• Private blockchain
  • PoA validation algorithm

Using geth attach MY-GETH-CLIENT, I want to check the sealer of a block as well as its reward.

Using eth.getBlock(BLOCK-NUMBER), the miner field is sometimes equal to 0x00...0:

    > eth.getBlock('216567')
      difficulty: 2,
      extraData: "0xd883010907846765746888676f312e31332e34856c696e757800000000000000a5d63126675c1b8f9811e995dd8cb5276486a64b06ad590a542c74aea142b68a64abc2f5bbd1ba3b10adfa8200ce678961b22c724f4eca81ba1bb770942c7d6e01",
      gasLimit: 8000000,
      gasUsed: 0,
      hash: "0xed19228537c738101308a08811c4232ca72176efa55a498f7286ef915be854f0",
      logsBloom: "0x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
      miner: "0x9a9ee44782accc4b5e893c0e7d16473ce19b79d6",
      mixHash: "0x0000000000000000000000000000000000000000000000000000000000000000",
      nonce: "0xffffffffffffffff",
      number: 216567,
      parentHash: "0x1f80f98bfa571053745d99146f2665a2a69004e8134cc750ba94b17bd2fd5639",
      receiptsRoot: "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
      sha3Uncles: "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
      size: 609,
      stateRoot: "0xe2236887f5f873fd7e4a12ba8e6bbf10ab6b2c70adcba3488bb6e9c9e89b1151",
      timestamp: 1577436727,
      totalDifficulty: 433020,
      transactions: [],
      transactionsRoot: "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
      uncles: []
    > eth.getBlock('216568')
      miner: "0x0000000000000000000000000000000000000000",
Some more properties

Checking the balance of the address 0x9a9ee44782accc4b5e893c0e7d16473ce19b79d6 returns 0:

> eth.getBalance('0x9a9ee44782accc4b5e893c0e7d16473ce19b79d6')

I've read here that the sealer address should be in the extra data, but which part is it in the following extradata (from block 216567 above) ?

extraData: "0xd883010907846765746888676f312e31332e34856c696e757800000000000000a5d63126675c1b8f9811e995dd8cb5276486a64b06ad590a542c74aea142b68a64abc2f5bbd1ba3b10adfa8200ce678961b22c724f4eca81ba1bb770942c7d6e01",

How can I get, in PoA, the sealer of a block and how can I know the block reward ?

PS: I have access to the following modules in geth: admin:1.0 clique:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0

1 Answer 1


PoA networks do not natively have rewards baked into the consensus. There are instances where these are created with smart contracts that make system calls (see Energy Web Chain and POS_DAO) , but if you run clique natively there will be no block rewards.


  • Finally an explicit answer about this. Thanks. Then the quantity of ether in the network is finite, right ? The network is condemned to no longer be functional after an amount of time (can be very very long, but still at the very end ...) Commented Dec 28, 2019 at 10:08
  • For clique? Or with the reward model? The security model is not premised on block incentives so they aren’t native. The block chain can continue to function for as long as you need it too. Incentives are not built into the consensus layer and if you need to add them, they have to be done at the application /smart contract level. Hope it makes sense
    – 0xsegfault
    Commented Dec 28, 2019 at 10:11
  • I'll come back when I've read the sources you gave me ;) Commented Dec 28, 2019 at 10:13

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