ADD file via upload

RootVerifier.sol

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+pragma solidity ^0.8.0;
+
+contract StateRootVerifier {
+    bytes32 private currentRoot;
+
+    function verifyAndUpdate(bytes32 oldRoot, bytes32 newRoot) external {
+        require(oldRoot == currentRoot, "Invalid old state root");
+
+        // 更新链上状态树根
+        currentRoot = newRoot;
+    }
+
+    function getCurrentRoot() external view returns (bytes32) {
+        return currentRoot;
+    }
+}