CAIP-13: Blockchain Reference for the Polkadot Namespace

Author	Pedro Gomes, Joshua Mir, Shawn Tabrizi
Discussions-To	https://github.com/ChainAgnostic/CAIPs/issues/13
Status	Superseded
Type	Standard
Created	2020-04-01
Updated	2020-04-02
Requires	2
Superseded By	https://github.com/ChainAgnostic/namespaces/pull/6

Simple Summary
Abstract
Motivation
Specification
- Polkadot Namespace
- Resolution Method
Rationale
Backwards Compatibility
Test Cases
Links
Copyright

Simple Summary

This document is about the details of the Polkadot 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 Polkadot chains.

Motivation

See CAIP-2.

Specification

Polkadot Namespace

The namespace is called “polkadot” to refer to Polkadot-like chains.

Reference Definition

The definition for this namespace will use the genesis-hash as an indentifier for different Polkadot chains. The format is a 32 character prefix of the block hash (lower case hex).

Resolution Method

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

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

// Response
{
  "id": 1,
  "jsonrpc": "2.0",
  "result": "0x91b171bb158e2d3848fa23a9f1c25182fb8e20313b2c1eb49219da7a70ce90c3"
}

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-13 compatible.

Rationale

The rationale behind the use of block hash from the genesis block stems from its usage in the Polkadot architecture in network and consensus.

Backwards Compatibility

Not applicable

Test Cases

This is a list of manually composed examples

# Kusama
polkadot:b0a8d493285c2df73290dfb7e61f870f

# Edgeware
polkadot:742a2ca70c2fda6cee4f8df98d64c4c6

# Kulupu
polkadot:37e1f8125397a98630013a4dff89b54c

Links