Google recently crossed a technological boundary that has puzzled scientists for decades—a boundary that is theoretically feasible but has long been difficult to reach in practice. On February 9, 2026, Google's quantum team successfully demonstrated quantum error correction technology below a threshold. The core significance of this achievement is that increasing the number of qubits in a quantum system not only does not increase the error rate but actually reduces it. On the surface, this may seem like just an internal engineering milestone for Google, but its impact extends far beyond the company itself, especially to the cryptocurrency field.

This breakthrough is crucial for Bitcoin and Ethereum holders because the entire security model of cryptocurrencies is built on a core assumption: certain mathematical problems are unsolvable within any reasonable timeframe. Quantum computers are designed to break this assumption. The most critical question now is how far are quantum computers from truly achieving this goal?

Objectively speaking, the answer is: closer to the goal than last year, but not yet at a level that warrants panic. Next, we will break down this issue from a rational perspective, clarifying the true impact of Google's quantum breakthrough and how to respond.

What is the true significance of Google's quantum chip for cryptocurrencies and Bitcoin?

We can compare a Bitcoin wallet to a 78-bit combination lock; even using a traditional computer to brute-force it would take far longer than the age of the universe. This is not an exaggeration, but a conclusion drawn from rigorous mathematical calculations.

Unlike traditional computers, quantum computers do not use brute-force methods, but rather solve problems that traditional computers cannot overcome through specific mathematical methods. For Bitcoin, the core security vulnerability lies in the ECDSA algorithm—this algorithm verifies a user's ownership of their Bitcoin holdings when they send a transaction.

The specific threat logic is that when a user sends a Bitcoin transaction, their public key is broadcast to the entire blockchain network. Theoretically, a sufficiently powerful quantum computer capable of running Shor's algorithm could completely reverse-engineer this public key to deduce the user's private key, thereby accessing the Bitcoin in the corresponding address.

Google's milestone is significant because it paves the way for the realization of fault-tolerant quantum computers. Although Google has not yet finalized a fault-tolerant quantum computer, this breakthrough proves that the technological path to achieving this goal is feasible.

This development has also given rise to a threat pattern known as "harvest-then-decrypt": experienced attackers can immediately record and store all transaction data on the blockchain, patiently waiting for quantum hardware to develop to a level sufficient to crack the private key. It's worth noting that those old, leaked public keys have already been archived and could become targets at any time.

However, some alarmist claims are unfounded. Quantum computers used in cryptography require thousands of stable, error-correcting logical qubits. Currently, even the most advanced quantum systems globally can only achieve stable operation with a handful of logical qubits. Most cryptographers generally believe that quantum computers will pose a substantial threat to cryptocurrencies within the next 10 to 20 years.

However, it must be clear that structural risks are real and increasingly severe. "Harvest-then-decrypt" attacks are not merely theoretical; they have already occurred.

It's important to note that not all cryptocurrency wallets face the same risks. For Bitcoin, addresses that have never sent transactions have their public keys never broadcast to the network, thus posing no risk of being cracked by quantum computers. Once a user sends the first transaction, the quantum threat clock officially begins. Furthermore, address reuse, a security vulnerability unique to Bitcoin, further amplifies the risk.

In contrast, Ethereum faces higher structural risks. According to Ethereum's design mechanism, after a user completes their first transaction, their public key is permanently stored on the blockchain—all Ethereum addresses that have ever sent transactions are exposed to public keys; this is Ethereum's default state.

Given this situation, the most honest stance is simple: the immediate risk is low, but structural risks are real and growing. The best time to prepare is before quantum hardware truly matures.

The Cryptocurrency Community Has Not Ignored This

In 2024, the National Institute of Standards and Technology (NIST) finalized its first batch of post-quantum cryptography standards: CRYSTALS-Dilithium for digital signatures and CRYSTALS-Kyber for key encapsulation. These standards will become the targets for the eventual migration of financial infrastructure, including cryptographic protocols.

In the cryptocurrency field, Ethereum's development path is relatively more flexible. Its account abstraction function provides a viable upgrade path for replacing signature schemes as quantum hardware matures.

Bitcoin's upgrade path, however, is much more difficult. To achieve post-quantum cryptography adaptation, Bitcoin needs a hard fork, and every node and user wallet in the network must make corresponding adjustments. Bitcoin's governance mechanism was designed for slow, gradual implementation. While this characteristic is beneficial for maintaining decentralization, it also presents significant challenges to coordinating network-wide upgrades. Currently, discussions have begun, but formal upgrade work has not yet started.

Currently Available Cost-Free Measures

It's important to clarify that no emergency action is needed today, but cultivating some cost-free good habits may provide significant security benefits in the future.

First, stop reusing Bitcoin addresses. Each transaction sent from the same Bitcoin address exposes that address's public key again, increasing the risk of quantum attacks. Most modern Bitcoin wallets automatically generate new addresses; users are advised to ensure their wallets have this feature enabled.

Second, transfer funds stored in old transaction addresses. If Bitcoin is stored in old addresses where transactions have been sent, it's recommended to move it to a new address where no transactions have been sent, thus resetting the transaction history and reducing the risk of public key exposure.

Third, closely monitor PQC compatibility announcements. As post-quantum cryptography standards are gradually applied to various financial infrastructures between 2026 and 2027, it is recommended to prioritize wallets and exchanges that have already achieved PQC compatibility.

Fourth, do not neglect long-term inactive wallets. Old wallets with exposed public keys and large balances will become prime targets for attackers when quantum hardware matures. Transferring funds from these inactive wallets to new addresses is a reasonable and necessary long-term security strategy.

In conclusion, this is not a panic warning, but routine security maintenance. Just as you wouldn't use a ten-year-old password for an important account indefinitely, the security maintenance of Bitcoin addresses should not be considered optional indefinitely.