Perfectly Secure Steganography Using Minimum Entropy Coupling

(via Bruce Schneier)

Steganography is the practice of hiding secret messages in other communications. Information theory provides a mathematical framework for analysing steganography, but perfect secrecy was thought impossible without perfectly simulating human language. New research shows that machine-generated text could enable perfectly secure steganography, as it uses well-defined generation processes rather than messy human language. Researchers developed algorithms that satisfy criteria for security by transmitting information through a channel in a way that makes the presence of a hidden message statistically undetectable. This approach could help people circumvent censorship but may also enable covert communication by spies and adversaries seeking to conceal information. The new algorithms represent an interesting intersection of information theory, machine learning, and practical steganography applications.