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Special Talk by Sophia Yakoubov on Ad Hoc Threshold Encryption and Large-Scale Secure Distributed Computation

2021.02.15 | Søs Küster Markussen

Date Fri 19 Feb
Time 09:00 10:00
Location Online - Microsoft teams meeting

Special Talk by Sophia Yakoubov on Ad Hoc Threshold Encryption and Large-Scale Secure Distributed

Abstract:

Threshold encryption makes it possible for a sender to transform a message into a ciphertext in such a way that any large enough subset of the intended recipients can recover the message, but without the cooperation of a large enough subset, the message remains hidden. Ad hoc threshold encryption has the additional advantage of not requiring any trusted setup; however, in the fifteen years since ad hoc threshold encryption was introduced, all known constructions have had the drawback of very large ciphertexts (ciphertexts of size linear in the number of senders). In this talk, I will describe the first ad-hoc threshold encryption construction with ciphertexts of constant size (joint work with L. Reyzin and A. Smith from Boston University), and mention some inherent limitations on ad-hoc threshold encryption ciphertext size (joint work with I. Damgård and K. G. Larsen from AU). I will also discuss an application of homomorphic ad hoc threshold encryption to large-scale secure distributed computation, both in the central-server model and in the You Only Speak Once (YOSO) model (joint with with C.Gentry, S. Halevi, H. Krawczyk, and T. Rabin from Algorand, and B. Magri, J. B. Nielsen from AU).

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