CAIP-4: Blockchain Reference for the BIP122 Namespace

Simple Summary

This document is about the details of the BIP122 namespace and reference for CAIP-2.

Abstract

In CAIP-2 a general blockchain identification scheme is defined. This is the implementation of CAIP-2 for BIP122 (Bitcoin).

Motivation

See CAIP-2.

Specification

BIP122 Namespace

The namespace is called "bip122" as in BIP122 ↗.

Reference Definition

The definition is delegated to BIP122's chain ID definition ↗. The format is a 32 character prefix of the block hash from BIP122 (lower case hex).

Resolution Method

To resolve a blockchain reference for the BIP122 namespace, make a JSON-RPC request to the blockchain node with method getblockhash, for example:

// Request
{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "getblockhash",
  "params": [0]
}

// Response
{
  "id": 1,
  "jsonrpc": "2.0",
  "result": "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f"
}

The response will return as a value for the result a hash for the block with height 0 that should be sliced to its first 16 bytes (32 characters for base 16) to be CAIP-4 compatible.

Rationale

We delegate the identification of Bitcoin-like chains to BIP122, as this is the best Bitcoin chain identification standard known to the authors of this CAIP.

Backwards Compatibility

Not applicable

Test Cases

This is a list of manually composed examples

# Bitcoin mainnet (see https://github.com/bitcoin/bips/blob/master/bip-0122.mediawiki#definition-of-chain-id)
bip122:000000000019d6689c085ae165831e93

# Litecoin
bip122:12a765e31ffd4059bada1e25190f6e98

# Feathercoin (Litecoin fork)
bip122:fdbe99b90c90bae7505796461471d89a

CAIP-4 - Blockchain Reference for the BIP122 Namespace