Should a quantum computer with the capability to dismantle modern encryption become operational today, Bitcoin would likely face an imminent threat — and it would go unnoticed.
“Everything would appear as legitimate access,” remarked David Carvalho, CEO of post-quantum infrastructure firm Naoris Protocol, in an interview with Cointelegraph. “If you think you’re observing a quantum computer at work, it may have been in control for months already.”
“You wouldn’t even have a clue,” he added.
Researchers at IBM, Google, and government-sponsored labs are racing against time to fill this gap, but the urgency is palpable. The US National Institute of Standards and Technology (NIST) has started to approve post-quantum algorithms, while many public blockchains continue to depend on encryption systems from the 1980s.
Currently, this poses a theoretical risk. However, Carvalho cautioned that should this theory materialize, Bitcoin’s defenses could collapse quicker than the network could defend itself.
How a quantum attack could compromise Bitcoin
The fundamental security of Bitcoin relies on the Elliptic Curve Digital Signature Algorithm (ECDSA), a cryptographic standard introduced in 1985. This system allows users to validate ownership using a private key, while only the associated public key is visible on the network.
Through Shor’s algorithm, a sufficiently powerful quantum computer could theoretically derive a private key from its corresponding public key. This would enable attackers to access any wallet where the public key has been revealed on-chain, including those used in early Bitcoin (BTC) transactions.
“It would be impossible to demonstrate that a quantum computer carried this out because it appears as legitimate access,” Carvalho noted. “You’d simply see those coins move as if their owners chose to spend them.”
Related: The countdown for Bitcoin’s quantum vulnerability has already started, says Naoris CEO
Kapil Dhiman, the CEO and founder of Quranium — a layer-1 blockchain startup focusing on post-quantum security — warned that the earliest and most prominent victims would be the oldest wallets.
“Satoshi’s coins would be prime targets,” he stated to Cointelegraph. “If those coins begin to move, trust in Bitcoin will shatter long before the system itself collapses.”
In such a scenario, the blockchain would continue to process transactions as usual. Blocks would be mined, and the ledger would remain intact, but ownership would have silently transitioned.
As of now, advancements in GPU power and superior algorithms render brute-force attacks marginally more achievable. However, ECDSA with Bitcoin’s 256-bit keys remains well beyond the reach of classical computing.
Bitcoin lags behind traditional finance in post-quantum encryption
While banks, telecommunication networks, and government organizations have begun testing post-quantum encryption, most prominent blockchains still utilize technology from the 1980s.
“All blockchains have recognized this vulnerability as a fundamental issue,” Dhiman stated, referring to the potential risk that current encryption methods like ECDSA could be compromised by quantum computing.
Moving Bitcoin to a quantum-resistant framework would necessitate a comprehensive update of the network’s consensus rules, which requires extensive collaboration among miners, developers, and users.
Related: If you lost your Bitcoin in California, you might recover it all
Researchers have proposed various initial concepts, including Bitcoin Improvement Proposal 360, which outlines possible approaches for adopting new cryptographic techniques, as well as the “Post Quantum Migration and Legacy Signatures Sunset” proposal, which aims to phase out legacy signature schemes. Meanwhile, Ethereum developers have explored lattice-based signatures and other quantum-resistant alternatives, though none have yet been implemented.
In the realm of traditional finance, the transition is already in progress. The US NIST has approved multiple algorithms, and JPMorgan has piloted a quantum-safe blockchain in collaboration with Toshiba. SWIFT has commenced post-quantum security training for its network.
“Traditional finance is actually ahead,” Carvalho stated. “They have centralized control, financial resources, and a single authority capable of implementing upgrades. Crypto lacks that. Everything requires consensus.”
Several newer blockchain ventures are positioning themselves as quantum-ready from the ground up. Naoris Protocol, led by Carvalho, was referenced in an independent proposal submitted to the US Securities and Exchange Commission concerning post-quantum standards, while Dhiman’s Quranium utilizes the NIST-approved Stateless Hash-Based Digital Signature Algorithm. Concurrently, Quantum Resistant Ledger is a blockchain built on XMSS hash-based signatures, now a standardized NIST algorithm.
What if Bitcoin fails the quantum challenge
For the typical Bitcoin holder, the main concern lies in a sudden loss of confidence, which could cause prices to plummet and affect traditional markets, where institutional crypto adoption has been gaining momentum.
“There is a non-zero probability of it being operational now. The consensus among scientific, research, and military circles suggests that it isn’t,” Carvalho mentioned.
“However, it wouldn’t be the first instance of world-class cryptography being compromised without public awareness,” he continued, alluding to the Enigma cipher.
Used by Nazi Germany during World War II, the Enigma cipher was regarded as unbreakable at the time. However, cryptanalysts led by Alan Turing and his team at Bletchley Park successfully cracked it. The Allies kept this breakthrough confidential to ensure Germany continued to employ the cipher.
“When you think you’re noticing a quantum computer, it has likely been in control for months,” Carvalho warned.
Nevertheless, experts remain hopeful that quantum-secure blockchain systems can be developed and that the industry will align with standards already being adopted in traditional finance.
“Quantum-secure systems are attainable,” Dhiman asserted. “We simply need to start building them before the threat becomes tangible.”
For now, quantum threats stay theoretical. Bitcoin’s encryption remains robust, and computers capable of breaching it exist only in theory.
Magazine: Bitcoin vs. the quantum computer threat: Timeline and solutions (2025–2035)
