diff --git a/src/SKIT.FlurlHttpClient.Wechat.Api/Utilities/AESUtility.cs b/src/SKIT.FlurlHttpClient.Wechat.Api/Utilities/AESUtility.cs
index 07d0a63f..1d79405d 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Api/Utilities/AESUtility.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Api/Utilities/AESUtility.cs
@@ -35,6 +35,31 @@ namespace SKIT.FlurlHttpClient.Wechat.Api.Utilities
             }
         }
 
+        /// <summary>
+        /// 基于 CBC 模式加密数据。
+        /// </summary>
+        /// <param name="keyBytes">AES 密钥字节数组。</param>
+        /// <param name="ivBytes">加密使用的初始化向量字节数组。</param>
+        /// <param name="plainBytes">待加密数据字节数组。</param>
+        /// <returns>加密后的数据字节数组。</returns>
+        public static byte[] EncryptWithCBC(byte[] keyBytes, byte[] ivBytes, byte[] plainBytes)
+        {
+            if (keyBytes == null) throw new ArgumentNullException(nameof(keyBytes));
+            if (ivBytes == null) throw new ArgumentNullException(nameof(ivBytes));
+            if (plainBytes == null) throw new ArgumentNullException(nameof(plainBytes));
+
+            using (SymmetricAlgorithm aes = Aes.Create())
+            {
+                aes.Mode = CipherMode.CBC;
+                aes.Padding = PaddingMode.PKCS7;
+                aes.Key = keyBytes;
+                aes.IV = ivBytes;
+
+                using ICryptoTransform transform = aes.CreateEncryptor();
+                return transform.TransformFinalBlock(plainBytes, 0, plainBytes.Length);
+            }
+        }
+
         /// <summary>
         /// 基于 CBC 模式解密数据。
         /// </summary>
@@ -54,5 +79,25 @@ namespace SKIT.FlurlHttpClient.Wechat.Api.Utilities
             );
             return Encoding.UTF8.GetString(plainBytes);
         }
+
+        /// <summary>
+        /// 基于 CBC 模式加密数据。
+        /// </summary>
+        /// <param name="encodingKey">经 Base64 编码后的 AES 密钥。</param>
+        /// <param name="encodingIV">经 Base64 编码后的 AES 初始化向量。</param>
+        /// <param name="plainText">待加密文本。</param>
+        /// <returns>经 Base64 编码的加密后的数据。</returns>
+        public static string EncryptWithCBC(string encodingKey, string encodingIV, string plainText)
+        {
+            if (encodingKey == null) throw new ArgumentNullException(nameof(encodingKey));
+            if (plainText == null) throw new ArgumentNullException(nameof(plainText));
+
+            byte[] plainBytes = EncryptWithCBC(
+                keyBytes: Convert.FromBase64String(encodingKey),
+                ivBytes: Convert.FromBase64String(encodingIV),
+                plainBytes: Encoding.UTF8.GetBytes(plainText)
+            );
+            return Convert.ToBase64String(plainBytes);
+        }
     }
 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Api/Utilities/Internal/XmlUtility.cs b/src/SKIT.FlurlHttpClient.Wechat.Api/Utilities/Internal/XmlUtility.cs
index 8cd97d73..190a3260 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Api/Utilities/Internal/XmlUtility.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Api/Utilities/Internal/XmlUtility.cs
@@ -11,18 +11,19 @@ namespace SKIT.FlurlHttpClient.Wechat.Api.Utilities
     internal static class XmlUtility
     {
         // REF: https://docs.microsoft.com/zh-cn/dotnet/api/system.xml.serialization.xmlserializer#dynamically-generated-assemblies
-        private static Hashtable _serializers = new Hashtable();
+        private static readonly Hashtable _xmlSerializers = new Hashtable();
+        private static readonly XmlRootAttribute _xmlRoot = new XmlRootAttribute("xml");
 
         private static XmlSerializer GetTypedSerializer(Type type)
         {
             if (type == null) throw new ArgumentNullException(nameof(type));
 
