XRP Ledger's Quantum Plan Adds 3.6 KB a Transaction, Not a Fee

The XRP Ledger Foundation has set out how accounts on the network could survive a working quantum computer, and who would carry the weight of it. An account would add a signing key built on ML-DSA-44, a post-quantum scheme the US National Institute of Standards and Technology approved in 2024, then disable the master key it signs with today. Key and signature together run to 3,732 bytes, against 105 bytes for the same fields in an ordinary payment. The base transaction fee does not change. CoinDesk filed the design at 04:51 UTC on Tuesday, from a Foundation quantum study attached to a roadmap updated on 4 November.

Turning the old key off is the hard part

Adding a quantum key is only half the migration. Every time an account signs a transaction it reveals a public key, CoinDesk said, and that exposure is where the design starts. Owners would add the new key and switch the old master key off without changing the address, which CoinDesk and crypto.news both describe. Accounts can already rotate a regular signing key, the one used day to day in place of the master key. Replacing one conventional key with another buys no protection, crypto.news said, and no second account this desk read makes that point.

Who absorbs 3.6 KB a transaction

Users would not pay for the extra bytes. Fees on the XRP Ledger are destroyed instead of collected, so the operators running the network take on the storage, CoinDesk said. A protected payment would occupy 5,331 bytes against a 1,704-byte baseline, a pair of figures all three accounts carry. CoinGape put it plainly: base fees stay the same despite the extra storage. crypto.news flagged larger transactions, bandwidth and long-term storage as questions for the migration study, neither of the other two accounts raises them, and none of the three gives a reserve cost for an account holder. One account alone breaks the 3,732 bytes into a 1,312-byte public key and a 2,420-byte signature.

Three budgets, one total

The amendment is costed at $215,000 to $255,000 plus 640 hours of development, and the three accounts do not agree on what sits inside that range. CoinDesk calls it review and auditing. CoinGape calls it technical reviews and security audits. crypto.news itemises it as $40,000 to $80,000 of Ripple review work, a $100,000 external security audit, a $50,000 reference implementation and $25,000 of wallet updates including Ledger hardware support, and it adds 400 hours of engineering review the other two do not mention. The totals match and the contents do not reconcile. Across all 24 amendments on the roadmap CoinDesk gives about $5 million to nearly $6 million; crypto.news gives $5.08 million to $5.74 million.

No number, no vote, and a bug in key generation

The proposal has no XLS number, the label an XRP Ledger standard carries once formally filed, and no account says it has gone to validators. Work is still under way, CoinDesk said. Developers are chasing a mismatch in which the Python prototype and the server and JavaScript versions can generate different keys from one starting seed, which all three accounts describe. Tests of the network with every validator running the new signatures have not been published. The amendment process is slow, as the ledger's own autumn shows: an earlier fix slipped to 4 November after validator support dipped for two hours.

A migration study comes in the first half of 2027, with development, review and auditing in late 2027 or 2028. The 2028 date attached to this work is Ripple's target for a full quantum transition, subject to testing and validator approval, and the bodies of all three accounts put it that way. One of the headlines hands 2028 to the proposal itself while its own body hands it to Ripple, so the two do not reconcile and this desk follows the body. Other networks are on their own clocks: Starknet put a post-quantum layer 1 to a research vote in October without naming a year. Nothing here is settled until validators adopt an amendment that does not yet have a number.