diff --git a/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_Net6/Services/HttpClients/IWechatTenpayCertificateManagerFactory.cs b/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_Net6/Services/HttpClients/IWechatTenpayCertificateManagerFactory.cs
index 300d6f4f..516dec90 100644
--- a/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_Net6/Services/HttpClients/IWechatTenpayCertificateManagerFactory.cs
+++ b/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_Net6/Services/HttpClients/IWechatTenpayCertificateManagerFactory.cs
@@ -1,9 +1,9 @@
-namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample.Services.HttpClients
+namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample.Services.HttpClients
 {
     using SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings;
 
     public interface IWechatTenpayCertificateManagerFactory
     {
-        CertificateManager Create(string merchantId);
+        ICertificateManager Create(string merchantId);
     }
 }
diff --git a/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_Net6/Services/HttpClients/Implements/WechatTenpayCertificateManagerFactory.cs b/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_Net6/Services/HttpClients/Implements/WechatTenpayCertificateManagerFactory.cs
index 3cf2aac9..442ef33f 100644
--- a/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_Net6/Services/HttpClients/Implements/WechatTenpayCertificateManagerFactory.cs
+++ b/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_Net6/Services/HttpClients/Implements/WechatTenpayCertificateManagerFactory.cs
@@ -1,4 +1,4 @@
-using System.Collections.Concurrent;
+using System.Collections.Concurrent;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample.Services.HttpClients.Implements
 {
@@ -6,14 +6,14 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample.Services.HttpClients.Imple
 
     internal partial class WechatTenpayCertificateManagerFactory : IWechatTenpayCertificateManagerFactory
     {
-        private readonly ConcurrentDictionary<string, CertificateManager> _dict;
+        private readonly ConcurrentDictionary<string, ICertificateManager> _dict;
 
         public WechatTenpayCertificateManagerFactory()
         {
-            _dict = new ConcurrentDictionary<string, CertificateManager>();
+            _dict = new ConcurrentDictionary<string, ICertificateManager>();
         }
 
-        public CertificateManager Create(string merchantId)
+        public ICertificateManager Create(string merchantId)
         {
             // NOTICE:
             //   这里的工厂方法是为了演示多租户而存在的，可根据商户号生成不同的证书管理器。
diff --git a/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_NetFramework47/Services/HttpClients/IWechatTenpayCertificateManagerFactory.cs b/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_NetFramework47/Services/HttpClients/IWechatTenpayCertificateManagerFactory.cs
index 9c7cd91d..516dec90 100644
--- a/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_NetFramework47/Services/HttpClients/IWechatTenpayCertificateManagerFactory.cs
+++ b/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_NetFramework47/Services/HttpClients/IWechatTenpayCertificateManagerFactory.cs
@@ -1,7 +1,9 @@
-namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample.Services.HttpClients
+namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample.Services.HttpClients
 {
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings;
+
     public interface IWechatTenpayCertificateManagerFactory
     {
-        CertificateManager Create(string merchantId);
+        ICertificateManager Create(string merchantId);
     }
 }
diff --git a/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_NetFramework47/Services/HttpClients/Implements/WechatTenpayCertificateManagerFactory.cs b/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_NetFramework47/Services/HttpClients/Implements/WechatTenpayCertificateManagerFactory.cs
index 73c08d60..bd45336c 100644
--- a/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_NetFramework47/Services/HttpClients/Implements/WechatTenpayCertificateManagerFactory.cs
+++ b/samples/SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample_NetFramework47/Services/HttpClients/Implements/WechatTenpayCertificateManagerFactory.cs
@@ -1,12 +1,16 @@
-namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample.Services.HttpClients.Implements
+using System.Collections.Concurrent;
+
+namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Sample.Services.HttpClients.Implements
 {
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings;
+
     internal partial class WechatTenpayCertificateManagerFactory : IWechatTenpayCertificateManagerFactory
     {
-        private readonly ConcurrentDictionary<string, CertificateManager> _dict;
+        private readonly ConcurrentDictionary<string, ICertificateManager> _dict;
 
         public WechatTenpayCertificateManagerFactory()
         {
-            _dict = new ConcurrentDictionary<string, CertificateManager>();
+            _dict = new ConcurrentDictionary<string, ICertificateManager>();
         }
 
