Chaffinch: A communication channel offering plausible deniability

George Danezis


Research into secrecy systems is very well established and some effort has been put into studying anonymous communications. While the content of messages and the communicating partners are protected by such systems, these offer very little protection against compulsion to reveal the keys used or the content of messages. "Chaffinch" is a communication channel, based on Ron Rivest's chaffing and winnowing, that offers plausible deniability. Using a mixture of information hiding techniques it is allowing users to deny that any communication, other than the cover traffic, took place. This talk will present the Chaffinch system and discuss the design and engineering trade-offs underlying it, as well as its interaction with recent UK legislation.


George Danezis is a graduate of Cambridge University in Computer Science and is currently a research student of Ross Anderson. His research interests include Anonymity systems, information hiding, and privacy policy. He has previously done work on real life failure modes of anonymizing proxies, plausible deniability, and properties of mixing networks. Recently he is working on traffic analysis and abstract modeling of anonymous communication systems.

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