For most of Bitcoin’s history, the threat of quantum computers breaking its cryptography was a distant theory. In 2026, repairs began.
On February 11, 2026, a proposal called BIP-360 was merged into the Bitcoin repository. It introduces the network’s first type of quantum resistance address. Two months later, BIP-361 presented a plan to migrate or freeze approximately 6.5 to 6.9 million Bitcoins located in vulnerable addresses. This includes approximately 1.7 million pieces believed to belong to Satoshi Nakamoto.
The real threat
The most common misconception is that quantum computers threaten Bitcoin mining. This is not the case. Mining uses SHA-256 hashing, which would require huge quantum resources to attack. The real vulnerability lies in the transaction signing, which uses elliptic curve cryptography. A quantum computer running Shor’s algorithm could derive a private key from an exposed public key.
A public key is only vulnerable once revealed on the blockchain. This happens when addresses send transactions or with old Pay-to-Public-Key outputs. Project Eleven estimates that around 6.9 million BTC is in addresses with exposed public keys.
Why now
Bitcoin developers moved to 2026 because the timeline seemed to be speeding up. Google researchers have published results suggesting that breaking 256-bit elliptic curve cryptography may require fewer quantum resources than previously thought. In April 2026, a researcher cracked a 15-bit elliptic curve key using real quantum hardware. This is a 512-fold improvement over the previous result.
A panel of cryptographers assembled by Coinbase concluded that a meaningful quantum computer would eventually be built. They said the migration must start now. Google has set its own post-quantum migration goal for 2029.
What does the BIP-360 do?
BIP-360 introduces a new output type called Pay-to-Quantum-Resistant-Hash. It works like Taproot but removes the element that a quantum computer could exploit. Spending uses post-quantum signature schemes based on NIST-approved algorithms. New addresses start with “bc1r”.
The design preserves compatibility. Legacy nodes treat the results as “anyone can spend”, while upgraded nodes validate them correctly. This allows for a soft fork rather than a disruptive hard fork.
There is a cost. Post-quantum signatures are larger than current signatures. Some schemes produce signatures of up to 8 kilobytes. This could result in higher fees unless miners give them a discount for witnesses.
The hardest: BIP-361
BIP-361 addresses vulnerable existing supply. He proposes setting a deadline for incumbents to migrate to quantum-resistant addresses. After that, the network stops honoring expenses for old vulnerable signature types.
The problem is the parts that cannot migrate. The estimated 1.7 million BTC in old addresses, including Satoshi’s, cannot be moved because the owners are lost. If BIP-361’s signature sunset takes effect, these rooms will be permanently frozen.
This opposes two Bitcoin principles: immutability and prevention of catastrophic theft. The debate is not resolved. Critics argue that the coin freeze is more dangerous than the quantum threat itself. Proponents counter that doing nothing guarantees possible theft.
How Bitcoin Compares to Other Chains
Ethereum has taken a more aggressive approach. Vitalik Buterin has published a quantum resistance roadmap targeting multiple layers. Ethereum can scale faster thanks to its more flexible governance.
Ripple’s XRP Ledger has a four-phase plan targeting quantum resistance by 2028. Hedera already uses hash-based cryptography that is inherently more resilient.
Bitcoin’s migration is more difficult due to its massive offering of exposed inheritance and consensus-driven governance. What looks like a slow move is partly because Bitcoin is facing a tougher version of the problem.
What this means for incumbents
There is no immediate danger. No quantum computer capable of breaking Bitcoin exists today. Incumbents do not need to do anything urgently.
The vulnerability only applies to addresses with exposed public keys. Coins held in modern address types that have never been spent are hash protected. When quantum-resistant addresses become available, holders will be able to migrate their coins to the new “bc1r” type.
The episode shows the adaptability of Bitcoin. The most controversial issue surrounding frozen coins remains unresolved and could prove to be one of the most difficult decisions Bitcoin has ever made. For now, what we need to remember is a calm conscience. The threat is real but distant. The response has begun. No urgent action is required. The most difficult choices remain to be made.
This article is for informational purposes and does not constitute financial advice. Cryptocurrency markets are volatile. Always do your own research.