         public CertificateManager Create(string merchantId)
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Settings/Credentials.cs
index 719c2205..1b9109fa 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/Settings/Credentials.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Settings/Credentials.cs
@@ -2,7 +2,7 @@ using System;
 
 namespace SKIT.FlurlHttpClient.Wechat.Ads.Settings
 {
-    public class Credentials
+    public sealed class Credentials
     {
         /// <summary>
         /// 初始化客户端时 <see cref="WechatAdsClientOptions.AgencyId"/> 的副本。
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Api/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.Api/Settings/Credentials.cs
index b190369b..46a665b1 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Api/Settings/Credentials.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Api/Settings/Credentials.cs
@@ -2,7 +2,7 @@ using System;
 
 namespace SKIT.FlurlHttpClient.Wechat.Api.Settings
 {
-    public class Credentials
+    public sealed class Credentials
     {
         /// <summary>
         /// 初始化客户端时 <see cref="WechatApiClientOptions.AppId"/> 的副本。
diff --git a/src/SKIT.FlurlHttpClient.Wechat.OpenAI/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.OpenAI/Settings/Credentials.cs
index 27d8e2af..e0ff3a0c 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.OpenAI/Settings/Credentials.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.OpenAI/Settings/Credentials.cs
@@ -1,8 +1,8 @@
-using System;
+using System;
 
 namespace SKIT.FlurlHttpClient.Wechat.OpenAI.Settings
 {
-    public class Credentials
+    public sealed class Credentials
     {
         /// <summary>
         /// 初始化客户端时 <see cref="WechatOpenAIClientOptions.AppId"/> 的副本。
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayBusiness/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayBusiness/Settings/Credentials.cs
index 869283f0..f50a61db 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayBusiness/Settings/Credentials.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayBusiness/Settings/Credentials.cs
@@ -2,7 +2,7 @@ using System;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayBusiness.Settings
 {
-    public class Credentials
+    public sealed class Credentials
     {
         /// <summary>
         /// 初始化客户端时 <see cref="WechatTenpayBusinessClientOptions.PlatformId"/> 的副本。
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Settings/Credentials.cs
index 51264b32..c4e63e5b 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Settings/Credentials.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Settings/Credentials.cs
@@ -2,7 +2,7 @@ using System;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV2.Settings
 {
-    public class Credentials
+    public sealed class Credentials
     {
         /// <summary>
         /// 初始化客户端时 <see cref="WechatTenpayClientOptions.MerchantId"/> 的副本。
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Settings/WechatpayHttpHandler.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Settings/WechatpayHttpHandler.cs
index 4a0de8b0..e28dea93 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Settings/WechatpayHttpHandler.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Settings/WechatpayHttpHandler.cs
@@ -6,7 +6,7 @@ using System.Security.Cryptography.X509Certificates;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV2.Settings
 {
-    public class WechatpayHttpHandler : DelegatingHandler
+    public sealed class WechatpayHttpHandler : DelegatingHandler
     {
         public WechatpayHttpHandler(byte[]? certificateBytes, string? certificatePassword)
         {
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventDecryptionExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventDecryptionExtensions.cs
index ad0837f7..5ea47d15 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventDecryptionExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventDecryptionExtensions.cs
@@ -3,6 +3,7 @@ using System;
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 {
     using SKIT.FlurlHttpClient.Primitives;
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Constants;
 
     public static class WechatTenpayClientEventDecryptionExtensions
     {
@@ -52,7 +53,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             string plainJson;
             switch (webhookEventResource.Algorithm)
             {
-                case Constants.EncryptionAlgorithms.AEAD_AES_256_GCM:
+                case EncryptionAlgorithms.AEAD_AES_256_GCM:
                     {
                         try
                         {
@@ -70,7 +71,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                     }
                     break;
 
