Bitcoin's Quantum Threat: A Serious Existential Risk

The threat of a viable quantum computer to Bitcoin is serious and existential.

The cryptographic system that underpins Bitcoin relies on the assumption that a functioning cryptographic system can produce unforgeable signatures. However, a quantum computer would break this assumption, rendering the entire mechanism for authenticating ownership and processing transactions obsolete.

This would mean that there's no way to actually own anything in the context of the Bitcoin protocol if this assumption breaks. As such, Bitcoin itself would break.

Fortunately, there are alternative cryptographic systems that exist, but they come with tradeoffs and hard choices need to be made. Fortunately, solutions do exist to mitigate the problems posed by a quantum computer, except for choosing which ones to use.