Musk-Backed Quantum Ceiling Sparks Debate Over Bitcoin's Safety

Elon Musk has endorsed a theory that capping quantum computers near 400 qubits could make Bitcoin (BTC) theoretically quantum-safe. According to investor Fred Krueger, this is because current estimates put the attack requirement at 835 logical qubits. However, not everyone is convinced, with security researcher Marin Ivezic cautioning that the same circuit burns about 20 times more Toffoli gates than rival designs.

Physicist Tim Palmer's theory suggests a usable ceiling of roughly 200 to 400 qubits on current hardware and no more than 1,000 under any design. This is based on his paper published in the Proceedings of the National Academy of Sciences in March. The estimate of 835 logical qubits needed to break Bitcoin's signature curve comes from a July paper by Han Luo and seven co-authors.

IBM plans to run 100 million gates on 200 logical qubits with its Starling system in 2029, but hardware remains the binding constraint. Public machines sit well short of that mark, making it unclear whether Palmer's theory holds true or if the attack estimate is accurate.