-                case Constants.EncryptionAlgorithms.AEAD_SM4_128_GCM:
+                case EncryptionAlgorithms.AEAD_SM4_128_GCM:
                     {
                         try
                         {
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventVerificationExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventVerificationExtensions.cs
index fa5e3cd4..6c8eec89 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventVerificationExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventVerificationExtensions.cs
@@ -1,8 +1,11 @@
 using System;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 {
     using SKIT.FlurlHttpClient.Primitives;
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Constants;
 
     public static class WechatTenpayClientEventVerificationExtensions
     {
@@ -29,7 +32,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 webhookNonce: webhookNonce,
                 webhookBody: webhookBody,
                 webhookSignature: webhookSignature,
-                webhookSignatureType: Constants.SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256,
+                webhookSignatureType: SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256,
                 webhookSerialNumber: webhookSerialNumber
             );
         }
@@ -64,5 +67,66 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 strSerialNumber: webhookSerialNumber
             );
         }
+
+        /// <summary>
+        /// <para>异步验证回调通知事件签名。</para>
+        /// <para>
+        /// REF: <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/merchant/development/interface-rules/signature-verification.html ]]> <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/partner/development/interface-rules/signature-verification.html ]]>
+        /// </para>
+        /// </summary>
+        /// <param name="client"></param>
+        /// <param name="webhookTimestamp">微信回调通知中的 "Wechatpay-Timestamp" 请求标头。</param>
+        /// <param name="webhookNonce">微信回调通知中的 "Wechatpay-Nonce" 请求标头。</param>
+        /// <param name="webhookBody">微信回调通知中请求正文。</param>
+        /// <param name="webhookSignature">微信回调通知中的 "Wechatpay-Signature" 请求标头。</param>
+        /// <param name="webhookSerialNumber">微信回调通知中的 "Wechatpay-Serial" 请求标头。</param>
+        /// <returns></returns>
+        public static Task<ErroredResult> VerifyEventSignatureAsync(this WechatTenpayClient client, string webhookTimestamp, string webhookNonce, string webhookBody, string webhookSignature, string webhookSerialNumber, CancellationToken cancellationToken = default)
+        {
+            return VerifyEventSignatureAsync(
+                client,
+                webhookTimestamp: webhookTimestamp,
+                webhookNonce: webhookNonce,
+                webhookBody: webhookBody,
+                webhookSignature: webhookSignature,
+                webhookSignatureType: SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256,
+                webhookSerialNumber: webhookSerialNumber,
+                cancellationToken: cancellationToken
+            );
+        }
+
+        /// <summary>
+        /// <para>异步验证回调通知事件签名。</para>
+        /// <para>
+        /// REF: <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/merchant/development/interface-rules/signature-verification.html ]]> <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/partner/development/interface-rules/signature-verification.html ]]>
+        /// </para>
+        /// </summary>
+        /// <param name="client"></param>
+        /// <param name="webhookTimestamp">微信回调通知中的 "Wechatpay-Timestamp" 请求标头。</param>
+        /// <param name="webhookNonce">微信回调通知中的 "Wechatpay-Nonce" 请求标头。</param>
+        /// <param name="webhookBody">微信回调通知中请求正文。</param>
+        /// <param name="webhookSignature">微信回调通知中的 "Wechatpay-Signature" 请求标头。</param>
+        /// <param name="webhookSignatureType">微信回调通知中的 "Wechatpay-Signature-Type" 请求标头。</param>
+        /// <param name="webhookSerialNumber">微信回调通知中的 "Wechatpay-Serial" 请求标头。</param>
+        /// <returns></returns>
+        public static Task<ErroredResult> VerifyEventSignatureAsync(this WechatTenpayClient client, string webhookTimestamp, string webhookNonce, string webhookBody, string webhookSignature, string webhookSignatureType, string webhookSerialNumber, CancellationToken cancellationToken = default)
+        {
+            if (client is null) throw new ArgumentNullException(nameof(client));
+
+            return WechatTenpayClientSigningExtensions.VerifySignatureAsync(
+                client,
+                strTimestamp: webhookTimestamp,
+                strNonce: webhookNonce,
+                strContent: webhookBody,
+                strSignature: webhookSignature,
+                strSignScheme: webhookSignatureType,
+                strSerialNumber: webhookSerialNumber,
+                cancellationToken: cancellationToken
+            );
+        }
     }
 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientParameterExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientParameterExtensions.cs
index 985dbcbe..f6cceaf7 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientParameterExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientParameterExtensions.cs
@@ -4,6 +4,8 @@ using System.Collections.ObjectModel;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 {
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Constants;
+
     public static class WechatTenpayClientParameterExtensions
     {
         /// <summary>
@@ -47,7 +49,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 { "timeStamp", timestamp },
                 { "nonceStr", nonce },
                 { "package", package },
-                { "signType", Constants.SignTypes.RSA },
+                { "signType", SignTypes.RSA },
                 { "paySign", sign }
             });
         }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientRequestEncryptionExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientRequestEncryptionExtensions.cs
index bde6a9cb..a6b1a5b8 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientRequestEncryptionExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientRequestEncryptionExtensions.cs
@@ -2,9 +2,12 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 {
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Constants;
     using SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings;
     using SKIT.FlurlHttpClient.Wechat.TenpayV3.Utilities;
 
