Nunchuk

Nunchuk is a Bitcoin wallet and multisignature coordinator for desktop and mobile. It focuses on Bitcoin custody, collaborative wallets and inheritance planning, rather than acting as a multi-chain portfolio wallet or an EVM smart-account for dapps.

Bitcoin policies coordinate independent hardware keys

A Nunchuk wallet combines signer extended public keys into a Bitcoin policy such as two-of-three. That public configuration lets the wallet derive addresses and follow balances without holding every private key, while the policy determines how many signatures are needed to spend.

Compatible hardware signers can use USB, NFC, QR or microSD-card exchange, including air-gapped signing. Nunchuk organizes the wallet policy, addresses and transaction exchange; each signer still independently decides whether to add its own signature. Multi-user wallets extend that coordination to family members or business partners without asking them to share seed phrases.

PSBT proposals gather signatures before broadcast

To spend, Nunchuk prepares a partially signed Bitcoin transaction, or PSBT. Required signers review that same transaction through their device or signing environment and add signatures. Once the configured threshold is met, Nunchuk can finalize and broadcast the Bitcoin transaction.

A lone signer cannot spend from a two-of-three policy. This proposal-and-signature sequence lets different people coordinate a payment while retaining separate keys. Coin control, scheduled transactions, spending limits and broadcast-delay or emergency-lockdown features can add further controls, but they do not replace the Bitcoin policy's signature requirement.

Recovery depends on keys and the wallet policy

Self-managed recovery requires enough recoverable signer keys and the wallet-policy details that identify the multisig arrangement. Keeping a seed without those policy details can make reconstructing the intended wallet much harder. Multiple keys can reduce dependence on one device, but they add backup and coordination work for every participant.

Nunchuk's assisted multisig offers key-health checks, automated key replacement, wallet rollover, assisted recovery and cloud backups. These services can help maintain a multi-key arrangement, yet the owner still needs to understand which keys and recovery information control the wallet.

Inheritance routes built around Bitcoin timelocks

Nunchuk offers an autonomous inheritance route using an onchain Bitcoin timelock. At the selected time, the policy removes the platform key and lowers the signing requirement so the beneficiary or trustee arrangement can claim under the planned rules. Direct, indirect and joint-control recovery designs allocate the necessary secrets differently among beneficiaries, guardians and trustees.

The plan includes a self-sovereign claim route based on a wallet-configuration backup and inheritance-key seed. It requires Miniscript-compatible hardware for relevant keys, and changing the inheritance protocol or timelock later means creating a new assisted wallet and moving funds. Safe is the EVM contrast: it uses an onchain account threshold and contract calls, whereas Nunchuk coordinates native Bitcoin PSBTs under a Bitcoin policy.