The rise of quantum computing has sparked concerns about the potential risks it poses to blockchain security. Experts suggest that XRP's architecture may be more resilient to these threats than Bitcoin's. XRP operates on the XRP Ledger, a decentralized, open-source blockchain that facilitates cross-border transactions through the fintech firm Ripple.
A key difference between XRP and Bitcoin lies in their exposure to quantum vulnerability. All major blockchains rely on cryptographic features, including private keys and public keys derived from them, which can be used to sign transactions. However, a powerful enough quantum computer using Shor's algorithm could theoretically reverse-engineer a private key from an exposed public key, allowing an attacker to drain funds.
Typically, a public key is exposed when a transaction is sent, making accounts that have sent funds more vulnerable to quantum attacks. A recent 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.
In contrast, dormant whale accounts that have transacted in the past and exposed their public keys are more vulnerable. The audit identified 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, which allows users to swap their signing key without moving funds, provide additional protection.
However, this feature is not foolproof, and dormant accounts that are not actively managed may still be vulnerable. Another defense against quantum risk is the escrow feature, which locks funds with a time lock, preventing withdrawal until a specified time has passed. While this protects the funds, the account that locked them can still carry quantum risks. In comparison, the quantum threat to Bitcoin appears more significant due to the sheer scale of vulnerable coins.
A significant portion of early bitcoin was mined using a format that exposed public keys directly, making them more susceptible to quantum attacks. Approximately 6.9 million BTC, or nearly 35% of Bitcoin's circulating supply, are vulnerable, compared to XRP's 0.03%. Bitcoin's lack of a key rotation feature also leaves holders with limited options to protect themselves, making them more structurally vulnerable to quantum attacks.