@@ -30,8 +33,94 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 
                 string signScheme = client.Credentials.SignScheme;
                 string algorithmType = // 签名方式与加密算法保持一致：RSA_SHA256 签名需 RSA 加密，SM3 签名需 SM2 加密
-                    Constants.SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256.Equals(signScheme) ? CertificateEntry.ALGORITHM_TYPE_RSA :
-                    Constants.SignSchemes.WECHATPAY2_SM2_WITH_SM3.Equals(signScheme) ? CertificateEntry.ALGORITHM_TYPE_SM2 :
+                    SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256.Equals(signScheme) ? CertificateEntry.ALGORITHM_TYPE_RSA :
+                    SignSchemes.WECHATPAY2_SM2_WITH_SM3.Equals(signScheme) ? CertificateEntry.ALGORITHM_TYPE_SM2 :
+                    throw new WechatTenpayException($"Failed to encrypt request. Unsupported signing scheme: \"{signScheme}\".");
+
+                ReflectionHelper.ReplaceObjectStringProperties(request, (_, currentProp, oldValue) =>
+                {
+                    if (currentProp is null || !currentProp.IsDefined(typeof(WechatTenpaySensitivePropertyAttribute)))
+                        return (false, oldValue);
+
+                    WechatTenpaySensitivePropertyAttribute? attribute = currentProp
+                        .GetCustomAttributes<WechatTenpaySensitivePropertyAttribute>()
+                        .FirstOrDefault(attr => attr.Scheme == signScheme);
+                    if (attribute is null)
+                        return (false, oldValue);
+
+                    string certificate;
+                    if (string.IsNullOrEmpty(request.WechatpayCertificateSerialNumber))
+                    {
+                        // 如果未在请求中指定特定的平台证书序列号，从管理器中取过期时间最远的
+                        IEnumerable<CertificateEntry> entries = client.PlatformCertificateManager.AllEntries()
+                            .Where(e => e.AlgorithmType == algorithmType)
+                            .OrderByDescending(e => e.ExpireTime);
+                        if (!entries.Any())
+                        {
+                            throw new WechatTenpayException("Failed to encrypt request, because the platform certificate manager is empty. Please make sure you have downloaded platform (NOT merchant) certificates first.");
+                        }
+
+                        CertificateEntry entry = entries.First();
+                        certificate = entry.Certificate;
+                        request.WechatpayCertificateSerialNumber = entry.SerialNumber;
+                    }
+                    else
+                    {
+                        // 如果已在请求中指定特定的平台证书序列号，直接从管理器中取值
+                        CertificateEntry? entry = client.PlatformCertificateManager.GetEntry(request.WechatpayCertificateSerialNumber!);
+                        if (!entry.HasValue)
+                        {
+                            throw new WechatTenpayException($"Failed to encrypt request, because the platform certificate manager does not contain a certificate matched the serial number \"{request.WechatpayCertificateSerialNumber}\". Please make sure you have downloaded platform (NOT merchant) certificates first.");
+                        }
+
+                        certificate = entry.Value.Certificate;
+                    }
+
+                    string newValue = GenerateEncryptedValueByCertificate(attribute.Algorithm, certificate, oldValue);
+                    return (true, newValue);
+                });
+
+                return request;
+            }
+            catch (WechatTenpayException)
+            {
+                throw;
+            }
+            catch (Exception ex)
+            {
+                throw new WechatTenpayException("Failed to encrypt request. Please see the inner exception for more details.", ex);
+            }
+        }
+
+        /// <summary>
+        /// <para>异步加密请求中传入的敏感数据。该方法会改变传入的请求模型对象。</para>
+        /// </summary>
+        /// <param name="client"></param>
+        /// <param name="request"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        public static Task<TRequest> EncryptRequestSensitivePropertyAsync<TRequest>(this WechatTenpayClient client, TRequest request, CancellationToken cancellationToken = default)
+            where TRequest : WechatTenpayRequest
+        {
+            if (client is null) throw new ArgumentNullException(nameof(client));
+            if (request is null) throw new ArgumentNullException(nameof(request));
+
+            if (client.PlatformCertificateManager is not ICertificateManagerAsync)
+            {
+                // 降级为同步调用
+                return Task.FromResult(request);
+            }
+
+            try
+            {
+                bool requireEncrypt = request.GetType().IsDefined(typeof(WechatTenpaySensitiveAttribute));
+                if (!requireEncrypt)
+                    return Task.FromResult(request);
+
+                string signScheme = client.Credentials.SignScheme;
+                string algorithmType = // 签名方式与加密算法保持一致：RSA_SHA256 签名需 RSA 加密，SM3 签名需 SM2 加密
+                    SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256.Equals(signScheme) ? CertificateEntry.ALGORITHM_TYPE_RSA :
+                    SignSchemes.WECHATPAY2_SM2_WITH_SM3.Equals(signScheme) ? CertificateEntry.ALGORITHM_TYPE_SM2 :
                     throw new WechatTenpayException($"Failed to encrypt request. Unsupported signing scheme: \"{signScheme}\".");
 
