Post-quantum Bitcoin Protection: QuFi Tests Bitcoin Security Without Blockchain Changes Post-quantum Bitcoin protection from QuFi Network demonstrates how digital assets can be prepared for future quantum risks without rewriting existing settlement networks. The company launched a post-quantum verification platform and showcased its operation on Bitcoin Testnet4. The overall principle of this protection is to preemptively replace or supplement vulnerable cryptographic elements with more robust schemes, without disrupting the operation of the network and wallets. Verification Beyond the Blockchain The main idea of QuFi Network is not to force the blockchain itself to perform all the heavy cryptographic work. The platform separates the verification of an operation from its final execution: independent nodes conduct cryptographic verification in advance and then transmit a compact proof to the network. This approach is intended to reduce the load on base networks if they need to transition to post-quantum cryptography. Post-quantum schemes often require more data, computations, and resources than traditional public key cryptography mechanisms, so directly embedding new signatures into each blockchain could increase storage, bandwidth, and transaction processing requirements. In addition to the load, migration may face compatibility issues with wallets, exchanges, bridges, and nodes: users will need to update tools, carefully transfer keys, and avoid errors when transitioning to new formats. QuFi Network relies on standards prepared under the initiative of the National Institute of Standards and Technology. NIST acts as the coordinator for standardization in this area: it collects candidates, opens them for public cryptanalysis, compares their resilience and practicality, and then approves the selected algorithms as standards. If we break down the schemes used by QuFi Network by roles, we get the following picture: - ML-DSA-65 --- lattice cryptography; digital signature; NIST standardization. - SLH-DSA --- hash signatures; additional digital signature scheme; NIST standardization. - ML-KEM-1024 --- lattice cryptography; secure