An XRPL Foundation contributor has proposed 2027 hybrid testing and a 2028 mainnet transition target.No official XRPL roadmap currently confirms the contributor’s proposed 2028 quantum-readiness deadline for mainnet deployment.XRPL currently supports secp256k1 and Ed25519 signatures, both exposed to sufficiently capable quantum computers someday.Existing RegularKey functionality allows XRPL accounts to change signing keys while retaining their public addresses.Ethereum researcher Justin Drake expects Ethereum’s three cryptographic layers to become post-quantum secure by 2029.