Contract Source Code:

// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.0;
import "./ERC20.sol";
import "./interfaces/IEON.sol";

contract EON is IEON, ERC20 {
    // Tracks the last block that a caller has written to state.
    // Disallow some access to functions if they occur while a change is being written.
    mapping(address => uint256) private lastWrite;

    // address => allowedToCallFunctions
    mapping(address => bool) private admins;
    //ower
    address public auth;
    // hardcoded max eon supply 5b
    uint256 public constant MAX_EON = 5000000000 ether;

    // amount minted
    uint256 public minted;

    constructor() ERC20("EON", "EON", 18) {
        auth = msg.sender;
    }

    modifier onlyOwner() {
        require(msg.sender == auth);
        _;
    }

    /**
     * enables an address to mint / burn
     * @param addr the address to enable
     */
    function addAdmin(address addr) external onlyOwner {
        admins[addr] = true;
    }

    /**
     * disables an address from minting / burning
     * @param addr the address to disbale
     */
    function removeAdmin(address addr) external onlyOwner {
        admins[addr] = false;
    }

    function transferOwnership(address newOwner) external onlyOwner {
        auth = newOwner;
    }

    /**
     * mints $EON to a recipient
     * @param to the recipient of the $EON
     * @param amount the amount of $EON to mint
     */
    function mint(address to, uint256 amount) external override {
        require(admins[msg.sender], "Only admins can mint");
        minted += amount;
        _mint(to, amount);
    }

    /**
     * burns $EON from a holder
     * @param from the holder of the $EON
     * @param amount the amount of $EON to burn
     */
    function burn(address from, uint256 amount) external override {
        require(admins[msg.sender], "Only admins");
        _burn(from, amount);
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override(ERC20, IEON) returns (bool) {
        // caught yah
        require(
            admins[msg.sender] || lastWrite[sender] < block.number,
            "hmmmm what are you doing?"
        );
        // If the entity invoking this transfer is an admin (i.e. the gameContract)
        // allow the transfer without approval. This saves gas and a transaction.
        // The sender address will still need to actually have the amount being attempted to send.
        if (admins[msg.sender]) {
            // NOTE: This will omit any events from being written. This saves additional gas,
            // and the event emission is not a requirement by the EIP
            // (read this function summary / ERC20 summary for more details)
            emit Transfer(sender, recipient, amount);
            return true;
        }

        // If it's not an admin entity (Shattered EON contract, pytheas, refinery. etc)
        // The entity will need to be given permission to transfer these funds
        // For instance, someone can't just make a contract and siphon $EON from every account
        return super.transferFrom(sender, recipient, amount);
    }
}

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity >=0.8.0;

/// @notice Modern and gas efficient ERC20 + EIP-2612 implementation.
/// @author Solmate (https://github.com/Rari-Capital/solmate/blob/main/src/tokens/ERC20.sol)
/// @author Modified from Uniswap (https://github.com/Uniswap/uniswap-v2-core/blob/master/contracts/UniswapV2ERC20.sol)
/// @dev Do not manually set balances without updating totalSupply, as the sum of all user balances must not exceed it.
abstract contract ERC20 {
    /*///////////////////////////////////////////////////////////////
                                  EVENTS
    //////////////////////////////////////////////////////////////*/

    event Transfer(address indexed from, address indexed to, uint256 amount);

    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 amount
    );

    /*///////////////////////////////////////////////////////////////
                             METADATA STORAGE
    //////////////////////////////////////////////////////////////*/

    string public name;

    string public symbol;

    uint8 public immutable decimals;

    /*///////////////////////////////////////////////////////////////
                              ERC20 STORAGE
    //////////////////////////////////////////////////////////////*/

    uint256 public totalSupply;

    mapping(address => uint256) public balanceOf;

    mapping(address => mapping(address => uint256)) public allowance;

    /*///////////////////////////////////////////////////////////////
                             EIP-2612 STORAGE
    //////////////////////////////////////////////////////////////*/

    bytes32 public constant PERMIT_TYPEHASH =
        keccak256(
            "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
        );

    uint256 internal immutable INITIAL_CHAIN_ID;

    bytes32 internal immutable INITIAL_DOMAIN_SEPARATOR;

    mapping(address => uint256) public nonces;

    /*///////////////////////////////////////////////////////////////
                               CONSTRUCTOR
    //////////////////////////////////////////////////////////////*/

    constructor(
        string memory _name,
        string memory _symbol,
        uint8 _decimals
    ) {
        name = _name;
        symbol = _symbol;
        decimals = _decimals;

        INITIAL_CHAIN_ID = block.chainid;
        INITIAL_DOMAIN_SEPARATOR = computeDomainSeparator();
    }

    /*///////////////////////////////////////////////////////////////
                              ERC20 LOGIC
    //////////////////////////////////////////////////////////////*/

    function approve(address spender, uint256 amount)
        public
        virtual
        returns (bool)
    {
        allowance[msg.sender][spender] = amount;

        emit Approval(msg.sender, spender, amount);

        return true;
    }

    function transfer(address to, uint256 amount)
        public
        virtual
        returns (bool)
    {
        balanceOf[msg.sender] -= amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(msg.sender, to, amount);

        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual returns (bool) {
        uint256 allowed = allowance[from][msg.sender]; // Saves gas for limited approvals.

        if (allowed != type(uint256).max)
            allowance[from][msg.sender] = allowed - amount;

        balanceOf[from] -= amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(from, to, amount);

        return true;
    }

    /*///////////////////////////////////////////////////////////////
                              EIP-2612 LOGIC
    //////////////////////////////////////////////////////////////*/

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) public virtual {
        require(deadline >= block.timestamp, "PERMIT_DEADLINE_EXPIRED");

        // Unchecked because the only math done is incrementing
        // the owner's nonce which cannot realistically overflow.
        unchecked {
            bytes32 digest = keccak256(
                abi.encodePacked(
                    "\x19\x01",
                    DOMAIN_SEPARATOR(),
                    keccak256(
                        abi.encode(
                            PERMIT_TYPEHASH,
                            owner,
                            spender,
                            value,
                            nonces[owner]++,
                            deadline
                        )
                    )
                )
            );

            address recoveredAddress = ecrecover(digest, v, r, s);

            require(
                recoveredAddress != address(0) && recoveredAddress == owner,
                "INVALID_SIGNER"
            );

            allowance[recoveredAddress][spender] = value;
        }

        emit Approval(owner, spender, value);
    }

    function DOMAIN_SEPARATOR() public view virtual returns (bytes32) {
        return
            block.chainid == INITIAL_CHAIN_ID
                ? INITIAL_DOMAIN_SEPARATOR
                : computeDomainSeparator();
    }

    function computeDomainSeparator() internal view virtual returns (bytes32) {
        return
            keccak256(
                abi.encode(
                    keccak256(
                        "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
                    ),
                    keccak256(bytes(name)),
                    keccak256("1"),
                    block.chainid,
                    address(this)
                )
            );
    }

    /*///////////////////////////////////////////////////////////////
                       INTERNAL MINT/BURN LOGIC
    //////////////////////////////////////////////////////////////*/

    function _mint(address to, uint256 amount) internal virtual {
        totalSupply += amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(address(0), to, amount);
    }

    function _burn(address from, uint256 amount) internal virtual {
        balanceOf[from] -= amount;

        // Cannot underflow because a user's balance
        // will never be larger than the total supply.
        unchecked {
            totalSupply -= amount;
        }

        emit Transfer(from, address(0), amount);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IEON {
    function mint(address to, uint256 amount) external;

    function burn(address from, uint256 amount) external;

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
}