Ripple is working to prepare the XRP Ledger for the eventual arrival of quantum computers capable of breaking the cryptography that secures blockchains, a moment the industry has nicknamed "Q-Day," according to a CoinDesk report published this week.
The report situates Ripple's effort inside a wider, industry-wide scramble. CoinDesk notes that an Anthropic model reduced the work required to break a leading post-quantum signature candidate by a factor of 67 million last month, and that both Bitcoin and Ethereum published their own migration plans during the same week. Taken together, those developments have pushed quantum readiness from a long-horizon research topic toward a live engineering priority for major networks.
Separately, Bitcoin.com reported that a quantum-resistant bitcoin transaction using a method developed by StarkWare researcher Avihu Levy, referred to as QSB, has been mined on Bitcoin's mainnet without requiring a soft fork. That detail matters because protocol-level changes to Bitcoin normally demand broad social and technical consensus, a process that can take years. A technique that can be used within the existing rule set, rather than through a consensus change, offers one possible path for users who want quantum-hardened protections sooner.
Some background helps explain why these stories are landing at once. Most public blockchains, including Bitcoin, Ethereum and the XRP Ledger, rely on elliptic-curve digital signatures to prove that a spender controls a given address. Elliptic-curve cryptography is considered secure against classical computers, but it is theoretically vulnerable to a sufficiently large, error-corrected quantum computer running Shor's algorithm, which could in principle derive a private key from a public key. No machine known to exist today is close to that capability, and estimates of when one might appear vary widely among researchers.
The concern is less about tomorrow than about lead times. Blockchain networks cannot simply push a mandatory security patch; changes to signature schemes typically require coordinated upgrades, wallet and exchange support, and in many cases user action to move funds to new address types. Coins sitting in addresses whose public keys are already exposed on-chain are frequently cited as the most sensitive category, since an attacker with a future quantum machine would not need to wait for a new transaction to see the key. Because migration could take years, developers argue that planning has to begin well before any credible threat materializes.
Standards bodies have been moving in parallel. Post-quantum signature and key-encapsulation algorithms have been standardized in recent years for general computing use, and blockchain projects have been evaluating how to adapt them to environments where signature size, verification cost and block space are tightly constrained. Post-quantum signatures are generally larger than the elliptic-curve signatures in use today, which creates trade-offs around fees, throughput and node storage that each network must weigh differently.
The CoinDesk item about an Anthropic model cutting the effort needed to attack a candidate post-quantum scheme also underscores a subtler point: the replacements themselves are still being stress-tested. Cryptographic candidates are routinely probed by academics and, increasingly, by automated tools, and some are weakened or withdrawn during that process. That is a normal part of standardization, but it complicates the choice facing blockchain developers, who must pick schemes durable enough to outlast a multi-year migration.
For now, the practical takeaway from this week's reporting is procedural rather than dramatic. Ripple is drafting a plan for the XRP Ledger, Bitcoin and Ethereum contributors have published migration outlines, and at least one quantum-resistant transaction technique has been demonstrated on Bitcoin mainnet. None of this indicates that existing funds are currently at risk, and none of it points to any particular market outcome.
This is a news summary for general information only — not financial advice, and nothing here is a recommendation to buy, sell, or hold any asset. Always verify against the original source and do your own research before making a financial decision.
Source: CoinDesk · 2026-08-30
