Justin Sun says AI and quantum computing threats make him bearish on Bitcoin

Justin Sun, the founder of TRON, says he has grown more bearish on Bitcoin due to the risks of AI and quantum computing. He believes holders of Bitcoin through exchange-traded funds have not fully accounted for these dangers.

The existing discussion revolves around whether the cryptography underlying Bitcoin can resist the accelerating speed of quantum research and developments in artificial intelligence.

What is Putting New Pressure on Bitcoin’s Cryptography

During a discussion with William Joy, Sun made a noteworthy observation.

He argued that improvements in AI mathematics might allow standard classical computers to crack current codes before a complete quantum achievement materializes.

“If you ask about my personal view, I am currently slightly more bearish. The reason is straightforward: the algorithm evolution of AI and the issue of QD (quantum computing). I believe it will be difficult for BTC to walk away unscathed from this,” Sun said.

No modern machine is near that level of power yet, but the expected timeframes for achieving it are shrinking. By March 2026, Google Quantum AI estimated that fewer than 500,000 physical qubits could be enough to break Bitcoin’s cryptography, about a 20-fold drop from previous estimates.

Google has since detailed further advances. On October 15, its researchers demonstrated magic state cultivation on the Willow processor, cutting errors roughly 40-fold. The results, which achieved 99.99% fidelity, were published in Science.

Willow has just 105 qubits, but the outcome could lead to smaller machines for breaking cryptographic keys. The achievement is significant as it tackles a central constraint in quantum computing.

Can Advances in Quantum Computing Undermine Bitcoin’s Security?

A substantial portion of Bitcoin is currently exposed. A co-founder of Glassnode stated that 6.04 million BTC, around 31.2% of the total mined supply, are located in addresses whose keys can be seen publicly.

Some assessments place the number at as much as 6.9 million BTC. In theory, these visible keys are the source of the vulnerability for those coins.

“Once QD or AI decryption arrives, these dormant assets will be breached, and in the worst case, the market could see massive selling pressure of more than 2 million BTC. Given BTC’s extremely high degree of decentralization, it is extremely difficult for the community and miners to reach consensus to freeze, confiscate, or restrict circulation through a hard fork,” Sun noted.

Coinbase, which holds a large amount of the supply, shared technical notes on October 13. It urged the community to begin preparing well before any quantum device capable of breaking cryptography comes into existence.

Altering consensus mechanisms and shifting the ecosystem both require years. Options including flexible output formats and phased hybrid protection are therefore relevant today.

Sun’s recent comments join an ongoing conversation among institutions and developers regarding whether the market is underestimating drawn-out cryptographic threats. For now, Bitcoin’s trading continues to be driven largely by unrelated considerations.