The countdown to a potential existential crisis for cryptocurrencies has already begun and it’s being led by quantum computing. As this revolutionary technology advances, experts warn that the cryptographic foundations securing digital currencies like Bitcoin and Ethereum could soon be rendered obsolete, possibly as early as 2027. This means that whoever controls a powerful quantum computer could decrypt private keys, impersonate wallet owners, and manipulate blockchain transactions. This can effectively destroy trust in the entire crypto ecosystem.
Many industry experts are taking the threat seriously. Google and IBM are racing toward quantum supremacy, while research labs across the world are rapidly increasing qubit counts. In 2019, Google’s Sycamore processor performed a task in 200 seconds that would have taken the fastest supercomputer 10,000 years. If this trajectory continues, experts estimate a quantum computer capable of cracking 256-bit encryption could emerge before 2027.
“The consensus seems to be 2035 but you can’t rule out breakthroughs. The directive for most organisations dealing with sensitive data is to ensure they move to PQC by 2030. 2027 seems a bit too optimistic. On Bitcoin, the only challenge will be with wallets that won’t / can’t move their bitcoins. Even with support for PQC, ancient wallets where the owner has forgotten the key, could be taken over,” says Sumit Dhar, former India Head of Resilience & Global Resilience Partner at Barclays.The Quantum Threat: How Superfast Computing May Destroy Cryptocurrencies
Cryptocurrencies rely on public-key cryptography, a mathematical system designed to make digital transactions secure and irreversible. It’s based on complex algorithms that would take classical computers millions of years to break. A fully functional quantum computer with sufficient qubits could break the elliptic curve encryption used by Bitcoin in minutes. What classical systems consider unbreakable, quantum machines can reduce to a routine calculation.
“I don’t agree with this view because it does not account for improvements in implementations that are underway. What this tells you is that the Cryptography that is in place today (for example RSA 1024/2048) will be vulnerable to breaches and compromise. However, the new guidelines that are being adopted raise the effort required to break these algorithms come 2027. For example, the new guideline is to use RSA 4096 which can’t be broken. The quantum power right now is around 40 Qubits which will increase to 2000 qubits by 2028. This is not sufficient to break RSA 4096 and other PQC’s. However, this could happen if new algorithms are not adopted,” says Hilal Ahmad Lone, CISO at Liminal Custody.
Quantum can process information exponentially faster than conventional machines
Quantum computers, powered by quantum bits (qubits), can process information exponentially faster than conventional machines. This allows them to solve the very equations that make cryptocurrency wallets and blockchain signatures secure in a matter of seconds. Top researchers say Bitcoin’s security could be broken in a matter of two years. They say it would not be due to price or regulation but due to physics.
“There is still a lingering question on interoperability. Advancements will continue on the quantum side, meanwhile, algorithm changes will also work in tandem,” says Sriram L, cybersecurity leader at one of India’s largest companies.
Crypto industry needs to reinvent security infrastructure now
However, it’s not all doom and gloom. Developers are already exploring post-quantum cryptography, which uses quantum-resistant algorithms to secure digital assets. Projects like Ethereum 3.0 and new-generation blockchains are experimenting with these encryption methods to future-proof their ecosystems.
Still, the window for transition is narrow. If quantum technology advances faster than anticipated, billions of dollars’ worth of digital assets could be at risk overnight. The crypto industry has to reinvent its security infrastructure now, not later. Quantum computing won’t wait for blockchain to catch up. By 2027, the battle between quantum innovation and digital decentralization may decide whether cryptocurrencies survive as secure assets or vanish as relics of a pre-quantum world.
