Digesting Data through the State Connector System
The Flare Network is designed to securely observe and interpret changes to the state of any integrated blockchain determined by governance for F-Assets. The first four blockchains to be integrated with the State Connector System are the XRP Ledger, Litecoin, Dogecoin, and Stellar. There are a couple of issues in the industry regarding the digesting of state changes to other blockchain networks. Many blockchains either require one to trust third parties or conform to their standards in order to digest the data. However, the Flare Network does not require any trust except for to the validators of the integrated blockchains. Furthermore, validators on the underlying blockchains do not even need to know about the existence of the Flare Network. This allows the Flare Network to freely digest all state changes on the integrated blockchains in regards to the existence, validity, and ordering of transactions.
Design of the State Connector System
The threat model design of the State Connector System is crucial to maintaining the accurate digesting of integrated blockchain state changes. This design requires attackers to alter the view of integrated blockchains through their own Flare Network validator and a quorum of other Flare Network validators. Additionally, this attack would have to last longer than the number of block confirmations required by a Flare Network application to digest state changes. The threat model design is established by requiring all Flare Network validators to independently observe the state changes to all integrated blockchains.
The first stage in digesting state changes to integrated blockchains requires a defined count of the number of blocks that are globally accessible to all Flare Network validators. All validators from integrated blockchains are able to compete in this process by delivering data availability proof transactions to the Flare Network over time. This process of tracking state change availability occurs via a smart contract on the Ethereum Virtual Machine (EVM) level. The integrated blockchain validators can submit a valid claim availability proof in a competition to be first, but only allows them to do so again after the timeout period has ended since the last valid claim availability proof. Additionally, a fee to submit the availability proofs is required to prevent attacking and spamming. The timeout period, fee, and count of finalized blocks from the integrated blockchains can all be changed via governance.
Once a validator submits a valid claim availability proof, then this proof must be verified by validators on the Flare Network. The verification process is handled using an EVM state transition call function that operates before and after a state transition. On top of this, the Flare Network validators must continually check to see if the new state information is available through their integrated blockchain validators. Each Flare Network validators’ EVM state will not be transitioned until the correct hash is retrieved from their integrated blockchain validator. Therefore, no proof can force anyone to assume an inaccurate state as long as the integrated blockchain validator is not compromised. The first integrated blockchain validator to successfully and accurately submit a verified availability proof is then awarded for doing so. The State Connector System contract will also receive information regarding the successful verification of a data availability proof.
The next stage in digesting state changes requires the Flare Network validators to prove the transaction. This requires some criteria to be met in order to prove that the transaction is valid before recording it to the State Connector System contract storage. Once these criteria are met and that data is available, then the stored transactions in the storage contract are now available to be referenced by any other contract on the Flare Network.
Advantages of the State Connector System
All advantages to the State Connector System are pulled from Flare Network documentation located here.
- Transaction validity references back to an underlying chain’s genesis block
- Safety depends on an underlying chain’s validators
- No cooperation needed from an underlying chain’s validators
- Can read the state of any blockchains
- No encoding of the current validators in control of an underlying chain to a smart contract on Flare
- Constant-sized proofs
- Every Flare validator independently verifies an underlying chain’s state
The State Connector System provides the Flare Network with flexibility to integrate other blockchains to the Flare Network. Data observed from these integrated blockchains is written into smart contracts on the Flare Network for use by any application on the network. This allows for the use of F-Assets throughout a multitude of applications.
Rewarding Integrated Blockchain Validators
A unique component of the Flare Network is its use of the validator ecosystems on its integrated blockchains. This means that control in the consensus of the Flare Network is proportionately doled out to the validators of all the integrated blockchains on the Flare Network, which are simply termed F-Assets. The proportions of control are weighted by market capitalization of each integrated blockchain. In short, the Flare Network is taking a unique approach to its consensus, which includes bootstrapping off the decentralization of previously formed blockchain networks. As the Flare Network integrations grow with other blockchains, so to can the robustness of the Flare Network’s own consensus protocol.
Every week the Flare Network will deterministically post a listing of integrated blockchain validators along with a weighting including market capitalization and how much each of these validators contributes to the consensus of their underlying chain. The process of creating this “ground truth listing” of validators will be publicly verifiable and decentralized. Additionally, there will be no size constraints on the future of the listing and all interested integrated blockchain validators can contribute. It is important to note that all miners on Proof of Work (PoW) blockchains can contribute; however, for blockchains utilizing a unique node list (UNL) like the XRP Ledger, validators will have to be listed on the UNL to receive any rewards.
Validators on the weekly ground truth listing will be randomly sampled through the State Connector System to provide data availability proofs, which will allow these validators to compete for a percentage of the inflationary Spark (FLR) rewards from the Flare Time Series Oracle. These rewards can be likened to block producing rewards on PoW blockchain networks. The State Connector System and its reward incentives allow the Flare Network to offer an alternative scaling solution to commonly used Proof of Stake (PoS) schemes by many smart contract networks, where the safety of the network is reliant on the total value staked in that network.