Crypto Under Quantum Threat: Experts Warn of Looming Danger

A commissioned report by Coinbase's advisory board, comprising renowned cryptographers and academics, signals a pressing yet cautious warning: while quantum computing does not currently pose an immediate threat to cryptocurrency, the industry must start preparing for the potential dangers that quantum computing could pose in the future. The 50-page document, authored by experts including Dan Boneh of Stanford University, Justin Drake of the Ethereum Foundation, and Sreeram Kannan of Eigen Labs, asserts that although current blockchains are secure, the advent of a fault-tolerant quantum computer capable of breaking commonly used encryption methods is becoming increasingly plausible. Recent months have seen heightened concerns regarding quantum risk, with Google researchers suggesting that a sufficiently advanced quantum computer could potentially break Bitcoin's cryptography. In response, major cryptocurrency ecosystems have begun outlining their strategies, with the Ethereum Foundation proposing new digital signature types designed to be quantum-resistant and Solana experimenting with wallet designs that can withstand quantum computing threats. The report underscores that current quantum machines lack the power to compromise the cryptography underlying Bitcoin, Ethereum, and other networks, as breaking standard encryption would require significant computational resources, a milestone still considered a substantial engineering challenge. Nonetheless, the authors advise against complacency, stating that the construction of a large-scale, fault-tolerant quantum computer is inevitable, although the timeline remains uncertain. This uncertainty poses a problem, with estimates ranging from a few years to over a decade, and no reliable means to predict breakthroughs. The U.S. National Institute of Standards and Technology recommends transitioning to quantum-resistant cryptography by 2035, a timeline that the report suggests may prove overly optimistic. The report cautions that waiting until the situation becomes urgent is not advisable, emphasizing that secure transitions across blockchains, wallets, and exchanges could take years to execute safely. Certain assets may be more vulnerable than others; for instance, Bitcoin wallets that have already revealed their public keys could be targeted, whereas those protected by hash functions may be safer in the short term. Fortunately, quantum-resistant cryptography already exists and is being standardized by NIST. However, the transition will not be straightforward, as post-quantum digital signatures can be significantly larger than current ones, potentially increasing blockchain data costs and reducing throughput. The report estimates that replacing current signatures with quantum-proof alternatives could expand block sizes by up to 38 times. Additionally, there are usability challenges, including the migration of millions of wallets and deciding the fate of lost or inactive funds that never upgrade. Instead of a single solution, the report outlines multiple transition strategies, including hybrid systems that combine existing cryptography with post-quantum updates or allow a gradual switch when needed. For the time being, the authors recommend flexible approaches that avoid compromising current security or performance while enabling rapid upgrades later. The report concludes that the time to start preparing for the quantum threat is now.