The quantum threat to Bitcoin: real risk or just another FUD?

The topic of quantum computers is often used as an argument against Bitcoin. Yes, the technology exists and yes, in theory it could create challenges. But the difference between “possible someday” and “a real threat today” is enormous.

Bitcoin relies on two main cryptographic mechanisms:

– ECDSA / Schnorr over secp256k1 for signing transactions
– SHA-256 for mining and address protection

Shor’s algorithm could theoretically compromise elliptic curve cryptography if the public key is exposed. Grover’s algorithm reduces the effective security of SHA-256 from 256 to 128 bits, but this still leaves brute-force attacks practically infeasible.

It is important to emphasize:

A quantum computer cannot change the 21 million BTC limit.
It cannot bypass proof-of-work.
It cannot “create” new coins.

If SHA-256 Falls, the World Has a Bigger Problem

SHA-256 is not a “Bitcoin technology.” It is a global cryptographic standard used across the banking system, government infrastructure, military communications, and critical digital networks worldwide. The same cryptographic principles protect sensitive information for institutions, states, and financial systems.

If SHA-256 were ever truly compromised, it would not be a “Bitcoin problem.” It would represent a systemic risk to a large portion of the world’s digital infrastructure.

This is why framing quantum computers as a Bitcoin-specific threat is often misleading. If such a technological breakthrough became realistic, the global scientific and cryptographic community would respond long before it turned into chaos. Not because of Bitcoin, but because of the broader financial and information systems that rely on the same foundations.

At present, SHA-256 represents one of the highest practical levels of cryptographic security, simply because there is no need for something stronger. Cryptography evolves in response to real-world threats, not hypothetical scenarios.

How many BTC are actually at risk?

Only addresses where the public key is visible are vulnerable, mainly legacy P2PK. They hold around 1.6 million BTC, approximately 8% of the total supply.

However, the real potential market impact is much smaller. Only about 10,200 BTC are in structures that could create noticeable liquidity if suddenly compromised.

The rest are distributed across tens of thousands of separate UTXOs of roughly 50 BTC each, making mass theft an extremely slow process even under highly optimistic quantum advancement scenarios.

More modern formats like P2PKH and P2SH hide the public key behind a hash and remain protected until the funds are spent.

How far are we from real danger?

To break secp256k1 within a single day would require around 13 million physical qubits, roughly 100,000 times more than current capabilities.

Estimates place cryptographically relevant quantum computers at least 10 to 20 years away.

Long-term attacks would require years of computation.
Short-term attacks within minutes remain far in the future.

Should aggressive changes be made now?

Introducing untested quantum-resistant formats or extreme measures such as burning vulnerable coins carries serious risks:

– potential technical errors
– unnecessary changes to network rules
– interference with private property
– waste of time and resources

Bitcoin has already proven that it can adapt through upgrades. If necessary, post-quantum protection can be introduced via a soft fork without disrupting the network.

The quantum threat is theoretical, limited, and far from reality today.

This is not an emergency.
It is a topic for long-term planning.

Bitcoin was built to adapt. History shows that when a real need arises, the network finds a solution.