reward

Overview ¶

Package reward implements the Klaytn Reward System. The Klaytn reward system manages stakingInfo and distributes block rewards.

Managing stakingInfo ¶

Klaytn uses WeightedRandom policy to choose a block proposer. It means, the percentage of becoming a block proposer depends on how much KLAY a node has staked. Therefore, a node with stakes more than others will have more opportunities than other nodes.

StakingInfo is a data including stakingAmount and addresses (node, staking, reward, KFF and KCF). StakingAmount is a balance how much KLAY each node has staked. Only CCO can stake KLAY. Each CCO stakes KLAY by a smart contract called staking contract. StakingAmount is derived by checking balance of staking contract. StakingInfo has 5 types of addresses. All addresses are obtained by the addressBookContract which is pre-deployed in the genesis block. stakingAddress are addresses of staking contracts of CCO. reward, KFF and KCF addresses are the addresses which get a block reward when a block has been created. StakingInfo is made every 86400 blocks (stakingInterval) and used in a next interval.

type StakingInfo struct {
	BlockNum              uint64
	CouncilNodeAddrs      []common.Address // Address of Council
	CouncilStakingAddrs   []common.Address // Address of Staking contract which holds staking balance
	CouncilRewardAddrs    []common.Address // Address of Council account which will get a block reward
	KCFAddr               common.Address   // Address of KCF contract
	KFFAddr               common.Address   // Address of KFF contract
	UseGini               bool             // configure whether Gini is used or not
	Gini                  float64          // Gini coefficient
	CouncilStakingAmounts []uint64         // StakingAmounts of Council. They are derived from Staking addresses of council
}

StakingInfo is managed by a StakingManager which has a cache for saving StakingInfos. The StakingManager calculates block number with interval to find a stakingInfo for current block and returns correct stakingInfo to use.

related struct
- RewardDistributor
- StakingManager
- addressBookConnector
- stakingInfoCache
- stakingInfo

Distributing Reward ¶

Klaytn distributes the reward of a block to proposer, KFF and KCF. The detail information of KFF and KCF is available on Klaytn docs.

Token Economy - https://docs.klaytn.foundation/content/klaytn/design/token-economy

Configurations related to the reward system such as mintingAmount, ratio and unitPrice are determined by the Klaytn governance. All configurations are saved as rewardConfig on every epoch block (default 604,800 blocks) and managed by a rewardConfigCache.

A proposer which has made a current block will get the reward of the block. A block reward is calculated by following steps. First, calculate totalReward by adding mintingAmount and totalTxFee (unitPrice * gasUsed). Second, divide totalReward by ratio (default 34/54/12 - proposer/KFF/KCF). Last, distribute reward to each address (proposer, KFF, KCF).

related struct
- RewardDistributor
- rewardConfigCache