4 ms·
> That is the definition of a cryptographically secure hash. It is not! None of the cryptographically secure hashes are proven to produce truly random output.
by dchest 7y ago
> That is the definition of a cryptographically secure hash.
It is not! None of the cryptographically secure hashes are proven to produce truly random output. They only strive to achieve indistinguishability from randomness, bounded by computational complexity of attacks.
Anyway, what you're talking about, in general, is called a randomness extractor. The protocol described in the article, apart from verification, uses "a strong quantum-proof randomness extractor to extract Ω(N) bits of randomness from the recorded string". So yeah, "pure, verifiable randomness is hard to come by".
- lisper 7y ago> > That is the definition of a cryptographically secure hash. > It is not! You're right, it's the definition of a secure psuedo-random function (PRF). https://en.wikipedia.org/wiki/Pseudorandom_function_family https://en.wikipedia.org/wiki/Pseudorandom_function_family However, all cryptographic hashes are PRFs. Any deviation from being a PRF would be an attackable weakness.