Bitcoin Forum

Hi everyone,

does anyone have a clue about what would happen to bitcoin if someone figured how to build a working and usable quantum computer? I do not now much about these machines but a colleague of mine who is a physicist told me that every standard encryption encryption - which is used quite a lot in bitcoin, right? - could be cracked in no time.

Would this be the end of bitcoin?

Niklas

That depends on what he means by "standard encryption", what he means by "cracked", and what he means by "no time".  It also depends on if he's right.

That being said, bitcoin will be the least of my worries if what he said is literally true.  No more secure access to websites. No more secure banking.  All the interbank transactions that occur right now would be compromised. The governments of the world could no longer communicate securely.  Businesses could no longer secure trade secrets. All wi-fi networks suddenly unlocked.

No this won't end bitcoin. Beacause it wolud mean that there is no more safe encrypted data anywhere.
Geeks will come up with some new methods. Perhpas 1024 MB encryption key? Will that be enough?

Quantum cryptography: photons through a fibre. Already been done.

Stephen Wiesner wrote about protecting banknotes with this method in the 1960s. A blueprint for a kind of cryptocurrency (but not as we understand it now with Bitcoin of course). Scientific American wrote him off as a hack.

This would be great for bitcoins.
A quantum computer would mean that bitcoin would be rewritten from the ground up and everything we learned would be implemented.

- No more long waiting on blockchains, every payment is instant.
- No more you lost your wallet, you loose your coins. Because your bitcoins is in the universe and can be access with your public and private key on every new install or by typing your bitcoinaddress in an ewallet, then your asked your private key.
- No more lost bitcoins, after a period of inactivity (minimum 5 years, after this timespan bitcoiners will be requested to vote other options) coins die and are reborn through mining.
- No more I got scammed, because you can send a suicidenote "Every bitcoin on that bitcoinaddress, will die and has to be mined to be reborn". You can only send a suicidenote if you did business with that bitcoinaddress, but if the coins are send to different addresses you can still send a deathnote to the bitcoin universe "All your stolen coins, will die and has to be mined to be reborn". There is a limit to the notes that you can send, so take note.
- No more waste of energy, bitcoiners can vote on which university will get the compute power to solve the next problem. It cool to work with schools, that way we get teenagers using bitcoins for a good cause.
- No more 51% but 100%

Quantum Computing would only mean that bitcoin gets way better then it is now. I sure hope Satoshi is learning quantum coding now, because who writes better then he does?

PS your old bitcoins would still be worth a lot and would be exchanged to the NEW STANDARD.

@pinnpe don't like to tell you this but you need to start reading about bitcoin again, you obviously don't understand it.

Your colleague clearly has no clue. Only certain types of public-key cryptography (including ECDSA, which is which is what Bitcoin uses) are especially vulnerable to quantum computers. Symmetric cryptography and hashing algorithms are slightly weakened, but not to the point of being "broken". Note that there are public-key algorithms which are not broken by quantum computers, and Bitcoin can switch to one of them if the need arises (the reason Bitcoin isn't using them now is because these quantum computer resistant algorithms are relatively new and untested and may have as-yet unknown flaws).

Solution: Post-quantum Cryptography (http://en.wikipedia.org/wiki/Post-quantum_cryptography)

@paraipan It's true I don't fully comprehend the mechanics of bitcoins.

Read & see how POST QUANTUM CRYPTO WORKS (http://www.securetoshare.com/technology.html)

Thank you for your answers!

Best, Niklas