Chore/improve eth contracts

core/eth/contracts/Terabethia.sol

@@ -67,27 +67,26 @@ contract Terabethia is Initializable, ITerabethiaCore {
         external
         returns (bytes32)
     {
-        simpleStorage().nonce += 1;
+        unchecked {
+            simpleStorage().nonce += 1;
+        }
+
+        uint256 nonce = simpleStorage().nonce;
 
         bytes32 msgHash = keccak256(
             abi.encodePacked(
                 uint256(uint160(msg.sender)),
                 to_address,
-                simpleStorage().nonce,
+                nonce,
                 payload.length,
                 payload
             )
         );
 
-        simpleStorage().messages[msgHash] += 1;
+        simpleStorage().messages[msgHash] = 1;
 
         // we only emit event, so we can auto-trigger message consumption on the IC
-        emit LogMessageToL2(
-            msg.sender,
-            to_address,
-            simpleStorage().nonce,
-            payload
-        );
+        emit LogMessageToL2(msg.sender, to_address, nonce, payload);
 
         return msgHash;
     }

eth_bridge/eth/contracts/EthProxy.sol

@@ -1,22 +1,30 @@
-pragma solidity ^0.8.0;
+pragma solidity 0.8.17;
 
 import "./ITerabethiaCore.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
+import "@openzeppelin/contracts/security/Pausable.sol";
 
-contract EthProxy {
+contract EthProxy is Ownable, Pausable {
     // Terabethia core contract.
     ITerabethiaCore terabethiaCore;
 
     // L2 Canister address
     uint256 constant CANISTER_ADDRESS = 0x00000000003001090101;
 
+    // Init event
+    event InitLog(address indexed terabethia_core);
+
     /**
       Initializes the contract state.
     */
     constructor(ITerabethiaCore terabethiaCore_) {
         terabethiaCore = terabethiaCore_;
+
+        // emit init event
+        emit InitLog(address(terabethiaCore));
     }
 
-    function withdraw(uint256 amount) external {
+    function withdraw(uint256 amount) external whenNotPaused {
         // Construct the withdrawal message's payload.
         uint256[] memory payload = new uint256[](2);
         payload[0] = uint256(uint160(msg.sender));
@@ -27,19 +35,14 @@ contract EthProxy {
         terabethiaCore.consumeMessage(CANISTER_ADDRESS, payload);
 
         // withdraw eth
-        require(
-            address(this).balance >= amount,
-            "Address: insufficient balance"
-        );
-
         (bool success, ) = payable(msg.sender).call{value: amount}("");
         require(
             success,
             "Address: unable to send value, recipient may have reverted"
         );
     }
 
-    function deposit(uint256 user) external payable {
+    function deposit(uint256 user) external payable whenNotPaused {
         require(msg.value >= 1 gwei, "DepositContract: deposit value too low");
         require(
             msg.value % 1 gwei == 0,
@@ -61,4 +64,12 @@ contract EthProxy {
         // Send the message to the IC
         terabethiaCore.sendMessage(CANISTER_ADDRESS, payload);
     }
+
+    function pause() public onlyOwner {
+        _pause();
+    }
+
+    function unpause() public onlyOwner {
+        _unpause();
+    }
 }

eth_bridge/eth/hardhat.config.ts

@@ -20,7 +20,7 @@ task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
 });
 
 const config: HardhatUserConfig = {
-  solidity: "0.8.11",
+  solidity: "0.8.17",
   networks: {
     goerli: {
       url: process.env.ALCHEMY_ENDPOINT,