4.2 KiB
description: Pantheon Clique Proof-of-Authority (PoA) consensus protocol implementation path: blob/master/config/src/main/resources/ source: rinkeby.json
Proof of Authority
Pantheon implements the Clique Proof-of-Authority (PoA) consensus protocol. Clique is used by the Rinkeby testnet and can be used for private networks.
In PoA networks, transactions and blocks are validated by approved accounts, known as signers. Signers take turns to create the next block. Existing signers propose and vote to add or remove signers.
Genesis File
To use Clique in a private network, Pantheon requires a PoA genesis file. When connecting to Rinkeby, Pantheon uses the rinkeby.json genesis file in the /pantheon/config/src/main/resources directory.
A PoA genesis file defines properties specific to Clique:
!!! example "Genesis JSON file (stripped)"
json { "config": { .... "clique": { "period": 15, "epoch": 30000 } }, ... "extraData": "0x0000000000000000000000000000000000000000000000000000000000000000dd37f65db31c107f773e82a4f85c693058fef7a90000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", ... }
The properties specific to Clique are:
period- Block time in seconds.epoch- Number of blocks after which to reset all votes.extraData- Initial signers are specified after the 32 bytes reserved for vanity data.
To connect to the Rinkeby testnet, start Pantheon with the --rinkeby command line option. To start a node on a PoA private network, use the --network-id command line option and --genesis option.
Adding and Removing Signers
To propose adding or removing signers using the JSON-RPC methods, you must enable the RPC interface using the --rpc-enabled option. If also using the --rpc-api option, include CLIQUE.
The JSON-RPC methods to add or remove signers are:
To propose adding a signer, call clique_propose specifying the address of the proposed signer and true.
!!! example "JSON-RPC clique_propose Request Example"
bash curl -X POST --data '{"jsonrpc":"2.0","method":"clique_propose","params":["0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73", true], "id":1}' <JSON-RPC-endpoint:port>
When the next block is created by the signer, a vote is added to the block for the proposed signer.
When more than half of the existing signers propose adding the signer and their votes have been distributed in blocks, the signer is added and can begin signing blocks.
Use clique_getSigners to return a list of the signers and to confirm that your proposed signer has been added.
!!! example "JSON-RPC clique_getSigners Request Example"
bash curl -X POST --data '{"jsonrpc":"2.0","method":"clique_getSigners","params":["latest"], "id":1}' <JSON-RPC-endpoint:port>
To discard your proposal after confirming the signer was added, call clique_discard specifying the address of the proposed signer.
!!! example "JSON-RPC clique_discard Request Example"
bash curl -X POST --data '{"jsonrpc":"2.0","method":"clique_discard","params":["0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73"], "id":1}' <JSON-RPC-endpoint:port>
The process for removing a signer is the same as adding a signer except you specify false as the second parameter of clique_propose.
Epoch Transition
At each epoch transition, all pending votes collected from received blocks are discarded. Existing proposals remain in effect and signers re-add their vote the next time they create a block.
Define the number of blocks between epoch transitions in the genesis file.