Solo Mining Calculator: Estimate Odds and Timeframes
Use a solo mining calculator correctly: enter productive hashrate, network conditions, uptime and time horizon, then read expected time and probability without.
Read article
ASIC mining knowledge centre
BIP 89 Chain Code Delegation: Private Multisig Guide
BIP 89 guide to deployed Chain Code Delegation, per-spend BIP32 tweaks, multisig privacy, non-blinded and blinded signing, nonce safety and verification.
This guide explains BIP 89 Chain Code Delegation in plain English. It covers the problem behind the BIP, why it matters and whether the proposal is part of Bitcoin today.
TL;DR
- What it is: BIP 89 specifies deployed Chain Code Delegation for multisignature wallets. A privileged delegatee keeps the BIP32 chain code associated with a delegator’s base public key and supplies only the scalar tweaks needed for particular signing contexts.
- Why it matters: Chain Code Delegation can reduce balance and activity visibility in collaborative custody without giving away a signing key. Its safety depends on strict role separation, authenticated tweak data, complete verification and uncompromising blind-nonce lifecycle controls.
- Current position: Require a second reviewer and explicit rollback or expiry, and pause payments, signing or network-dependent services until post-change evidence is complete.
What this means in simple English
A BIP is a document that proposes or explains a Bitcoin idea, standard or rule. A BIP number does not mean the idea is active. Some BIPs are widely used, while others are drafts or historical proposals.
You do not need to read code to understand the main point. Start with the status, the problem being addressed and the practical effect on ordinary users, wallets, miners or node operators.
Simple example
Think of a mempool as one node’s waiting room for valid transactions that have not yet entered a block. Different nodes can have different waiting rooms, and the contents can change from one second to the next.
Key terms in plain English
- BIP:
- Bitcoin Improvement Proposal: a document describing a proposed rule, standard or process. Its status must be checked separately.
- Node:
- A computer running Bitcoin software that checks data and communicates with other peers.
Roles and objective
The delegator retains a non-extended keypair but no chain code. The delegatee holds the corresponding chain code, computes child tweaks and may share its xpub with other delegatees, limiting what the delegator can scan.
Derivation boundary
All derivation from the delegated public extended key is non-hardened because the delegatee has no private key. Hardened indices must fail rather than be silently transformed.
Tweak bundle
For each signing context the authenticated bundle maps participant base public keys to 32-byte big-endian aggregate scalar tweaks. Transport is outside the BIP, so deployments must specify authentication, replay protection and versioning.
Non-blinded mode
The delegator receives the child-key tweak and message, can reconstruct the relevant script, verify inputs and optional change, and produce a BIP340 signature while learning only that signing context.
Blinded mode
The alternative reveals only a blinded challenge and parity information. Its plain protocol is not concurrently secure: sessions must not overlap and every blind nonce must be single-use and erased after signing.
Policy limits
Input and change verification can confirm the supplied tweaks reproduce the expected script and help calculate outflow. Recipient, amount and organisational approval checks remain application responsibilities.
How specialists test it
Developers test the proposal with made-up data on an isolated test network. They check normal cases and deliberately invalid cases. Different implementations should reach the same result before anyone relies on the proposal.
Frequently asked questions
What is BIP 89 Chain Code Delegation?
BIP 89 specifies deployed Chain Code Delegation for multisignature wallets. A privileged delegatee keeps the BIP32 chain code associated with a delegator’s base public key and supplies only the scalar tweaks needed for particular signing contexts.
Is BIP 89 Chain Code Delegation active or supported today?
Require a second reviewer and explicit rollback or expiry, and pause payments, signing or network-dependent services until post-change evidence is complete.
Why does BIP 89 Chain Code Delegation matter?
Chain Code Delegation can reduce balance and activity visibility in collaborative custody without giving away a signing key. Its safety depends on strict role separation, authenticated tweak data, complete verification and uncompromising blind-nonce lifecycle controls.
Do beginners need to use the technical details?
No. Most readers only need to understand the idea and its current status. Developers and node operators can use the primary sources when they need the exact technical rules.
Conclusion
Chain Code Delegation can reduce balance and activity visibility in collaborative custody without giving away a signing key. Its safety depends on strict role separation, authenticated tweak data, complete verification and uncompromising blind-nonce lifecycle controls.
Primary sources
Check the current specification status and the documentation for the exact implementation you operate before moving production funds or changing a mining node.
On this page
Search More Guides
BIP-110 Explained: Rules, Signalling and Why It Closed
BIP-110 explained in detail: its seven consensus restrictions, 55% signalling threshold, chain-split risk and August 2026 closure.
Read article
Bitcoin Core 29.4 Release: Chainstate Disk I/O Guide
Bitcoin Core 29.4 guide covering repeated chainstate rewrites, regular compaction, LevelDB seek compaction, transaction-data lifetime and wallet sizing fixes.
Read article
Need Advice for Your Mining Setup?
Use our guidance to build your shortlist, then speak to our team when you want help comparing hardware, power, hosting or repairs.