Bitcoin multisig inheritance

A multisig wallet uses multiple possible keys and a preset threshold for how many signatures are required, commonly 2-of-3 or 3-of-5. Most often several signatures are required, but other thresholds technically exist. Always check how many signatures the found wallet actually requires. That is a deliberate security design, and it has specific inheritance consequences: some keys may be with other people or institutions, and the death of the main keyholder does not end the wallet.

What multisig is

With multisig, several parties or keys must cooperate before crypto can be moved; in a 2-of-3 setup, for example, two valid signatures are needed. The combination “how many of how many” is called the threshold. Multisig is used by businesses, joint ownership and people who want extra protection against theft, and it changes what an estate needs to find.

How it changes inheritance

• The wallet survives the keyholder. The estate needs to securely identify both sufficient signing material and the wallet policy and configuration; the number of private keys found alone does not always say enough. As long as enough keys and the right configuration (policy, public keys, script type, derivation paths) are available, the funds can still be moved, the multisig does not “die” with its owner.
• The other signers may be technically necessary. Family and executors may not even know the other signers exist.
• In multisig, both the keys and the wallet configuration matter. So preserve all found keys, hardware wallets, wallet files and configuration or export files. Do not throw anything away until it is clear how the multisig wallet is set up and which data is needed for recovery.
• A missing signing key or other required signing authority can block a multisig wallet. With 2-of-3, the configured threshold remains technically achievable as long as two valid signing authorities are available; with 2-of-2, both are required. The death or unavailability of a person does not automatically make their signing material technically unavailable. So establish separately which signing material still exists and which route can be lawfully used. For reconstruction, in addition to enough valid signing authorities, the wallet policy and configuration may be needed, for example public keys/xpubs, script type, descriptor or other wallet-specific configuration and derivation data. So also preserve such configuration information.
• Descriptors and scripts are technical reality. Wallets today use descriptors (output script descriptors), the estate may need an expert just to understand what the setup is. That is a technical question, not a reason to hand over secrets.

What owners should plan

1. Document the structure, not the secrets: which keys exist, who holds them, what threshold applies, without including the key material itself.
2. Name the co-signers in your estate map and tell them you have done so (privacy permitting) so they can technically cooperate when needed; whether they are legally authorised to act is a separate estate question that must be established first.
3. Plan for missing authorisation. Is the threshold still reachable if a required key or authorisation is no longer available?
4. Changing signers is not a generic feature of a fixed multisig. The signers are part of the locking policy; a change usually means the authorised signers move the funds to a new wallet policy. Discuss this with a qualified adviser. After a death, migration can technically be possible when the required threshold is available and the authorised people can lawfully act.
5. Arrange a secure reserve for one of your keys (a bank box, a trusted person under a formal arrangement) so the threshold remains reachable.

What heirs should do

• Find the documentation before touching anything (estate inventory).
• Do not reconstruct the multisig setup from memory. A wrong reconstruction can make you see the wrong wallet or addresses and therefore wrongly think funds are missing. Preserve all configuration data found and first establish how the wallet is actually built.
• Understand the limits, multisig adds complexity, and if too many keys are lost, even a specialist cannot invent them (wallet recovery: what is realistically possible).
• Get a professional review of the setup, a multisig configuration is not a standard setup; the structure, documentation and continuity arrangements deserve periodic expert assessment alongside the legal adviser.

Multisig can be a strong planning tool for inheritance, but only when the structure is documented in the estate plan. See crypto inheritance planning for the full method.