Foreign media reports suggest that Bitcoin's primary risk from quantum computing may not just be the public private keys of wallets linked to addresses. CoinDesk, citing Andrew Gault, CEO of ZeroTier and an early investor in the quantum field, argues that a more pressing issue lies in the continuous transmission of encrypted authentication data between institutions. This data may have been collected by adversaries over a long period, awaiting decryption once quantum computing power matures.

The focus of risk shifts to data transmission

Gault argues that the most vulnerable part of the financial system is not statically stored data, but rather the authentication records, payment information, and digital signatures that are constantly flowing through the network. According to him, attackers don't necessarily need to understand this information now; they can simply store it at low cost and process it once quantum computing reaches a certain threshold.

This approach is commonly referred to in cryptography as "collect first, then decrypt." It targets not a single wallet, but a broader institutional communication layer, including exchange API authentication, cross-chain bridge proofs, signed transactions in public mempools, and back-end signed traffic between cold wallets and trading desks.

Google and Citi have already done scenario modeling.

In March of this year, Google's security team announced plans to complete its quantum cryptography migration by 2029. The team stated at the time that its insider threat model now places greater emphasis on authentication services and digital signatures, rather than just traditional data encryption.

Google also explicitly stated in its related article that "store first, decrypt later" is a threat that needs to be addressed. This aligns with Gault's assessment that the real priority for hardening is institutional-grade signature and authentication infrastructure.

In February of this year, Citigroup also simulated a similar scenario in the banking system. Its report estimated that if the system of one of the top five U.S. banks accessing Fedwire's funding services were to suffer a quantum attack, it could trigger a cascading shock of $2 trillion to $3.3 trillion in the U.S. economy.

There is no unified migration action in the crypto industry yet.

The report mentioned that a Google Quantum AI study that attracted market attention in March pointed out that if quantum computers are powerful enough, the private key of a Bitcoin address with an exposed public key could be derived in about 9 minutes. Since then, market discussions have focused on the exposed public key addresses corresponding to the approximately 6.9 million BTC on the Bitcoin blockchain, and the lack of a clear post-quantum migration scheme for Bitcoin.

But Gault believes this is only part of the problem. For the crypto industry, a greater exposure may lie in the communication layers of exchanges, custodians, and cross-chain infrastructure, because a large amount of signing and authentication activity does not occur directly in the user's wallet interface, but runs continuously in the background system.

• Google's goal: to complete quantum cryptography migration by 2029.
• Citigroup estimates the potential impact to be between $2 trillion and $3.3 trillion.
• GRI estimates that the probability of a quantum computer emerging before 2034 is between 19% and 34%.

The report also noted that Ethereum has initiated coordinated post-quantum migrations, while Bitcoin has not yet taken similar unified action. Most major cryptocurrency exchanges and custodians have not yet publicly committed to deploying the same level of post-quantum protection for such signature infrastructure.