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Emoticon-based Text Steganography in Chat
Chair Professor: Chin-Chen Chang (張真誠) Feng Chia University National Chung Cheng University National Tsing Hua University
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Outline Introduction Related Work The Proposed Scheme
Experimental Results Conclusions
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Introduction Information hiding in text
Synonym substitution Syntactic transformation Semantic transformation Translation Information hiding in binary text Information hiding in hypertext
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Synonym substitution 0 wonderful 1 decent 2 fine Taichung is a 0 city
3 great 4 nice Taichung is a 0 city 1 town little Secret message: (3)5(1)2 Taichung is a great little town
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Syntactic Transformations
Syntactic: the way that words and phrases are put together to form sentences in a language
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Semantic transformation
Semantic :Describe things that deal with the meanings of words and sentences Grafting: adding or repeating information Pruning: removing repeated information Substitution: replacing information
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Grafting He is detained in Japan.
He, an American citizen, is detained in Japan.
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Afghanistan has been under attack since October
Pruning The Pentagon ordered two new spy planes to the region to start flying over Afghanistan. Afghanistan has been under attack since October, and the Pentagon ordered two new spy planes to the region to start flying over there. Afghanistan has been under attack since October
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Substitution The Pentagon ordered two new spy planes to the region to start flying over Afghanistan. Afghanistan Taliban ruled country The Pentagon ordered two new spy planes to the region to start flying over the Taliban ruled country.
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Translation 法文: C’est la vie 英文: That’s life. That is the life.
It is the life. It’s life. Message Stego object Alice Bob Cover object
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Translation Rule # Rule Code Prob. (1) S -> AB 0.5 (2) S -> CB 1
0.5 (2) S -> CB 1 (3) A -> It is (4) A -> It’s (5) C -> That is (6) C -> That’s (7) B -> life (8) B -> the life 10 0.25 (9) B -> a life 11 Secret: 1010 Prefix Rule Output 1 (2) CB (5) That is B 10 (8) That is the life
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Information hiding in binary text
Add-pattern Delete-pattern Binary image
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Information hiding in binary text
Embedding Secret bit 0 : A-pattern D-pattern D-pattern D-pattern Secret bit 1 : D-pattern A-pattern A-pattern A-pattern Extracting D-pattern Secret bit 0 A-pattern Secret bit 1
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Information hiding in hypertext
Secret message Cover hypertext Embedding Stego hypertext Secret key Extraction Secret message
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Information hiding in hypertext
<HTML> </HTML> 0110 <body <p Secret: … 1 </title> capital letters small letters 0 1 :the written states Tags text file 1 2 3 4 5 6 <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=big5"> <title> 多媒體暨網路安全實驗室 </title> </head> <body bgcolor="#D27D1O"> <p align="center"><img border="0" src="msn.jpg" width="338" height="345"></p> <p align="center"><font face="標楷體" color="#f4efe8" size="7">~歡迎加入~</font></p> </body> </html> <META
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Information hiding in hypertext
capital letters small letters 0 1 :the written states text file 1 2 3 4 5 6 <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=big5"> <title> 多媒體暨網路安全實驗室 </title> </head> <body bgcolor="#D27D1O"> <p align="center"><img border="0" src="msn.jpg" width="338" height="345"></p> <p align="center"><font face="標楷體" color="#f4efe8" size="7">~歡迎加入~</font></p> </body> </html> <HTML> <META <body <p </HTML> Secret: …
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Related Work Text Steganography in Chat
Shirali-Shahreza, M.H., Shirali-Shahreza, M., “Text Steganography in Chat,” Proceedings of the Third IEEE/IFIP International Conference in Central Asia on Internet the Next Generation of Mobile, Wireless and Optical Communications Networks, Tashkent, Uzbekistan, Sep. 2007, pp. 1-5.
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Related Work SMS-Texting
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Related Work Usual abbreviated words univ. university
PC Personal Computer M.S. master of science UN United Nations Dr doctor
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Related Work SMS list + abbreviated words list Check list
0 full form, 1 abbreviated form
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Related Work Check list secret bits “10” Embedding :
“Please call me when you feel upset.” secret “10” “Please CM when you feel upset.” Extracting : Check list secret bits “10”
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The Proposed Scheme Emoticon-based Text Steganography in Chat
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The Proposed Scheme Phase1: Classify the emoticons by their meaning
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The Proposed Scheme Example: N = 16 hide log2N = 4 bits per emoticon
sender uses second symbol receiver can extract 4 bits “0001”
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The Proposed Scheme Phase2: emoticon || sentence : secret = 0
sentence || emoticon : secret = 1 I lost my bag secret = 0 I lost my bag secret = 1
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The Proposed Scheme , I lost my bag
Phase3: emoticon , sentence : secret = 0 emoticon , sentence : secret = 1 , I lost my bag secret = 0 I lost my bag secret = 1
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Experimental results 1110 Phase1 Phase3 Phase2 001||1||1
zhihui wants to send secret bits “ ” to Kieu The Duc. 1110 Phase1 Phase3 Phase2 001||1||1
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Experimental results The proposed method can be combined with the previous method to increase the hiding capacity Example: “Please call me when you feel upset” “Please CM when you feel ”
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Conclusions Propose a new simple text steganography scheme used in chat rooms The proposed method is applicable to secret exchange: many people use chat tools in their daily communications The proposed method has high capacity: many chat tools are available and each chat tool has many emoticons for use
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Thanks for your listening
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