What happens if 1-way functions no longer exist?

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Advances in AI and nanobiotech can radically increase intelligence to the point where unsolved mathematical problems get solved.

What happens to Bitcoin (and other cryptocurrencies) if ⨕ 1-way functions cease to exist?

Pacerier

Posted 2017-10-25T14:37:00.397

Reputation: 2 055

hash functions, or all one way functions?MCCCS 2017-10-25T15:29:18.593

@MCCCS, All 1-way functions. Otherwise we would simply replace the hash function with that new function isn't it?Pacerier 2017-10-25T15:47:35.187

No, I mean Bitcoin uses ECDSA too but that's not "hash", but a one way function.MCCCS 2017-10-25T15:56:21.907

I'd use "if", not "when", in the main question.ypercubeᵀᴹ 2018-02-28T16:17:02.840

AI and nanobiotech??? Have these ever been used to defeat one-way functions? Or are you just spouting buzzwords?abelenky 2018-02-28T16:36:44.593

Answers

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without modifications the current bitcoin system would simply be compromised.

it seems very likely all private-public key cryptography would be compromised as well, and society as we know it would change.

however, given unknown advances to begin with, there is always the chance that something entirely different could replace the current system of secrecy when it comes to trust.

there is also the possibity that no matter how many advances we get, 1-way functions might be impossible to completely break, or that we find new maths that guarantees breakage if any 1-way function but with a cost that is prohibitive.

Jonathan Silverblood

Posted 2017-10-25T14:37:00.397

Reputation: 144

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Luckily, reverting the one-way-ness of cryptographic hash functions is not a mathematical problem. Rather, cryptographic hash functions destroy part of the information by projecting from an infinite space to a finite space. Reversing this is only possible by brute-forcing, and the finite space is sufficiently large that this is considered to be infeasible. It's not clear to me how either nanobiotech or advances in AI should improve the speed of brute-forcing.

However, quantum computing is brought up frequently in that context since it allows to try many different possibilities in parallel. Should we succeed at creating quantum computers that can search sufficiently large number spaces in parallel this would be very efficient at brute-forcing the reversion of hash functions. Mining difficulty would grow exponentially over night and ECDSA would possibly be broken as well.

Also see: What effects would a scalable Quantum Computer have on Bitcoin?

Murch

Posted 2017-10-25T14:37:00.397

Reputation: 41 609