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Braid#

Braid is a proposed double merged-mined sidechain of Bitcoin and Ergo. Its whitepaper frames the chain around stablecoins, real-world assets, Bitcoin DeFi, and programmable money with low trust assumptions.

Treat Braid as research and prototype material, not as a deployed Ergo sidechain. The public repository contains the whitepaper, early merged-mining notes, and minimal implementation scaffolding; it has no published releases.

Design Goals#

Braid aims to combine Bitcoin's proof-of-work security, Ergo's contractual model, and fast transaction-carrying blocks.

The whitepaper targets:

  • Bitcoin and Ergo double merged mining.
  • Fast proof-of-work-secured blocks, using Ergo input-block ideas for low-latency transaction inclusion.
  • Stablecoin and real-world-asset issuance with precise transfer rules.
  • Trust-minimized Bitcoin DeFi through Bitcoin collateral and Bitcoin-chain metadata.
  • Ergo-style UTXO programmability, including Sigma protocols and contract-first token logic.
  • Liquidity routes with Bitcoin, Ethereum, BNB Chain, Cardano, and a two-way Ergo peg as design goals.

Consensus Sketch#

Braid separates consensus into two block roles:

  • Bitcoin-merged ordering blocks: committed through Bitcoin merged-mining data. They witness the best input-block chain seen by a miner and commit to state such as the UTXO-set digest and interlink vector.
  • Ergo-merged input blocks: committed through Ergo input blocks, allowing transaction-carrying Braid blocks every few seconds in the proposal.

This design tries to get slow, high-security Bitcoin ordering plus fast Ergo-style input blocks. The result is not the same as a normal Ergo sidechain: Braid explicitly depends on both Bitcoin and Ergo for merged-mined commitments.

Programmable Money Model#

Braid follows Ergo's UTXO and contract-first approach:

  • Boxes carry typed registers and token data.
  • Contracts define spending rules directly.
  • Applications can use data from both Bitcoin and Ergo as contract context.
  • Existing Ergo applications could, in principle, be ported because the model stays close to ErgoScript and UTXO semantics.

The whitepaper also proposes Global Transfer Policies: token-level policy contracts that can require whitelist/blacklist checks, application-specific rules, mandatory payments, jurisdiction-specific transfer logic, or policy propagation across outputs.

Privacy And Compliance Circuits#

Braid's design tries to support both transparent and private monetary circuits:

  • Dark tokens would hide amounts with homomorphic commitments and validity proofs.
  • Transfer policies could require stealth-address-like receiver handling or other privacy constraints.
  • Issuers could keep one circuit transparent and bridge into a darker circuit under defined policy rules.

This is still design-level material. Do not treat these features as live wallet or node functionality.

Stablecoins And RWAs#

The whitepaper explicitly connects Braid to Ergo stablecoin work:

  • SigmaUSD / Djed-style collateralized stablecoins.
  • Gluon-style assets such as GluonGold.
  • Dexy-style assets such as DexyGold.
  • ChainCash-style peer-to-peer credit and stablecoin designs.
  • Insurance-style contracts for tokenized physical asset delivery risk.

Braid's core motivation is to give issuers programmable circuits with policy granularity, while still retaining proof-of-work security and interoperability with Bitcoin and Ergo.

Ergo Merged-Mining Notes#

The repository's Ergo merged-mining note sketches how sidechain progress can be stored on Ergo. It models sidechain progress as a tuple containing height, state changes, a UTXO-set AVL+ digest, and a commitment chain over previous sidechain states.

The note proposes:

  • Identifying the sidechain data box with an NFT.
  • Storing a hash of sidechain data in register R4.
  • Storing the previous sidechain data box id in register R5.
  • Updating sidechain data through miner-authorized refresh transactions.
  • Using Merkle proofs and sigma-rust support to verify sidechain data refreshes.

Status#

Braid is early research:

For current Ergo sidechain context, also see Sidechains on Ergo, Sigma Chains, and Weak Blocks.