Ripple Prepares XRP Ledger for Quantum Threats Before ‘Q-Day’

Ripple is preparing the XRP Ledger for the “Q-Day” scenario, the point when quantum computers become powerful enough to threaten the digital signatures protecting wallets and blockchain transactions. The plan announced by Ripple in 2026 sets a target to bring XRPL to post-quantum readiness before 2028, as the broader crypto industry accelerates preparations for new cryptographic risks following NIST standards and new research from Google Quantum AI.

Ripple’s Post-Quantum Roadmap

Ripple announced its post-quantum readiness roadmap for the XRP Ledger on April 20, 2026, aiming to bring the network into a state of “full readiness” no later than 2028. The company describes this not as a single algorithm swap, but as an upgrade process involving performance, storage, usability, cryptography, and protocol design.

This plan aims to help financial infrastructure adapt before quantum computing becomes a direct threat, rather than waiting until a transition could disrupt XRPL systems, assets, and users, Ayo Akinyele, senior director of engineering at Ripple, told CoinDesk.

Ripple’s roadmap consists of four main phases:

• Quantum-Day readiness: preparing contingency response plans if quantum computing presents risks earlier than anticipated, including mechanisms to move assets to more secure accounts.
• H1 2026 testing: evaluating risks on XRPL and testing post-quantum algorithms, focusing on performance, storage, bandwidth, and verification costs.
• H2 2026 hybrid rollout: introducing post-quantum signatures to Devnet under a hybrid model, running in parallel with current elliptic-curve signatures for developers to test.
• 2028 full transition target: proposing an amendment to support native post-quantum signatures, then expanding into a network-wide transition process.

According to Project Eleven, this collaboration includes evaluating XRPL’s validator, custody, networking, and wallet layers, deploying hybrid signatures, benchmarking on Devnet, and building custody wallet prototypes supporting post-quantum security.

Q-Day Puts Exposed Public Keys at Risk

“Q-Day” is how researchers refer to the point when quantum computers are powerful enough to break the cryptographic algorithms protecting many today’s digital systems. For blockchains, the vulnerable point lies in digital signatures and public keys, not the ability to “break the entire blockchain” in a generic sense. Many major networks still rely on elliptic-curve cryptography to verify transactions; the XRP Ledger specifically currently supports keys based on secp256k1 and Ed25519.

When an account signs a transaction, that account’s public key can appear on-chain. If a cryptographically relevant quantum computer emerges, an attacker could theoretically use that public key to derive the private key and gain control of the assets. Therefore, accounts that have previously sent transactions are typically more vulnerable than accounts that have only received assets, while accounts holding long-term value represent the group that needs early migration preparation.

Research published by Google Quantum AI in March 2026 has made this discussion more urgent. Google estimates that an attack on the “elliptic-curve discrete logarithm” on secp256k1, the foundational problem protecting many blockchain signatures today, could require no more than 1,200 logical qubits and 90 million Toffoli gates, or no more than 1,450 logical qubits and 70 million Toffoli gates. Under a given hardware model, this figure could correspond to under 500,000 physical qubits, significantly lower than many previous estimates.

Google’s estimates do not create an immediate operational risk for major blockchains, but they make it difficult for migration plans to be postponed indefinitely. For networks with millions of users involving numerous wallets, exchanges, validators, and custody providers, cryptographic transition is a multi-year process, not a reaction of a few weeks.

The Industry Is Moving Toward Post-Quantum Standards

Ripple is not the only organization preparing for the post-quantum era. On August 13, 2024, the U.S. National Institute of Standards and Technology (NIST) approved the first three post-quantum cryptography standards: FIPS 203 for ML-KEM, FIPS 204 for ML-DSA, and FIPS 205 for SLH-DSA. Among them, ML-DSA and SLH-DSA are two digital signature standards directly relevant to protecting transactions, wallets, and digital identities.

Ethereum has also incorporated post-quantum cryptography into its official security roadmap, with a dedicated post-quantum research team at the Ethereum Foundation and the Lean Ethereum roadmap targeting around 2029 for core infrastructure protection. Bitcoin also has proposals such as BIP-360 and BIP-361 regarding quantum-resistant addresses and signatures, although there is no official transition schedule yet.

AI-assisted cryptanalysis is also emerging in discussions on post-quantum security. In July 2026, Anthropic reported that Claude Mythos Preview took approximately 60 hours and an estimated $100,000 in API costs to find a better attack vector against HAWK, a post-quantum signature candidate in NIST’s additional evaluation process. This finding reduced the difficulty of HAWK-256 from roughly 2^64 to 2^38, equivalent to a reduction of about 67 million times, but it does not affect NIST’s finalized standards.

What Makes XRPL’s Migration Different

XRPL has an inherent advantage in its account design: users can change the key controlling an account without needing to change the account itself. The regular key mechanism and key rotation allow the separation of an account address from the key pair used to sign transactions—a feature that could make the transition to new signatures less complex compared to forcing users to migrate entirely to a different address.

However, this advantage does not mean XRPL is already “quantum-proof.” Ripple still needs to prove that new algorithms can operate stably on the network—ranging from signature size, verification costs, and data storage to the impact on wallets, exchanges, and custody providers. For a blockchain used for fast payments and settlement, a ledger closing time of just a few seconds means every change at the signature layer must be thoroughly tested before being deployed to the mainnet.

Part of the challenge lies in how XRPL implements protocol changes. Amendments must be approved by validators and the surrounding infrastructure ecosystem before becoming part of the mainnet. As a result, Ripple’s post-quantum roadmap depends not only on the chosen algorithm, but also on the speed with which wallets, exchanges, custody providers, and node operators prepare for the transition.