diff --git a/packages/protocol/contracts/L1/verifiers/SgxAndZkVerifier.sol b/packages/protocol/contracts/L1/verifiers/SgxAndZkVerifier.sol
index cc29915099e..e22c5dca41e 100644
--- a/packages/protocol/contracts/L1/verifiers/SgxAndZkVerifier.sol
+++ b/packages/protocol/contracts/L1/verifiers/SgxAndZkVerifier.sol
@@ -38,6 +38,7 @@ contract SgxAndZkVerifier is EssentialContract, IVerifier {
         TaikoData.TierProof calldata proof
     )
         external
+        onlyFromNamed("taiko")
     {
         TaikoData.TierProof memory _proof;
         _proof.tier = proof.tier;
diff --git a/packages/protocol/contracts/L1/verifiers/SgxVerifier.sol b/packages/protocol/contracts/L1/verifiers/SgxVerifier.sol
index 8708a1aa930..d345cd8838c 100644
--- a/packages/protocol/contracts/L1/verifiers/SgxVerifier.sol
+++ b/packages/protocol/contracts/L1/verifiers/SgxVerifier.sol
@@ -17,6 +17,7 @@ pragma solidity 0.8.20;
 import "lib/openzeppelin-contracts/contracts/utils/cryptography/ECDSA.sol";
 import "../../common/EssentialContract.sol";
 import "../../thirdparty/LibBytesUtils.sol";
+import "../ITaikoL1.sol";
 import "../TaikoData.sol";
 import "./IVerifier.sol";
 
@@ -59,6 +60,17 @@ contract SgxVerifier is EssentialContract, IVerifier {
     error SGX_INVALID_INSTANCES();
     error SGX_INVALID_PROOF();
 
+    /// @dev Modifier that ensures the caller is either taikoL1 or SgxAndZkVerifier.
+    modifier onlyTaikoOrCombinedVerifier() {
+        if (
+            msg.sender != resolve("taiko", true)
+                && msg.sender != resolve("tier_sgx_and_pse_zkevm", true)
+        ) {
+            revert RESOLVER_DENIED();
+        }
+        _;
+    }
+
     /// @notice Initializes the contract with the provided address manager.
     /// @param _addressManager The address of the address manager contract.
     function init(address _addressManager) external initializer {
@@ -92,7 +104,16 @@ contract SgxVerifier is EssentialContract, IVerifier {
         external
         returns (uint256[] memory ids)
     {
-        bytes32 signedHash = keccak256(abi.encode("ADD_INSTANCES", extraInstances));
+        address taikoL1 = resolve("taiko", false);
+        bytes32 signedHash = keccak256(
+            abi.encode(
+                "ADD_INSTANCES",
+                ITaikoL1(taikoL1).getConfig().chainId,
+                address(this),
+                newInstance,
+                extraInstances
+            )
+        );
         address oldInstance = ECDSA.recover(signedHash, signature);
         if (!_isInstanceValid(id, oldInstance)) revert SGX_INVALID_INSTANCE();
 
@@ -108,6 +129,7 @@ contract SgxVerifier is EssentialContract, IVerifier {
         TaikoData.TierProof calldata proof
     )
         external
+        onlyTaikoOrCombinedVerifier
     {
         // Do not run proof verification to contest an existing proof
         if (ctx.isContesting) return;
@@ -134,10 +156,21 @@ contract SgxVerifier is EssentialContract, IVerifier {
         bytes32 metaHash
     )
         public
-        pure
+        view
         returns (bytes32 signedHash)
     {
-        return keccak256(abi.encode(tran, newInstance, prover, metaHash));
+        address taikoL1 = resolve("taiko", false);
+        return keccak256(
+            abi.encode(
+                "VERIFY_PROOF",
+                ITaikoL1(taikoL1).getConfig().chainId,
+                address(this),
+                tran,
+                newInstance,
+                prover,
+                metaHash
+            )
+        );
     }
 
     function _addInstances(address[] calldata _instances) private returns (uint256[] memory ids) {
diff --git a/packages/protocol/test/L1/SgxVerifier.t.sol b/packages/protocol/test/L1/SgxVerifier.t.sol
index 90e71ab9186..f619ff81952 100644
--- a/packages/protocol/test/L1/SgxVerifier.t.sol
+++ b/packages/protocol/test/L1/SgxVerifier.t.sol
@@ -33,21 +33,30 @@ contract TestSgxVerifier is TaikoL1TestBase {
         _instances[0] = SGX_Y;
         _instances[1] = SGX_Z;
 
-        bytes memory signature = _getSignature(_instances, 0x4);
+        bytes memory signature = _getSignature(SGX_X_1, _instances, 0x4);
 
         vm.prank(Bob, Bob);
         sv.addInstances(0, SGX_X_1, _instances, signature);
     }
 
     function _getSignature(
+        address _newInstance,
         address[] memory _instances,
         uint256 privKey
     )
         private
-        pure
+        view
         returns (bytes memory signature)
     {
-        bytes32 digest = keccak256(abi.encode("ADD_INSTANCES", _instances));
+        bytes32 digest = keccak256(
+            abi.encode(
+                "ADD_INSTANCES",
+                ITaikoL1(L1).getConfig().chainId,
+                address(sv),
+                _newInstance,
+                _instances
+            )
+        );
         (uint8 v, bytes32 r, bytes32 s) = vm.sign(privKey, digest);
         signature = abi.encodePacked(r, s, v);
     }