Quantum Computer vs Bitcoin

[tisata]

I heard that Quantum Computer can destroy bitcoin.
Is it possible?

[1715403508]

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[1715403508]

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[DannyHamilton]

I heard that Quantum Computer can destroy bitcoin.
Is it possible?

<sarcasm>
Yes.

The word "quantum" is a synonym for "magic".  A quantum computer is a magic computer that can do anything you want it to do as fast as you want it to do it.
</sarcasm>

There is no reason to think that a quantum computer will destroy bitcoin.  Extraordinary claims require extraordinary evidence.

[aplistir]

I heard that Quantum Computer can destroy bitcoin.
Is it possible?

Yes and no.

Efficient quantum computer can get the private key from public key, which means it could empty wallets that have been spend from. A single send action from an address reveals the public key.

However. If you use bitcoin properly and do not re-use addresses, then you are safe from quantum computers, because they cannot break SHA256 hash.

Also if/when quantum computers would ever become big enough, bitcoins encryption is probably going to be changed to something quantum resistant.

How do we know when the time has come?
There are several addresses with over 1000000000$:s worth of bitcoins in them, that have send actions in them and they have published their public keys. When someone starts emptying them, then we know it is time to do something.... or hopefully long before that.

And it is not only quantum "magic" computers we need to worry. Maye someday some hacker will find a way to break bitcoin crypto even without quantum magic.

[trimulia]

and i heard too that quantum computer can destroy bitcoin system is just a myth

[M3TH0DM4DN3SS]

I'm probably wrong but here's my opinion on the subject. Others please feel free to correct me if I say something false.

So the whole structure of bitcoin is based on a p2p (peer to peer) network. Each wallet (full node) and miner that is has a copy of the blockchain verify the activity. The vulnerability that comes to mind when I think of a crazy super quantum computer's ability to attack bitcoin is this; what if the computer was able to create enough of it's own nodes to control over half of the network? Hopefully someone with more knowledge will elaborate on this. Because I don't think I understand how bitcoin works fully.

[yojodojo21]

Quantum computer is already existing but none of the issue that bitcoin will be destroyed by any super what kind is it done it. Creator can only destroy bitcoin. Nodes,block,codes etc. If this is copied in the original of it then it might happen. But the question is why going to destroy bitcoin if youll be able to use it and become millionaire.

[cr1776]

I'm probably wrong but here's my opinion on the subject. Others please feel free to correct me if I say something false.

So the whole structure of bitcoin is based on a p2p (peer to peer) network. Each wallet (full node) and miner that is has a copy of the blockchain verify the activity. The vulnerability that comes to mind when I think of a crazy super quantum computer's ability to attack bitcoin is this; what if the computer was able to create enough of it's own nodes to control over half of the network? Hopefully someone with more knowledge will elaborate on this. Because I don't think I understand how bitcoin works fully.

No.  The fear is that if could do something like get a private key from a public key, but the hash function should mitigate that risk unless you are reusing addresses.

You could spin up 10000 nodes right now pretty easily.

My main hope is that quantum computers revolutionize search since this has been discussed many times before. 😂

[haltingprobability]

I heard that Quantum Computer can destroy bitcoin.
Is it possible?

It's something that Bitcoin's designers need to keep in mind as a "tail risk".

Quantum computers reduce the effective security of our strongest cryptographic primitives (hashes, symmetric ciphers) by about half. That is, a 256-bit hash gives about 128 bits of effective security in a world where quantum computers are used for at-scale computation. 128 bits of security is pretty good security - searching 10³⁷ gives about a 10% chance of breaking a particular hash (finding the hash preimage). 10³⁷ is 10 quadrillion quadrillion quadrillion - that's more than a billion billion times the number of hashes performed by the combined hashpower of all Bitcoin miners in order to mine a block.

The hash address is only 160 bits but it still requires 256 bits of search to break, that is, address=RIPEMD160(SHA256(pubkey)) minus a few technical details. Once you get the pubkey, we typically assume that a quantum computer will easily recover the private key from the public key. However, quantum-resistant public key encryption is still possible. Because of its quadratic advantage (theoretical) over classical computers, we have to double the key space (note that this may more than double key size). IIRC, secp256k1 is 128-bits equivalent security which we have to cut in half in a quantum-computation world - effective security is 64-bits. While 64-bits is too small for securing a large asset (such as all bitcoins), note that each address is secured by 64-bits security. So the cost of breaking all addresses in the UTXO set is at least 64 * nUTXO where nUTXO is the number of unspent transaction outputs. In other words, even with a quantum computer, you still have to break each address separately, and there are a lot of addresses.

