Quantum threat to Bitcoin: Harvest now, decrypt later
Quantum computers could quietly break Bitcoin, and a former hacker says the countdown has already begun.
David Carvalho, a one‑time teenage spam hacker turned CEO of cybersecurity firm Naoris Protocol, warns that the blockchain’s cryptographic defenses may not withstand the coming wave of quantum computing and AI‑driven breakthroughs.
At the center of his warning is a tactic known as “harvest now, decrypt later,” where attackers stockpile encrypted Bitcoin transactions today, waiting for future machines powerful enough to crack the private keys.
Carvalho’s story adds weight to his warnings. He started hacking at 13, later advising NATO and Fortune 500 companies before founding Naoris Protocol. Now he’s sounding the alarm that Bitcoin vulnerabilities to quantum computing are real; its SHA‑256 and Elliptic Curve Digital Signature Algorithm (ECDSA) protections could face a silent collapse of Bitcoin systems if the industry hesitates on upgrades.
Did you know? Google’s Willow quantum chip demonstrated an astonishing speed benchmark, solving problems in minutes that would take the fastest classical supercomputers around 10²⁵ years.
Bitcoin’s vulnerabilities to quantum computing
Bitcoin’s security relies on two cryptographic pillars: SHA‑256, which protects the mining process and transaction integrity, and ECDSA, which secures private keys behind signatures considered unbreakable by today’s machines.
Under classical computation, brute‑forcing either system would take longer than the age of the universe, but the quantum threat to Bitcoin changes that equation.
Algorithms like Shor’s could one day allow a powerful quantum computer to derive a private key from a public key in minutes, making it possible to hijack funds from any exposed address before a transaction even settles.
Security experts stress that cryptocurrency security doesn’t mean “safe until Q‑Day.” State actors and cybercrime groups are already harvesting data for the harvest now, decrypt later crypto risk, quietly building archives they hope to unlock when hardware catches up.
The mix of AI in crypto and quantum technology may speed up this timeline dramatically. Carvalho argues that AI could help identify weak points in blockchain cryptography, while quantum hardware delivers the raw power to exploit them. This combination — “how AI and quantum could break Bitcoin,” as he frames it — could bring forward the day when current cryptography no longer holds.
The exposure is already measurable. Roughly 25%-30% of all Bitcoin — some 6 million-7 million Bitcoin (BTC) — sits in legacy address types like pay-to-public-key (P2PK) or reused P2PK hashes. These formats reveal public keys, leaving them instantly vulnerable once quantum attacks become feasible. Those dormant and reused coins represent a huge chunk of circulating BTC and, by extension, overall Bitcoin price stability and Bitcoin adoption confidence.
Meanwhile, agencies like the National Institute of Standards and Technology and the National Security Agency are already urging a pivot to post‑quantum cryptography in crypto, with migration targets set for 2030-2035 to protect critical systems. If Bitcoin’s own upgrade lags, it could become a global case study in Bitcoin vs. quantum — a clash between the world’s leading digital asset and a new class of computing that rewrites the rules of digital asset protection and cryptocurrency security.
Carvalho warns the transition window is already narrowing. Without a decisive Bitcoin cryptography update and investment in quantum‑resistant blockchain security, he fears the industry could discover too late that the risk of quantum disruption wasn’t a distant “someday.”
Did you know? Hardware studies suggest that breaking a Bitcoin wallet’s ECDSA key within one hour would (optimistically) require around 13 million logical qubits (or more than 300 million physical qubits, depending on error correction regimes).
The silent collapse of Bitcoin systems?
David Carvalho warns of what he calls a “silent collapse of Bitcoin systems,” a new breed of AI‑driven quantum attacks that could break signatures, transfer funds and bypass detection entirely.
Instead of a headline‑grabbing exploit, these assaults would slowly corrode trust in the blockchain itself, reshaping balances and consensus without leaving obvious forensic traces.
In this vision, conventional security measures would prove almost useless. Penetration tests, anomaly‑detection software and even watchdog nodes might all miss the breach. AI could automatically probe for weak spots in blockchain cryptography, simulate network behavior and adapt its…
cointelegraph.com