Key Highlights
- Coinbase analyst warns that quantum computers could threaten Bitcoin wallets, mining, and the network itself.
- Bitcoin’s security relies on two systems, Elliptic Curve Digital Signature Algorithm (ECDSA) and SHA-256, which protect transactions and mining.
- Quantum computers could steal coins from old wallets and give some miners too much power, raising Bitcoin security risks.
Concerns about quantum computing and Bitcoin are once again drawing attention, after a senior Coinbase analyst warned that the risks may go far beyond hacked wallets and stolen coins. David Duong, Coinbase’s Global Head of Investment Research, said future quantum computers could threaten not only how Bitcoin users protect their money, but also the deeper economic and security structure of the entire network.
In a recent public post on LinkedIn, Duong explained that once quantum machines reach a certain advanced stage, often called “Q-day,” they could become powerful enough to run powerful algorithms that weaken the cryptography Bitcoin relies on.
Security pillars under pressure
Bitcoin’s security depends on two main systems. As Duong explained, “Bitcoin’s security relies primarily on two cryptographic pillars: the Elliptic Curve Digital Signature Algorithm (ECDSA) for transaction signatures and SHA-256 for the proof-of-work mining processes.” To explain simply, ECDSA verifies that a holder of a wallet has the right to spend their coins, and the SHA-256 hashing algorithm secures the mining of Bitcoin and the blockchain database through proof-of-work.
Duong said quantum computers could attack both. On the wallet side, quantum machines running Shor’s algorithm could, in theory, work backwards from a public key to uncover a private key. This could pose a threat to stealing Bitcoins from vulnerable addresses.
This is especially true for older address formats and wallets that have reused addresses because their public keys are already visible on the blockchain.
Duong approximates that about 6.51 million Bitcoins, which is about 32.7% of the existing Bitcoins, are more vulnerable to long-range quantum attacks. He shared, “These include Pay-to-Public-Key (P2PK), bare multisig (P2MS), and Taproot (P2TR), with Satoshi-era coins a known subset of legacy P2PK outputs.”
He also said this threat has two forms: long-range attacks on old coins whose public keys are already public, and short-range attacks that could happen in the brief moment when a transaction appears in the mempool.
Mining, power, and network control
Quantum computing could also affect Bitcoin mining. Future computers may also use Shor’s and Grover’s algorithm to edit the current calculation for finding valid blocks, enabling them to search much faster than today’s computers can. A small group of miners may possess such advantages if the technology is available only to a few miners.
This could disrupt Bitcoin mining, reduce decentralization, and raise concerns about who controls the network. It could let 51% attacks become a problem. This attack occurs when most of the computing power of the network belongs to one or more miners.
Duong said this mining risk is likely a lower priority for now. “That said, we think quantum mining itself remains a lower-priority concern for now given scaling constraints, making signature migration the central issue,” he wrote.
Not an emergency, but a long-term challenge
Despite the warnings, Duong emphasized there is no immediate danger. Today’s quantum computers are far too weak to break Bitcoin’s cryptography, and machines capable of doing so do not yet exist.
Still, upgrading cryptographic systems can take years. This explains why US and European authorities are encouraging the adoption of post-quantum cryptography, with visions for 2030 and beyond. Organizations such as BlackRock are also taking notice, issuing warnings within the context of Bitcoin-related documents.
The crypto community is divided. Skeptics like Blockstream’s CEO & Co-Founder Adam Back said the threat is decades away, while others warn that waiting too long could be risky, as securing a global, decentralized network is slow and complex. Strategy’s Michael Saylor also said quantum computing won’t break Bitcoin but will make it stronger by forcing upgrades.
Duong’s primary point is that preparation matters. Using quantum-resistant signatures can protect both older coins and future transactions as the question shifts from “if” to “when.”
Also Read: Bitcoin Recovery Picks Up, But Market Remains Cautious: Glassnode