This repo is a collection of proof-of-concepts, examples, essays and experiments in cryptography, cryptanalysis, steganography, steganalysis and covert channels that I originally wrote in 2015.

Individual sub-directories have their own README.md files describing their contents in detail.

Topics covered include:

• Implementation of a covert storage channel between two isolated processes
• Linear cryptanalysis attack against a block cipher
• Correlation attack against a stream cipher
• LSB steganography using pseudorandom password-based embedding
• Steganalysis of images using Mean Square Error (MSE) and Peak Signal to Noise Ratio (PSNR) measures of image quality degradation
• Side channel attacks and countermeasures