Since 2009, Bitcoin has been considered one of the most secure digital assets in the world. Its strength comes from cryptography, specifically Elliptic Curve Cryptography (ECC). But a new technology is rising fast: quantum computers. Could they put Bitcoin at risk?
The Security Behind Bitcoin
Bitcoin wallets and transactions are protected with private and public keys.
- Private key → a secret only the owner knows.
- Public key → generated from the private key and sometimes visible on the blockchain.
- Address → what people use to send or receive Bitcoin.
On normal computers, turning a public key back into a private key would take billions of years.
How Quantum Computers Change the Game
Quantum computers use the strange rules of quantum physics—like superposition and entanglement—to solve problems far faster than classical machines.
One method, called Shor’s algorithm, could break ECC. With a powerful enough quantum computer, attackers might calculate private keys from public ones, unlocking wallets and stealing coins.
How Close Are We?
Today’s quantum computers operate with around 1,000 qubits. Breaking Bitcoin would likely require millions of stable qubits. So, at the moment, there’s no real danger.
Still, tech giants like IBM, Google, and Microsoft are aiming for million-qubit machines within the next decade. Some researchers warn that Bitcoin’s cryptography could be vulnerable by the late 2020s or early 2030s.
Which Bitcoins Are at Risk?
Studies suggest that about 30% of Bitcoin’s supply (6–7 million BTC) is more vulnerable to future quantum attacks. That’s because older addresses expose public keys directly on the blockchain.
Even newer address types aren’t fully safe—when coins are spent, the public key becomes visible, creating a small but real risk once quantum power grows.
Possible Solutions
- Switch to quantum-resistant cryptography → Replace ECC with stronger, post-quantum algorithms like lattice-based cryptography.
- Avoid old address formats → Users should move coins to modern wallets.
- Prepare for “harvest now, decrypt later” attacks → Hackers may already be storing blockchain data to crack in the future.
- Follow institutional best practices → For example, El Salvador redistributed its Bitcoin reserves across multiple addresses to reduce exposure.
Quantum computers are not a threat today—but they might be tomorrow. While there’s no need for panic, the crypto community must prepare. If Bitcoin fails to adapt, its reputation for unbreakable security could face its biggest test yet.