Finally, quantum computation will actually help Bitcoin more than it will hurt it. As QC's begin to approach sufficient complexity to be able to mount serious attack against Bitcoin's cryptographic primitives, they are going to force cryptographers to revise usage across many cryptographic applications - traditional banking, government communication and data-storage, military communications systems, and so on. Quantum cryptography offers the promise of new modes of communication that are not possible with classical communication channels. Perhaps you can secure your Bitcoin address with an entangled set of qubits such that only the holder of the originally entangled qubits can prove ownership of the address. So, Bitcoin should not be having FUD about QC.

[MisterPrada]

Security agencies and the US DoD have tech that is at least 30 years in advance of the stuff you buy on Amazon. Quantum was likely put into production for breaking RSA 2048 in the 1990's, which is why they stopped making such a big fuss. The fact that publicly available crypto is allowed to be freely shared should tell you it's all broken.

[ranochigo]

So the whole structure of bitcoin is based on a p2p (peer to peer) network. Each wallet (full node) and miner that is has a copy of the blockchain verify the activity. The vulnerability that comes to mind when I think of a crazy super quantum computer's ability to attack bitcoin is this; what if the computer was able to create enough of it's own nodes to control over half of the network? Hopefully someone with more knowledge will elaborate on this. Because I don't think I understand how bitcoin works fully.

As said, quantum computing isn't magical. It's really not difficult to create 5000 nodes right now, even.

While its true that Bitcoin nodes are the backbone of the network, you cannot technically destroy the whole network. The only thing sybil attack (the most damaging IMO) can achieve, is to isolate people from the network. This could potentially allow attackers to execute a double spend attack on them and tricking them to see confirmations that they don't actually have. That isn't easy either. You will need to generate valid blocks and also have thousands of IPs which a quantum computer has no advantage of.
Quantum computers can weaken ECDSA but that doesn't mean private keys can be cracked instantly and without cost.

[hasmukh_rawal]

Why do you think of the destruction of Bitcoin while you could have made the same thread for increasing the efficiency of Bitcoin through quantum computers. Quantum computers do exist right now but I don't think they will be able to destroy the efficiency of Bitcoin. The current quantum computers are obviously more developed than electronic/digital computers but are not so well developed that they can crack any private key. To destroy the functionality of BTC  not only a super quantum computer is need but also the algorithm to break the BTC's code. It will at least take a few decades to build such a super quantum computer to achieve this thing and by the time it is possible BTC would have been far more developed seeing it's growth right now.

May I ask the wise ones whether quantum computer can be used to increase the efficiency/development of BTC in some way ?

[lionelho]

Don't worry too much. Read more technical materials and you will see the quantum computing is not good at the decryption in the crypto currency.

[Borilla]

I heard that Quantum Computer can destroy bitcoin.
Is it possible?

Yes and no.

Efficient quantum computer can get the private key from public key, which means it could empty wallets that have been spend from. A single send action from an address reveals the public key.

However. If you use bitcoin properly and do not re-use addresses, then you are safe from quantum computers, because they cannot break SHA256 hash.

Also if/when quantum computers would ever become big enough, bitcoins encryption is probably going to be changed to something quantum resistant.

How do we know when the time has come?
There are several addresses with over 1000000000$:s worth of bitcoins in them, that have send actions in them and they have published their public keys. When someone starts emptying them, then we know it is time to do something.... or hopefully long before that.

And it is not only quantum "magic" computers we need to worry. Maye someday some hacker will find a way to break bitcoin crypto even without quantum magic.

good answer. I would add that a QC could  mine blocks way faster using something similar to Grover's algorithm

[Drnice]

I heard that Quantum Computer can destroy bitcoin.
Is it possible?

<sarcasm>
Yes.

The word "quantum" is a synonym for "magic".  A quantum computer is a magic computer that can do anything you want it to do as fast as you want it to do it.
</sarcasm>

There is no reason to think that a quantum computer will destroy bitcoin.  Extraordinary claims require extraordinary evidence.

