Can quantum computers crack Bitcoin?

Elon Musk has raised new questions about the long-term security of Bitcoin amid the rapid development of quantum computing. The CEO of Tesla and SpaceX, using his AI chatbot, Grok, explored the possibility that Bitcoin's SHA-256 hashing algorithm could be cracked by a powerful quantum computer. His question coincided with IBM's announcement of major plans for its next-generation quantum system, "Blue Jay," which is expected to have 2,000 global qubits by 2033. According to Grok's analysis, the risk of a quantum computer cracking Bitcoin's encryption within the next five years is extremely low, with the AI estimating the probability to be close to zero. However, by 2035, the probability will increase slightly, though it will still be below 10%. These figures are based on expert assessments and current quantum computing capabilities. "Based on the 2025 assessments by the National Institute of Standards and Technology (NIST) and IBM, as well as expert surveys, the probability of a quantum computer cracking SHA-256 using the Grover algorithm (which reduces the complexity of the preimage search to approximately 2^128 operations) will be close to 0% over the next five years and below 10% before 2035. This requires millions of error corrections..." — Grok (@grok) August 2, 2025 Musk's concerns are not unfounded. Companies like Google and Microsoft are developing their own quantum platforms (Willow and Majorana 1), sparking discussion about whether cryptocurrencies like Bitcoin could be vulnerable to attacks from these powerful systems in the future. Currently, most quantum systems have only around 1,000 qubits, far fewer than the millions of error-correcting qubits that scientists believe are needed to crack Bitcoin's encryption defenses. Grok added that if necessary in the future, stronger algorithms such as SHA-3 or SHA-512 can be used as alternatives. At the same time, a recent analysis by global audit firm Deloitte shows that quantum computers may soon threaten the security of the Bitcoin blockchain. Currently, about 25% of Bitcoin is at risk of being stolen by quantum attacks. Analysts say that quantum computers could eventually become powerful enough to crack entire transaction processes. To mitigate this risk, the Bitcoin network needs to adopt post-quantum cryptography, an emerging but complex solution currently being explored by cryptographers worldwide. IBM's new system, "Blue Jay," will have a computational power exceeding 1 billion gates, far exceeding the capabilities of current computers. This is a key step in the company's pursuit of being at the forefront of quantum computing by the early 2030s. With industry giants like Google and Microsoft nipping at the heels, the competition is intensifying. Musk's interest is more than academic. Tesla currently holds 11,500 bitcoins, worth approximately $1.3 billion at current prices. SpaceX also holds a significant amount, reportedly worth approximately $850 million. Musk himself has confirmed that he holds bitcoin in his personal portfolio.

Given the size of these holdings, it's no wonder Musk wants to prepare for potential threats in advance. His tweets, while seemingly lighthearted, reflect the growing concern in the tech world about the impact that advances in quantum technology could have on cryptocurrencies and the financial sector.