Meta Channel Network

Tokens are sent to deployer when deploying the contract. This could be a centralization risk as the deployer can distribute tokens without obtaining the consensus of the community.

In functions `_takeburnFee()` and `_takeburnFeeZZ()`, if the `_tFeeTotal` is larger than 39,000,000 ether, it sets variables `_burnFee` and `_burnFeeZZ` to zero but still burns the fee. ```solidity=1831 if(_tFeeTotal >= 39000000 * 10**18)_burnFee = 0; _tOwned[address(0)] = _tOwned[address(0)].add(tAmount); _tFeeTotal = _tFeeTotal.add(tAmount); ``` However, the burned fee is not subtracted from `tAmount` at the end of the transfer process. ```solidity=1997 uint256 recipientRate = 10000 - _burnFee - _burnFeeZZ - _marketFee - _ReturnFee - _inviterFee; ```

Buying tokens from DEX will transfer tokens from the pair to the buyer. If `WhiteList` is enabled and the token sender is a pair, then only whitelisted users can receive tokens from DEX. ```solidity=1743 if (from == uniswapV2Pair||from == BNBPair) { if(WhiteList){ require(_isWhiteList[to] , "OnlyIsWhiteList"); } } ``` The following statements are redundant, as the `recipient` will not be the `address(uniswapV2Router)`. ```solidity=1891 if (sender == uniswapV2Pair||sender == BNBPair) {//buy cur = recipient; if (cur == address(uniswapV2Router)) { _tOwned[address(0)] = _tOwned[address(0)].add(tAmount.div(10000).mul(_inviterFee)); emit Transfer(sender, address(0), tAmount.div(10000).mul(_inviterFee)); return; } } else { ```

Users can only sell 999/1000 of their token balance in a transaction. If they want to sell 1000 ether tokens, they need to sell 999 ether on the first sale, sell 999/1000 ether on the second sale, and so on, thus bring the worse user experience. ```solidity=1753 if (to == uniswapV2Pair||to == BNBPair) { require(amount <= balanceOf(from) * 999 / 1000); } ```

Performing integer division before multiplication truncates the low bits, losing the precision of calculation.

The functions which are never called internally within the contract should have external visibility for gas optimization.

The value of `takeFee` cannot be 2, it is redundant to check if it is equal to 2. ```solidity=1813 if (takeFee == 1 || takeFee == 2|| takeFee == 3) restoreAllFee(); ```

The burn fee `_previousburnZZFee` lacks a reasonable cap and can be set to a very high rate.

The contract has one or more payable functions, but does not have a function to withdraw the fund. ```solidity=1598 receive() external payable {} ```

Addresses should be checked before assignment or external call to make sure they are not zero addresses. ```solidity=1576 BNBPair = account; ``` - `account` is not zero-checked before being used.