                 ReflectionHelper.ReplaceObjectStringProperties(request, (_, currentProp, oldValue) =>
@@ -52,7 +141,11 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                             throw new WechatTenpayException("Failed to encrypt request, because the platform certificate manager is not initialized.");
 
                         // 如果未在请求中指定特定的平台证书序列号，从管理器中取过期时间最远的
-                        IEnumerable<CertificateEntry> entries = client.PlatformCertificateManager.AllEntries()
+                        IEnumerable<CertificateEntry> entries = ((ICertificateManagerAsync)client.PlatformCertificateManager)
+                            .AllEntriesAsync(cancellationToken)
+                            .ConfigureAwait(false)
+                            .GetAwaiter()
+                            .GetResult()
                             .Where(e => e.AlgorithmType == algorithmType)
                             .OrderByDescending(e => e.ExpireTime);
                         if (!entries.Any())
@@ -67,7 +160,11 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                     else
                     {
                         // 如果已在请求中指定特定的平台证书序列号，直接从管理器中取值
-                        CertificateEntry? entry = client.PlatformCertificateManager?.GetEntry(request.WechatpayCertificateSerialNumber!);
+                        CertificateEntry? entry = ((ICertificateManagerAsync)client.PlatformCertificateManager)
+                            .GetEntryAsync(request.WechatpayCertificateSerialNumber!, cancellationToken)
+                            .ConfigureAwait(false)
+                            .GetAwaiter()
+                            .GetResult();
                         if (!entry.HasValue)
                         {
                             throw new WechatTenpayException($"Failed to encrypt request, because the platform certificate manager does not contain a certificate matched the serial number \"{request.WechatpayCertificateSerialNumber}\". Please make sure you have downloaded platform (NOT merchant) certificates first.");
@@ -76,49 +173,11 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                         certificate = entry.Value.Certificate;
                     }
 
