Professionalism and focus, win-win cooperation Filecoin's cryptographic and economic mechanisms combine to align participants' incentives with the network's goals and mission. Participants are incentivized with block rewards and storage order rewards, and when participants deviate from their commitment to the network, slashing their rewards is the primary form of mitigation for bad behavior. Slashing uses game theory and scientific decision-making to help solve one of the most important challenges facing decentralized storage networks like Filecoin. Without centralized control, Filecoin needs a built-in way to ensure the integrity of the network and align the incentives of its participants. Slashing their earnings can be achieved by fining on-chain nodes. If these nodes seek to maximize their personal interests at the expense of the broader Filecoin ecosystem, then slashing their earnings can effectively ensure the stability of the network. For any node participating in Filecoin, the most rational choice is always to act in good faith to maintain the network. Slashing Mechanism Introduction Every node that provides storage capacity to the network must stake in the form of Filecoin, and negligence or malicious behavior by the node will result in its earnings being "slashed" or forced to forfeit part of its collateral. After all, these actions will threaten the reputation and reliability of the network. In this way, slashing its earnings will create bad economic incentives for nodes, thereby preventing bad behavior by nodes on the chain. Slashing is therefore a built-in incentive mechanism to keep all nodes on the Filecoin network honest and reliable. Nodes will have to behave well or risk losing Filecoin collateral and storage capacity. When does Slashing appear? In three cases, nodes on the Filecoin network will face revenue cuts: When a node deletes data before the storage deal expires (contract expiration). When a node fails to submit its proof of spacetime as required (storage errors slashing). When a node attempts to fork the Filecoin blockchain or manipulate elections (consensus slashing).
In each case, the node failed to act in a way that honored its commitment to the network. Let’s look at each of these in more detail. Transaction failure leads to slashing Nodes store data in storage partitions called "sectors" on the Filecoin network. In each sector, nodes can sign storage transaction contracts with customers and provide transaction collateral to guarantee that the transaction will be well maintained. The protocol requires a minimum transaction collateral for a basic level of guarantee, and if the transaction is terminated, the income is slashed. However, nodes can provide higher transaction guarantees, which means providing a higher level of service and reliability to potential customers. The Filecoin network expects that a node will continuously store a client's files for a set period of time determined by its storage contract: the node is responsible for keeping all sectors online and continuously available until the end of the contract period. A node may fail to meet this expectation, either by defaulting before the contract expires or by neglecting to continuously store a client's data as promised. One of the following two methods can prove that the node has breached the contract: 1. By taking committed storage sectors offline prior to the contract end date, or voluntarily terminating the contract early. 2. Nodes that voluntarily terminate their contracts are required to pay a termination fee. Nodes that completely fail to keep storage sectors online will be slashed; they will automatically forfeit a portion of their Filecoin collateral and have their storage capacity reduced. Storage failure causes slashing As mentioned in previous articles, Filecoin uses a cryptographic protocol (proof system) to verify the storage behavior performed by nodes for the network and ensure that storage is provided as promised. Part of this proof system is Filecoin's unique Proof of Spacetime (PoSt), which issues random cryptographic challenges (WindoPoSt) to nodes every day. Only when the nodes are able to query the customer data they promised to store can they reply to verify that they are indeed providing storage. The Filecoin protocol considers a node that fails at least one WindowPoSt to be in a failed state. The node will lose storage capacity on the sector where the failure was discovered. It can only restore its sector strength after successfully responding to subsequent WindowPoSt. However, if the nodes on the chain maintain this state for two consecutive days, the storage failure fee will be reduced every day. After all, Filecoin only incentivizes reliable and useful storage, and it is critical for storage clients to know that all data is reliably stored on Filecoin. If a sector reaches the maximum number of consecutive failure days allowed, all rewards earned by the sector and its initial pledged collateral will be cut. Consensus Errors Lead to Slashing The Filecoin blockchain is arranged by block height. At each height, nodes can participate in a leader election to determine who will mine the next block of the Filecoin blockchain and receive its block reward. Leaders are selected based on the Filecoin Pool selected for its storage capacity. The protocol for leader election is called Expected Consensus (EC) . In leader election, each node draws a random seed provided by Drand Beacon. The node then performs a proof-of-election function on that random seed. If the value generated by the proof-of-election function is valid, the node is eligible to mine a block. When nodes generate new blocks during an EC, these blocks are clustered together to form a "tip set," a family of blocks mined in the same epoch and connected to the same parent block from a previous epoch. Filecoin's EC is unique in that many nodes can win in the leader election: at each block height, different nodes can generate multiple valid blocks at once. In order to avoid the Filecoin blockchain splitting or "forking" into multiple competing chains, nodes must agree that the canonical or true blockchain is the blockchain with the heaviest set of tips, that is, the most tips at the block height. A consensus flaw occurs when two different blocks are mined at the same height. When this happens, the node's storage is temporarily suspended and it is penalized. Unlike storage failures and contract termination failures, other nodes in the Filecoin network must report consensus failures. In this case, slashing is not automatically performed. However, Filecoin nodes have an incentive to report consensus errors. The Filecoin network uses a slashing mechanism to create strong economic incentives for node misbehavior. Since misbehaving nodes will always suffer a loss of their collateral and storage capacity, there is no good reason for nodes to ignore or harm the Filecoin network. In this way, Slashing helps clients feel confident that nodes will store their data exactly as promised. Therefore, Slashing is a special feature of the Filecoin protocol that protects the integrity, reliability, and reputation of the Filecoin ecosystem. |
