Reward Manager

1. Biweekly Reward Cycle

The Curvance Protocol operates on a biweekly (2-week) epoch cycle for distributing rewards point amounts across all supported chains. This process is coordinated by the MessagingHub contract which serves as the cross-chain communication layer.

Key aspects:

• Each epoch lasts exactly 2 weeks as defined by EPOCH_DURATION in the CentralRegistry.

• The MessagingHub coordinates epoch transitions by querying points across all chains.

• The RewardManager tracks which epoch's rewards have been delivered using nextEpochToDeliver .

• State transitions occur when the MessagingHub calls recordEpochRewards() with the calculated reward amounts.

State machine:

2. Pro-Rata Distribution

Rewards are distributed proportionally across all chains based on the amount of points on each chain.

Key aspects:

• The MessagingHub uses Wormhole's Cross-Chain Query (CCQ) to get accurate point counts from all chains.

• Reward distribution is calculated as: (Chain's Points / Total Points) * Total Rewards .

• Each chain receives a pro-rata share of the total protocol fees based on its proportion of points.

• This creates an incentive for chains to accumulate points to increase their share of rewards.

Data flow:

3. Reward Accumulation

The system allows users to accumulate rewards over multiple epochs without having to claim them immediately.

Key aspects:

• Each user has a userNextClaimIndex that tracks the next epoch they can claim rewards from.

• epochRewardsPerPoint records the rewards allocated per point for each epoch.

• Users can claim multiple epochs of accumulated rewards in a single transaction.

• The formula for a user's rewards for an epoch is: (User's Points * epochRewardsPerPoint[epoch]) / WAD .

4. USDC Distribution via CCTP/Wormhole

The cross-chain movement of rewards (primarily USDC) is handled through Circle's Cross-Chain Transfer Protocol (CCTP) and Wormhole's messaging system.

Key aspects:

• The protocol uses CCTP to transfer USDC between chains, ensuring secure token transfers.

• Wormhole's automatic relayer system delivers cross-chain messages with execution guarantees.

• The MessagingHub sends both USDC tokens via CCTP and reward metadata via Wormhole.

• When a chain receives USDC, it routes the tokens to its local RewardManager.

Cross-chain token flow:

This architecture ensures that rewards are efficiently distributed across chains while maintaining a consistent state of reward records throughout the entire protocol.