ABSTRACT: PrivaTegrity allows smartphones to send and receive messages, with little extra bandwidth or battery usage, while achieving anonymity for senders and recipients among all messages sent globally in batches defined by each one-second time interval. To learn anything about which inputs correspond with which outputs of the batch of messages, the entire cascade of ten mix servers, each preferably operating independently in a different country, would have to be compromised. None of the real-time computation, neither by the mixes nor smartphones, uses public-key operations — achieving several orders of magnitude performance improvement over comparable earlier work. Untraceable communication is fundamental to freedom of inquiry, freedom of expression, and increasingly to online privacy generally, including person-to-person communication. To address these needs a system should support, ideally within combined anonymity sets, the most common use cases: chat, photo/video sharing, feed following, searching, posting, payments, all with various types of potentially pseudonymous authentication. To achieve this, rather than layering such services on top of its mixing, PrivaTegrity instead integrates such services directly into its mixing with standardized formats and payload sizes. It includes what aims to be a comprehensive range of lightweight services efficiently supporting the above use cases, bringing much of them into the same anonymity sets as those for chat messages. The talk presents the concept of the novel underlying cryptographic protocol and the essential protocol elements used to implement the various use cases. BIO: David Chaum is the inventor of digital cash, eCash, issued by Deutsche Bank in the 1990’s. He is also known for other fundamental innovations in cryptography, including privacy technology and secure election systems. With a PhD in Computer Science from UC Berkeley, he taught at NYU Graduate School of Business and the University of California and founded the International Association for Cryptologic Research, DigiCash, Perspectiva Fund (“There will never be a better visual experience than Perspectiva — eye limited resolution, variable focus, wide field of view and color gamut — yet it uses only a passive film laminated into the lenses of any style of prescription eyewear with small projectors along the temple side arms”), and rsvoting.org (“Far lower cost, better quality and more democratic, random-sample voting can be used locally, nationally, regionally, or even globally, with results that are more irrefutable than with current elections, but at less than one-thousandth of the cost”)

Hosted by Professor Rafail Ostrovsky

REFRESHMENTS at 3:45 pm, SPEAKER at 4:15 pm