# Overview ### Introduction BlockRazor RPC provides users with MEV protection and refunds, and supports BSC and Ethereum. Transactions submitted by users, if processed by regular RPC, will be publicly broadcasting between node P2P networks. Transactions are extremely vulnerable to MEV attacks, resulting in the potential rebate space generated by transactions being squeezed out. Compared to regular RPC, transactions submitted to BlockRazor RPC will be kept in a private channel, thus resisting MEV attacks of sandwich and frontrunning. And BlockRazor RPC supports users to customize the disclosure of transaction data, and the generated profit will also be refunded to users in real-time. ### Advantages **Security** Scutum supports protection for all types of transactions on Ethereum and BSC, resisting MEV attacks of sandwich and frontrunning. **Fast inclusion** Auction of bundle, supporting multi-layer nested backrun strategy, is adopted to maximize the value of transaction, which will be then sent to top block builders on Ethereum and BSC with extremely low latency utilizing the technique of high-performance network **Refund in real time** The potential transaction profits will be refunded to users in real time. Refund transactions will be built in advance within the RPC and sent to the block builder immediately after the user's transaction, and included in the same block. **Rapid Integration** Traders can add RPC to their wallets with one click, and project builders can customize RPC URL and trading privacy data to complete rapid RPC integration. ### FAQ **How can transactions receive refunds while resisting MEV attacks?** * The transactions are shared with Searchers according to custom disclosure. Searchers can only perform harmless backrun strategies on transactions, thereby not only defending against sandwich and front-running attacks but also refunding the profits generated from backrun to users. **When and in what form will I receive the refund?** * If there is an opportunity to execute the backrun strategy for the transactions submitted by the project, the refund is completed by the Searcher calling the smart contract in real-time, meaning that the refund transaction and the project transaction will be successfully executed within the same block. **Will the transactions be reverted?** * If Scutum detects that a transaction will revert and its revert protection is enabled, it will not be included in the block. **How are profits distributed among various roles?** * If there is profit margin in the transaction and it is included in the block after the bid is successful, BlockRazor RPC will refund part of the bid to the user, and the remaining will be used to pay BlockRazor RPC's handling fee and to pay the builder for bribe to get the transaction included in the very next block. ### New to MEV #### MEV The full name of MEV is Maximal Extractable Value, which means that during the production process of new blocks, the MEV robot will reorder the transactions in the mempool to maximize the overall value of the block while making profits from price fluctuations. In the MEV strategy, the sandwich attack is the most harmful to users. The robot will construct an attack transaction right before and after the target transaction (usually a DEX SWAP transaction), causing the user to receive a smaller amount of cryptocurrency than expected #### Searcher Searchers refer to independent network participants who find and exploit MEV opportunities. They detect profitable MEV opportunities by running complex algorithms, construct [bundles](overview.md#bundle) and submit them to [MEV Protect RPC](overview.md#rpc) or block builders, with a view to including the bundle into the block to obtain profits. Among the MEV strategies executed by Searcher, [sandwich](overview.md#sandwich) and [frontrunning](overview.md#frontrunning) are the most harmful to users, while the backrun strategy is harmless to users because it is executed after user transactions. #### Sandwich Sandwich is a malicious MEV strategy. This attack usually occurs on decentralized exchanges (DEX). When a user (such as Alice) wants to buy a token on the DEX, a malicious trader (such as Bob) can detect this transaction and insert two of his own transactions before and after Alice's transaction. Bob first buys token A before Alice’s transaction(Bob will insert a transaction with high gas before Alice's transaction to ensure that it is processed with priority. This type of attack is also called frontrunning), which pushes up the price of token A. Then, after Alice's transaction, Bob sells token A. At this time, since the price has been pushed up, Bob can profit from it. This attack method not only affected the execution price of Alice's original transaction, but also allowed Bob to gain profits by manipulating the price. #### Backrun Backrun is a harmless MEV strategy. The executor of the backrun strategy will strategically execute a backrun transaction immediately after a high-value transaction, taking advantage of the arbitrage opportunities generated by the price fluctuation of the previous transaction to obtain profits. Since the backrun transaction is executed after the user's transaction, it will not affect the previous transaction. #### Bundle In MEV, Searcher captures arbitrage opportunities by putting user transactions and strategy transactions into a bundle in a certain order. Bundles are atomic. If any transaction simulation in the bundle fails, the entire bundle will not be executed, which means that all transactions in the bundle will either execute successfully or fail. #### RPC RPC (Remote Procedure Call) is a protocol that allows one program (client) to request services from another program (server) over a network without knowing the details of the underlying network. In the context of blockchain, RPC is usually used for node communication and client interaction. Blockchain clients (such as wallets or DApp front-ends) interact with blockchain nodes through RPC to send transactions, query account balances, and obtain blocks. Information etc. ### Privacy Statement BlockRazor RPC does not track any kind of user information (i.e. IP, location, etc.). Only information that is public on the blockchain is preserved, such as timestamp of a transaction.