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Black-box Anonymous Proofs


Alessandra Scafuro

Professor/a organitzador/a

Oriol Farrs Ventura


North Carolina State University


08-06-2018 16:15


A black-box protocol is simply a protocol that uses cryptographic primitives as oracles. For example, assume a protocol uses a cryptographic hash function H, we say that the protocol is black-box if it invokes H as an external oracle and it does not need to know how H is actually implemented (i.e., whether it is SHA3, SHA2, etc). The black-box approach is clearly the most natural and desirable way to develop any protocol. However, while natural, it becomes quite challenging to use a crypto primitive as a black-box when one needs to prove something about the output the crypto primitive itself, without revealing the input. For example, this is the case when a party commits to some secret value and then later needs to prove that the committed value satisfies some known property. This challenge is vastly amplified in settings where we also want anonymity, that is, we want to additionally hide which commitments satisfy a certain property. In this talk I will discuss the challenges in developing black-box commit-and-prove protocol in anonymity settings, and show some preliminary positive results based only on black-box access to a hash function and their application to ring signatures.


Aula 213