Filecoin’s cryptographic and economic mechanisms combine to align participants with the network’s goals and mission. Filecoin incentivizes participants with block rewards as well as storage order rewards, but 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 decision science 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. If there are miners seeking to maximize their own personal interests at the expense of the broader Filecoin ecosystem, then slashing can curb this behavior by fining miners . For any miner participating in Filecoin, the most rational choice is always to act in good faith to maintain the network. Every miner who provides storage capacity to the network must post Filecoin as collateral. If any miner acts negligently or maliciously, they will be "slashed," or forced to forfeit part of their collateral. After all, the reputation and reliability of the network is at stake. In this way, slashing creates bad economic incentives for miners, thereby discouraging bad behavior. Slashing is therefore a built-in incentive mechanism to keep all miners on the Filecoin network honest and reliable. Miners will have to behave well or risk losing Filecoin collateral and storage capacity. When does slashing occur? There are three scenarios in which Filecoin miners can be slashed. These are: When miners delete data before the storage deal expires (contract expiration). When a miner fails to submit their proof of spacetime as required (storage errors will be slashed). When a miner attempts to fork the Filecoin blockchain or manipulate an election (consensus slashing).
In each case, miners are unable to act in a way that honors their commitment to the network, and so, miners’ rewards should be cut. Slashing of failed transactions Miners store data in storage partitions called "sectors" on the Filecoin network. In each sector, miners 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 with a basic guarantee level, and if the transaction is terminated, the collateral will be significantly reduced. However, miners can offer higher transaction guarantees, which means a higher level of service and reliability to potential customers. The Filecoin network expects that miners will continuously store clients’ files for a set period of time determined by their storage contracts: miners are responsible for keeping all sectors online and available until the end of the contract period. Miners may fail to meet this expectation, either by defaulting before the contract expires or by neglecting to continuously store clients’ data as promised. There are two ways a miner can indicate that they have defaulted : by taking committed storage sectors offline before the contract end date, or by voluntarily terminating the contract early. Miners who voluntarily terminate their contracts are required to pay a termination fee. Miners whose storage sectors cannot remain online will be slashed ; they will automatically forfeit a portion of their Filecoin collateral and have their storage capacity reduced.
Slashing of storage failure As mentioned in the previous article, Filecoin uses a cryptographic protocol (proof system) to verify the storage behavior performed by miners for the network and ensure that miners provide storage as promised. Part of this proof system is Filecoin's unique Proof of Spacetime (PoSt), which issues random cryptographic challenges (WindoPoSt) to miners every day. Miners can only answer this challenge if they can query the customer data they promised to store. Verify that they are indeed providing storage. The Filecoin protocol considers miners that fail WindowPoSt to be in a failed state. This indicates that the miner loses storage capacity on the sector that finds and discovers the failure. The miner can only recover its sector storage capacity after successfully responding to subsequent WindowPoSt. However, if a miner maintains 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 allowed number of consecutive failure days, all rewards earned by the sector and its initial staked collateral will be cut. Blocks on the Filecoin blockchain are arranged by height, and at each height, miners participate in a leader election to determine who will mine the next block of the Filecoin blockchain and receive its block reward. Leaders are elected based on the pool of Filecoin miners selected for their storage capacity. The protocol for conducting leader elections is called Expected Consensus (EC). In leader election, each miner draws a random seed provided by Drand Beacon. The miner then performs a proof-of-election function on that random seed. If the value generated by the proof-of-election function is valid, the miner is eligible to mine. When miners generate new blocks during an EC, these blocks come 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 miners can win in the leader election: at each height, different miners can generate multiple valid blocks at once. To avoid the Filecoin blockchain splitting or "forking" into multiple competing chains, miners must agree that the canonical or true blockchain is the blockchain with the heaviest tip set, that is, the tip set with the most blocks in history.A consensus flaw occurs when two different blocks are mined at the same height. When this happens, the miner's storage is temporarily suspended and they are penalized. Unlike storage failures and contract-breaking failures, other miners in the Filecoin network must report consensus failures. In this case, slashing is not automatically performed, however, Filecoin miners have an incentive to report consensus errors. The Filecoin network uses slashing to create strong economic incentives for miner misbehavior. Since misbehaving miners will always suffer the loss of their collateral and storage capacity, miners have no good reason to ignore or harm the Filecoin network. In this way, slashing helps clients feel confident that miners will store their data exactly as promised. As such, slashing is a feature of the Filecoin protocol that protects the integrity, reliability, and reputation of the Filecoin ecosystem. |
