Topic: The Quantum Threat to Bitcoin: Implications for Miners, Nodes, and Wallets - page 2. (Read 642 times)

You should read previous page to understand, but it's technical, sha256 proven to be strong enough at least so far, many experts work on breaking it, if one of them finds a weakness, the whole world will know about it and will have time to use a stronger hash function.

If a weakness is found in EC, it should be revealed for everyone, then if everyone wants to continue using crypto, they will have to use another type of curve, a different and stronger one. If it happens gradually bitcoin can survive, if it gets exploited in mass and suddenly, it would be difficult to restore things back to normal. These are speculations, not expert's opinions.

About wallet tracking, it is unrelated to this topic, but if you don't want anyone to connect your wallets to  certain transactions, use a mixer.

thank you for the explanation.
So an update to a new secure hash algorithm would be a problem from a mempool point of view, but a new EC would be?
Would comprimising sha256 be a privacy concern if it is used for generating addresses? Would it mean someone could connect all addresses from one wallet?

Computers used to fill an entire room, now better computers are in everyones pocket, so we never know how accessible quantum computing could get

IBM last year launched 'IBM Osprey', a new 433-quantum bit (qubit) processor and this is quite a progress in development of Quantum Computers, in 2001 we have 7 qubit quantum computers. There is predictions from experts that 2500-4000 logical Qubits would break ECDSA (source). Bitcoin is composed of many technologies, SHA256 is used to encrypt blocks of Bitcoin and in case any technology get compromised we have problem.  

Quantum computing is in its early stages and may take some years before getting launch. We cant deny it.

Sha256 hash function is used in bitcoin signatures/transactions, mining and generating addresses, it has nothing to do with private keys and elliptic curve. They are different. Have you ever seen a quantum computer? It's like some sort of alien spaceship engine, I don't think those who can build one enough powerful would use it to target crypto.

If hash functions are compromised there is a chance to survive for  bitcoin, but with EC compromised, the whole concept of public key cryptography is doomed. So there will be no transferring of anything.😑

lets say quantum computing comes slowly and a new algorithm is found that is secure against it. Then bitcoin would most likely change from sha256 to it. So all new wallets/addresses are secure by the new algorithm. What happens with the old ones? If sha256 is broken, you could get the private key from the public Key. Or am i wrong with that? So everyone would need to transfer their funds from their old addresses to new ones. Wouldnt that completly blow up the mempool and with that the transaction prices? Most people would lose a lot of their value just to transact to a safer address or they would leave their funds in the open for anyone with the algorithm to get them.

Advancements in technology are never welcomed in the start. Not many are taking Quantum computing seriously at the moment. But Quantum computing is a reality though it may take time to arrive. Quantum is not only a threat to crypto but to many other technologies like blockchain, VPNs and more. The idea behind Quantum is that its targeting the hard problem behind cryptography like Integer Factorisation and once it solves the problem there is no point in increasing the key size.

Yeah I always run two nodes on and off. so I always have 1 offline for 10 days.

So i always have a full chain backup off line which is 1 to 10 days old.

I cant be the only one that does this.

Bitcoin on it's own will survive any attack, even attacks such as rewriting the whole chain, because it's a distributed ledger, whatever happens people won't simply say Ok this experiment was fun, now that it's under serious attack lets just forget about hundreds of billions and move on to a new experiment, No there will be lots of bankruptcies and thousands of lives will be destroyed but it will rise from the ashes, because "decentralization" is what they signed up for, meaning no central crisis management organization (unit) will step in to handle the situation.

Problem is with mining machines, any new algo, solution should be based on one thing; whatever developers and manufacturers do, they need to make it compatible with current infrastructure in place, because if I am mining and suddenly they pull the plug and say you no longer can use these miners because there was an attack, well what am I supposed to do now?

Of course the usual answer is, "developers will fix it don't worry", developers can't keep their wallets safe, how can they keep a giant network safe when it's under attack?
(We knew these risks when we signed up for Bitcoin.)

 

we can argue quantum threat and the implications and one implication is

a quantum miner can increase the diff to 1000t vs the 55t it is now.

it is 2040 and btc diff has jumped to 1000t.

China has quantum mining in effect. as they developed a 200ph miner that uses 3000 watts.

just like they tore the top off btc rally in April 2021 they do it in 2040

they drop the diff down from 1000t to 100t the blockchain effectively freezes

and miners have to switch to a non quantum algo say scrypt with the ltc/doge stuff set up and ready.

Btc may not recover from that type of attack as it involves quantum only inlplace on the sha-256 mining Asic.

title of thread mean what effects can a quantum pc do to btc.

so a twofold attack would be trash btc sha256 and offer a replacement  algo scrypt

this is a two prong attack which needs quantum pc mining and a replacement algo

I suppose btc would need to alter its algo in an immediate move and the alternate would need to be an in place working algo. that has a lot of gear.

