POA Overview

As mentionned in the design document, the MONET Hub relies on a Proof of Authority (POA) system to control the validator-set of the underlying consensus system (Babble). Here we explain how this system is implemented in monetd.


The whitelist is a list of members who are allowed to run a validator node in the network. Upon processing an Internal Transaction from Babble (related to a join request), monetd queries the whitelist and accepts the request if and only if the corresponding address is whitelisted. For more information about Internal Transactions and Babble’s membership protocol please refer to Babble docs.

POA Smart Contract

Technically, the whitelist is implemented in the POA smart-contract, which is defined in the genesis file, and hence automatically provisioned upon starting a node, along with the pre-funded genesis accounts.

Adding Addresses to the Whitelist

It is possible to pre-populate the whitelist (cf. giverny) to include addresses at genesis. Once the network is up an running, it is also possible to add new addresses on the fly via a voting mechanism.

To add an address to the whitelist, someone already on the whitelist has to nominate the address, and everyone on the whitelist needs to cast a yes vote on that nomination. When the nomination collects yes votes from everyone, the address is automatically moved from the nominee list to the whitelist. This logic is implemented in the POA smart-contract, and can be called using monetcli.

monetcli whitelist displays the current whitelist.

monetcli nominee list displays the current nomineelist.

monetcli nominee vote is used to cast a vote for a nomination.