-                    string newValue;
-                    switch (attribute.Algorithm)
-                    {
-                        case Constants.EncryptionAlgorithms.RSA_2048_ECB_PKCS8_OAEP_WITH_SHA1_AND_MGF1:
-                            {
-                                newValue = RSAUtility.EncryptWithECBByCertificate(
-                                    certificatePem: certificate,
-                                    plainData: oldValue,
-                                    paddingMode: RSAUtility.PADDING_MODE_OAEPWITHSHA1ANDMGF1
-                                )!;
-                            }
-                            break;
-
-                        case Constants.EncryptionAlgorithms.RSA_2048_ECB_PKCS1:
-                            {
-                                newValue = RSAUtility.EncryptWithECBByCertificate(
-                                    certificatePem: certificate,
-                                    plainData: oldValue,
-                                    paddingMode: RSAUtility.PADDING_MODE_PKCS1
-                                )!;
-                            }
-                            break;
-
-                        case Constants.EncryptionAlgorithms.SM2_C1C3C2_ASN1:
-                            {
-                                newValue = SM2Utility.EncryptByCertificate(
-                                    certificatePem: certificate,
-                                    plainData: oldValue,
-                                    asn1Encoding: true
-                                )!;
-                            }
-                            break;
-
-                        default:
-                            {
-                                throw new WechatTenpayException($"Failed to encrypt request. Unsupported encryption algorithm: \"{attribute.Algorithm}\".");
-                            }
-                    }
-
+                    string newValue = GenerateEncryptedValueByCertificate(attribute.Algorithm, certificate, oldValue);
                     return (true, newValue);
                 });
 
-                return request;
+                return Task.FromResult(request);
             }
             catch (WechatTenpayException)
             {
@@ -129,5 +188,35 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 throw new WechatTenpayException("Failed to encrypt request. Please see the inner exception for more details.", ex);
             }
         }
+
+        private static string GenerateEncryptedValueByCertificate(string algorithm, string certificate, string value)
+        {
+            switch (algorithm)
+            {
+                case EncryptionAlgorithms.RSA_2048_ECB_PKCS8_OAEP_WITH_SHA1_AND_MGF1:
+                    return RSAUtility.EncryptWithECBByCertificate(
+                        certificatePem: certificate,
+                        plainData: value,
+                        paddingMode: RSAUtility.PADDING_MODE_OAEPWITHSHA1ANDMGF1
+                    )!;
+
+                case EncryptionAlgorithms.RSA_2048_ECB_PKCS1:
+                    return RSAUtility.EncryptWithECBByCertificate(
+                        certificatePem: certificate,
+                        plainData: value,
+                        paddingMode: RSAUtility.PADDING_MODE_PKCS1
+                    )!;
+
+                case EncryptionAlgorithms.SM2_C1C3C2_ASN1:
+                    return SM2Utility.EncryptByCertificate(
+                        certificatePem: certificate,
+                        plainData: value,
+                        asn1Encoding: true
+                    )!;
+
+                default:
+                    throw new WechatTenpayException($"Failed to encrypt request. Unsupported encryption algorithm: \"{algorithm}\".");
+            }
+        }
     }
 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseDecryptionExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseDecryptionExtensions.cs
index 09b8e359..4cb42f13 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseDecryptionExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseDecryptionExtensions.cs
@@ -5,6 +5,7 @@ using System.Reflection;
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 {
     using SKIT.FlurlHttpClient.Primitives;
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Constants;
     using SKIT.FlurlHttpClient.Wechat.TenpayV3.Models;
     using SKIT.FlurlHttpClient.Wechat.TenpayV3.Utilities;
 
@@ -31,7 +32,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 
                 switch (certificate.EncryptCertificate.Algorithm)
                 {
-                    case Constants.EncryptionAlgorithms.AEAD_AES_256_GCM:
+                    case EncryptionAlgorithms.AEAD_AES_256_GCM:
                         {
                             if (string.IsNullOrEmpty(client.Credentials.MerchantCertificatePrivateKey))
                                 throw new WechatTenpayException("Failed to decrypt response, because the merchant private key is not set.");
@@ -45,7 +46,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                         }
                         break;
 
-                    case Constants.EncryptionAlgorithms.AEAD_SM4_128_GCM:
+                    case EncryptionAlgorithms.AEAD_SM4_128_GCM:
                         {
                             if (string.IsNullOrEmpty(client.Credentials.MerchantV3Secret))
                                 throw new WechatTenpayException("Failed to decrypt response, because the merchant APIv3 secret is not set.");
@@ -120,7 +121,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                     string newValue;
                     switch (attribute.Algorithm)
                     {
-                        case Constants.EncryptionAlgorithms.RSA_2048_ECB_PKCS8_OAEP_WITH_SHA1_AND_MGF1:
+                        case EncryptionAlgorithms.RSA_2048_ECB_PKCS8_OAEP_WITH_SHA1_AND_MGF1:
                             {
                                 newValue = RSAUtility.DecryptWithECB(
                                     privateKeyPem: client.Credentials.MerchantCertificatePrivateKey,
@@ -130,7 +131,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                             }
                             break;
 
