BIP 81 Coloured Voting-Pool Wallet Hierarchy Explained

BIP 81 Coloured Voting-Pool Hierarchy: This guide explains BIP 81 Hierarchy for Coloured Voting Pool Deterministic Multisig Wallets in plain English. It covers the problem behind the BIP, why it matters and whether the proposal is part of Bitcoin today.

What coloured assets meant here

A colouring protocol assigned off-chain asset meaning to selected Bitcoin outputs and transfer rules. Bitcoin nodes validated ordinary transactions, not the claimed asset semantics. A voting pool therefore had to preserve both multisignature custody and the external colour definition used to interpret which outputs represented which asset.

Eight-level path structure

The proposal used purpose, series, five colour-definition levels and address index. Hardened purpose and series branches separated wallet namespaces and cold-storage generations. Public derivation across the colour and address levels let participants reproduce deposit keys once they agreed the same definition and pool contract.

Encoding the colour definition

A colour definition was shortened to 20 bytes with HASH160, divided into five four-byte groups and interpreted little-endian as path values. Five levels avoided squeezing the whole identifier into one 32-bit child index. Byte order and exact canonical definition bytes were therefore essential interoperability inputs.

Series and custody separation

Like BIP 80, series supported staged cold storage and withdrawal operations. The same colour could exist across several series, so a recovery system needed to scan all activated series and addresses. Activating the wrong series with incomplete signer availability could turn a bookkeeping error into inaccessible multisig outputs.

Out-of-band multisig contract

Public keys at the final index constructed deposit scripts according to a separately shared schema. Threshold, cosigner order, wrapper and derivation origins were not recoverable from the path alone. Colour data also did not authenticate the commercial issuer or guarantee redemption rights.

Collision and semantic limits

HASH160 makes accidental branch collision remote, but a hash match does not prove two parties interpret the colour rules identically. Changes in canonical serialisation, issuance history or wallet code can split semantic views without invalidating Bitcoin transactions. Asset accounting requires its own reproducible validation record.

Forensic reconstruction

Hash the preserved colour definition, show all five path components in little-endian form and reproduce known deposit scripts on isolated software. Scan every documented series and index, then compare external asset records with raw transactions. Do not send new funds merely because historical addresses can be regenerated.

Conclusion

BIP 81 separated coloured voting-pool branches deterministically, but neither the seed nor the blockchain explains the external asset contract. Safe recovery needs exact colour bytes, series history, multisig policy and independent asset records.