diff --git a/lib/network/util/cache.dart b/lib/network/util/cache.dart
index 884a0ea..1b83a53 100644
--- a/lib/network/util/cache.dart
+++ b/lib/network/util/cache.dart
@@ -33,6 +33,8 @@ class ExpiringCache<K, V> {
     _expirationTimes[key] = Timer(duration, () => remove(key));
   }
 
+  void operator []=(K key, V value) => set(key, value);
+
   V? putIfAbsent(K key, V Function() ifAbsent) {
     if (_cache.containsKey(key)) {
       return _cache[key];
@@ -46,12 +48,21 @@ class ExpiringCache<K, V> {
     return _cache[key];
   }
 
-  remove(K key) {
+  V? operator [](K key) => get(key);
+
+  void remove(K key) {
     _expirationTimes[key]?.cancel();
     _expirationTimes.remove(key);
     _cache.remove(key);
   }
 
+  void clear() {
+    for (var timer in _expirationTimes.values) {
+      timer.cancel();
+    }
+    _expirationTimes.clear();
+    _cache.clear();
+  }
 }
 
 class LruCache<K, V> {
@@ -79,8 +90,8 @@ class LruCache<K, V> {
     final value = ifAbsent();
     set(key, value);
     return value;
-
   }
+
   void set(K key, V value) {
     if (_cache.containsKey(key)) {
       // Remove the old value
@@ -101,4 +112,4 @@ class LruCache<K, V> {
   void clear() {
     _cache.clear();
   }
-}
\ No newline at end of file
+}
diff --git a/lib/network/util/crts.dart b/lib/network/util/crts.dart
index e4da3a3..29eb26f 100644
--- a/lib/network/util/crts.dart
+++ b/lib/network/util/crts.dart
@@ -30,6 +30,7 @@ import 'package:proxypin/network/util/logger.dart';
 import 'package:proxypin/network/util/random.dart';
 import 'package:proxypin/utils/lang.dart';
 
+import 'cache.dart';
 import 'cert/cert_data.dart';
 import 'cert/extension.dart';
 import 'cert/key_usage.dart';
@@ -39,16 +40,14 @@ import 'file_read.dart';
 Future<void> main() async {
   await CertificateManager.getCertificateContext('www.jianshu.com');
   CertificateManager.caCert.tbsCertificateSeqAsString;
-
-  String cer = CertificateManager.get('www.jianshu.com')!;
-  print(cer);
 }
 
 enum StartState { uninitialized, initializing, initialized }
 
 class CertificateManager {
   /// 证书缓存
-  static final Map<String, String> _certificateMap = {};
+  static final ExpiringCache<String, SecurityContext> _certificateMap =
+      ExpiringCache<String, SecurityContext>(const Duration(minutes: 15));
 
   /// 服务端密钥
   static AsymmetricKeyPair _serverKeyPair = CryptoUtils.generateRSAKeyPair();
@@ -63,7 +62,7 @@ class CertificateManager {
   static StartState _state = StartState.uninitialized;
   static Completer<void> _initializationCompleter = Completer<void>();
 
-  static String? get(String host) {
+  static SecurityContext? get(String host) {
     return _certificateMap[host];
   }
 
@@ -76,22 +75,27 @@ class CertificateManager {
 
   /// 获取域名自签名证书
   static Future<SecurityContext> getCertificateContext(String host) async {
-    var cer = _certificateMap[host];
-
-    if (cer == null) {
-      if (_state != StartState.initialized) {
-        await initCAConfig();
-      }
-      cer = generate(_caCert, _serverKeyPair.publicKey as RSAPublicKey, _caPriKey, host);
-      _certificateMap[host] = cer;
+    SecurityContext? securityContext = _certificateMap[host];
+    if (securityContext != null) {
+      return securityContext;
     }
 
+    if (_state != StartState.initialized) {
+      await initCAConfig();
+    }
+
+    String cer = generate(_caCert, _serverKeyPair.publicKey as RSAPublicKey, _caPriKey, host);
+
     var rsaPrivateKey = _serverKeyPair.privateKey as RSAPrivateKey;
 
-    return SecurityContext(withTrustedRoots: true)
+    securityContext = SecurityContext(withTrustedRoots: true)
       ..useCertificateChainBytes(cer.codeUnits)
       ..allowLegacyUnsafeRenegotiation = true
       ..usePrivateKeyBytes(CryptoUtils.encodeRSAPrivateKeyToPemPkcs1(rsaPrivateKey).codeUnits);
+
+    _certificateMap[host] = securityContext;
+
+    return securityContext;
   }
 
   /// 生成证书