Topic: Will quantum computing kill crypto? - page 4. (Read 9173 times)

Bitcoin is inherently resistant to quantum computing as it does not disclose the public key, instead it hashes it twice! So the attacker literally has no chance to 'derive' the private key even armed to a super quantum computer like in a science fiction.

So far so good, BUT when one 'spends' his wallet, eventually has to disclose his/her public key and if s/he accidentally tries to use the same address again, well, from here on the alarming flags should be raised if there are powerful enough QCs commercially available.

Note:
In the limited interval between the time of the spend Tx even for the brand new addresses, until they get confirmed, there is a window for the QC attack to compromise the private key and generate another transaction with higher fee and priority and steal funds, taking advantage of this window needs very huge QCs to break the code very fast, not like few days, but few seconds. Such QCs not likely to be built ever.

Anyway, when it comes to upgrade, there will be a soft fork, implementing new address types and thus new cryptographic algorithms. After  the fork, all new transactions will be safe in heaven, the only weakness will be the elder UTXOs with used addresses, though it will be the holders' responsibility to renew their wallets asap

" Do you think we will see new quantum cryptos released once the technology is ready? Or do you think Bitcoin will adopt a new layer of quantum security if that is even possible"


The bolded would likely be the case. Been following the Quantum stuff for years now, looks like it is year 2030 technology, by then developers will most likely figure out how to keep things from being hacked or we will never have Crypto and Blockchain anymore.

By the way IBM may have developed some basic quantum computers/technology. They have been on the Quantum thing for years

Wat.

Against any poison always has an antidote. Quantum computers, it will not be soon. If you panic because you, we urgently need to curtail all space programs because someday it will built a spaceship with photon drive.

Probably not, honestly.

So, when quantum computing leaves its infancy, I'm pretty sure it'll be the catalyst that moves humanity closer to singularity. With actual quantum computing, we'll be able to effectively simulate the universe.

Ideally, Bitcoin and all currencies will be dead by this point and capitalism will have fallen entirely.

I don't know why you say that.  Even in Satoshi's genesis block, the output script is

41 04 67 8A FD B0 FE 55 48 27 19 67 F1 A6 71 30 B7 10 5C D6 A8 28 E0 39 09 A6 79 62 E0 EA 1F 61
DE B6 49 F6 BC 3F 4C EF 38 C4 F3 55 04 E5 1E C1 12 DE 5C 38 4D F7 BA 0B 8D 57 8A 4C 70 2B 6B F1
1D 5F AC

that is essentially a bitcoin ADDRESS, meaning, it is a hash of a public key.

Sure I get that but just look at where there internet has gone in the last 20 years. I'm sure if you went back in time 20 years today's reality would have been thought of as impossible. Technology moves at such a great rate that it would be hard to predict 5 years into the future let alone another 20.

Quantum computing is still in its starting phase. It will still need couple of decades to become a threat to cryptocurrencies. I read it somewhere that at present quantum computing is focused upon only energy landscape issues and not on solving regular mathematical problems. We need a major revolution in our ability to build reliable qubit logic before we can even think about solving complex cryptography and that problem is nowhere near being solved at the moment.

Glad to hear most people think that Bitcoin will survive. I suppose its a bit of a guessing game but for now at least we are on top of any potential changes

it will not kill it, but crypto's will have to adapt to quantum computing.,

No, because quantum is still in early stage of development, and with quantum computing, also quantum cryptography will be developed.

Good thought. Personally I think blockchains will be the way to go, since banks will probably lag in the update to quantum resistant security measures. Communities like these are faster at adopting such technologies.

The main threat, as have been mentioned earlier in this topic, is an imaginary multi million qubit quantum computer being so powerful that can crack a disclosed public key while its container (a spend transaction) is stuck in the mempool (few minutes). It is mainly due to the fact  that this hypothetical crack wont compromise the wallet as a whole (we re-use our wallets).

HD wallets are de-facto standard and commonly used now and they secure the process in a way that  the attacker MUST complete its mission in the short time frame in which a transaction is publicly announced and not confirmed yet. The trick is that once the confirmation takes place, compromised public and private keys will become useless, the remaining balance has mowed to a fresh, although dependent, new public/private pair of keys which their master private key is well secured by the owner (hope so) and the master public key have not to be exposed ever.

For the fictional ultra-super quantum computer giant case, the solution is out there with quantum resistant cryptography, it is just about implementation and a soft fork for which we have a lot of time, say 1-2 centuries. It really takes that long with any measure to have multi million qubit quantum computers around.

Conspiracy theories have been proposed that NSA or CIA have access to much powerful QC tech than what is publicly disclosed, while it is disputable and controversial and one can ask that how far they can go, anyhow, in practice, they can't  use their hypothetical "super power" against bitcoin even once, because by doing this, they will disclose their access to such a technology and escalate competition and research for countermeasures.

It is crazy just how many things scientists have considered "impossible", only for them to be achieved sometimes centuries earlier than predicted. One recent example is AlphaGO. With that said, I wouldn't put anything past the realm of possibility, but with the amount of money invested in Bitcoin globally it is unlikely that if this were to happen we wouldn't find a solution.

It's going to take some time.

It wont be soon, to decipher the secret key for an acceptable time, you need to have a computer with 100 million qubits, and now only a computer with 49 qubits is being developed.

Also, the moment you spend bitcoins from an address you reveal that address's public key. Not a problem, if you never reuse an address (which is how most wallets work now, creating new change addresses for each tx). Although if quantum computers are fast enough to break a private key in a few minutes to an hour, you could potentially take any tx from the mempool with a fat public key, reverse its private key, build a new tx spending the funds to your address and replace the old one with replace-by-fee.

Really, I wasnt aware of that. That would surely be profitable for someone if they could exploit that vulnerability in the early blocks. At least it wouldnt bring down Bitcoin as whole though....

Unfortunately, in the earlier stages of Bitcoin, P2PK was implemented instead of P2PKH. The earlier transactions, specifically those that were mined to were vulnerable with the default implementation using P2PK.

That includes the genesis block and many addresses with transactions around that time.

Those addresses with 50BTC can potentially be vulnerable.

Of course, I didnt even think about the fact the public key is already hashed!

Glad to hear our Bitcoin will be safe from the world of science fiction.

I think a long Sunday afternoon must have taken it's toll, my imgination has been for a good wonder today...

Thanks for the info though!