It would be a true mess.
Another way to fight a difficulty attack could be an emergency difficulty adjustment.

There is a topic about tail supply, good luck: https://bitcointalksearch.org/topic/surprisingly-tail-emission-is-not-inflationary-a-post-by-peter-todd-5405755
Also, there is another topic, which popped up more recently: https://bitcointalksearch.org/topic/can-tail-emmision-be-a-soft-fork-5466502
Which means, there are many better places to discuss it, than this topic.

What if diff is 200t it is the year 2040 and miners simply realize ltc/doge algo is far superior due to Doge never lowering its 10000 coin reward.

Doge is progressively lower % wise in inflation every year but always has a decent reward level for miners.


This threat above is greater than any other. Miners are the value bodyguards for a coin.  They will simply follow profits.  Much more threatening than a 'special' computer cracking address and taking fund out.

Has anyone ever thought that "quantum computing" (as we are being sold it, destroyer of worlds) might just be complete pseudo-science?

Should we sit around debating what will happen when the first mining farm discovers free energy?

You can easily find it out, if you see someone that is trying to break some altcoin. Or you can feel the same thing, if you try to solve security-related puzzles, like those ones: http://www.wechall.net/ (in general, we had many people on forums, who thought that someone successfully broke ECDSA, hash functions, and things like that; they were all wrong, but their feelings were probably genuine).

In case of altcoins, the right way of doing that, is full disclosure on forums. Inform anyone and everyone about a particular weakness, and create a situation, where a statistical CPU owner can mount a successful attack. And then, if developers are wise, they will fix it immediately, and everyone will be safe and happy again. But if they will try to ignore that constructive criticism, then such altcoin should be burned, and all attackers can just destroy it. I saw that many times on bitcointalk, there are whole groups that collect a lot of Bitcoins, just by finding and destroying half-baked altcoins, which are full of security holes.

This is bad idea. That means, someone else will just discover the same thing, and it will be worse, because the coin with that weakness will reach higher values, and more people will be harmed, when it will be destroyed in the future.

This is never the case. First, as vjudeu mentioned, it is not "secure vs broken" game. There is always some particular attack, and your defense will depend on that particular attack. Look at hardened SHA-1. Why it was created? Because of backward-compatibility. How it was created? Of course, based on the attack from 2017. If that would not happen, and if we would have a different attack in 2023, then hardened SHA-1 would use a completely different algorithm, designed specifically for that 2023 attack.

Exactly the same, as with every other security issue. First, write to the developers, inform them, give them some time to fix it. And if nothing will happen, then reveal everything publicly on forum. If it is still not sufficient, then demonstrate a practical attack on some test network, if there is any. And then, if messed up testnet is ignored, attack the mainnet. Because you revealed everything, and reached every previous stage of "inform and wait for the fix", you can publicly, and openly attack and destroy everything, to bring all of us into a world, that is safer, and resistant to this particular attack. Because if you won't, then that coin will grow further, and collapse in a worse way in the future.

Those steps in the middle can vary a little bit, but the general approach is simple: contact with developers, give them some time, and then publish it in a full disclosure model. You can find a list of previous BTC issues, and see, how exactly they were submitted in the past, how they evolved, which of them are solved, and which of them are still wide open, and wait for the future solution: https://en.bitcoin.it/wiki/Common_Vulnerabilities_and_Exposures

Edit: https://www.youtube.com/watch?v=4k1GcX1cqMg

This scenario isn't particularly realistic as first powerful enough quantum computers will most probably be owned by governments or corporations not cybercriminals. So Bitcoin devs will have time to migrate to another more safe protocol which would withstand a quantum attack.

I'm just thinking of the person who could be behind that. A crypto-hobbyist, with expertise in cryptography and the like. What would he feel first after that "eureka" moment? What should they do if they prioritized the collective benefit? Keeping it secret, and never exploiting it? Publishing it, and making every mining infrastructure worth zero? What would be the best approach for that person? Maybe they start searching for past suggestions on Internet boards.  

If they start mining, that will look weird, unless they mine blocks very rarely. Otherwise, if they were to set lots of times higher difficulty, then we'll notice an unknown group of miners suddenly acquiring vast amounts of hash rate without any ASIC being sold. That will start stinking fishy.

I am not a genius. But here we are in a "Development & Technical Discussion" board, so I can expect at least some basic knowledge about programming, because in other cases, those topics should land in some other, general discussion boards. Posting it here means that OP expects a technical response. And if you want to give any technical answer, then you have to know, how internally SHA-256 works. If you treat it like a black box, then that discussion will go nowhere.

