The emergence of quantum computing has sparked concerns about the potential risks it poses to legacy blockchains. Experts suggest that XRP's architecture may be better equipped 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 delve into the details.
The primary concern is that a powerful quantum computer could potentially reverse-engineer a private key from an exposed public key, allowing it to drain funds. Typically, a public key is exposed when a transaction is sent, and the account activity makes it vulnerable, not the balance or how long the address has been held. 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 signing key rotation feature can help mitigate this risk. This feature allows users to swap their signing key without moving funds, effectively changing the lock on their account without having to move. While this feature is available to everyone, the problem arises when people are not around to use it, making them vulnerable.
Another defense against quantum risk is the escrow feature, which locks funds with a time lock, making them safe due to logic rather than cryptography. In comparison, the quantum threat to Bitcoin appears more severe due to its sheer scale and the fact that a significant portion of early bitcoin was mined using a format that exposed public keys directly. Approximately 6.9 million BTC are vulnerable, which is nearly 35% of Bitcoin's circulating supply. Unlike XRP, Bitcoin's blockchain lacks a key rotation feature, leaving holders with only one option: moving funds to a new address, which still poses a risk during the transaction process.