I am creating a pool as a pet project and using open-ethereum-pool as reference. I am working at share verification phase right now. But for some miner sends invalid shared. After viewing logs I found that difficulty is much lower than I set in my pool (2000MH).

Logs for both mine and open-ethereum-pool from Claymore (I just run it at the same time on 2 different GPU's): https://gist.github.com/ssbb/6266b783896ef56ab8e1b19c5874c3f9

You can see from open-ethereum-pool:

07:19:22:520    8e0 buf: {"id":0,"jsonrpc":"2.0","result":["0xd10ad5d96675e0b6758637046cc0537158201392a8f5cd927c00d5a805c57485","0xcdf42a47e552f9b4eb01d44a7b6a2b057fbfa1070f3148fd8e7f937a417ffdc1","0x0225c17d04dad2965cc5a02a23e254c0c3f75d9178046aeb27ce1ca574"]}

07:19:22:536    8e0 parse packet: 236
07:19:22:536    8e0 ETH: job changed
07:19:22:551    8e0 new buf size: 0
07:19:22:551    8e0 ETH: 06/14/17-07:19:22 - New job from
07:19:22:567    8e0 target: 0x0000000225c17d04 (diff: 2000MH), epoch #21

And from my pool:

07:19:23:630    12b4    buf: {"result":["0xd10ad5d96675e0b6758637046cc0537158201392a8f5cd927c00d5a805c57485","0xcdf42a47e552f9b4eb01d44a7b6a2b057fbfa1070f3148fd8e7f937a417ffdc1","0x225C17D04DAD2965CC5A02A23E254C0C3F75D9178046AEB27CE1CA574"],"jsonrpc":"2.0","id":3}

07:19:23:646    12b4    parse packet: 235
07:19:23:646    12b4    ETH: job changed
07:19:23:661    12b4    new buf size: 0
07:19:23:661    12b4    ETH: 06/14/17-07:19:23 - New job from
07:19:23:677    12b4    target: 0x000000225c17d04d (diff: 125MH), epoch #21

As you see - header, seed and diff are the same. But for some reason it's 2000MH for open-ethereum-pool and only 125MH for my pool.

Why this may happen? Which values will affect this?

  • "But for some miner sends invalid shared" I mean "But for some reason miner sends invalid shared"
    – ssbb
    Jun 14, 2017 at 14:47
  • Hard to say something without looking at the code, perhaps the "This mode is not currently supported and will cause more stale shares." in the logs is related.
    – Ismael
    Jun 14, 2017 at 15:42
  • do you know the suitable diff amount for 20/25 GH/s private pool, diff could work ?
    – mcm
    Aug 24, 2018 at 17:02
  • If you have a new question, please ask it by clicking the Ask Question button. Include a link to this question if it helps provide context. - From Review
    – Ismael
    Aug 24, 2018 at 18:04

1 Answer 1


Just found an issue. In open-ethereum-pool hex hashes are prefixed with 0x0 and not just 0x. works fine with prefixed difficulty.


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