The birth of the cheapswap protocol

The original is published in https://github.com/33357/smartcontract-apps This is a Chinese community , Analyze the architecture and implementation of smart contract application on the market . Welcome to the open source knowledge project ！

CheapSwap The birth of the agreement

Why is there CheapSwap

If you want to withdraw money from a centralized exchange USDT To ETH On the chain , Will be scared by its high handling fees . With Binance For example , Withdrawal ETH To ERC20 Only 1.4 USDT The handling charge , Cash withdrawal USDT To ERC20 But it needs to be whole 10 USDT The handling charge . It's obvious that ,USDT There is no fee for transfer ETH Transfer fee 7 Twice as many , This is what the exchange deliberately set up , Its purpose is to let everyone out USDT Pay more money when you're ready .

However CheapSwap The protocol developers have found loopholes in the embodiment process of the centralized exchange . With Binance For example , When the user withdraws ETH When ,binance Will send a gasLimit by 207128,maxFeePerGas by 102 Of ETH Transfer transaction . The of the deal maxFee the height is 0.021127056 ETH, Much higher than the user's cash withdrawal cost 1.4 USDT.

therefore ,CheapSwap The protocol hopes to exploit this vulnerability , Help users spend only cash ETH To ERC20 The cost of , Cash withdrawal completed USDT To ERC20 The job of .

CheapSwap Protocol principle

CheapSwap The agreement took advantage of Binance Withdrawal ETH The extra service charge you get when you get there , Withdrawal in progress ETH At the same time UNISWAP_V3 Admiral ETH Switch to USDT, And will USDT To the user's account .

In order to achieve this function , Users need to CheapSwapFactory Create a contract account on the contract , This contract will record the user's address and the information that needs to be changed TOKEN Address . Users only need to be in Binance Admiral ETH Withdraw cash to this contract address , All operations will be completed automatically .

CheapSwap The protocol will charge for each call of this function 0.001 ETH The handling charge , To help the development of the agreement .

How to use CheapSwap agreement

1. open CheapSwapFactory Contract website
   https://etherscan.io/address/0xb5852e69be43f4f71fe656144485d2b2675bdb7a#writeContract

2. Click on connet to web3 Connect wallet

3. Click on createTokenOutAddress, Input USDT Contract address 0xdAC17F958D2ee523a2206206994597C13D831ec7, Click on write, Wait for the wallet to confirm the transaction .

4. Click... After confirming the wallet read Contract, Click on tokenOutAddressMap, First enter your wallet address , The second input USDT Contract address 0xdAC17F958D2ee523a2206206994597C13D831ec7, Click on Query, Get your ETH Withdrawal address .

5. stay Binance Normal cash withdrawal ETH To Yours ETH Withdrawal address , After the transaction is confirmed, you will get an equal amount of USDT.

CheapSwap The problem of the agreement

1. CheapSwap agreement At present, it relies on Binance Of ETH Withdrawal vulnerability exists , If Binance Fix the problem ,CheapSwap agreement Need to find another exchange .

2. Due to the particularity of the transaction on the chain ,CheapSwap agreement Not applicable to large amount USDT Withdrawal . It is recommended that the withdrawal amount be less than 3000 USDT.

CheapSwap The development of the agreement

If Binance Continue to allow CheapSwap The agreement continues to make use of its excess withdrawal costs , that CheapSwap The agreement will continue to support preferential withdrawal in more currencies . If other developers want to take advantage of it ,CheapSwap The agreement will also provide technical support .

Project open source address

CheapSwap The protocol is open source ,github The address is https://github.com/33357/cheap-swap-contract