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利用網路聊天室傳送機密訊息

利用網路聊天室傳送機密訊息. Chair Professor Chin-Chen Chang Feng Chia University National Chung Cheng University National Tsing Hua University http://msn.iecs.fcu.edu.tw/~ccc http://msn.iecs.fcu.edu.tw/. S ynonym substitution. I nformation hiding in general text. S yntactic transformation.

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利用網路聊天室傳送機密訊息

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  1. 利用網路聊天室傳送機密訊息 Chair Professor Chin-Chen Chang Feng Chia University National Chung Cheng University National Tsing Hua University http://msn.iecs.fcu.edu.tw/~ccc http://msn.iecs.fcu.edu.tw/

  2. Synonym substitution Information hiding in general text • Syntactic transformation • Semantic transformation • Translation • Inter-word spacing schemes Information hiding in binarytext Information hiding in hypertext Information hiding in chat text • Text steganography in chat • Emoticon-based steganographyin chat

  3. Synonym substitution 0 wonderful 1 decent 2 fine 3 great 4 nice Taichung is a 0 city 1 town little Secret message: (3)5(1)2 Taichung is a great little town

  4. Syntactic transformations Syntactic: the way that words and phrases are put together to form sentences in a language

  5. 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

  6. Grafting He is detained in Japan. He, an American citizen, is detained in Japan.

  7. 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

  8. 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.

  9. 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

  10. Translation Secret: 1010

  11. Thisisabook. Secret bits: {0 1 0} Thisisabook. Inter-word spacing scheme 1 • This scheme exploits inter-word space of text to encode data.

  12. Weemploythecombinationoftherepeatedwords…Weemploythecombinationoftherepeatedwords… Secret bits: { 1 0 1 1} Space change: ＋ －　　　　　 ＋ We employthecombinationof therepeatedwords… Inter-word spacing scheme 2 • Keep spaces between groups unchanged.

  13. Information hiding in binarytext Delete-pattern Add-pattern Binary image

  14. Information hiding in binarytext • 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

  15. Cover hypertext Stego hypertext Information hiding in hypertext Secret message Embedding Secret key Extraction Secret message

  16. 1 0110 capital letterssmall letters 01 :the written states 3 <HTML> 1 </title> 2 4 <body 5 <p 6 </HTML> Information hiding in hypertext 0 Secret: 010110… Tags text file <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

  17. capital letterssmall letters 01 :the written states 3 1 2 4 5 6 Information hiding in hypertext text file <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: 010110…

  18. 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.

  19. Text steganography in chat SMS-Texting

  20. Text steganography in chat Usual abbreviated words • univ.  university • PC  Personal Computer • M.S.  master of science • UN  United Nations • Dr  doctor

  21. Text steganography in chat • SMS list + abbreviated words list  Check list • 0  full form, 1  abbreviated form

  22. Text steganography in chat Embedding : “Please call me when you feel upset.” secret “10” “Please CM when you feel upset.” Extracting : “Please CM when you feel upset.” Check list secret bits “10”

  23. Emoticon-based steganography in chat Emoticon-based Text Steganography in Chat

  24. Emoticon-based steganography in chat Phase1: Classify the emoticons by their meaning

  25. Emoticon-based steganography in chat Example: N = 16 hide log2N = 4 bits per emoticon sender uses second symbol receiver can extract 4 bits “0001”

  26. Emoticon-based steganography in chat Phase2: emoticon || sentence : secret = 0 sentence || emoticon : secret = 1 I lost my bag secret = 0 secret = 1 I lost my bag

  27. Emoticon-based steganography in chat Phase3: emoticon , sentence : secret = 0 emoticon, sentence: secret = 1 ,I lost my bag secret = 0 I lost my bag secret = 1

  28. Emoticon-based steganography in chat Zhihui wants to send secret bits “11100000111” to Alan3c. Alan3c says : You are a bad student! Zhihui says: 1110 0 0 Alan3c says: Just a kidding, you are the nicest guy I know in the world. Zhihui says: Phase1 Phase3 Phase2 001||1||1

  29. Future Research Direction • Chinese text steganography • 壞的毛病 壞毛病 • 山東的蘋果 山東蘋果 • 我的媽媽 我媽媽 • 主要的問題 主要問題 • 另外的一件事 另外一件事 • 其他的問題 其他問題 • 北京的大學 北京大學

  30. Thanks for your listening

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