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Topic
Board Development & Technical Discussion
Merits 1 from 1 user
Re: Bitcoin must upgrade or fall victim to quantum computing in 5 years
by
stwenhao
on 13/08/2025, 12:56:17 UTC
⭐ Merited by ABCbits (1)
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Do you think that an average person will have access to quantum computer?
No. Or: at least not at the beginning.

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By the way, how does quantum computer beat a good 2FA and a password.
It doesn't, because 2FA uses hash functions, and not public key cryptography. More than that: you can use three hash functions inside Script: OP_SHA1, OP_RIPEMD160, and OP_SHA256. And also, it is possible to add more restrictions, by using OP_CHECKLOCKTIMEVERIFY or OP_CHECKSEQUENCEVERIFY. Which means, that even if the whole public key cryptography will be broken, then still, the system can be safely used by miners, as long as block reorganizations won't be too deep. And again: users can lock their coins with Proof of Work, if needed.

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Am I saying nonsense or does it actually make a sense?
Currently, it is very difficult to break many hash functions, when it comes to their preimage resistance. Even if you use MD5, and you can generate collisions in seconds on a CPU, then nobody still knows, how to make MD5 preimages fast. And to successfully break ECDSA through SHA-256, preimage attack is needed.

When it comes to quantum algorithms, they can break things based on public key cryptography. But they are very far from breaking any hash functions, and it is quite likely, that they won't beat existing ASICs, when it comes to mining, and grinding double SHA-256 hashes.