Quantum computing

Quantum computing is a way of computing based on the principles of quantum physics. It isn’t crypto, but it could affect crypto security.

What is quantum computing?

A regular computer computes using bits. A bit is always either a 0 or a 1. A quantum computer uses qubits. A qubit can represent a combination of 0 and 1. This is called superposition.

As a result, a quantum computer could potentially solve certain problems faster. This doesn’t apply to every task. Which computer works better depends on the problem and the program being used.

An example of quantum computing

Suppose an attacker knows the public key of a crypto wallet. That key can be visible. The private key must remain secret because it’s used to sign transactions.

A sufficiently powerful and reliable quantum computer could potentially calculate the private key in a vulnerable system. The attacker could then sign unauthorized transactions. This is a theoretical scenario, not a description of an attack that has taken place.

Why is quantum computing important in crypto?

Many cryptocurrencies use digital signatures. These let the network verify that someone is authorized to spend crypto. Quantum computing could pose a future risk to some of these signatures.

That’s why the term comes up in discussions about security research and post-quantum cryptography. These are security methods designed to withstand attacks from both regular and quantum computers. Such a change could require updates to blockchain protocols, wallet software, and the way users move crypto.

Quantum computers don’t automatically break all crypto security. Doing so would require a huge amount of reliable computing power, and there’s no generally accepted date for when this might become practical. A claim that a project is “quantum-safe” also doesn’t automatically mean it’s secure.