Quantum computing has been talked about for years as a possible danger to cryptocurrencies like Bitcoin. The main worry is that, one day, quantum computers could become powerful enough to break the cryptographic systems that protect digital currencies. In 2026, that concern is making a comeback as big tech companies increase their investments and progress in quantum technology.

While quantum computers are still not ready for everyday use, companies are making progress. For example, Microsoft recently introduced a new chip called “Majorana 1,” which uses a unique design known as Topological Core architecture. This has sparked fresh conversations about how soon quantum computing could start affecting real-world systems like blockchain networks.

Even with all the attention, most experts agree that the threat to cryptocurrencies from quantum computers is not immediate. The bigger issue is what hackers might be doing today to prepare for a future when quantum machines are ready. Some believe bad actors are already storing encrypted data, planning to crack it later when the technology becomes powerful enough.

Clark Alexander from Argentum AI believes that quantum computing will have very limited use in 2026. Nic Puckrin from Coin Bureau is even more skeptical, saying the idea that quantum computers will soon break Bitcoin is mostly hype and marketing. According to him, we’re likely at least ten years away from any real threat.

Right now, Bitcoin and other major blockchains use public-key cryptography to secure wallets and verify transactions. This system relies on private keys to sign transactions and public keys to confirm them. If a quantum computer could figure out private keys just by looking at public keys, it could potentially steal large amounts of crypto.

Some regulators are paying attention too. Last year, the U.S. Securities and Exchange Commission (SEC) received a warning that future quantum computers might be able to break Bitcoin’s encryption.

Experts say digital signatures are the weakest part of blockchain security in a quantum world. These signatures, especially the Elliptic Curve Digital Signature Algorithm (ECDSA), could be broken if a powerful enough quantum computer comes along. However, the SHA-256 hash functions used in Bitcoin are much harder to crack, even with quantum tech.

Another major vulnerability is when users reuse addresses. Once a public key is exposed on-chain, it becomes more vulnerable to future attacks using quantum machines.

Despite these concerns, it’s still extremely unlikely that quantum computers will be strong enough to break Bitcoin by 2026. That’s because current quantum devices are still far from having the capabilities needed. They only have a few hundred or thousand “qubits,” and they’re very noisy — meaning they make too many errors. To actually break cryptography, you’d need millions of high-quality qubits that can perform long sequences of operations without errors.

There are also big challenges in materials science and engineering that need to be solved before we get there. Some experts even believe that current approaches may never get us to a point where Bitcoin’s cryptography is at real risk.

Still, there’s another kind of threat happening right now: “harvest now, decrypt later.” Hackers may be downloading and storing encrypted data today with the hope that they can decrypt it in the future using quantum computers. This includes public blockchain data where public keys are already exposed.

An estimated 25%–30% of all Bitcoin — around 4 million BTC — may already be sitting in vulnerable addresses. These addresses have exposed public keys and could be targeted first once quantum machines become powerful enough.

To stay safer, users are advised not to reuse addresses and to keep their public keys hidden until they spend their funds. People should also get ready to move their crypto into wallets that use post-quantum cryptography when those become available.

The crypto world is already working on solutions. In mid-2023, researchers shared a plan to update Bitcoin’s signature system with quantum-resistant options. Around the same time, a company called Qastle announced tech that brings quantum-level security to hot wallets by using quantum-generated randomness and post-quantum encryption — all without needing extra hardware or complex setup.

So while there’s no need to panic about a quantum doomsday in 2026, awareness is growing. The question is no longer “if” quantum will impact crypto — it’s “when.”

Experts say the chances of a major quantum attack happening by 2026 are low to moderate. But there’s a high chance that by then, quantum threats will become a key focus in crypto security planning.