FEATURE: decentralised Hydra-Tally-App ( Removal of Federation)

[matiwinnetou]

Hydra Tally App is currently working in a federated mode, that is all Hydra Head Operator need to trust each other. This is obviously not how Hydra is supposed to be working, operators do not trust themselves by definition.

In order to fully decentralise smart contract and Hydra-Tally-App one needs to find a solution and fix number of identified issues / existing attack vectors within a Hydra Head:

• Deduplication of imported votes to smart contract, e.g. by using multi-validator approach: Smart Contract (e.g. using https://github.com/micahkendall/distributed-set)
• Preventing any Hydra Operator to close the head while tallying the votes (e.g. by forcing them to lock up in a contract and slashing in case of early fan-out)
• Prevent accumulator eUTxO fraud, any Hydra operator could commit fraudulent eUTxO to the contract address (e.g. Watch Towers to check if eUTxO is pointing to the root via a fraud proof transaction, try this with 2 contracts instead)