3

So I was wondering, if say a quantum computer is ever made could it be used to break the privacy of past transactions?

Would that mean at that someone could just work though the blockchain and De-anonymize everyone who's used monero?

  • Ah I just noticed this is a duplicate -- original here – bekah Dec 2 '16 at 22:41
4

Yep, using Shor's algorithm for finding the discrete log would allow the person in possession of a quantum computer to find every x used in a key image x.H(R) (not immediately, but in a feasible amount of time), and hence know exactly which accounts are linked by transactions.

There's actually a bigger issue than deanonymising all the transactions if quantum computers become a reality in the near future though -- Schnorr signatures and EdDSA are both based on the hardness of the discrete logarithm problem, which means an adversarial actor with a quantum computer will be able to compute your private key from any signature you produce, and attempt to spend your funds before your transaction is accepted into a block, or some other similar attack :(

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.