Why Quantum Computing Matters for Bitcoin
Bitcoin has long been viewed as one of the most secure digital systems ever built, but a new warning from Coinbase suggests that quantum computing could eventually test that assumption. According to Coinbase’s head of global investment research David Duong, advances in quantum technology may introduce long-term risks to Bitcoin’s cryptographic foundations if the industry does not adapt in time.
Bitcoin’s security relies on modern cryptography, particularly the Elliptic Curve Digital Signature Algorithm (ECDSA) used to authorize transactions and SHA-256 used in proof-of-work mining. These systems are considered extremely robust against today’s classical computers.
However, Duong warned that cryptographically relevant quantum computers (CRQCs) could one day run algorithms like Shor’s and Grover’s, which would dramatically reduce the difficulty of breaking cryptographic protections.
This concern has already reached Wall Street. In May 2025, BlackRock flagged quantum computing as a potential risk in an amended prospectus for its iShares Bitcoin Trust ETF, stating that Bitcoin’s cryptographic infrastructure could eventually become “flawed or ineffective.”
Private Keys and Signatures are the Biggest Risk
Duong emphasized that quantum mining - using quantum machines to mine blocks faster - is a secondary concern for now. The more pressing issue is transaction signatures.
If quantum computers mature enough, they could theoretically derive private keys from exposed public keys, allowing attackers to steal funds from vulnerable Bitcoin addresses. Duong explained that the risk plays out in two ways:
- Long-range attacks, targeting old outputs whose public keys are already visible on-chain
- Short-range attacks, where attackers attempt to front-run transactions as public keys briefly appear in the mempool during spending
Both scenarios point to the need for quantum-resistant signature schemes in the future.
Over 30% of Bitcoin Supply Could Be Exposed
One of the most striking findings in Duong’s analysis is the scale of potential exposure. He estimates that 32.7% of Bitcoin’s total supply, roughly 6.51 million BTC, could be vulnerable to long-range attacks if quantum threats materialize.
This exposure is largely due to address reuse and older script types that reveal public keys on-chain, including Pay-to-Public-Key (P2PK), bare multisig (P2MS), and even some Taproot (P2TR) outputs.
While the probability of an imminent quantum attack remains extremely low, Duong stressed that migration planning must begin well before the threat becomes real.
Bitcoin Isn’t Alone - TradFi May Be Hit Harder
Interestingly, Duong noted that traditional finance could face even greater challenges from quantum computing due to its reliance on closed, legacy systems. Open-source protocols like Bitcoin and Ethereum, he argued, are at least positioned to coordinate upgrades transparently when needed.
That adaptability may prove critical as quantum research accelerates globally.
Scientists Warn Timelines May Be Shrinking
Quantum computing remains in its early stages, but progress is accelerating. In October 2025, Google quantum scientist Pierre-Luc Dallaire-Demers warned that advanced quantum systems could potentially break Bitcoin’s cryptography within five years.
More recently, Google reported breakthroughs combining AI and quantum computing, claiming new algorithms could guide practical quantum applications faster than previously expected. While these developments don’t immediately endanger Bitcoin, they reinforce the need for long-term cryptographic upgrades.
The Takeaway: Time To Prepare, Not Panic
Despite the alarming headlines, Duong made clear that Bitcoin is not facing an immediate existential threat. Instead, quantum computing represents a future risk vector that the ecosystem must proactively address.
The good news? Bitcoin has successfully navigated major upgrades before. With sufficient coordination, quantum-resistant cryptography could one day become part of the protocol - ensuring Bitcoin remains secure even in a post-quantum world.