-                        case Constants.EncryptionAlgorithms.RSA_2048_ECB_PKCS1:
+                        case EncryptionAlgorithms.RSA_2048_ECB_PKCS1:
                             {
                                 newValue = RSAUtility.DecryptWithECB(
                                     privateKeyPem: client.Credentials.MerchantCertificatePrivateKey,
@@ -140,7 +141,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                             }
                             break;
 
-                        case Constants.EncryptionAlgorithms.SM2_C1C3C2_ASN1:
+                        case EncryptionAlgorithms.SM2_C1C3C2_ASN1:
                             {
                                 newValue = SM2Utility.Decrypt(
                                     privateKeyPem: client.Credentials.MerchantCertificatePrivateKey,
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseVerificationExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseVerificationExtensions.cs
index 41d2f7c3..64b77160 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseVerificationExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseVerificationExtensions.cs
@@ -1,9 +1,12 @@
 using System;
 using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 {
     using SKIT.FlurlHttpClient.Primitives;
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Constants;
 
     public static class WechatTenpayClientResponseVerificationExtensions
     {
@@ -59,7 +62,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 responseNonce: responseNonce,
                 responseBody: responseBody,
                 responseSignature: responseSignature,
-                responseSignatureType: Constants.SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256,
+                responseSignatureType: SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256,
                 responseSerialNumber
             );
         }
@@ -94,5 +97,96 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 strSerialNumber: responseSerialNumber
             );
         }
+
+        /// <summary>
+        /// <para>异步验证响应签名。</para>
+        /// <para>
+        /// REF: <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/merchant/development/interface-rules/signature-verification.html ]]> <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/partner/development/interface-rules/signature-verification.html ]]>
+        /// </para>
+        /// </summary>
+        /// <typeparam name="TResponse"></typeparam>
+        /// <param name="client"></param>
+        /// <param name="response"></param>
+        /// <returns></returns>
+        public static Task<ErroredResult> VerifyResponseSignatureAsync<TResponse>(this WechatTenpayClient client, TResponse response, CancellationToken cancellationToken = default)
+            where TResponse : WechatTenpayResponse
+        {
+            if (client is null) throw new ArgumentNullException(nameof(client));
+            if (response is null) throw new ArgumentNullException(nameof(response));
+
+            return VerifyResponseSignatureAsync(
+                client,
+                responseTimestamp: response.WechatpayTimestamp,
+                responseNonce: response.WechatpayNonce,
+                responseBody: Encoding.UTF8.GetString(response.GetRawBytes()),
+                responseSignature: response.WechatpaySignature,
+                responseSignatureType: response.WechatpaySignatureType,
+                responseSerialNumber: response.WechatpayCertificateSerialNumber,
+                cancellationToken: cancellationToken
+            );
+        }
+
+        /// <summary>
+        /// <para>异步验证响应签名。</para>
+        /// <para>
+        /// REF: <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/merchant/development/interface-rules/signature-verification.html ]]> <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/partner/development/interface-rules/signature-verification.html ]]>
+        /// </para>
+        /// </summary>
+        /// <param name="client"></param>
+        /// <param name="responseTimestamp"></param>
+        /// <param name="responseNonce">。</param>
+        /// <param name="responseBody"></param>
+        /// <param name="responseSignature"></param>
+        /// <param name="responseSerialNumber"></param>
+        /// <returns></returns>
+        public static Task<ErroredResult> VerifyResponseSignatureAsync(this WechatTenpayClient client, string responseTimestamp, string responseNonce, string responseBody, string responseSignature, string responseSerialNumber, CancellationToken cancellationToken = default)
+        {
+            return VerifyResponseSignatureAsync(
+                client,
+                responseTimestamp: responseTimestamp,
+                responseNonce: responseNonce,
+                responseBody: responseBody,
+                responseSignature: responseSignature,
+                responseSignatureType: SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256,
+                responseSerialNumber: responseSerialNumber,
+                cancellationToken
+            );
+        }
+
+        /// <summary>
+        /// <para>异步验证响应签名。</para>
+        /// <para>
+        /// REF: <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/merchant/development/interface-rules/signature-verification.html ]]> <br/>
+        /// <![CDATA[ https://pay.weixin.qq.com/docs/partner/development/interface-rules/signature-verification.html ]]>
+        /// </para>
+        /// </summary>
+        /// <param name="client"></param>
+        /// <param name="responseTimestamp"></param>
+        /// <param name="responseNonce">。</param>
+        /// <param name="responseBody"></param>
+        /// <param name="responseSignature"></param>
+        /// <param name="responseSignatureType"></param>
+        /// <param name="responseSerialNumber"></param>
+        /// <returns></returns>
+        public static Task<ErroredResult> VerifyResponseSignatureAsync(this WechatTenpayClient client, string responseTimestamp, string responseNonce, string responseBody, string responseSignature, string responseSignatureType, string responseSerialNumber, CancellationToken cancellationToken = default)
+        {
+            if (client is null) throw new ArgumentNullException(nameof(client));
+
+            return WechatTenpayClientSigningExtensions.VerifySignatureAsync(
+                client,
+                strTimestamp: responseTimestamp,
+                strNonce: responseNonce,
+                strContent: responseBody,
+                strSignature: responseSignature,
+                strSignScheme: responseSignatureType,
+                strSerialNumber: responseSerialNumber,
+                cancellationToken
+            );
+        }
     }
 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/__Internal/WechatTenpayClientSigningExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/__Internal/WechatTenpayClientSigningExtensions.cs
index 542542a8..5062bd4b 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/__Internal/WechatTenpayClientSigningExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/__Internal/WechatTenpayClientSigningExtensions.cs
@@ -1,8 +1,11 @@
 using System;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 {
     using SKIT.FlurlHttpClient.Primitives;
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Constants;
     using SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings;
 
