Go-ethereum: How to calculate trusted checkpoint for a network

[hadv]

I found that in the ethereum config, there're some trusted checkpoint for light client and peer validation.

It's very helpful if we have a detail document guide to calculate it then community can know how to calculate the trusted checkpoint for their private network. Thank you so much!

I mean how to calculate those below item for a chain

        SectionIndex: 216,
        SectionHead:  common.HexToHash("0xae3e551c8d60d06fd411a8e6008e90625d3bb0cbbf664b65d5ed90b318553541"),
        CHTRoot:      common.HexToHash("0xeea7d2ab3545a37deecc66fc43c9556ae337c3ea1c6893e401428207bdb8e434"),
        BloomRoot:    common.HexToHash("0xb0d4176d160d67b99a9f963281e52bce0583a566b74b4497fe3ed24ae04004ff"),

[hadv]

@rjl493456442 @zsfelfoldi I know how to setup SectionIndex and SectionHead. Do you have any document guide to calculate CHTRoot and BloomRoot? Thank you!

[rjl493456442]

You don't need to calculate the trusted checkpoint by yourself. You can retrieve them from a full node(as well as a synced light client).

Steps

• Setup a full node with les server enabled(e.g. --lightserv 100)
• Retrieve checkpoint from console
  geth attach <path-to-ipc>
admin.nodeInfo
  You can see cht like
  cht: { bloomRoot: "0xc1ac19553473ebb07325b5092a09277d62e9ffe159166a1c6fbec614c4dfd885", chtRoot: "0xce7235999aa8d73c4493b8f397474dafc627652a790dec60c4a968e2dfa5d7be", sectionHead: "0xd0c206e064c8efea930d97e56786af95354ea481b35294a20e5a340937e4c2c9", sectionIndex: 26 },

Or you can retrieve checkpoint from RPC

• Setup a full node with les server enabled(e.g. --lightserv 100) and les RPC exposed (--rpcapi "eth,les")
• Send RPC call
  curl -X POST -H "Content-Type: application/json" localhost:8545 --data '{"jsonrpc":"2.0","method":"les_latestCheckpoint","params":[],"id":1}'
curl -X POST -H "Content-Type: application/json" localhost:8545 --data '{"jsonrpc":"2.0","method":"les_getCheckpoint","params":[26],"id":1}'

[rjl493456442]

Btw If you want to deploy the checkpoint oracle for your own private network, you can use tool checkpoint-admin https://github.com/ethereum/go-ethereum/tree/master/cmd/checkpoint-admin.

Step:

• Deploy a checkpoint oracle via checkpoint-admin
• Add the oracle information(e.g. address, signers, threshold) to config file
• Use checkpoint-admin to sign and publish some latest checkpoint

[hadv]

@rjl493456442 magnificent! appreciate it! 🙇