Steganography Team 6 Megan Enns Tim Weninger Dan

Steganography Team 6 Megan Enns Tim Weninger Dan Razafsky Brett Wolfington

Overview § § § History of Steganography Modern Steganography Techniques Examples Steganalysis

History of Steganography § First known example - head tattoos § Invisible ink § WWII – espionage Germans used null ciphers Cipher text: Apparently neutral’s protest is thoroughly discounted and ignored. Isman hard hit. Blockade issue affects pretext for embargo on by products, ejecting suets and vegetable oils. Package: Pershing sails from NY June 1.

Modern Steganography § Definition: concealing messages within images or files = covert communications § Most commonly hidden in digital images, but can also be done for music files and video files, or any type of information carrier § Watermarking § Used primarily in espionage (business secrets) § Rumored to be used for terrorism

Techniques § Objective: make changes visually and statistically negligible § Techniques: First encrypt and/or compress payload Use password to hide message Least-significant bit substitution (most popular) Append message to file Distortions are least detectable in high energy areas: bright colors in images or high intensity in sound files Complicated algorithms find unused or noisy areas of image Spread spectrum - spread payload across frequency spectrum by adding random noises to signal

Example

Steganography Software § Open-source software: Out. Guess Stego. Magic Hide and Seek S-Tools MP 3 Stego

Steganalysis § Definition: detecting presence of hidden message (as opposed to cryptanalysis) § Can be extremely difficult to detect steganography due to huge variety of techniques and knowing where to look § Simplest method: compare to original § Statistical analysis can identify suspect files Look at color palette, signal level, histogram, etc § Open-source software: Steg. Detect

Summary § § Historical and Modern Steganograpy Techniques and Examples Steganalysis Importance: covert communications