@cafter With respect, it is incorrect that it will take "5 - 10 years" to develop a 4000+ qubit machine. IBM will have one in 2025 (two years from now), making P2PK public addreses (which are not hashed) vulnerable as I said above. So not all of bitcoin will be vulnerable, true, but plenty of it will be, especially because since Taproot, the real unhashed public keys are left exposed after making a transaction so it is correct that the stop gap solution if one is using bitcoin is not to reuse public address, but this does not address the economic / market issue of loss of confidence that would occur if even one P2PK address were compromised. So this is why it is negligence of the highest order for the BTC devs to be continually dismissing this real problem as "FUD" when it would be an easy matter (a soft fork) to replace ECC with something like a hash-based algorithm which is more secure. Just absolute irresponsibility on the part of the bitcoin leadership.

Source that IBM will have 4,158 qubit machine in 2025 (and they have since 2017 always hit their quantum computing roadmaps, so it needs to be taken with the upmost gravity): https://spectrum.ieee.org/ibm-condor

I am not a trader though I am a developer and have worked at a manager level in a cryptocurrency company in the past so I know what I am talking about (I like to hope lol) from a technical standpoint. So I am here to warn about technical vulnerability but cannot give financial advice - there is a short bitcoin ETF (BITI) I have heard about (I am not invested in this myself, again I am not a trader, I just do boring old 401K / index funds lol) so that may be one way to profit, by shorting bitcoin, but again not financial advice.

The point is, in today's internet world, secrets don't stay secret for long. I am sure IBM would not knowingly let its system be used to hack bitcoin, but if they can build such a system, others could - say a state actor like China / North Korea. Yes of course a quantum computer could be used to hack other things too and it probably would - but if you were China (say) you could make millions / billions even, shorting bitcoin if you knew you could take it down, and I am sure they have already thought about this. Also, it is not just about money, it is an ego thing for them - they would love to take down bitcoin in order to stick it to the USA and the West.

And even just these possibilities may be enough to spook the market. Think about it - it is not needed for a country like say North Korea to use a nuclear weapon in order to cause concern - just the fact that North Korea Has a nuclear weapon means we have to take them seriously and try not to provoke them too much. Similarly, just the fact that a system to take down bitcoin *could* be built and used by bad actors, is enough to cause concern and cause ppl to get out of the bitcoin market, causing a crash. So just the existence (in 2025) of a 4000+ qubit machine by IBM (code-named "Kookaburra" - google it) could be enough to crash bitcoin market (because, again, it only takes 6 * 256 qubits, 1,536, to take out ECDSA encryption and allow someone to guess a private key based on the corresponding public key).

Again , not financial advice, I am not a trader and don't care about that. I do care that too many ppl are taking too big risks they cannot afford and they don't understand these risks. Maybe bitcoin will replace ECDSA with a quantum-safe algorithm and I hope they do. But right now they haven't even started on that and they are basically like the Titanic going full steam ahead, ignoring all iceberg warnings. So this is my iceberg warning as a former developer / manager in this space - get to the lifeboats while there is still time.

BTC is not quantum secure. IBM will have a QC of 4,000+ qubits by 2025 (in two years). It takes only 1556  qubits to break the ECDSA encryption used to correllate private to public keys. What this means is if you have an exposed (unhashed) public key - which if you ever used your wallet it leaves an unhashed copy of your public key out there on the network for anyone to have - a quantum computer of 1556 or more qubits can take that public key and reverse engineer out your private key. Game over. Bitcoin has no value other than as a way to Secure information - security is literally its only selling point - when that security breaks, as it will, it has no more usefulness and the value will crash to probably just a few dollars, propped up by die-hard dead-ender BTC maxis. If you want to get rich on bitcoin, short it by buying a short bitcoin etf (example is ticker BITI - not financial advice). Doing anything else will result in losing investment.

Google this / do your own research - this is not "FUD", this is just sober fact. Bitcoin public keys can fall with QC's of just 1556 qubits. (Source: https://security.stackexchange.com/questions/33069/why-is-ecc-more-vulnerable-than-rsa-in-a-post-quantum-world ). Misinformation you hear is that it takes many qubits to crack RSA hence bitcoin is safe - this only relates to the bitcoin mining algorithm not the ECDSA algorithm used to relate public/private keys which is more vulnerable. Again - in 2 years or so IBM will have QC strong enough to reverse engineer private key from unhashed public key. When this happens panic will spread and bitcoin will crash. This is as predictable as the housing bubble collapse of 2008 and just like then, there are people who will shout "FUD" at anyone showing the plain and simple facts. Don't be on the wrong side of this.

There may be a temporary bitcoin recovery, but it is doomed long run b/c it is not quantum secure. IBM wll have a QC of 4,000+ qubits by 2025 (in two years). It takes only 1556  qubits to break the ECDSA encryption used to correllate private to public keys. What this means is if you have an exposed (unhashed) public key - which if you ever used your wallet it leaves an unhashed copy of your public key out there on the network for anyone to have - a quantum computer of 1556 or more qubits can take that public key and reverse engineer out your private key. Game over. Bitcoin has no value other than as a way to Secure information - security is literally its only selling point - when that security breaks, as it will, it has no more usefulness and the value will crash to probably just a few dollars, propped up by die-hard dead-ender BTC maxis. If you want to get rich on bitcoin, short it by buying a short bitcoin etf (example is ticker BITI - not financial advice). Doing anything else will result in losing investment.

Google this / do your own research - this is not "FUD", this is just sober fact. Bitcoin public keys can fall with QC's of just 1556 qubits. (Source: https://security.stackexchange.com/questions/33069/why-is-ecc-more-vulnerable-than-rsa-in-a-post-quantum-world ). Misinformation you hear is that it takes many qubits to crack RSA hence bitcoin is safe - this only relates to the bitcoin mining algorithm not the ECDSA algorithm used to relate public/private keys which is more vulnerable. Again - in 2 years or so IBM will have QC strong enough to reverse engineer private key from unhashed public key. When this happens panic will spread and bitcoin will crash. This is as predictable as the housing bubble collapse of 2008 and just like then, there are people who will shout "FUD" at anyone showing the plain and simple facts. Don't be on the wrong side of this.