och-suit

Project Overview

Certus Protocol is a decentralized cross-chain Oracle that truly implements a new generation of cross-chain Oracle service protocol for data on-chain verification, and open a compensation channel for data users who suffer business losses from using Oracle data.

Certus Protocol is a stochastic secure Oracle solution developed based on the Substrate framework, supporting hybrid Babe and off-chain workhorses, incorporating on-chain governance, bringing the Optimistic challenge model into the Oracle space, supporting the Ink contract ecosystem, and bringing better quality Oracle services to blockchain developers.

Project Details

The project structure consists of staking-extends that control Pallet-Staking, certus-oracle that controls quotation and audit work, oracle-politics that controls political management, and their high-level abstraction layer oracle-provider-support.

From the perspective of validators, new nodes will have the opportunity to apply to become validators of certus-chain by staking on Pallet-Staking. The staking-extends module is responsible for capturing new validators, and certus-oracle is responsible for creating audit tasks for new validators. and ask these nodes to execute, If the node executes successfully, it means that the audit is passed, otherwise the staking-extend module will remove the failed ones and make it impossible to participate in the election normally.

After the audit, the passed nodes participate in the operation of certus-chain. In addition to enjoying the normal NPos rewards, they can also receive commissions for paid quotations. These proof-of-work and reward distribution are all done through the oracle-politics module.

certus-component-workflow

Pallet: certus-oracle

• submit_local_xray An offline method that submits and saves the local publicly data by the validator node to the chain for debugging.

• submit_ask_data Submit an certus-data request, The request is processed by all online validators, and the aggregated result is returned immediately.

• submit_forced_clear_purchased_price_payload_signed An offline method that submits and saves the purchase-result data. If the count of validator submitted by purchase-id already reached the threshold requirements, then average price will be aggregation and mark PURCHASED_FINAL_TYPE_IS_PART_PARTICIPATE

• submit_purchased_price_unsigned_with_signed_payload An offline method that submits and saves the purchase-result data. If all validators submit price-result, then average price will be aggregation and mark PURCHASED_FINAL_TYPE_IS_ALL_PARTICIPATE

• submit_price_unsigned_with_signed_payload An offline method that submits and saves the free certus-data results.

• submit_create_pre_check_task Submit a pre-check task. When a new validator is elected, a pre_check_task task will be submitted through this method within a specific period. This task is used to ensure that the certus-data response function of the validator node can be used normally.

• submit_offchain_pre_check_result When the validator responds to the pre-check task, the pre-check result data is submitted to the chain. If approved, it will be passed in the next election cycle, not immediately.

• submit_offchain_http_err_trace_result When there is an error in the offchain http request, the error data will be submitted to the chain through this Call

• update_purchased_param Updating the purchase-related parameter settings requires the Technical-Committee signature to execute.

• update_och_control_setting Update the control parameters of certus-oracle

• revoke_update_request_propose Revoke the key-pair on the request token list.

• update_request_propose Modify or add a key-pair to the request list.

• update_allowable_offset_propose Update the value of the allowable offset parameter to determine the abnormal range of the submitted price

• update_pool_depth_propose Update the depth of the price pool. When the price pool reaches the maximum value, the average price will be aggregated and put on the chain.

• update_pre_check_token_list Update the pre-checked Trading pairs list for checking the validator price feature.

• update_pre_check_session_multi session-multi indicates the trigger pre-check session period before the era.

• update_pre_check_allowable_offset The maximum offset allowed for pre-check when validation.

Workflow

Validator Pre-Audit

Certus-oracle obtains the newly elected validator through the IStakingNpos::pending_npos trait, and submits the pre-check task to the chain through submit_create_pre_check_task extrinsics. Use the IStakingNpos::near_era_change trait to determine whether the session period close to the election has been reached, and if so, submit the new verification task to the chain through submit_offchain_pre_check_result extrinsics. Validators that do not pass the review will not appear in the list of targets for elections.

Free Trade-data

When the offchain is working, the block author of the current block will be obtained according to the data provided by authorship. If the "authority-id" corresponding to the block author is consistent with the local "keystore", obtain the list of "transaction information" corresponding to the block, and send an http request to obtain its data, then call the submit_data_unsigned_with_signed_payload extrinsics upload the result to the chain . The chain will verify whether the submission matches the block author of the current block, and if so, the result will be stored in the data pool. When the data pool reaches the specified depth (this depth can be modified by the extrinsics update_pool_depth_propose), the average data aggregation event Event::AggregatedData occurs, which will generate data to the chain. The data related to a politics can be read through the certusOracle.certusData store.

Paid Trade-data

Users can submit a submit_ask_data transaction to have all nodes on the chain make an offer, but this requires payment some fee, which is more time-sensitive than getting the data for free. If submit a task successfully, you need to get the purchase_id from the Event::NewPurchasedRequest event, which will be used as the associated key value for other queries. The amount of payment is related to the number of data requests. If the nodes participating in the response are less than the response threshold, the task will fail, and the fee will not be deducted. (This threshold can be modified by extrinsics update_purchased_param). Once the data are aggregated successfully, an Event::PurchasedData event will be generated, and the relevant fees will be deducted from the origin account. Users can also read the corresponding result data through the certusOracle.purchasedData store.

