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‫‪:Readable Watermarking‬‬ ‫ﺧﻮاﻧﺪن ‪ watermark‬ﺑﺪون اﻃﻼع ﻗﺒﻠﻲ از آن‬

‫ƒ‬ ‫ƒ‬

‫ƒ‬ ‫ƒ‬ ‫ƒ‬

‫ƒ‬

readable watermark ‫ ﺑﺎ ﺷﺮوع از ﻳﻚ‬detectable watermark ‫ﺳﺎﺧﺖ ﻳﻚ‬

----------------------------------------------------------(invertibility and quasiquasi-invertibility) ‫ﭘﺬﻳﺮي‬ ‫ﻣﻌﻜﻮس ﺬ‬ ‫ﺷﺒﻪ ﻜ‬ ‫ﭘﺬﻳﺮي و ﺷ‬ ‫ﻣﻌﻜﻮس ﺬ‬ ‫ﻜ‬ :‫ ﻣﻌﻜﻮس ﭘﺬﻳﺮ‬Watermarking‰ ε= embedding function and D= detector function and nonnon-blind detectable watermarking Then if for any asset A: Otherwise the watermarking scheme is said to be non-invertible non invertible Af= fake original asset , Wf= fake watermak

:‫ﻣﺜﺎل‬ SWICO ‫ﺣﻤﻠﻪ‬

Public asset = A= A’+Wa , Wf=Wb , Af= A-Wb= A’+Wa-Wb

ε(Af)= ε(A’+Wa (A’+Wa--Wb)= A’+Wa A’+Wa--Wb+Wb= A’+Wa

=> invertible watermarking

(Quasi-invertibility):‫ ﺷﺒﻪ ﻣﻌﻜﻮس ﭘﺬﻳﺮ‬Watermarking

‰

In non-blind detectable watermarking If for any asset A:

(Reversibility) :‫وارون ﭘﺬﻳﺮي‬ S Strict-sense reversible (SSR) (SS )‰ ُ

‫ ﻣﺮﺑﻮﻃﻪ اش ﺧﺎرج ﻛﻨﻴﻢ‬host asset ‫ ﻛﺮدﻳﻢ ﻣﻲ ﺗﻮان آﻧﺮا از‬Decode/Detect ‫ را‬watermark ‫ƒزﻣﺎﻧﻴﻜﻪ ﻳﻚ‬ ‫ اﺻﻠﻲ را ﺑﺎزﻳﺎﺑﻲ ﻛﻨﻴﻢ‬asset ‫ƒﭘﺲ ﻣﻲ ﺗﻮان‬

Wide-sense reversible (WSR)‰

undetectable/undecodable ‫ ﻛﺮدﻳﻢ ﻣﻲ ﺗﻮان آﻧﺮا‬detect/decode ‫ را‬watermark ‫ƒﻫﻨﮕﺎﻣﻲ ﻛﻪ ﻳﻚ‬ ‫ ﺣﺎﺻﻞ ﺷﻮد‬host asset ‫ﻛﺮد ﺑﺪون اﻧﻜﻪ ﺗﻐﻴﻴﺮات ﻣﺤﺴﻮﺳﻲ در‬ ‫ن ﻧﻴﺰﺰ ﻫﺴﺖ‬ ‫ﺑﻮدن‬ ‫ ﻮ‬WSR ‫ﻲ‬ ‫ ﺑﻪ ﻣﻌﻨﻲ‬SSR ‫ƒﻗﺎﺑﻠﻴﺖ‬

‫رن‪:‬‬ ‫‪ Watermaking‬ﻣﺘﻘﺎرن‬ ‫‪g‬‬ ‫ƒ‬

‫در ‪ watermarking‬ﻣﺘﻘﺎرن‪ ،‬در ﻓﺎز ‪ decoding/detection‬از ﻫﻤﺎن ﻣﺠﻤﻮﻋﻪ ﭘﺎراﻣﺘﺮﻫﺎي زﻣﺎن‬ ‫‪ embedding‬اﺳﺘﻔﺎده ﻣﻲ ﺷﻮد‬

