# Bitcoin Quantum (BTQ)

> Bitcoin Quantum is a quantum-resistant fork of Bitcoin. It preserves Bitcoin's
> UTXO model, SHA-256 proof-of-work and 21 million coin supply cap, and replaces
> ECDSA transaction signatures with NIST-standardized CRYSTALS-Dilithium
> (ML-DSA, FIPS 204). A public testnet is live; mainnet has not launched.

Key network parameters: 21,000,000 BTQ maximum supply; 1 minute target block
time; 8 MB per-block size limit; CRYSTALS-Dilithium (ML-DSA) signatures per NIST
FIPS 204; BIP-360 Pay-to-Merkle-Root (P2MR) outputs. The full-node
implementation is BTQ Core, an MIT-licensed fork of Bitcoin Core.

## Core pages

- [Bitcoin Quantum](https://bitcoinquantum.com): What BTQ is, why post-quantum signatures matter, and the headline network parameters.
- [Protocol](https://bitcoinquantum.com/protocol): Architecture — UTXO model, SHA-256 proof-of-work, Dilithium signing, network parameters and ports.
- [Testnet](https://bitcoinquantum.com/testnet): Run a node. BTQ Core downloads, the mining guide, block explorer and public mining pool.
- [FAQ](https://bitcoinquantum.com/faq): Common questions on cryptography, BTQ vs Bitcoin, mining, security model and supply.

## Technical guides

- [From ECDSA to Dilithium](https://bitcoinquantum.com/guides/quantum-secure-bitcoin/signature-migration): What changing Bitcoin's signature algorithm actually requires: opcodes, size impacts, wallet changes, and running both schemes in one block.
- [The 20x Problem](https://bitcoinquantum.com/guides/quantum-secure-bitcoin/block-size-tradeoffs): Why quantum-resistant transactions need bigger blocks, and how every parameter change cascades through emission schedules, witness economics, chain growth, and node viability.
- [Why Taproot Is Quantum-Vulnerable](https://bitcoinquantum.com/guides/quantum-secure-bitcoin/taproot-quantum-vulnerability): Taproot exposes the public key on-chain, so a quantum-resistant script in a P2TR container is false security. BIP-360's P2MR removes the key path entirely.
- [Quantum-Safe Addresses](https://bitcoinquantum.com/guides/quantum-secure-bitcoin/address-formats): A 1,312-byte Dilithium public key never lands in an address. Hash160 holds ECDSA and legacy Dilithium addresses to 20 bytes; P2MR commits to a 32-byte Merkle root.
- [Mining a Quantum-Resistant Network](https://bitcoinquantum.com/guides/quantum-secure-bitcoin/mining-and-bootstrapping): SHA-256 proof-of-work is unchanged, so existing ASICs work. The hard parts are paying miners in 15x-larger transactions and bootstrapping without stealth.

## Related sources

- [BTQ Core source](https://github.com/btq-ag/btq-core): The full-node implementation (MIT). Also carries the operator documentation — INSTALL.md, TESTING_GUIDE.md and doc/.
- [NIST FIPS 204](https://csrc.nist.gov/pubs/fips/204/final): The ML-DSA standard BTQ signatures implement.
- [BIP-360](https://bip360.org/): The Pay-to-Merkle-Root output type BTQ implements.

Two further BTQ services exist but are deliberately not listed above, because
they refuse automated clients and would return 403 to anything that followed
them: docs.bitcoinquantum.com (operator and mining documentation) and
explorer.bitcoinquantum.com (live testnet chain data). Both are open to people
in a browser. Read the BTQ Core repository instead — the same operator material
lives there and is fetchable.