Introduction to Steganography

• Definition: The art and science of hiding messages within other, seemingly innocuous media
• Etymology: From Greek steganos (covered) + graphia (writing)
• Historical context: Ancient Greece, invisible ink, microdots in WWII
• Difference from cryptography

Why Use Steganography?

• Avoid suspicion - message presence is hidden
• Used in censorship-heavy regimes
• Digital watermarking and copyright protection
• Cybersecurity

Types of Steganography

• Text
  • Linguistic tricks
  • Text display manipulation
  • Yellow dots in printed documents
• Image
  • later
• Audio
  • Images hidden in spectrograms
• Video
  • Hidden tracks in matroska files
• Network
  • Hidden data in TCP/IP headers or packet timing

Tools and Techniques

• Popular software: OpenPuff, Steghide, SilentEye, StegoSuite
• Manual techniques vs automated encoding
• Steganalysis: detecting hidden messages

Steganalysis and Countermeasures

• Statistical analysis and pattern detection
• Comparing image entropy before/after
• Machine learning for anomaly detection
• Challenges in reliable detection

Real-World Examples

• Terrorist communication
• Whistleblowers hiding sensitive data in public images

Live demo!

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