README.md

MinerId extension fields

BRFC	title	authors	version
a224052ad433	minerIdExt-blockInfo	nchain	0.1

Block info

This extension enables the miner to give further information about the block not contained in the block header.

Location

The blockInfo object should be located under the extensions field of the dynamic-CD

{
  // basic MinerId fields

  "extensions": {
    "blockInfo": {
      "txCount": number,
      "sizeWithoutCoinbase": number
    }
  }
}

field	function
txCount	number of transactions in current block
sizeWithoutCoinbase	size of current block excluding the coinbase transaction (in bytes)

Note: Since the data in this extension will go into the coinbase document before being signed, it is impossible to definitively know what the total size of the block will be (since Bitcoin/DER signatures are not fixed length and vary between 71 and 73 bytes). For this reason, the sizeWithoutCoinbase is provided instead of the full block size. Also anyone who has access to this data will already likely have access to the coinbase tx and thus can add its length to the sizeWithoutCoinbase to calculate the exact block size (as shown below).

blockSize = size(coinbase_tx) + sizeWithoutCoinbase

Example

{
  // basic MinerId fields

  "extensions": {
    "blockInfo": {
      "txCount": 1517,
      "sizeWithoutCoinbase": 1008368
    }
  }
}