Castle Island Ventures co-founder Nic Carter pointed out that quantum computing is approaching the threshold to “crack Bitcoin,” and approximately 1.7 million exposed public key Bitcoins may become targets. He strongly urges relevant technologists to address encryption issues.

(Background summary: Citibank’s latest forecast: Bitcoin may rise to $143,000 in 2026, ETF capital influx remains unstoppable)

(Additional background: The largest Bitcoin options expiration in history! Glassnode: Market still prices in downside risk, Bitcoin volatility may erupt in the new year)

Table of Contents

• Quantum Threat Shifts from Physical Theory to Engineering Timeframe
• 1.7 Million Exposed UTXOs Become On-Chain Bounties
• Freeze or Let Go?

Many may have forgotten who Nic Carter, co-founder of Silicon Valley venture capital firm Castle Island Ventures, is. He has been viewing the Bitcoin systemically as a “digital asset” since 2017 and has been a strong crypto advocate, especially in the early development of smart contracts, with high expectations for programmable finance.

Recently, such a person is very concerned about attacks from quantum computers. He posted a long article on X platform, directly stating that quantum computing cracking Bitcoin (Bitcoin) keys has moved from “theoretical” to an “engineering challenge.” All sectors should take this “future problem” very seriously.

https://t.co/piG7n6RuhM

— Nic Carter (@nic_carter) December 20, 2025

Quantum Threat Shifts from Physical Theory to Engineering Timeframe

In the article, Nic Carter cites quantum computing authority Scott Aaronson’s research. If a quantum computer running Shor’s algorithm reaches enough qubits (qubits) and entanglement time, it can reverse-engineer ECDSA/secp256k1 private keys. (The author also admits not fully understanding this part, only quoting directly.)

He emphasizes:

Quantum cracking is no longer science fiction; it is explicitly scheduled.

This contrasts with Bitcoin core developer Adam Back’s view of “waiting another 10–20 years.”

###1.7 Million Exposed UTXOs Become On-Chain Bounties

On-chain data shows that early P2PK block rewards and frequently reused addresses have accumulated about 1.7 million Bitcoins, with their public keys fully exposed.

If quantum algorithms target these unmanaged UTXOs first, it’s equivalent to gaining access to about $7.18 trillion in liquidity at once. Nic Carter describes these “zombie addresses” as “free bounties” in the quantum era. Once stolen and sold, market impact could be more severe than any single exchange bankruptcy.

Freeze or Let Go?

Currently, the Bitcoin development community has proposed several soft fork drafts for “post-quantum” signatures and new Opcodes. But the real controversy is how to handle the old coins that cannot migrate on their own. The community discussion is splitting into two camps:

• Passive Waiting: Maintain the status quo, letting the market bear the risk; if hackers succeed, Bitcoin’s supply remains nominally unchanged, but trust and price could be destroyed.
• Proactive Freezing: Use soft forks to mark and freeze high-risk UTXOs, or even consider destroying them. While this can prevent sell-offs, it breaks the principle that “no one’s assets can be controlled by others.”

Strategy CEO Michael Saylor has described the freezing plan as “supply reduction,” but most developers remain highly skeptical of using consensus to strip private key control, as this would undermine Bitcoin’s decentralization.

Should Bitcoin holders start worrying about quantum attacks? Optimists still say, “It’s just an engineering challenge,” but how much time it will take to solve this challenge remains unknown. After quantum computing arrives, the first to suffer may not even be Bitcoin. Let the big capital worry about this major issue.