If yes, that quantum computer can impose threat to bitcoin and other crypto currencies, it then means that not only with the shutting down of the internet will be the threat of crypto currencies.

[nc50lc]

I heard that Quantum Computer can destroy bitcoin.
Is it possible?

<sarcasm>
Yes.

The word "quantum" is a synonym for "magic".  A quantum computer is a magic computer that can do anything you want it to do as fast as you want it to do it.
</sarcasm>

There is no reason to think that a quantum computer will destroy bitcoin.  Extraordinary claims require extraordinary evidence.

Your sarcasm was straight to the point
Scientists nowadays are:
"Hey this should be researched, I need a lot of funds"

We're going back to "Earth as the center of the solar system" in the field of "Quantum" physics because of these kind of researchers.

OP: Looking at the current development in Qcomputing, Quantum computers will not be a threat to Bitcoin. There are more threaths than that to look after.

[haltingprobability]

If i'm right, Quantum Computer is best for solving exponential problem (2^x) while Bitcoin cryptography either based on polynomial (x^2) or/and Elliptic-curve/ECDSA (y^2=x^3+ax+b), so bitcoin security won't affect much by Quantum Computer. CMIIW.

There are a couple errors, here. First, 2^x (EXP) is way harder than x² (P) - a computer that could solve 2^x problems wouldn't even have to break a sweat to solve x² problems.

In theory, quantum computers (QC) can store information exponentially in the number of qubits - 20 qubits can store a megabit (2²⁰ classical bits) of information. But the exponential space advantage of QC does not necessarily translate to an exponential time advantage. QC has a quadratic time advantage for search problems vis-a-vis a classical computer.

[SpeedRacerF1]

If i'm right, Quantum Computer is best for solving exponential problem (2^x) while Bitcoin cryptography either based on polynomial (x^2) or/and Elliptic-curve/ECDSA (y^2=x^3+ax+b), so bitcoin security won't affect much by Quantum Computer. CMIIW.

There are a couple errors, here. First, 2^x (EXP) is way harder than x² (P) - a computer that could solve 2^x problems wouldn't even have to break a sweat to solve x² problems.

In theory, quantum computers (QC) can store information exponentially in the number of qubits - 20 qubits can store a megabit (2²⁰ classical bits) of information. But the exponential space advantage of QC does not necessarily translate to an exponential time advantage. QC has a quadratic time advantage for search problems vis-a-vis a classical computer.

Fools who think replacing science with math somehow makes for legitimate concepts...and after a google search followed by a link to wikipedia, we can rest assured you're all experts on quantum mysticism. haha

[haltingprobability]

I heard that Quantum Computer can destroy bitcoin.
Is it possible?

No. Quantum theory is fake "science" and does not exist, nor do "quantum computers".

Not fake at all. In fact, the computer you are using would not be able to operate without specifically quantum effects - the semiconductor effect (field effect) is itself a result of the quantum behavior of properly doped silicon. Without this quantum phenomenon, we would not have solid state electronics and our computers would all be running on vacuum tubes - a computer equivalent to a TI calculator would require megawatts of power to operate.

You can directly observe quantum phenomena for yourself with a helium discharge tube and a diffraction grating - you will see spectral lines (emission and absorption lines) which contradicts the classical theory of light. An even easier experiment is to layer a couple polarization filters and a polarity rotation filter to "erase" the effect of one of the filters using quantum erasure. It's a simple experiment that anyone can do and you will directly observe quantum erasure in a way that contradicts your intuition about the way that the filters should behave.

[nexus2k14]

I heard that Quantum Computer can destroy bitcoin.
Is it possible?

Yes it's possible but in fact is a very long process, it can not happen before year 2027/2028.  Bitcoin uses secp256k1 cryptography that can not be hacked today, and when this will be possible using Quantum computers I am sure Bitcoin will be ready and have the quantum fork for quantum resistance cryptography standard,
right now there is one proposal already now called qBitcoin.
https://spectrum.ieee.org/tech-talk/computing/networks/qbitcoin-making-bitcoin-quantumcomputer-proof

[shensu]

All cryptography will be threatened by this, not just bitcoin.