The emergence of quantum computing has sparked concerns about the security of legacy blockchains, with Google warning that a powerful enough machine could compromise them with less effort than previously thought. For XRP holders, experts offer a more nuanced assessment, suggesting that XRP's architecture provides better protection against quantum threats than Bitcoin's.

This is because XRP operates on the XRP Ledger, an open-source, decentralized blockchain that facilitates cross-border transactions through Ripple, a fintech company. To understand the nature of this threat, it's essential to delve into the cryptographic features shared by major blockchains, including the use of private and public keys for transactions. A sufficiently powerful quantum computer running Shor's algorithm could theoretically reverse-engineer a private key from an exposed public key, allowing it to drain funds.

The exposure of public keys during transactions makes accounts quantum vulnerable, but not the balance or the duration for which an address has been held. Recently, a quantum vulnerability audit of the XRP Ledger found that approximately 300,000 XRP accounts, holding 2.4 billion XRP, have never sent funds and thus have never exposed their public keys to the network, making them quantum-safe by default.

However, dormant whale accounts that have transacted in the past and exposed their public keys are at risk, with two such accounts holding 21 million XRP identified. This represents only 0.03% of the circulating supply, significantly less than the estimated 35% of Bitcoin's supply that is vulnerable. The XRP Ledger's feature allowing for signing key rotation without moving funds provides an additional layer of protection, although its effectiveness depends on users being active enough to utilize it.

Another defense mechanism is the escrow feature with time locks, which protects funds logically rather than cryptographically, preventing withdrawal until a specified time has passed. While this protects the funds, the account itself remains vulnerable to quantum risks.

In comparison, Bitcoin's exposure to quantum threats appears more significant due to its larger scale and the use of formats like P2PK, which directly exposes public keys. Approximately 6.9 million BTC are estimated to be vulnerable, including Satoshi Nakamoto's 1 million BTC, which has never been moved. The lack of a key rotation feature in Bitcoin means holders must move funds to a new address to protect them, but this process temporarily exposes the public key, creating a window of vulnerability.

Although the risk is still theoretical, it highlights the relative structural vulnerability of Bitcoin holders compared to those of XRP.