Integrating nBTC via IBC

IBC is a blockchain interoperability protocol used by 110+ chains. This page gives a high-level overview of how to integrate nBTC into any IBC-compatible chain.

Prerequisites

As a prerequisite, follow the instructions to configure an IBC relayer to work with Nomic. IBC transactions require the relayer account to be funded with a small amount of nBTC, as IBC-related transactions are charged a fee of 1 Satoshi each.

Creating a channel

Once hermes is configured for Nomic, the next step is to create an IBC channel with Nomic.

hermes create channel --a-chain <your-chain-id> --b-chain nomic-stakenet-3 --a-port
transfer --b-port transfer --new-client-connection

Nomic currently requires both ends of the channel to use the "transfer" port.

Relaying operator keys

To ensure that nBTC is recoverable by the remote chain's validator set in the event of an Emergency Disbursal, run:

nomic relay-op-keys <COUNTERPARTY-RPC> <CLIENT_ID>

This command may be re-run anytime to refresh the operator keys of the remote chain's validator set. If an Emergency Disbursal occurs on Nomic, a portion of the Bitcoin reserves equal to the nBTC held in channels backed by the specified client will become spendable by 2/3+ of the voting power of that network's top 30 validators.

Interchain Deposits

Interchain Deposits allow the generation of Bitcoin addresses which commit to an ICS-20 token transfer packet, automatically forwarding any received funds to an address on the counterparty chain.

Interchain Deposits require communication with a Bitcoin relayer. The set of relayers used by your front-end should be selected with care.

After a channel has been opened between your chain and Nomic, see nomic-bitcoin-js for information on generating and displaying deposit addresses.

Withdrawals to Bitcoin

nBTC may be withdrawn as Bitcoin directly from the counterparty chain. ICS-20 transfer packets support a memo field. Providing a memo of the form "withdraw:<dest>" for an incoming nBTC transfer packet to Nomic will trigger a withdrawal of the Bitcoin to <dest> at the next checkpoint. <dest> may be either:

1. A Bech32 Bitcoin address.

2. A hex-encoded Bitcoin script.