---
title: "Collaborative Custody: The Service Key Model (PDF)"
url: "https://bip39-phrase.com/list-phrase/securing-assets-with-multi-signature-wallets-2026-05-07/"
language: "en"
updated: "2026-10-22T00:00:00+00:00"
---

# Collaborative Custody: The Service Key Model

Understand how collaborative multisig balances self-custody with an institutional key, including recovery paths if the company goes offline.

PDF document · Published May 7, 2026 · Updated October 22, 2026 

[ Open the PDF (6 pages, 203 KB) ](/list-phrase/securing-assets-with-multi-signature-wallets-2026-05-07-en.pdf) 

## Contents

1. What the Service Key Can and Cannot Do
2. Recovery Assistance and Inheritance Protocols
3. Surviving Coordinator Disappearance
4. Custody Model Comparison
5. FAQ
6. Sources
7. Example sequences from the BIP39 wordlist
8. Reading a BIP39 phrase
9. See also

Keywords: 

collaborative custody · multisig wallet · 2-of-3 bitcoin · wallet descriptor · PSBT

Topic: 

[Crypto Wallets: Hardware, Software and Multisig](/topics/wallets/)

## Guides on the same subject

- [How Does Multisig Work for Bitcoin? 2-of-3 Explained](/multisig-work-for-bitcoin/)  
A Bitcoin multisig wallet needs M of N keys to sign, such as any 2 of 3\. How the script works, which setup to pick, what to back up and what it costs.
- [Custodial vs Non-Custodial Wallet: Differences and How to Choose](/custodial-vs-non-custodial-wallet/)  
A custodial wallet means a company holds your private keys; a non-custodial wallet leaves them with you. How they differ on recovery, KYC, freezes and fees.
- [Cold Sharding: Splitting a Private Key Into Offline Shamir Shares](/cold-sharding-method-private-key-storage-strategy/)  
Cold sharding splits a key or seed into offline Shamir shares, such as any 3 of 5, so one share reveals nothing. How it works, its risks and multisig compared.

One of the documents in the [Seed Phrase PDF Archive](/list-phrase/), listed on [archive page 10](/list-phrase/10/).