Moudle: oracle-provider-support

• has_pre_check_task Determine whether there is a pre-check task for the validator through a stash account.

• get_pre_task_by_authority_set Get the pre-check information related to a certain certus-authority collection, the specific matching authority-id, account-id, and the block submitted by the task. Precheck tasks that only match the first certus-authority

• check_and_clean_obsolete_task Trigger this method on a specific cycle to clean up too old and passed tasks

• take_data_for_pre_check Obtain PreCheckList result data according to Data Type specified by check_config

• save_pre_check_result Will verify the data on-chain based on the result of PreCheckList and return PreCheckStatus as the result

• get_pre_check_status Get the pre-check status that a validator has stored, this status will affect whether it will be added to the validator list.

• clean_pre_check_status Remove pre-check status stored by a validator

• create_pre_check_task Create a pre-check task, return true if the creation is successful else return false

Workflow

KeyTypeId of Certus

Configure the definition of the sr25519 AuthorityId provided by the scrypto module into certus-oracle::AuthorityCertus. If session is enabled, certus-oracle needs to be configured into SessionKey.

Pre-review task flow

• Use has_pre_check_task to determine whether a validator has a pre-check task.
• If there is a pre-review task, get the corresponding price response through take_price_for_pre_check.
• Check and save the result data through save_pre_check_result, the returned results include PreCheckStatus::Prohibit and PreCheckStatus::Pass.
• Pass the block height to the check_and_clean_obsolete_task function to remove obsolete pre-review tasks and pre-check result to prevent overbloating.

Pallet: oracle-politics

• current_era_num To get the current ear, you need to consider that if the era-length changes, you still need to guarantee that the vector of time zones increases.

• get_earliest_reward_era Get the earliest reward era.

• calculate_fee_of_ask_quantity Input in a price_count to calculate the cost of the purchase.

• reserve_for_ask_quantity Keep the balance for the purchase.

• unreserve_ask Release the funds reserved for the purchase, which occurs after the failure of the ask-data.

• pay_to_ask Execute the payment, which will transfer the user’s balance to the Pallet

• record_submit_point Record the Points of the validator under an order

• get_record_point Get the Point of the record

• take_reward Claim all rewards under a given era

• get_era_income Get total income balance for an era.

• get_era_point Read the total balance for an era.

• check_and_slash_expired_rewards Check for expired rewards and destroy them if overdue

• take_purchase_reward Validators get rewards corresponding to eras. Note: An ear cannot be the current unfinished era, and rewards are not permanently stored. If the reward exceeds the depth defined by T::HistoryDepth, you will not be able to claim it.

• take_all_purchase_reward Validators get rewards, it will help validators get all available rewards Note: An ear cannot be the current unfinished era, and rewards are not permanently stored. If the reward exceeds the depth defined by T::HistoryDepth, you will not be able to claim it.

Workflow

Reward Deposit

• Payment is through the Trait provided by IForPrice. It is necessary to call reserve_for_ask_quantity to reserve the part balance of asker and associate it with the order-id.

• Through the Trait implementation provided by IForReporter, call record_submit_point to save the point. The block height needs to be passed in, and the pallet will convert it to the corresponding era and record it under an order-id.

• After the price-response is successful, call pay_to_ask to release the Balance reserved above, and pay the actual ask fee to the oracle-finance pallet.

Claim Reward

• Rewards are claimed by era, and rewards cannot be obtained for unfinished eras. You need to calculate the 'Balance' corresponding to each point in the corresponding era. Algorithm: Single Point Bonus = Total Revenue/Total Points on era.
• The validator needs to use the Controller account to perform the claim operation, This is for security reasons. The total amount received is equal to: Validator Points * Single Point Bonus.
• Rewards are transferred to the validator's Stash account via oracle-politics pallet.

Module: staking-extend

• current_staking_era() / Get the Era of the current Staking pallet.

near_era_change()

• period_multiple: session-multi indicates the trigger pre-check session period before the era.

old_npos()

• Get the list of validators before the election.

pending_npos()

• Get the list of new validators after the current election, excluding validators from the previous session.

Workflow

Adapter execution

• ElectionProvider of Staking Config is set to staking_extend::elect::OnChainSequentialPhragmen, GenesisElectionProvider is set to staking_extend::elect::OnChainSequentialPhragmenGenesis
• DataProvider of frame_election_provider_support::onchain::Config is set to staking_extend::data::DataProvider
• DataProvider of pallet_election_provider_multi_phase::Config is set to staking_extend::data::DataProvider
• After that, the staking election request will be sent to staking_extend, and then the Election module will also obtain the candidate list from staking_extend, and the adapter connection is successful.
• Call the pending_npos method to obtain a list of the new elected list, and then cooperate with the implementation of the ICertusOraclePreCheck::get_pre_check_status trait to block the newly selected validator.