Consensus Mechanism | The Symbol blockchain uses an innovative consensus mechanism called Proof-of-Stake Plus (PoS+), a modified version of the traditional Proof-of-Stake (PoS) algorithm. This enhanced mechanism aims to improve upon standard PoS by factoring in not only an account’s stake but also its overall activity in the ecosystem, thereby encouraging network participation and supporting its long-term health. Key Features of Symbol's Consensus Mechanism: 1. Proof-of-Stake Plus (PoS+): Stake: Similar to traditional PoS, PoS+ considers the total amount of harvested mosaics an account holds. Accounts with larger balances are incentivized to help ensure the ecosystem's success, but only accounts holding more than 10,000 harvesting mosaics are eligible to participate in harvesting. Activity: In addition to stake, the system rewards network participants based on their level of activity. This includes the amount of fees paid by an account and the frequency of their interaction with the network. Active users, particularly those who engage by paying fees, are rewarded, ensuring that all participants who contribute to the network’s growth have a higher chance of harvesting. Node Contribution: The system also considers the participation of accounts in running nodes. Accounts that benefit from fees collected by a node are incentivized, thus encouraging decentralization and network health. 2. Importance Score: The Symbol blockchain calculates an importance score for each eligible account based on three factors: stake, transaction activity, and node participation. The importance score is periodically recalculated every 720 blocks (roughly every 6 hours), ensuring it reflects an account’s current stake and activity in the network. The final importance score is used to determine the probability of an account being selected to harvest the next block. Accounts with higher importance scores are more likely to be chosen. 3. Partial Scores: Stake Score: The percentage of an account’s balance relative to the total of all high-value accounts’ balances. Transaction Score: The percentage of total fees paid by the account relative to all high-value accounts. Node Score: The frequency with which an account benefits from node fees, relative to other accounts. Activity Score: A weighted average of transaction and node scores, which is adjusted based on the account’s balance to give smaller accounts more influence. 4. Harvesting Probability: Activity and Stake Weighting: The final harvesting probability is based on the lower of the importance scores calculated from stake and activity. This ensures a balanced approach between users who hold large amounts of tokens and those who are actively engaged in the network. Incentivizing Small Accounts: Small accounts are given a relative boost in their importance score through the activity factor, allowing them a fairer chance to participate in block harvesting despite lower stakes. 5. Finality and Security: The PoS+ mechanism ensures that once a block is harvested, it is confirmed and final, maintaining high security and ensuring that malicious actions or inconsistencies do not compromise the network. |
Incentive Mechanisms and Applicable Fees | Incentive Mechanism: 1. Validator Rewards: Block Rewards: Validators, chosen based on their importance score, receive newly minted tokens (XEM) for successfully validating and adding blocks to the blockchain. The more a validator participates in the network and holds tokens, the higher their chances of receiving rewards. Transaction Fees: In addition to block rewards, validators also receive transaction fees from the transactions included in the blocks they validate. These fees are paid by network participants who initiate transactions. 2. Staking Rewards: Delegated Staking: Token holders can stake their XEM tokens and delegate them to selected validators. In return, delegators receive a share of the block rewards and transaction fees that the validator earns. This allows even users who do not operate a node to participate in the network’s consensus and earn rewards. Delegator Participation: The staking mechanism allows for both small and large participants to contribute to the network’s security and governance, and the rewards are distributed based on the amount of XEM tokens staked. 3. Activity Incentives: Transaction Fees and Activity: The Symbol network also rewards participants for their transaction activity. The more an account interacts with the network by paying transaction fees, the higher their chances of being selected as a validator or block producer in the future. This incentivizes active participation and promotes the growth and use of the network. 4. Node Incentives: Node Fee Distribution: Accounts that run nodes and receive transaction fees as part of their operation are incentivized by the number of times their node is the recipient of fees. This ensures that running a node is rewarding, further supporting decentralization and security across the network. Applicable Fees: 1. Transaction Fees: Fee Calculation: Each transaction on the Symbol network requires a transaction fee, which varies based on the complexity of the transaction and the current network conditions. Fees are generally calculated by the size of the transaction in bytes. Fee Distribution: Transaction fees are collected by the validators who include the transaction in a block. These fees serve as an additional incentive for validators to prioritize transactions and maintain the network’s efficiency. 2. Storage Fees: Symbol blockchain charges fees for storing data on the network, such as for smart contracts, tokens, and other data stored on the blockchain. This encourages users to manage their data efficiently, ensuring that the network's storage resources are used effectively. 3. Energy and Bandwidth Fees: Energy Usage: Symbol uses a resource model where participants must stake XEM tokens to access network resources, such as bandwidth and energy. The more XEM tokens staked, the more resources are available to perform transactions and interact with smart contracts. Bandwidth Usage: Each user is allocated a certain amount of bandwidth based on their XEM holdings. Users who exceed their allocated bandwidth can pay additional fees in XEM to ensure that their transactions are processed and included in blocks. |