Kephi Audit

In the contract `FactoryErc721`, the role `DEFAULT_ADMIN_ROLE` has the authority over the following function: - `setFee()`: allows the `DEFUALT_ADMIN_ROLE` to modify `fee`; - `setReceiver()`: allows the `DEFAULT_ADMIN_ROLE` to modify `receiver`. In the contract `FactoryErc1155`, the role `DEFAULT_ADMIN_ROLE` has the authority over the following function: - `setFee()`: allows the `DEFUALT_ADMIN_ROLE` to modify `fee`; - `setReceiver()`: allows the `DEFAULT_ADMIN_ROLE` to modify `receiver`. In the contract `ERC1155Main`, the role `SIGNER` has the authority over the following function: - `mint()`: allows the `SIGNER` to mint token given a URI. In the contract `ERC721Main`, the role `SIGNER` has the authority over the following function: - `mint()`: allows the `SIGNER` to mint token given a URI. In the contract `Exchange`, the role `SIGNER` has the authority over the following function: - `makeExchangeERC1155()`: allows the `SIGNER` to exchange an ERC1155 token between a buyer and a seller; - `makeExchangeERC721()`: allows the `SIGNER` to exchange an ERC721 token between a buyer and a seller. Any compromise to the `DEFAULT_ADMIN_ROLE` and `SIGNER` accounts may allow the hacker to take advantage of these functions.