The recent focus on quantum computing, fueled by Google's claims that a powerful enough machine could breach legacy blockchains more easily than anticipated, has sparked concern among cryptocurrency holders. For XRP, experts suggest its architecture may offer better protection against such threats than Bitcoin's. XRP operates on the XRP Ledger, an open-source, decentralized blockchain used by fintech firm Ripple for cross-border transactions. Let's break down the details.
The primary threat to blockchains from quantum computers lies in their ability to potentially reverse-engineer private keys from public keys, thus allowing unauthorized access to funds. Typically, a user's public key is exposed when they send a transaction, making their account activity a factor in quantum vulnerability, rather than their balance or how long they've held an address.
A recent audit of the XRP Ledger found that around 300,000 accounts, holding 2.4 billion XRP, have never sent funds and are thus quantum-safe by default. However, dormant accounts that have transacted in the past and exposed their public keys are at risk. The audit identified two such accounts holding 21 million XRP, which, although significant, represents only 0.03% of the circulating supply. The XRP Ledger's feature allowing for the rotation of signing keys without moving funds provides an additional layer of protection.
This means users can change their account's 'lock' without having to move their funds, keeping them safe from potential quantum attacks. Mayukha Vadari, a staff software engineer at Ripple, also pointed out the 'escrow feature' as a defense mechanism, where funds locked with a time lock are safe due to logical rather than cryptographic reasons.
While this protects the funds, the account itself remains vulnerable to quantum risks. In comparison, Bitcoin's exposure to quantum threats appears more significant.
A substantial portion of early bitcoin, including Satoshi Nakamoto's 1 million BTC, was mined using a format that directly exposed public keys, making them vulnerable to quantum attacks. Google estimates about 6.9 million BTC, or nearly 35% of bitcoin's circulating supply, is at risk. Unlike XRP, Bitcoin lacks a key rotation feature, forcing holders to move funds to a new address to protect them, which temporarily exposes the old address's public key to potential quantum exploitation.
Although this risk is still theoretical, and Bitcoin developers are working on quantum resistance proposals, XRP's design and features may offer its holders an advantage in terms of protection against quantum computer threats.