The recent focus on quantum computing has highlighted potential risks to legacy blockchains, with Google suggesting that a powerful enough machine could exploit them with less effort than previously thought. For XRP holders, experts offer a nuanced view, suggesting that XRP's architecture may be better positioned to withstand these threats than Bitcoin's. XRP operates on the XRP Ledger, an open-source, decentralized blockchain used by Ripple for cross-border transactions.
Let's examine the details step by step. The primary concern with quantum computing is its potential to reverse-engineer private keys from exposed public keys, thereby draining funds. Typically, a public key is exposed when a transaction is sent, and the account activity, rather than the balance or the duration of holding an address, is what makes an account quantum-vulnerable.
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 whale 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 is only 0.03% of the circulating supply. The XRP Ledger's feature allowing for signing key rotation without moving funds provides an additional layer of security, although it may not be perfect and is not useful for dormant accounts that are no longer active.
Mayukha Vadari, a staff software engineer at Ripple, also pointed out the escrow feature as a defense against quantum risk, as funds locked in escrow with a time lock are safe due to logic rather than cryptography. In contrast, the quantum threat to Bitcoin appears more significant, with a larger portion of early bitcoin mined using a format that exposed public keys directly. Google estimates that about 6.9 million BTC are vulnerable, which is nearly 35% of Bitcoin's circulating supply. Bitcoin holders face a structural problem, as the blockchain lacks a key rotation feature, leaving them with no option but to move funds to a new address, which still exposes the old public key for a short time.
While Bitcoin developers have initiated proposals to develop quantum resistance, XRP's design and features may provide better protection against quantum computing threats.