## Breaking 256-bit Elliptic Curve Encryption with a Quantum Computer

Researchers have calculated the quantum computer size necessary to break 256-bit elliptic curve public-key cryptography:

Finally, we calculate the number of physical qubits required to break the 256-bit elliptic curve encryption of keys in the Bitcoin network within the small available time frame in which it would actually pose a threat to do so. It would require 317 × 10

^{6}physical qubits to break the encryption within one hour using the surface code, a code cycle time of 1μs, a reaction time of 10μs, and a physical gate error of 10^{-3}. To instead break the encryption within one day, it would require 13 × 10^{6}physical qubits.

In other words: no time soon. Not even remotely soon. IBM’s largest ever superconducting quantum computer is 127 physical qubits.

JL Sardinas • February 9, 2022 6:30 AM

They may want to use hybrids in the meantime… and algorithms may continue evolving, so the time frame is still uncertain. Maybe not too close, but uncertain definitely 🙂