             string skey = type.AssemblyQualifiedName ?? type.GetHashCode().ToString();
-            XmlSerializer? xmlSerializer = (XmlSerializer?)_serializers[skey];
+            XmlSerializer? xmlSerializer = (XmlSerializer?)_xmlSerializers[skey];
             if (xmlSerializer == null)
             {
-                xmlSerializer = new XmlSerializer(type, new XmlRootAttribute("xml"));
-                _serializers[skey] = xmlSerializer;
+                xmlSerializer = new XmlSerializer(type, _xmlRoot);
+                _xmlSerializers[skey] = xmlSerializer;
             }
 
             return xmlSerializer;
diff --git a/src/SKIT.FlurlHttpClient.Wechat.OpenAI/Utilities/Internal/XmlUtility.cs b/src/SKIT.FlurlHttpClient.Wechat.OpenAI/Utilities/Internal/XmlUtility.cs
index 4d305cc9..569681fc 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.OpenAI/Utilities/Internal/XmlUtility.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.OpenAI/Utilities/Internal/XmlUtility.cs
@@ -11,18 +11,19 @@ namespace SKIT.FlurlHttpClient.Wechat.OpenAI.Utilities
     internal static class XmlUtility
     {
         // REF: https://docs.microsoft.com/zh-cn/dotnet/api/system.xml.serialization.xmlserializer#dynamically-generated-assemblies
-        private static Hashtable _serializers = new Hashtable();
+        private static readonly Hashtable _xmlSerializers = new Hashtable();
+        private static readonly XmlRootAttribute _xmlRoot = new XmlRootAttribute("xml");
 
         private static XmlSerializer GetTypedSerializer(Type type)
         {
             if (type == null) throw new ArgumentNullException(nameof(type));
 
             string skey = type.AssemblyQualifiedName ?? type.GetHashCode().ToString();
-            XmlSerializer? xmlSerializer = (XmlSerializer?)_serializers[skey];
+            XmlSerializer? xmlSerializer = (XmlSerializer?)_xmlSerializers[skey];
             if (xmlSerializer == null)
             {
-                xmlSerializer = new XmlSerializer(type, new XmlRootAttribute("xml"));
-                _serializers[skey] = xmlSerializer;
+                xmlSerializer = new XmlSerializer(type, _xmlRoot);
+                _xmlSerializers[skey] = xmlSerializer;
             }
 
             return xmlSerializer;
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Utilities/Internal/XmlUtility.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Utilities/Internal/XmlUtility.cs
index 0b331691..19d8e8d7 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Utilities/Internal/XmlUtility.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Utilities/Internal/XmlUtility.cs
@@ -11,18 +11,19 @@ namespace SKIT.FlurlHttpClient.Wechat.Work.Utilities
     internal static class XmlUtility
     {
         // REF: https://docs.microsoft.com/zh-cn/dotnet/api/system.xml.serialization.xmlserializer#dynamically-generated-assemblies
-        private static Hashtable _serializers = new Hashtable();
+        private static readonly Hashtable _xmlSerializers = new Hashtable();
+        private static readonly XmlRootAttribute _xmlRoot = new XmlRootAttribute("xml");
 
         private static XmlSerializer GetTypedSerializer(Type type)
         {
             if (type == null) throw new ArgumentNullException(nameof(type));
 
             string skey = type.AssemblyQualifiedName ?? type.GetHashCode().ToString();
-            XmlSerializer? xmlSerializer = (XmlSerializer?)_serializers[skey];
+            XmlSerializer? xmlSerializer = (XmlSerializer?)_xmlSerializers[skey];
             if (xmlSerializer == null)
             {
-                xmlSerializer = new XmlSerializer(type, new XmlRootAttribute("xml"));
-                _serializers[skey] = xmlSerializer;
+                xmlSerializer = new XmlSerializer(type, _xmlRoot);
+                _xmlSerializers[skey] = xmlSerializer;
             }
 
