How Does Shor’s Algorithm on a Quantum Computer Pose a Threat to This Assumption?
Shor's algorithm is a theoretical quantum algorithm that can efficiently solve the Discrete Logarithm Problem and, by extension, the Elliptic Curve Discrete Logarithm Problem (ECDLP). A sufficiently powerful, fault-tolerant quantum computer running Shor's algorithm could break 256-bit ECDSA keys in a matter of hours or minutes.
This represents an existential threat to all current public-key cryptography, including the security of most cryptocurrencies.