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An analysis of steganographic techniques and terrorists can use them

An analysis of steganographic techniques and terrorists can use them






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    An analysis of steganographic techniques and terrorists can use them An analysis of steganographic techniques and terrorists can use them Presentation Transcript

    • An Analysis of Steganographic Techniques and How Terrorists Can Use Them Presenter’s Name: Sohel Imroz Date: May 4, 2004
    • Introduction
      • Steganography = “Steganos” + “Graphos”
      • “ Steganos” means covered or secret
      • “ Graphos” means drawing or writing
      • Direction of Steganography:
        • Protection against detection
        • Protection against removal
          • Watermarking
          • Fingerprinting
    • Brief History
      • Two stories of Herodotus
        • King Darius of Susa
          • Shaved the head of a prisoner
        • Demeratus of Sparta
          • Removed the wax of a tablet
      • Romans used invisible ink
        • Fruit juice, milk, etc.
      • World War I and II
        • Null ciphers, microdots, etc.
    • Techniques
      • Encoding secret messages in
        • Texts
        • Images
        • Audio
    • Secret messages in texts
      • Line-shift encoding
        • Vertically shifts text lines 1/300 th of an inch up or down
      • Word-shift encoding
        • Uses horizontal spaces between words
      • Feature specific encoding
        • Hardest text encoding method.
        • Example: “Pershing sails from NY June 1”
    • Secret messages in images
      • Least significant bit (LSB) insertion
        • Simplest to accomplish
        • Data is inserted in the least and second to least bits of pixels
      • Masking and filtering technique
        • Also known as digital watermarking
        • Actual bits are scattered throughout the image
      • Algorithms and transformation
        • Used to transmit JPEG images
    • Secret messages in audio
      • Least significant bit (LSB) insertion
        • Stores data in the least significant bit
        • Resampling and channel noise may alter data
        • Simple to perform
        • Lacks dependability
      • Phase encoding
        • Substitution of the phase of an initial audio segment with a reference phase
    • Secret messages in audio (Cont.)
      • Spread-spectrum
        • Requires the embedded data to be spread across the frequency spectrum
        • Example: Direct Sequence Spread Spectrum
        • Resistant to modification
      • Echo data hiding
        • Introduces an echo
        • Works well with high quality audio files
    • Steganography as a terrorist tool
      • Use image files via email, news groups, porno sites, etc.
      • Use public auction sites like eBay, Amazon, etc.
      • Use corporate web sites.
    • Detecting Steganography
      • Detecting Steganography in texts
        • By looking at the patterns in texts, odd use of language, unusual amount of white space
      • Detecting Steganography in images
        • Look for suspicious properties of the file
        • Statistical analysis
      • Detecting Steganography in audio
        • Differences in pitch, echo, or background noise
      • Compare MD5 Hash values
    • Conclusion
      • Steganography is useful.
      • It can be used for evil purpose.
      • We must be aware of its uses, and prevent any misuse.