An Analysis of Steganographic Techniques and  How Terrorists Can Use Them Presenter’s Name: Sohel Imroz Date: May 4, 2004
Introduction <ul><li>Steganography = “Steganos” + “Graphos” </li></ul><ul><li>“ Steganos” means covered or secret </li></u...
Brief History <ul><li>Two stories of Herodotus </li></ul><ul><ul><li>King Darius of Susa </li></ul></ul><ul><ul><ul><li>Sh...
Techniques <ul><li>Encoding secret messages in  </li></ul><ul><ul><li>Texts </li></ul></ul><ul><ul><li>Images </li></ul></...
Secret messages in texts <ul><li>Line-shift encoding </li></ul><ul><ul><li>Vertically shifts text lines 1/300 th  of an in...
Secret messages in images <ul><li>Least significant bit (LSB) insertion </li></ul><ul><ul><li>Simplest to accomplish </li>...
Secret messages in audio <ul><li>Least significant bit (LSB) insertion </li></ul><ul><ul><li>Stores data in the least sign...
Secret messages in audio (Cont.) <ul><li>Spread-spectrum </li></ul><ul><ul><li>Requires the embedded data to be spread acr...
Steganography as a terrorist tool <ul><li>Use image files via email, news groups, porno sites, etc. </li></ul><ul><li>Use ...
Detecting Steganography <ul><li>Detecting Steganography in texts </li></ul><ul><ul><li>By looking at the patterns in texts...
Conclusion <ul><li>Steganography is useful. </li></ul><ul><li>It can be used for evil purpose. </li></ul><ul><li>We must b...
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An analysis of steganographic techniques and terrorists can use them

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An analysis of steganographic techniques and terrorists can use them

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

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