Wallet Setup Guide

This guide walks you through setting up a quantum-insured Bitcoin wallet using the Quantroot soft-fork implementation. All commands use bitcoin-cli on regtest.

1. Create a Wallet

$ bitcoin-cli -regtest createwallet "quantum"

2. Create a SPHINCS+ Key

Derives a SPHINCS+ keypair from the wallet's master key and registers a quantum-insured descriptor. The key is deterministic — recoverable from the wallet seed.

$ bitcoin-cli -regtest createsphincskey

{ "sphincs_pubkey": "ab12...ef34", "qi_descriptor": "qr(Q1.../0/*)" }

3. Generate a Quantum-Insured Address

Addresses use a hybrid tapleaf: both Schnorr and SPHINCS+ signatures are required in the emergency spending path. Normal spending uses efficient key-path (~64 bytes).

$ bitcoin-cli -regtest getnewaddress "" bech32m

bcrt1p...

The address is a standard Taproot (bech32m) address — indistinguishable from any other Taproot output on-chain.

4. Export the Quantum-Insured Extended Key

Export a qpub for watch-only wallets, or qprv for full backup. Both encode the BIP 32 key hierarchy plus the SPHINCS+ key.

$ bitcoin-cli -regtest exportqpub

{ "qpub": "Q1CFYH..." }

5. Import into a Watch-Only Wallet

A watch-only wallet tracks incoming payments to all QI addresses derived from the qpub, without access to private keys.

$ bitcoin-cli -regtest createwallet "watchonly" true true

$ bitcoin-cli -regtest -rpcwallet=watchonly importqpub "Q1CFYH..."

Hybrid Script Anatomy

Each quantum-insured address contains a single hybrid tapleaf:

<sphincs_pk> OP_CHECKSPHINCSVERIFY OP_DROP <schnorr_pk> OP_CHECKSIG

Normal Operation

Key-path spend with Schnorr signature (~64 bytes). The hybrid leaf is never revealed.

Quantum Emergency

Script-path spend requiring both SPHINCS+ and Schnorr signatures. An attacker must break both.

Available RPCs

Command	Description
createsphincskey	Derive SPHINCS+ key and register QI descriptor
getquantumaddress	Derive a quantum-insured Taproot address
listsphincskeys	List all SPHINCS+ keys in the wallet
exportqpub	Export quantum-insured extended public key (Q1...)
importqpub	Import qpub as watch-only QI descriptor
exportqprv	Export quantum-insured extended private key
importqprv	Import qprv with full signing capability

6. Quantum-Insured Extended Keys

The qpub and qprv formats extend BIP 32 extended keys with SPHINCS+ key material, enabling watch-only wallets and full backups.

Format	Size	Prefix	Contains
qpub	110 bytes	Q1... / T4...	BIP 32 xpub + 32B SPHINCS+ pubkey
qprv	142 bytes	Q1... / T5...	BIP 32 xprv + 64B SPHINCS+ secret

A watch-only wallet holding a qpub can derive all quantum-insured addresses without private key access.

7. Seed-Derived SPHINCS+ Keys

The SPHINCS+ key is derived deterministically from the wallet's master extended key, so your mnemonic phrase is the only backup you need.

HMAC-SHA512("Sphincs seed", master_ext_privkey || account_path)

→ sk_seed[0:16] || sk_prf[16:32] || pk_seed[32:48]

Account path: m/395'/coin_type'/account'. One SPHINCS+ key per account. Stateless — key reuse does not weaken security.

8. Encrypted Wallet Support

Operation	Locked	Unlocked
createsphincskey	Fails	Works
listsphincskeys	Works	Works
getquantumaddress	Works	Works
exportqpub	Works	Works
exportqprv	Fails	Works
Spending	Fails	Works

9. Descriptor Syntax

The qr() descriptor is a drop-in replacement for tr() that auto-constructs the hybrid SPHINCS+ tapleaf from a qpub.

qr(Q1.../0/*)

For advanced use with custom Taproot trees, the qis() fragment is also available:

tr(xpub/0/*, qis(SPHINCS_HEX, xpub/0/*))

Both expand to the same hybrid script:

<SPHINCS_HEX> OP_CHECKSPHINCSVERIFY OP_DROP <EC_KEY> OP_CHECKSIG

When registered as the active BECH32M descriptor, getnewaddress bech32m automatically produces quantum-insured addresses.