Add Soft Slashing Mechanism

[HDauven]

Summary

To maintain network integrity and security within the Succinct Attestation consensus protocol, a "soft" slashing mechanism is proposed. Provisioners, who are essential for creating blocks and confirming transactions, should be encouraged to act honestly and efficiently through this mechanism.

The proposed slashing will lower the impact of their stake, rather than reducing the actual stake, ensuring the total circulating DUSK will stay within our pre-defined limits and Provisioners are not dis-proportionally penalized.

The slashing mechanism is crucial for disincentivizing unwanted behavior (Nodes not responding, nodes spamming the network with wrong consensus messages) while ensuring participant engagement. The mechanism's design and implementation should prevent potential exploitation and ensure fairness.

Possible solution design or implementation

Penalty implementation

A soft slashing algorithm that lowers the impact of a non-compliant Provisioner's stake should be implemented, instead of reducing the actual stake. This means the staking contract should be extended with either a negative multiplier or calculation to reduce a stake.

Slashing conditions

We need to define clear conditions and thresholds for slashing, such as missing more than xx% of blocks, with a minimum threshold, to prevent penalizing honest nodes for sporadic issues.

We can consider a penalty proportional to the number of missed blocks, with the possibility of increased percentages for missing consecutive blocks or epochs.

Alternatively, we can also consider a "recovery" pathway if a node does end up responding again. This would allow Provisioners to not having to unstake and restake.

Additional context

Refer to the initial discussion and proposal here for more context. It might make sense to open a DIP for the slashing implementation as well.