You need at least a basic understanding of hash functions, if you want to talk seriously about it. You need to know at least how SHA-256 uses internal 32-bit values, and how they are mixed in each round. If you don't understand this pseudocode from Wikipedia, then sorry, but it is just an entry level to think seriously about any attacks on hash functions: https://en.wikipedia.org/wiki/SHA-2#Pseudocode

If you ask some technical question, and you receive an answer that is beyond your level of understanding, you should not be worried about it. When I started exploring hash functions, I knew nothing about them. Then, I read this pseudocode from Wikipedia. Then I wrote a simple program in C++ to produce a single hash. Then I experimented with it, started tweaking constants, changing parameters, and playing with all of that. And then, after many months, I wrote this topic: https://bitcointalksearch.org/topic/why-hash-functions-are-safe-5402178

As you can see, it took me many months of exploring the topic, to even think about writing something like that. And I am far from being genius or expert, because if you read, how many rounds can be broken on preimage or collision level, and if you read some PDFs, posted by mathematicians, then you will see, that my level of understanding is very basic, compared to them. I am still at round 20, when it comes to SHA-1 preimage. People went much, much further, and achieved much more than that, and I am still learning to get there later.

As I mentioned, you can overwrite the whole chain, without reaching even collision level of SHA-256. You don't need "to produce custom double hashes", because it is not a low-hanging-fruit. Even if you take "broken" hash functions like MD5 or SHA-1, you still cannot produce preimages for them, you can "only" find collisions. And if you can set a million times higher difficulty, that means you can also easily overwrite the whole chain.

It depends. Because as I said, it is not a "broken vs secure" game. If you can produce "a preimage", instead of "the preimage", then that kind of attack wouldn't work in some scenarios. For example, if SHA-256 is used to produce a deterministic R-value of a signature, and it is used to concatenate some private key with some message, then if you can produce "a preimage", then you would probably get a completely different (key,message) pair, and then you wouldn't know, what is the original private key, even if you can produce a valid signature for that.

Then they will be reversed, and those funds will be stolen. Later, they could be burned, or returned to the original owner, but any post-attack solution should be backward-compatible, and the chain should follow the heaviest Proof of Work.

Edit: Currently, you can even find websites, where you can explore SHA-256 round-by-round, step-by-step. So yes, we have that "knowledge at our fingertips", because anyone can visit https://sha256algorithm.com/ and play with SHA-256 in a browser.

Reading that article, clearly the journalist knows nothing to little about bitcoin, one could tell after reading he used private address instead of private key.

He also states what if someone mined 2016 blocks in 1 minute and left the scene? He says it would take 700+ years for difficulty readjustment, lol as if people would live their normal lives after seeing 2016 blocks in 1 min.  Of course in that case everything will change accordingly.

And if someone could mine 2016 blocks in 1 min, they could practically break sha256, so why bother announcing such capability to the world like that?

About double spending by hijacking txs from the mempool, well there is a solution, when it happens then all miners will have to accept a fork which disables RBF, so when all miners refuse to process RBF txs, an attacker no longer has the ability to double spend, there could be some implementations to record first seen txs and any tx from that address with different recipient, fee would be invalid.

Of course if miners refuse such a fork, they should start looking for something else to use their ASICs for other than mining.

While all "experts" talk about quantum computers and qbits, ECC is breakable by math, their opinions is based on current useless DLP solving algorithms, while with the right algo, you no longer need a QC.

Although it is possible to break Bitcoin with quantum computers still it will take hundred or more years to do that
here is what I have read but still it will take time and maybe some of us will not be around
https://cybernews.com/crypto/bitcoin-in-danger-quantum-computing-advances/#:~:text=If%20a%20Quantum%20computer%20is,before%20the%20transaction%20is%20finalized.

I love it when you expect everyone else to be a genius like yourself, it's like we have the means and knowledge at our fingertips to do the things you suggest. If OP knew how to attack SHA256, he wouldn't be here asking questions about wallets.

This is one dangerous idea, thinking about it makes you wonder, what if they can use their ability to produce custom double hashes and start collecting all the mining rewards?  And when they figure out a way to break sha256, what if for years they keep it a secret and then have access to everything dependent on sha256 security?

What if they manage to reverse some transactions in the future?

If sha256 is broken, miners and ASIC manufacturers are doomed, because they will have to throw all their rigs into trashcan.
This is why independent research is extremely vital especially for bitcoin, because as we know, we are on our own, because we chose decentralization we need to keep this system safe, no government will come to rescue if something happens, they have done all they could think of to limit and restrict bitcoin adoption, if something happens, they will sit and watch with joy and smile on their face.