Quantum-Ready Blockchains Compared, Part 2: Born Safe — QRL and the Cost of Going First

Disclosure: I hold CKB. This series presents information, not recommendations, and nothing in it is investment advice. Previously: Part 1 showed that a quantum computer can attack four different parts of a blockchain, and that "quantum-ready" claims usually cover only one. It set out five tests and a seven-rung readiness ladder that every chain in this series is measured against. Most of this series is about chains trying to become quantum-safe. This part is about the one that started that way. QRL, short for Quantum Resistant Ledger , launched its main network in June 2018. From its first block, every account on it has been protected by a signature scheme that a quantum computer cannot break. It has no exposed addresses to worry about and no migration to organize. On the readiness ladder from Part 1, its current chain sits alone on the top rung. That is a genuine achievement, and it is worth understanding properly. It is also worth understanding what it cost, because QRL is the clearest real-world test of a question every other chain in this series faces: what do you give up by putting quantum safety first? The short version: QRL solved the cryptography years before anyone else, and has spent those years paying for it in convenience, signature size and scale. What QRL is QRL is a standalone blockchain with its own token, also called QRL. Its original network, which the project now calls QRL 1.x, is secured by proof-of-work mining. Every account signs transactions with XMSS (eXtended Merkle Signature Scheme) , a hash-based signature scheme. The launch code was audited in 2018 by two security firms, Red4Sec and X41 D-Sec. XMSS was not a fringe choice. It is one of the most conservative signature designs available, because its security rests only on hash functions, the same kind of building block that already protects mining on Bitcoin and Nervos. NIST (the U.S. National Institute of Standards and Technology) later approved XMSS in its Special Publication 800-208. In…