A draft XRP Ledger amendment would add quantum-resistant signatures across accounts and network operations, but its larger data footprint and manual migration requirements leave key design questions for a 2027 study.
The Foundation’s roadmap lists an unnumbered “Quantum” amendment. It selects ML-DSA-44, a parameter set in the Module-Lattice-Based Digital Signature Algorithm standard, FIPS 204. The National Institute of Standards and Technology (NIST) published the standard on Aug. 13, 2024. The proposal covers account transactions as well as validator manifests and validations, consensus proposals and peer handshakes.
The draft specifies a 1,312-byte public key and signatures of up to 2,420 bytes. The Foundation estimates that a protected payment would total 5,331 bytes when history and database overhead are included, compared with 1,704 bytes for an ordinary payment. Its study calculates 3,627 additional bytes per signed transaction against the conventional-payment baseline.
The proposal keeps the existing fee schedule. The Foundation says the added data may increase bandwidth use and the storage needed for transaction history; its migration study is expected to consider whether transaction size warrants a separate fee rule. The study identifies exchanges, custodians and issuers with large balances as an initial audience for the change.
Accounts would not convert on their own. Holders would need to rotate to a Dilithium key or transfer funds to a newly derived Dilithium account. The Foundation study warns that putting a post-quantum key in the regular-key slot would still leave the classical master key enabled, so account migration remains an open part of the work.
Ripple says account public keys become visible when owners sign transactions, which could create a future concern if quantum computers can break current cryptography. The company says that does not mean assets are at risk today and has set 2028 as its target for a full post-quantum transition.
The Foundation schedules a migration study for the first half of 2027, followed by development, review and audit work in late 2027 or 2028. Its estimate includes 640 build hours, 400 hours of Ripple review and $215,000 to $255,000 in costs. The amendment remains a draft and would require validator approval to activate.
