Topic: Hackers/Public will have Access to Quantum Computers in 5-10 years? - page 3. (Read 498 times)

The general topic of quantum computers as a potential threat to Bitcoin and other cryptocurrencies has been discussed many times here. Nobody knows for sure how that technology is going to develop and whether it will go significantly beyond what we already have. To make cryptos obsolete, we need a breakthrough in quantum computing, and so far, the topic has been around for years without breakthroughs. When the technology is at early stages, it's really hard to predict if it thrives in the future. When people landed on the Moon in 60s, tourism to planets of the Solar system by the end of the 20th century sounded like a very realistic prediction. And yet, here we are 60 years later, still only being able to go into space and to land of the Moon at best. What I'm saying is that maybe the threat of quantum computers to cryptos will remain the same in 60 years, too.

It is fascinating. I am glad you posted this, because I was about to post a thread on this. Had not heard about the threat to crypto from quantum computers in probably a decade, but quantum technology seems to be making major(?) breakthroughs, recently.

Google recently announced they had developed "time crystals," which from my dumbed down interpretation are basically quantum transistors. The problem with quantum computers is that their current "transistors" decay rapidly, are hard to manufacturer and have to be replaced frequently. Time crystals solve both of these problems and potentially make quantum computers a reality. (Don't be evil) Google is the LAST company I would want making these discoveries.

Then again, they have been talking about quantum computing probably before I was born, so who knows how close they really are. But the concern is real if governments were able to develop these machines or have already done so.

China already has a quantum computer?
Good to know. What about the hashing algorithm itself? Could it hijack mining?

More bits will simply be added to new keys.
How many more bits will depend on the strength of the quantum computers.
Addresses will have to update before old ones are crack (still a big if).
Hopefully this will happen slowly enough so that individuals can update their addresses.
Satoshi's coins would though possibly be cracked, and perhaps we will learn more about the identity of SN.

I've never understood the hype around quantum computers. Isn't it just a move back to analog, with a fancy new term?
The problem doesn't change much for much more powerful computers, quantum or otherwise.

No, they can't.

Quantum computers can exponentially speed up solving the discrete logarithm problem, but can only linearly speed up finding a collision for a hash. What this means in practice is that they are only useful for brute forcing private keys in which the attacker knows the public key. Given that you public key is only revealed when you make a transaction, sign a message, or otherwise choose to share it, then if you only ever send bitcoin to brand new addresses which you never reuse and never share the public key of, then your bitcoin is 100% safe. A quantum attacker cannot obtain a private key only from knowledge of the address.

Further, quantum computers aren't an "all or nothing" thing. Sure, the first quantum computer might hit the market in a decade, but it will be inefficient and have a very small number of qubits. It would still take thousands of years to crack a single private key. It will be centuries before quantum computers reach the stage that they can reverse a public key to a private key in a "fraction of a second".

At some point, bitcoin will fork to a quantum resistant algorithm.

There's a couple of interesting white papers to read:

https://arqit-res.cloudinary.com/image/upload/v1627024109/Assessment_of_Quantum_Threat_To_Bitcoin_and_Derives_Cyrptocurrencies_nrp6iq.pdf

https://arqit-res.cloudinary.com/image/upload/v1627369111/Digital_assets_The_security_problem__yya4bn.pdf


So Quantum Computers will be available to buy in the shops in lets say 10 years time from now and 5 years from now the first commercial business grade quantum computers will be available for sale for businesses.

Quantum computers can get anyone's private keys in fraction of a second.

The few quantum computers in the world today owned by the Big tech giants such as google, Microsoft, even china has one is used to harvest all that data from billions of people to a single point Ai. These quantum computers are massive, require a lot of cooling and are power hungry that require nuclear reactors to run them. But these are the 1st generation quantum computers.

Eventually these quantum computers will get smaller, more efficient to run off the electricity in your home and everyone will have quantum computer in their bedrooms when they hit the shelves in shops or on Amazon online in 10 years time but at a crazy price tag so not everyone can afford one in 10 years time but they will get cheaper and become mainstream especially with gamers for obvious reasons. Playing fortnite at crazy 16k resolution at million frames per second.

So how can Bitcoin survive in this technological quantum era? The B in Bitcoin stands for Bits. Quantum computing is Qubits meaning it can be a binary 1 or 0 at the same time similarly like a light switch being on or off at the same time that sounds crazy and impossible.

Will there be Qitcoin or somewhat?