Ripple maps XRPL quantum-security transition through 2028

Ripple is moving ahead with a four-phase programme to prepare the XRP Ledger for post-quantum cryptography, targeting a transition to quantum-resistant signatures by 2028 while testing security mechanisms before a large-scale quantum threat becomes practical.

The roadmap, set out by Ripple in April and detailed by its engineering team, is designed to protect accounts and transactions if powerful quantum computers eventually become capable of breaking the elliptic-curve cryptography now used across blockchain networks. Ripple says the work is being treated as a multi-year infrastructure migration rather than one software patch.

Ayo Akinyele, Ripple’s senior director of engineering, said the objective was to ensure financial infrastructure could evolve before quantum computing becomes an immediate threat, without disrupting the assets, applications and users that depend on the ledger.

The first phase centres on emergency preparedness for what researchers often call “Q-Day”, the point at which quantum machines could compromise public-key cryptography. Ripple is exploring a contingency mechanism that would stop acceptance of vulnerable classical signatures and provide a secure route for account holders to move funds to post-quantum accounts.

One approach under study would use post-quantum zero-knowledge proofs to allow users to demonstrate control of existing keys without exposing those keys during a migration. Ripple has stressed that this remains exploratory work rather than a deployed capability.

The second phase covers risk assessment and experimentation with post-quantum algorithms recommended or standardised by the US National Institute of Standards and Technology. Engineers are evaluating how larger keys and signatures could affect transaction throughput, storage, bandwidth and verification costs on XRPL.

Ripple is also working with post-quantum security company Project Eleven on validator testing, Devnet benchmarking, hybrid signing and a prototype custody wallet. Project Eleven said the collaboration includes an audit of validator, custody, networking and wallet layers, followed by testing of security systems that combine existing and quantum-resistant cryptography.

The third phase is intended to place candidate post-quantum signature schemes alongside current elliptic-curve signatures on development networks, allowing application developers and infrastructure operators to test the two approaches in parallel. Ripple is also examining quantum-resistant cryptographic primitives for zero-knowledge proofs and homomorphic encryption, areas that could affect privacy and compliance features.

The fourth phase, targeted for completion no later than 2028, would involve designing, building and proposing an XRPL amendment for native post-quantum signatures. Any production transition would depend on the ledger’s amendment process and coordination across its independent validator community, rather than a unilateral switch by Ripple.

XRPL currently supports secp256k1 and Ed25519 signing algorithms. Its account architecture also allows key rotation without requiring a user to abandon the underlying account, a feature Ripple argues could reduce disruption during a future cryptographic migration. Seed-based key generation provides another mechanism for deriving new key material as standards change.

Those features do not themselves make XRPL quantum-resistant. The ledger’s documentation states that sufficiently capable quantum computers running algorithms such as Shor’s could threaten elliptic-curve cryptography, while some XRPL cryptographic features, including confidential-transfer designs based on EC-ElGamal over secp256k1, are also not considered quantum-safe.

The cryptography industry has already begun shifting towards post-quantum standards. NIST finalised three principal post-quantum cryptography standards in 2024, including ML-DSA and SLH-DSA for digital signatures, and has urged organisations to begin migration planning because replacing vulnerable public-key systems can take years.

Ripple’s programme is therefore focused on cryptographic agility rather than selecting one permanent algorithm. The company says it intends to support multiple standardised approaches where appropriate, allowing the ledger to adapt as post-quantum research, implementation experience and performance requirements develop.

Performance remains a central constraint. Post-quantum signatures can be substantially larger than the signatures used by existing blockchain systems, creating potential costs for network bandwidth, ledger storage and transaction processing. Ripple’s testing programme is intended to measure those trade-offs under XRPL workloads before any mainnet proposal is advanced.

Project Eleven’s work is expected to produce working code and performance data that can inform that process. Ripple has not said that XRP holdings face an immediate quantum attack, and its roadmap assumes a staged transition unless cryptographic advances force an emergency response.