About
BTCQ is a fork of Bitcoin with every classical cryptographic primitive replaced by post-quantum alternatives standardized by NIST. It exists because the quantum threat timeline keeps accelerating, and the window to prepare is narrowing.
Q-Day is the point at which a quantum computer can break the cryptography protecting today’s digital systems — including Bitcoin. Shor’s algorithm running on a sufficiently powerful quantum computer would crack the elliptic curve discrete logarithm problem (ECDLP) that underpins every Bitcoin signature. A private key could be derived from a public key, making exposed funds vulnerable to theft.
Until recently, this was considered decades away. That’s changed rapidly.
Three major papers in three months have rewritten the quantum threat timeline:
RSA-2048 breakable with fewer than 1 million noisy qubits in under a week — down from 20 million in the 2019 estimate.
Pinnacle architecture using QLDPC codes reduces requirements to fewer than 100,000 physical qubits — another ~10x reduction.
Elliptic curve cryptography (protecting Bitcoin) breakable with fewer than 500,000 physical qubits in minutes. A 20-fold reduction from prior estimates.
QUBIT REQUIREMENTS FOR BREAKING ECDLP-256
In March 2026, Google Quantum AI published research demonstrating that the elliptic curve cryptography protecting Bitcoin and Ethereum could be broken with fewer than 500,000 physical qubits in a runtime measured in minutes. A quantum computer could derive a Bitcoin private key from a public key in roughly nine minutes — less than Bitcoin’s average block confirmation time of ten.
Google established a 2029 migration deadline for transitioning to post-quantum cryptography, working alongside Coinbase, Stanford Institute for Blockchain Research, and the Ethereum Foundation. An estimated one-third of all bitcoin — held in addresses with exposed public keys — could be stolen at leisure by a sufficiently powerful quantum computer.
Read the Google Research paper2026 — YEAR OF QUANTUM SECURITY
The FBI, NIST, and CISA have designated 2026 the “Year of Quantum Security.” NIST has finalized post-quantum standards (ML-KEM, ML-DSA, SLH-DSA) and set a timeline to deprecate all quantum-vulnerable algorithms by 2035. The “harvest now, decrypt later” threat is no longer theoretical — state actors are already collecting encrypted data today with the expectation of decrypting it when quantum computers arrive.
BTCQ is a fork of Bitcoin Core — the same codebase, the same UTXO model, the same consensus architecture — with every quantum-vulnerable cryptographic primitive swapped out for a NIST-standardized post-quantum replacement.
| Component | Bitcoin | BTCQ |
|---|---|---|
| Signatures | secp256k1 / ECDSA | ML-DSA-65 (FIPS 204) |
| PoW hash | SHA-256d | SHA3-512 |
| Block/tx hash | SHA-256d | SHA3-256 |
| Address hash | RIPEMD160(SHA256) | SHA3-256 truncated to 20 B |
| P2P transport | BIP324 (ECDH) | PQ-v2 (ML-KEM-768) |
| HD derivation | BIP32 (EC group) | HMAC-SHA512 + FIPS 204 |
| Key storage | Full expanded key | 32-byte seed (RFC 9881) |
Bitcoin’s consensus process moves slowly by design. A change as fundamental as replacing every signature scheme, hash function, and key exchange protocol would take years of BIPs, review, and deployment — time the quantum timeline may not afford. A fork lets us build and test post-quantum Bitcoin now, producing real working code that demonstrates the changes are possible and that the chain functions correctly with lattice-based cryptography end to end.
BTCQ isn’t trying to replace Bitcoin. It’s a proving ground: an existence proof that the Bitcoin architecture can be made quantum-resistant, and a reference for what that migration looks like in practice.
BTCQ was developed with significant AI assistance — deliberately. This project is as much a learning experience in AI-assisted systems programming as it is in post-quantum cryptography. The goal was to understand how far AI tooling can go in modifying a complex, security-critical codebase like Bitcoin Core: replacing cryptographic primitives, adapting consensus logic, writing and passing test suites, and building the surrounding infrastructure.
Every change was validated by deterministic tests, sanitizer builds, cross-compiler verification, and multi-node regtest. AI generated code; humans verified correctness. The result is a working post-quantum blockchain that also serves as a case study in responsible AI-assisted development on systems that demand mathematical precision.
BTCQ is in the regtest testnet phase. The core cryptographic replacements are implemented and passing deterministic test suites across multiple compilers with sanitizer validation. The project is actively progressing through its roadmap toward broader testing and eventual public availability.
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