XRPL Adopts Quantum-Safe Signatures

• The XRP Ledger has adopted CRYSTALS-Dilithium as its cryptography standard for digital signatures.
• Unlike the previously used elliptic curve cryptography, the new standard is not vulnerable to attacks from quantum computers.

Q-Day, which is the day when a quantum computer will be capable of breaking widely used public-key cryptography, is on the horizon. While there’s no consensus among experts on the timeline, the crypto world is bracing for a post-quantum world. The latest to upgrade to quantum-resistant standards is the XRP Ledger, which has now adopted a new cryptography standard.

AlphaNet, the network reserved for developers to test early features on the XRP Ledger, “has gone quantum,” announced XRPL Labs software engineer Denis Angell. The network’s consensus, accounts, and transactions are now fully quantum secure, he added.

XRPL has been relying on elliptic curve cryptography (ECC) to authenticate accounts and sign transactions. ECC is the most popular standard, with Bitcoin, Ethereum, Solana, Cardano, Polkadot, Avalanche, Stella,r and other major blockchains all reliant on it, but with varying implementations.

ECC has been impossible to breach with today’s classical computers. Its discrete logarithm maths problem is hard enough that a normal computer can’t recover a private key from a public key (or more simply, your public key can’t be reverse engineered to reveal your private key). However, quantum computers solve the challenge and can derive your private keys and even forge your digital signature.

XRPL Now Quantum Ready

XRPL will now run on CRYSTALS-Dillithium, a new digital signature scheme designed to withstand quantum attacks. While it signs transactions just as ECC would, it relies on lattice-based cryptography for which there’s no known workaround, even with the most powerful quantum computers.

While CRYSTALS-Dillithium makes XRPL quantum-secure, it comes at a cost. First, the keys and signatures will be much longer (nearly 40 times larger), resulting in higher bandwidth and storage costs. This also leads to blocks filling up quicker and nodes having to relay more data, which could end up in higher transaction fees. Transactions could also become slower, especially for a high-throughput chain like XRPL.

XRPL joins others like Algorand and Solana in testing post-quantum technology. Algorand implemented Falcon, yet another signature scheme relying on lattice-based cryptography. Most recently, Aptos proposed its first post-quantum digital signature scheme under the AIP-137 proposal, as CNF reported. The scheme, dubbed SLH-DSA-SHA2-128s, will be rolled out gradually, with users getting the option to either upgrade or rely on slower less secure schemes.

XRP trades at $1.84, gaining slightly in the past day, despite a 40% dip in trading volume.