Title: Traitor Deterring Schemes: Using Bitcoin as Collateral for Digital Contents
Abstract: We will introduce a new cryptographic primitive called a Traitor Deterring Scheme (TDS) as a new generation of cryptographic technique for copyright protection. A TDS is a multi-recipient public-key encryption scheme where an authority issues decryption keys to a set of users. The distinguishing feature of a TDS is that secret-keys are issued only after the users provide some private information as a form of collateral. The traitor deterring property ensures that if a malicious coalition of users (aka ``traitors'') produces an unauthorized (aka ``pirate'') decryption device, any recipient of the device will be able to recover at least one of the traitors' collaterals with only black-box access to the device. On the other hand, honest users' collaterals are guaranteed to remain hidden.
We show how bitcoin can be used as collateral for real world deployment of TDS's for the distribution of digital content. Along the way, we present cryptographic building blocks that may be of independent interest, namely fuzzy lockers, and comparison predicate encryption schemes for exponentially large domains. If time allowed, I may also discuss the connection of TDS to a 20-year open problem of digital signet proposed by Dwork, Lotspiech and Naor at STOC 96.
Bio: Qiang Tang is currently an assistant professor at New Jersey Institute of Technology and also a core member of the Cybersecurity Research Center (http://centers.njit.edu/cybersecurity/). His research interests are applied and theoretical cryptography, privacy and computer security. In particular, in the intersection of accountability, post-Snowden Cryptography, and blockchain technology. Before joining NJIT, Qiang was a postdoctoral associate at Cornell University and was also affiliated with IC3: the Initiative of CryptoCurrency and Contract (http://www.initc3.org/). Qiang obtained his Ph.D from the University of Connecticut and was awarded Taylor Booth fellowship. He was also holding visiting researcher positions at the University of Wisconsin, Madison, NTT research, Tokyo, and the University of Athens, Greece. Qiang's work has appeared at various top venues including Eurocrypt, CCS, Asiacrypt, and IEEE TIFS.