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cambrian / accumulator

Cryptographic accumulators in Rust.
https://cambrian.github.io/accumulator
MIT License
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Do we need to call hash_to_prime in Poe? #40

Closed eddiew closed 5 years ago

eddiew commented 5 years ago

hash_to_prime is slow, and (unless I'm mistaken) the only property of it that we use is that it's a 256-bit number. Can this be replaced with a constant?

whaatt commented 5 years ago

Normally PoE is an interactive protocol, and making it non-interactive applies the Fiat-Shamir heuristic (hashing the transcript of the interaction thus far) to generate the challenge prime.

(Ctrl+F "Fiat-Shamir" in the accumulators paper for a better explanation)

If the challenge prime were a constant, I believe the prover can construct an attack, although I haven't worked out the details