Catenaa, Tuesday, May 19, 2026- Citigroup researchers warned that Bitcoin may face greater long-term risks from quantum computing than Ethereum because of the cryptocurrency’s slower governance structure and difficulties implementing major protocol changes.
In a new research report, Citi analysts said advances in quantum computing are shortening the timeline for practical attacks on blockchain encryption systems, with some estimates now placing potential threats between 2030 and 2032.
The bank said Bitcoin’s design leaves transactions temporarily vulnerable because public keys become exposed during transaction broadcasting before confirmation.
Researchers cited recent work from Google suggesting that future quantum computers with roughly 500,000 qubits could theoretically break current cryptographic protections within minutes.
While such machines do not yet exist, analysts said technological progress is accelerating faster than previously expected.
Citi argued Bitcoin’s biggest weakness may not be technical but organizational.
Transitioning Bitcoin toward quantum-resistant cryptography would likely require broad community consensus, extensive testing and a potential hard fork, a process historically difficult within Bitcoin’s conservative governance model.
Ethereum and several proof-of-stake blockchains were described as more adaptable because of their history of frequent network upgrades and more flexible governance systems.
Still, Citi warned those networks also face risks if quantum attackers eventually gain access to enough validator private keys to disrupt network operations.
The report highlighted another major concern involving dormant Bitcoin wallets.
Analysts estimated roughly 6.7 million to 7 million bitcoin remain stored in older wallets where public keys are already exposed, making them especially vulnerable to future quantum attacks.
That includes approximately one million bitcoin widely believed to belong to Satoshi Nakamoto.
The dormant holdings are currently valued at more than $80 billion.
Citi said proposed Bitcoin upgrades including BIP-360 and BIP-361 may become increasingly important as the industry prepares for post-quantum cryptography.
