6 ms·

Astronomical. You could convert every computer into existence into hunting for used private keys, and run them for the lifetime of the universe, and you’d be un

Astronomical. You could convert every computer into existence into hunting for used private keys, and run them for the lifetime of the universe, and you’d be unlikely to find even one used key.

bhouston 5y ago
What is the expected speed up if using quantum techniques? Can quantum techniques allow one to more effectively search for a specific private key to a BTC account?
- robbiep 5y ago
  Well, theoretically, instantly. But that’s kind of like asking what if I had this potion that instantly cured every disease known to man and then some, what would happen. What sort of quantum computer are you talking about? How many qubits?
  - shawabawa3 5y ago
    not exactly true BTC addresses that have never sent BTC are not vulnerable to quantum computers as the public key is only sent when a transaction is made. The address you send to is a hash of the public key and irreversible even with quantum computers
    - robbiep 5y ago
      The more you know. Thankyou
    - garmaine 5y ago
      This is no longer the case with Taproot, btw.
- lvass 5y ago
  I think it's square root of classical computing time, using Grover's algorithm.
  - HPsquared 5y ago
    How do the units work there? The dimensions would be time^(1/2)... That isn't a physical time. It's it the number of operations which is the square root? (Presumably the different types of computer don't take the same amount of time per operation)
  - garmaine 5y ago
    That’s reversing hashes. Finding the private key for a given public key would be basically instant if your quantum computer was large enough.
- shawabawa3 5y ago
  Quantum computers can be used to crack public keys for a bitcoin account yes, but an addresses public keys are only published when a transaction is made Best practice for secure bitcoin accounts is to always send the entire balance when making a transaction, and have the "change" go back to a new address
  - garmaine 5y ago
    Not anymore. With taproot the key used is published on the blockchain when the output is created.
    - shawabawa3 5y ago
      That doesn't make sense. I haven't published the public key to my bitcoin wallet. If someone sends to my address how do they publish the public key? There are new output formats with taproot but they aren't mandatory and you can still send to addresses with no published public key

Astronomical. You could convert every computer into existence into hunting for used private keys, and run them for the lifetime of the universe, and you’d be unlikely to find even one used key.

bhouston 5y ago

What is the expected speed up if using quantum techniques? Can quantum techniques allow one to more effectively search for a specific private key to a BTC account?

robbiep 5y ago
Well, theoretically, instantly. But that’s kind of like asking what if I had this potion that instantly cured every disease known to man and then some, what would happen. What sort of quantum computer are you talking about? How many qubits?
- shawabawa3 5y ago
  not exactly true BTC addresses that have never sent BTC are not vulnerable to quantum computers as the public key is only sent when a transaction is made. The address you send to is a hash of the public key and irreversible even with quantum computers
  - robbiep 5y ago
    The more you know. Thankyou
  - garmaine 5y ago
    This is no longer the case with Taproot, btw.
lvass 5y ago
I think it's square root of classical computing time, using Grover's algorithm.
- HPsquared 5y ago
  How do the units work there? The dimensions would be time^(1/2)... That isn't a physical time. It's it the number of operations which is the square root? (Presumably the different types of computer don't take the same amount of time per operation)
- garmaine 5y ago
  That’s reversing hashes. Finding the private key for a given public key would be basically instant if your quantum computer was large enough.
shawabawa3 5y ago
Quantum computers can be used to crack public keys for a bitcoin account yes, but an addresses public keys are only published when a transaction is made Best practice for secure bitcoin accounts is to always send the entire balance when making a transaction, and have the "change" go back to a new address
- garmaine 5y ago
  Not anymore. With taproot the key used is published on the blockchain when the output is created.
  - shawabawa3 5y ago
    That doesn't make sense. I haven't published the public key to my bitcoin wallet. If someone sends to my address how do they publish the public key? There are new output formats with taproot but they aren't mandatory and you can still send to addresses with no published public key