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Bitcoin and quantum computing

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Re: Bitcoin and quantum computing

#41

Post by schlauerfox »

fluxusars wrote: post #35

The thing that supposedly sets Bitcoin apart from other cryptocurrencies is that it's deflationary and 'immutable', in that Satoshi is gone forever and any deviation of Bitcoin from his golden idea will result in undermining its essence. If Bitcoin can get quantum-attacked then, from a technical point of view, nothing will be lost. The Bitcoin core devs can issue a word-of-god statement stating that they'll roll back…

This was already pretty well hashed out (heh) during the 'core'/'cash' issue when there was an attempt to fork in an expanded the block size. Both chains still exist. Bitcoin operation is entirely up to the miners to determine the heaviest chain, and that's like two entities (the number of entities required is called the Nakamoto coefficient). It's not magic, but there is a huge cult built up around it by scammers, rubes, opportunists and speculators.

Re: Bitcoin and quantum computing

#43

Post by wmf »

schlauerfox wrote: post #41
fluxusars wrote: post #35

The thing that supposedly sets Bitcoin apart from other cryptocurrencies is that it's deflationary and 'immutable', in that Satoshi is gone forever and any deviation of Bitcoin from his golden idea will result in undermining its essence. If Bitcoin can get quantum-attacked then, from a technical point of view, nothing will be lost. The Bitcoin core devs can issue a word-of-god statement stating that they'll roll back…

This was already pretty well hashed out (heh) during the 'core'/'cash' issue when there was an attempt to fork in an expanded the block size. Both chains still exist. Bitcoin operation is entirely up to the miners to determine the heaviest chain, and that's like two entities (the number of entities required is called the Nakamoto coefficient). It's not magic, but there is a huge cult built up around it by scammers, r…

Miners enforce the consensus rules but they can't change them. If miners try to change the rules, exchanges have no obligation to follow.

Re: Bitcoin and quantum computing

#44

Post by tomtomtom777 »

fluxusars wrote: post #35

The thing that supposedly sets Bitcoin apart from other cryptocurrencies is that it's deflationary and 'immutable', in that Satoshi is gone forever and any deviation of Bitcoin from his golden idea will result in undermining its essence. If Bitcoin can get quantum-attacked then, from a technical point of view, nothing will be lost. The Bitcoin core devs can issue a word-of-god statement stating that they'll roll back…

> The Bitcoin core devs can issue a word-of-god statement stating that they'll roll back the chain to before the attack, and all is well. Then they'll change the cryptography.

That doesn't work, because once the signature scheme has been broken, nobody can prove that their coins are theirs. No roll back or word-of-god would help.

The only way to make bitcoin quantum-safe, is to introduce a quantum safe signature scheme, to encourage everyone to move their coins and to somehow accept that those who don't are not longer in control of their coins.

Re: Bitcoin and quantum computing

#45

Post by hparadiz »

fluxusars wrote: post #35

The thing that supposedly sets Bitcoin apart from other cryptocurrencies is that it's deflationary and 'immutable', in that Satoshi is gone forever and any deviation of Bitcoin from his golden idea will result in undermining its essence. If Bitcoin can get quantum-attacked then, from a technical point of view, nothing will be lost. The Bitcoin core devs can issue a word-of-god statement stating that they'll roll back…

No because you are not changing the ledger. You are changing the authentication mechanism for transactions. It's like adding a new supported password hash.

Re: Bitcoin and quantum computing

#46

Post by tomtomtom777 »

EthanHeilman wrote: post #2

"A CRQC is an existential threat to Bitcoin (you might believe this is very low-likehood). Your measurement of this threat should literally be: (A) How likely you think it is a CRQC appears by a given time, multiplied by (B) How likely it is you think Bitcoin will not successfully upgrade by that time." It would interesting to survey people about their answers. My off the cuff answer is: 2030: A=0.05, B=0.01 2035: A=…

2045 A=~1.0 seems way off. CRQC is still a theoretical construct with hurdles to overcome. Yes, there is a significant risk that it will exist somewhere in the next decades, but there is also still a significant chance that it will be shown to be practically impossible.

Re: Bitcoin and quantum computing

#47

Post by block_dagger »

fluxusars wrote: post #35

The thing that supposedly sets Bitcoin apart from other cryptocurrencies is that it's deflationary and 'immutable', in that Satoshi is gone forever and any deviation of Bitcoin from his golden idea will result in undermining its essence. If Bitcoin can get quantum-attacked then, from a technical point of view, nothing will be lost. The Bitcoin core devs can issue a word-of-god statement stating that they'll roll back…

Bitcoin core devs do not make decisions for the distributed network. Yes they have outsized power but with the whole BIP110 thing going on now and Bitcoin Knots gaining adoption, I'm more confident now that sudden changes from the core devs will not be blindly accepted by all. That aside, it will be necessary to hard fork the chain from a point before a quantum attack, but there will be several proposals and the community will vote with their nodes.

Re: Bitcoin and quantum computing

#48

Post by block_dagger »

glerk wrote: post #20

One thing that is not addressed: say this quantum attack happens tomorrow and everyone agrees it was an attack, what would prevent the community (miners, node operators, and users) to hard fork the chain at a snapshot before the attack, patch the protocol, and call that Bitcoin? There would be loss of value of course, but it is not unrecoverable. It’s worth remembering that Ethereum forked for much less (not even a b…

I'd argue there may be an increase in value over time if the community handles the fork well.

Re: Bitcoin and quantum computing

#49

Post by EthanHeilman »

glerk wrote: post #20

One thing that is not addressed: say this quantum attack happens tomorrow and everyone agrees it was an attack, what would prevent the community (miners, node operators, and users) to hard fork the chain at a snapshot before the attack, patch the protocol, and call that Bitcoin? There would be loss of value of course, but it is not unrecoverable. It’s worth remembering that Ethereum forked for much less (not even a b…

> fork the chain at a snapshot before the attack, patch the protocol, and call that Bitcoin?

It won't work. The only way to authenticate who ones what coins is with signatures. If the signature algorithm is broken, you can't tell who the original owner is to move the coins to a safe signature algorithm.

You need to more to safer signature algorithm before the break, after the break it is game over.

> It’s worth remembering that Ethereum forked for much less

Ethereum could simply return the coins to the original owners. If the signature scheme is insecure, returning the coins just means the attacker can steal them again.

Re: Bitcoin and quantum computing

#50

Post by Ferret7446 »

fluxusars wrote: post #35

The thing that supposedly sets Bitcoin apart from other cryptocurrencies is that it's deflationary and 'immutable', in that Satoshi is gone forever and any deviation of Bitcoin from his golden idea will result in undermining its essence. If Bitcoin can get quantum-attacked then, from a technical point of view, nothing will be lost. The Bitcoin core devs can issue a word-of-god statement stating that they'll roll back…

For better or worse, Bitcoin is a true democracy. If all/most users decide to switch to a new quantum safe algorithm, then it is so.
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