Quantum computers are unlikely to cause an immediate "collapse" of cryptocurrencies in 2026, but discussions around the threat have intensified as investments in quantum research grow. The focus is less on instantly breaking the blockchain and more on the practice of accumulating encrypted data today for future decryption.
Quantum Computers and Threats to Cryptocurrencies
Why quantum machines are considered dangerous: cryptocurrencies rely fundamentally on public-private cryptography, and theoretically, a quantum algorithm could recover a private key from a public one. However, most experts note that the practical danger in 2026 remains theoretical rather than immediate.
Interest in quantum hardware development surged after Microsoft unveiled the Majorana 1 chip in February, which the company described as the "world's first quantum chip" with a new architecture. This event revived debates about when lab breakthroughs will transition into operational use.
Expert opinions on the 2026 threat vary: Clark Alexander expects "extremely limited commercial application" of quantum tech in 2026, while Nic Puckrin calls the Bitcoin threat narrative "90% marketing and 10% real threat," emphasizing that practical cryptography breaches are likely still far off.
Cryptocurrency Vulnerabilities to Quantum Attacks
How keys work: in blockchain, the private key signs transactions, the public key verifies them, and hash functions protect the ledger's integrity. If a private key can be derived from a public key, wallets become vulnerable to fund theft.
Experts agree the weakest link is the ECDSA signature algorithm. Sofia Kireeva notes that Shor's algorithm can efficiently solve the mathematical problems underlying the security of systems based on factorization and similar challenges, while Ahmad Shadid explicitly points out ECDSA's vulnerability, especially with address reuse.
Meanwhile, hash functions like SHA-256 remain less vulnerable: Grover-like speedups offer only quadratic advantages and can be partially offset by strengthening hashing.
Technical Barriers to Quantum Attacks
Significant physical and engineering challenges stand in the way of real quantum attacks. Current devices have hundreds or thousands of noisy qubits, far from what's needed to run deep cryptanalytic algorithms at scale.
Sofia Kireeva believes practical decryption would require millions of physical qubits, extremely low gate errors, the ability to perform millions of sequential operations without coherence loss, plus breakthroughs in materials science and control.
Clark Alexander goes further, suggesting that with current approaches, quantum computers may never become widespread tools for breaking cryptography, and that the threat from advances in classical computing should not be underestimated either.
The "Harvest Now, Decrypt Later" Strategy
The real and practical threat is attackers collecting encrypted data today to decrypt later when computational power becomes available. Sean Ren and other experts note that malicious actors are already gathering public data that could be useful for future attacks.
The typical scenario—"harvest now, decrypt later"—involves collecting public keys and other on-chain data so that in the future, with sufficient quantum resources, private keys can be recovered and funds stolen. Leo Fan points out this as the most realistic threat path in the near term.
Crypto Industry's Preparation for Quantum Threats
Estimates of exposure vary, but Sofia Kireeva assesses that 25–30% of all BTC (about 4 million coins) are on addresses with already exposed public keys, making them more vulnerable to private key recovery if a powerful quantum computer emerges. In response, the industry is developing plans to transition to quantum-resistant signatures.
Practical steps are underway: in July, cryptographers proposed a plan to replace current signature systems with post-quantum alternatives, and in November, Qastle announced quantum protection for hot wallets, using quantum-generated randomness and post-quantum encryption to secure keys and communications.
For more on ecosystem responses and practical measures, see the articles on Bitcoin's reaction and on the transition to post-quantum standards, which discuss specific approaches and roadmaps.
Why This Matters
If you are a miner with 1–1000 devices in Russia, the direct risk of your farm being hacked by quantum computers in 2026 is low, but the passive threat is real: published addresses can be collected and used later. Therefore, it's important to understand which wallets and operations increase risk and what technical changes the market is preparing.
Moreover, industry preparation means new address and wallet formats, as well as updates to exchange and provider infrastructure, will emerge in the coming years—potentially affecting convenience and compatibility requirements for your operations.
What to Do?
Briefly and practically for miners: minimize risk without inventing complex solutions. First, avoid reusing addresses: always create a new address for withdrawals so that public keys aren't visible longer than necessary.
Second, monitor wallet and provider updates: when post-quantum options and migration tools appear, update software and transfer funds following secure instructions. Finally, keep most funds in formats and locations deemed more secure by providers and experts, and use quantum or post-quantum protected solutions for hot wallets whenever possible.