Moving off the blockchain: a payment hub for fast, anonymous off-chain Bitcoin payments

Speaker: Foteini Baldimtsi
Assistant Professor in the Computer Science Department at George Mason University

Abstract: In this talk I will focus in two major technical challenges facedby Bitcoin today: (1) scaling Bitcoin to meet increasing use, and (2) protecting the privacy of payments made via Bitcoin. To address these challenges, I will present TumbleBit, an unidirectional unlinkable payment hub that uses an untrusted intermediary, the Tumbler, to perform off the blockchain transactions. TumbleBit allows to scale the volume and velocity of bitcoin-backed payments while being fully compatible with today’s Bitcoin protocol. At the same time, Tumblebit offers anonymity to the transactions routed through the Tumbler, guaranteeing that no-one, not even the Tumbler, can link a payment from its payer to payee. I will explain how a combination of cryptographic tools and blockchain properties is used to make Tumblebit work and discuss how these techniques are relevant beyond Bitcoin. Based on joint work with: Ethan Heilman, Leen Alshenibr, Alessandra Scafuro and Sharon Goldberg

Bio: Foteini Baldimtsi is an Assistant Professor in the Computer Science Department at George Mason University. She received her Ph.D. from Brown University in May 2014 and worked as a postdoctoral researcher in Boston University and University of Athens. Her research interests are in the areas of cryptography, security and data privacy with a special focus in electronic payments, Bitcoin and blockchain technologies and private authentication techniques. During her PhD she was a recipient of a Paris Kanellakis fellowship and currently her research is supported by NSF and an IBM faculty award. 

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