BIP122 Namespace - Chains

CAIP-2

For context, see the CAIP-2 specification.

Rationale

The chain ID identifiers for BIP122 are specified in BIP122’s chain ID definition.

Syntax

The syntax for BIP122 chain ID can be summarized as a 32-character prefix from the hash of the genesis block of a given chain, in lowercase hex representation.

Resolution Method

To query for a Chain ID to represent or checksum a BIP122 reference, 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 result value the hash for the block with height 0 that should be sliced to its first 16 bytes (32 characters for base 16) to be compatible with the reference syntax defined above.

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

# Bitcoin Cash mainnet (forked from Bitcoin mainnet, the first Bitcoin Cash block is 478559)
bip122:000000000000000000651ef99cb9fcbe

# Litecoin mainnet
bip122:12a765e31ffd4059bada1e25190f6e98

# Dogecoin mainnet
bip122:1a91e3dace36e2be3bf030a65679fe82

# Bitcoin testnet
bip122:000000000933ea01ad0ee984209779ba

# Litecoin testnet
bip122:4966625a4b2851d9fdee139e56211a0d

# Dogecoin testnet
bip122:bb0a78264637406b6360aad926284d54

References

• BIP13: Bitcoin Improvement Proposal specifying “Script Hash” addresses
• BIP21: Bitcoin Improvement Proposal specifying bitcoin URI scheme
• BIP122: Bitcoin Improvement Proposal specifying blockchain URI scheme

Rights

Copyright and related rights waived via CC0.

Citation

Please cite this document as:

Simon Warta, ligi, Pedro Gomes, RareData, "namespaces/bip122-caip2: BIP122 Namespace - Chains [DRAFT]," Chain Agnostic Namespaces, bip122-caip2, December 2019 / August 2024. [Online serial]. Available: https://github.com/ChainAgnostic/namespaces/bip122-caip2.md