The recent focus on quantum computing, sparked by Google's claims that a powerful machine could exploit legacy blockchains with less effort than previously thought, has raised concerns among cryptocurrency holders. For XRP, experts suggest that its architecture provides better protection against quantum 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 it down.
The primary threat to blockchains comes from the potential for a sufficiently powerful quantum computer to reverse-engineer private keys from exposed public keys, allowing attackers to drain funds. Typically, public keys are exposed when sending transactions, making account activity a factor in quantum vulnerability.
Recently, a quantum vulnerability audit of the XRP Ledger found that around 300,000 accounts holding 2.4 billion XRP have never sent funds and are therefore quantum-safe by default. However, dormant whale accounts that have transacted in the past and exposed their public keys are at risk. The audit found two such accounts holding 21 million XRP, which is only 0.03% of the circulating supply.
The XRP Ledger's account-based system and key rotation feature allow users to swap signing keys without moving funds, providing an additional layer of protection. Mayukha Vadari, a staff software engineer at Ripple, also pointed to 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 comparison, the quantum threat to Bitcoin appears more significant due to the large portion of early bitcoin mined using the P2PK format, which exposed public keys directly. Google estimates that about 6.9 million BTC are vulnerable, equating to nearly 35% of bitcoin's circulating supply. Bitcoin's lack of a key rotation feature leaves holders with only one option: moving funds to a new address, which exposes the old address's public key to potential quantum attacks.