Runes on Bitcoin
Every BRUNE coin is also a native Bitcoin Rune, etched and paid for by BRUNE.
What a Rune is
Runes is the fungible-token protocol native to Bitcoin, live since block 840,000. A Rune is created by an etching, a Bitcoin transaction that fixes its name, divisibility, symbol and supply forever. Runes live in ordinary Bitcoin outputs, so they are held and moved with Bitcoin wallets that support them.
How BRUNE etches your coin
After your coin is live on BNB Chain, BRUNE etches its Rune:
- Supply: 1,000,000,000 with divisibility 18, exactly matching the BNB Chain token: one Rune unit is one token unit, so nothing is ever rounded when you bridge.
- Premine: the entire supply goes to the coin's own 2-of-2 custody address, where it backs the BNB Chain side 1:1 (how custody works).
- Name: a reserved Rune name assigned by Bitcoin itself, so it can never collide with another Rune (or the name you chose, see Choosing a Rune name). It works like a CA; see Rune names are addresses.
- Symbol: the one character you picked, or none, so wallets show Bitcoin's generic sign ¤.
- Metadata: every BRUNE Rune is etched with its metadata, in the same transaction (see below).
BRUNE pays the Bitcoin network fees: 2× the next-block fee rate (at least 5 sat/vB), so your Rune makes the next block. Their cost is part of the launch price you approve.
Etched with its metadata
A plain Rune has no image, no description and no links. Every BRUNE Rune does: it is etched by the reveal transaction of an inscription, so that inscription is the Rune's parent and belongs to it from its very first block. It holds:
| In the parent inscription | |
|---|---|
| Logo | Your image, fitted to 256 × 256 (at most 4 KiB), plus a link to the full-size image on IPFS |
| Name and ticker | The coin's real brand (the Rune name is only its address) |
| Description and links | Your description, X, Telegram and website |
| BNB Chain token | The CA of the same coin on BNB Chain (bep20) and the chain ID (56) |
Inscriptions are permanent: nobody, including BRUNE, can change or remove them. Most wallets do not read this metadata yet; see Bringing Runes back for why we expect that to change.
Verification
When the etching is in a block, BRUNE checks the Rune ID, the name, the full premine in custody and the inscription before going further. After 6 confirmations the Rune is final, and only then is the bridge switched on.
Linking the two chains
- Bitcoin → BNB Chain: the inscription's metadata contains the BNB Chain token address.
- BNB Chain → Bitcoin: the bridge contract stores the Rune ID for the token. It is set once and can never change.