‫‪ 9‬اﻳﻦ ﺣﺎﻟﺖ ﺗﻘﺎرن ﻣﻮﺟﺐ ﭘﺎﻳﻴﻦ آﻣﺪن ﺳﻄﺢ اﻳﻤﻨﻲ و ﺣﻔﺎﻇﺖ ﺧﻮاﻫﺪ ﺷﺪ‬

‫ﻣﻌﺮﻓﻲ ‪ watermaking‬ﻧﺎﻣﺘﻘﺎرن‪:‬‬

‫ƒ‪ Ks‬ﻛﻠﻴﺪ اﺧﺘﺼﺎﺻﻲ اﺳﺖ‬ ‫ƒ‪ Kp‬ﻛﻠﻴﺪ ﻋﻤﻮﻣﻲ اﺳﺖ‬ ‫ﺣﺪس زد‬ ‫را ﺪ‬ ‫اﺧﺘﺼﺎﺻﻲ ا‬ ‫ﺪ اﺧﺘ ﺎ‬ ‫ﻛﻠﻴﺪ‬ ‫ﺬف ﻛﻛﺮدد و ﻳﺎﺎ ﻛﻠ‬ ‫ﺗﻮان ‪ watermark‬راا ﺣﺬف‬ ‫ﻛﻠﻴﺪ ﻋﻤﻮﻣﻲ ﻧﻧﻤﻲ ﺗ ا‬ ‫داﻧﺴﺘﻦ ﻛﻠ ﺪ‬ ‫ƒﺑﺎﺎ داﻧ ﺘ‬ ‫ƒﭘﺲ دﻳﮕﺮ ﺣﺎﻻ ‪ WSR‬را ﻧﺨﻮاﻫﻴﻢ داﺷﺖ – ‪ decode‬ﻛﺮدن ﺑﻪ ﻣﻌﻨﻲ اﻣﻜﺎن ﺣﺬف ﻧﻴﺴﺖ‬

‫ﻣﺨﻔﻲ ﺳﺎزي داده ﻫﺎي در‪:‬‬ ‫‪Still image, image sequences, video signals, audio signals‬‬ ‫ﻣﺸﺘﺮك‪:‬‬ ‫ﺮ‬ ‫ﻣﻮارد‬ ‫ﻮر‬ ‫‰‬ ‫‰‬ ‫‰‬ ‫‰‬ ‫‰‬

‫ﻛﺪ ﻛﺮدن داده ﻫﺎﻳﻲ ﻛﻪ ﺑﺎﻳﺪ ﻣﺨﻔﻲ ﺷﻮﻧﺪ‬ ‫ﺗﻌﺮﻳﻒ ﻗﺎﻧﻮن ﺟﺎﺳﺎزي‬ ‫زي آآﮔﺎﻫﺎﻧﻪ‬ ‫ﺟﺎﺳﺎزي‬ ‫ﺟ‬ ‫ﺗﺌﻮري ﺗﺸﺨﻴﺺ‬ ‫آﻧﺎﻟﻴﺰ ﺗﺌﻮرﻳﻚ داده ﻫﺎ‬

‫اﻛﺜﺮ ﺗﺤﻘﻴﻘﺎت ﻣﺨﻔﻲ ﺳﺎزي داده ﻫﺎ ﺑﺮ روي ﺗﺼﺎوﻳﺮ اﻧﺠﺎم ﺷﺪه اﺳﺖ )‪(image watermarking‬‬ ‫اﻟﮕﻮرﻳﺘﻤﻬﺎي آن ﻣﻲ ﺗﻮاﻧﻨﺪ ﺑﺮاي ﺗﺼﺎوﻳﺮ ﻣﺘﺤﺮك و ﻳﺎ ﺻﺪا ﻫﻢ ﺑﻜﺎر ﺑﺮوﻧﺪ‬ ‫رﻓﺘﺎر ﺑﺎ ﻓﺮﻳﻤﻬﺎي وﻳﺪﺋﻮﻳﻲ ﺑﻪ ﻋﻨﻮان ﺗﻌﺪادي ﺗﺼﻮﻳﺮ ﺛﺎﺑﺖ‬

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