Suppose there could be a master key which can open any lock in the world. That is the type of power quantum computers would have in the future over the digital locks that surround our current reality. Our online information, our financial systems, and even the money you might hold in a digital wallet are all secured by complex mathematical problems. Problems that today’s computers find incredibly difficult to solve.
Yet, a new kind of computer is being developed in labs all over the world, one that obeys the crazy laws of quantum physics. It provokes a burning question to anyone interested in the digital future: Is the predecessor of cryptocurrency, Bitcoin, prepared to enter the quantum world? Or is it under the existential threat? Let’s find out, so when making any transaction using your 20Bet login, you know that you’re part of the future.
The Foundation
To understand the threat, you first need to understand the defence. Bitcoin doesn’t rely on a bank vault or a government guarantee, as its security is built on a form of cryptography called public-key cryptography. Think of it as a two-key system for every person.
First, you have a public key, which is like your account number or a locked mailbox’s address. It’s meant to be shared with everyone. When someone sends you Bitcoin, they send it to this public address. This public key is actually mathematically derived from your second key.
Your second key is your private key. This is the master key. It is the deeply guarded secret that proves you own the Bitcoin associated with your public address. It allows you to unlock your mailbox and spend your funds.
Critically, while it’s easy to generate a public key from a private key, it is practically impossible for any computer we have today to reverse the process and figure out the private key from the public one. The math is just too hard. It would take a conventional supercomputer thousands of years. This one-way mathematical function is the bedrock of Bitcoin’s security.
The Quantum Threat
This is where quantum computers enter the scene. They are fundamentally different from the laptops you’re using now. They utilise quantum bits, or “qubits,” which can exist in many states simultaneously (a phenomenon known as superposition). They perform massive calculations in parallel, exploring many possible solutions to a problem at the same time.
How a Quantum Computer Could Attack
A powerful enough quantum computer could use a specific algorithm (Shor’s Algorithm) to attack the cryptographic relationship between your public and private key. It wouldn’t just guess the key through brute force. It would use its quantum properties to solve the underlying mathematical problem directly, efficiently deriving your private key from your public one. If someone can do that, they can steal your Bitcoin. Simple as that.
But Wait, There’s a Catch… Or Two
Before you panic-sell your Satoshis, there are crucial caveats.
First, the quantum computers that exist today are nowhere near powerful enough to break Bitcoin’s cryptography, and are fragile, error-prone machines that operate in highly controlled environments. We are likely years, if not decades, away from a “cryptographically relevant” quantum computer.
Second, not all Bitcoin addresses are equally vulnerable. The biggest risk is to “p2pkh” addresses (those that start with a “1”), where the public key is exposed on the blockchain before the Bitcoin is spent. Once a transaction is broadcast, the public key is visible for a short time, creating a window of opportunity for a quantum attacker. Yet, many modern wallets now use “p2sh” or “bech32” addresses (starting with ‘3’ or ‘bc1’) that do not reveal the public key until after the transaction is signed and completed. This narrows the attack window by a huge margin.
The Current State of Play
The immediate risk is low, as the tech isn’t here yet, and the Bitcoin network isn’t a sitting duck. The community is acutely aware of the threat.
The good news is that the entire field of cybersecurity isn’t just watching. A global effort is underway to develop “post-quantum cryptography” (PQC) or “quantum-safe cryptography.” New mathematical algorithms are designed to be secure against attacks from both classical and quantum computers.
These approaches include lattice-based cryptography (finding shortest paths in complex multidimensional grids) and hash-based cryptography (leveraging quantum-resistant hash functions). There is also code-based cryptography (decoding random linear codes) and multivariate cryptography (solving complex systems of polynomial equations).
