Quantum computing threat looms larger for Bitcoin than Ethereum, Citi warns
Citi analysts warn that quantum computing advances could break Bitcoin's cryptographic security sooner than Ethereum's, posing a greater risk to the largest cryptocurrency.
Citi analysts have warned that quantum computing advances are accelerating the timeline for practical attacks on digital assets, with Bitcoin facing a greater existential threat than Ethereum due to its older cryptographic architecture.
In a research note published on May 18, Citi highlighted that Bitcoin's reliance on the SHA-256 hash function and ECDSA signatures makes it more vulnerable to Shor's algorithm, which quantum computers could use to derive private keys from public keys. Ethereum, by contrast, has a more flexible upgrade path and is already exploring quantum-resistant signatures through its account abstraction model. The report suggests that Bitcoin's fixed protocol and large base of unspent transaction outputs (UTXOs) create a larger attack surface, while Ethereum's state-based model allows for smoother transitions. For crypto traders, this divergence in quantum risk could influence long-term portfolio allocation, with some investors already rotating from Bitcoin to Ethereum on perceived safety grounds. NowPrice's live crypto dashboard tracks price movements for both assets, allowing traders to monitor market reactions to these developments in real time.
The quantum threat is not imminent, but Citi's warning adds to growing institutional awareness. The timeline for a practical quantum attack remains uncertain, with estimates ranging from 5 to 20 years. However, the report urges crypto projects to begin transitioning to quantum-resistant algorithms now. Bitcoin's decentralized governance makes such upgrades difficult, while Ethereum's more agile development community could implement changes faster. Traders should watch for any protocol-level discussions or proposals addressing quantum resistance, as these could become key catalysts for relative performance between the two largest cryptocurrencies. The next major milestone will be the first real-world demonstration of a quantum attack on a blockchain, which would likely trigger a sharp repricing of risk across the entire crypto market.