             return xmlSerializer;
diff --git a/test/SKIT.FlurlHttpClient.Wechat.Api.UnitTests/WechatApiSecurityTests.cs b/test/SKIT.FlurlHttpClient.Wechat.Api.UnitTests/WechatApiSecurityTests.cs
index fa91c2ba..439a77e5 100644
--- a/test/SKIT.FlurlHttpClient.Wechat.Api.UnitTests/WechatApiSecurityTests.cs
+++ b/test/SKIT.FlurlHttpClient.Wechat.Api.UnitTests/WechatApiSecurityTests.cs
@@ -1,9 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
 using Xunit;
 
 namespace SKIT.FlurlHttpClient.Wechat.Api.UnitTests
@@ -16,9 +11,9 @@ namespace SKIT.FlurlHttpClient.Wechat.Api.UnitTests
             string rawData = "jsapi_ticket=HoagFKDcsGMVCIY2vOjf9nGrZ3eaM0qXs5ROFN_3k_HrGc0VocemA6wMXkvrL-Ei4IitXxwKF62CJWR8mWXZ3Q&noncestr=e7b435f73835402da44f16640ddc8696&timestamp=1621348162&url=https://mp.weixin.qq.com/debug/cgi-bin/sandbox?t=jsapisign";
 
             string actualHash = Security.SHA1Utility.Hash(rawData);
-            string expectdHash = "b214ea1f8ae019c207f8c6ffb843c8474cbab28c";
+            string expectedHash = "b214ea1f8ae019c207f8c6ffb843c8474cbab28c";
 
-            Assert.Equal(expectdHash, actualHash, ignoreCase: true);
+            Assert.Equal(expectedHash, actualHash, ignoreCase: true);
         }
 
         [Fact(DisplayName = "信息摘要（HMAC-SHA-256）")]
@@ -28,9 +23,22 @@ namespace SKIT.FlurlHttpClient.Wechat.Api.UnitTests
             string rawData = "appid=wx1234567&offer_id=12345678&openid=odkx20ENSNa2w5y3g_qOkOvBNM1g&pf=android&ts=1507530737&zone_id=1&org_loc=/cgi-bin/midas/getbalance&method=POST&secret=zNLgAGgqsEWJOg1nFVaO5r7fAlIQxr1u";
 
             string actualHash = Security.HMACSHA256Utility.Hash(secret, rawData);
-            string expectdHash = "1ad64e8dcb2ec1dc486b7fdf01f4a15159fc623dc3422470e51cf6870734726b";
+            string expectedHash = "1ad64e8dcb2ec1dc486b7fdf01f4a15159fc623dc3422470e51cf6870734726b";
 
-            Assert.Equal(expectdHash, actualHash, ignoreCase: true);
+            Assert.Equal(expectedHash, actualHash, ignoreCase: true);
+        }
+
+        [Fact(DisplayName = "AES-CBC 解密")]
+        public void AesCbcDecryptTest()
+        {
+            string iv = "KEWv/gyiIwAfHvjrLeaX6w==";
+            string key = "YZJqKnNFi0KAiKUc0ggC2g==";
+            string cipherText = "Gu2PVnxVWl+jK4F8c0liGxfkB5Bj3m5HRvwgEIk1Yb+36RZ3Bg7YmUnud/ooiHz0PQroipsH7GCjlGwUeT04NwmrFaP1y3dRYPLpS43ed9QZWcFIFo+8vTs3Zco6S98DUvaNEAs8duhz/BzfBOZaIHMziRqEtPFI0ZDzCgJluBirJ6Wl3UkygZ5/QLo3KA53qGdip7K48Rq8XbCwuidTCw==";
+            
+            string expectedPlainData = "{\"phoneNumber\":\"186****5613\",\"purePhoneNumber\":\"186****5613\",\"countryCode\":\"86\",\"watermark\":{\"timestamp\":1634545675,\"appid\":\"wxc****17e87e0e0a7\"}}";
+            string actualPlainData = Utilities.AESUtility.DecryptWithCBC(encodingKey: key, encodingIV: iv, encodingCipherText: cipherText);
+            
+            Assert.Equal(expectedPlainData, actualPlainData, ignoreCase: true);
         }
     }
 }