Ripple publishes a four-phase post-quantum roadmap for the XRP Ledger, targeting full readiness by 2028. source
1 Signature scheme 0/10, weighted 30%
Mainnet transactions are signed with secp256k1 or Ed25519 and nothing post-quantum protects live XRP. ML-DSA has been deployed on AlphaNet, which is a pre-Devnet test network, so no post-quantum signature guards funds on the public ledger. source