     internal static class WechatTenpayClientSigningExtensions
@@ -11,36 +14,68 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
         {
             if (client is null) throw new ArgumentNullException(nameof(client));
 
+            CertificateEntry? entry = client.PlatformCertificateManager.GetEntry(strSerialNumber);
+            if (!entry.HasValue)
+            {
+                return ErroredResult.Fail(new Exception($"The platform certificate manager does not contain a certificate with serial number \"{strSerialNumber}\"."));
+            }
+
+            return GenerateSignatureResultByCertificate(
+                scheme: strSignScheme,
+                certificate: entry.Value.Certificate,
+                message: GenerateMessageForSignature(timestamp: strTimestamp, nonce: strNonce, body: strContent),
+                signature: strSignature
+            );
+        }
+
+        public static async Task<ErroredResult> VerifySignatureAsync(this WechatTenpayClient client, string strTimestamp, string strNonce, string strContent, string strSignature, string strSignScheme, string strSerialNumber, CancellationToken cancellationToken = default)
+        {
+            if (client is null) throw new ArgumentNullException(nameof(client));
+
+            if (client.PlatformCertificateManager is not ICertificateManagerAsync)
+            {
+                // 降级为同步调用
+                return VerifySignature(client, strTimestamp, strNonce, strContent, strSignature, strSignScheme, strSerialNumber);
+            }
+
+            CertificateEntry? entry = await ((ICertificateManagerAsync)client.PlatformCertificateManager).GetEntryAsync(strSerialNumber, cancellationToken).ConfigureAwait(false);
+            if (!entry.HasValue)
+            {
+                return ErroredResult.Fail(new Exception($"The platform certificate manager does not contain a certificate with serial number \"{strSerialNumber}\"."));
+            }
+
+            return GenerateSignatureResultByCertificate(
+                scheme: strSignScheme,
+                certificate: entry.Value.Certificate,
+                message: GenerateMessageForSignature(timestamp: strTimestamp, nonce: strNonce, body: strContent),
+                signature: strSignature
+            );
+        }
+
+        private static string GenerateMessageForSignature(string timestamp, string nonce, string body)
+        {
+            return $"{timestamp}\n{nonce}\n{body}\n";
+        }
+
+        private static ErroredResult GenerateSignatureResultByCertificate(string scheme, string certificate, string message, string signature)
+        {
             ErroredResult result;
 
-            switch (strSignScheme)
+            switch (scheme)
             {
-                case Constants.SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256:
+                case SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256:
                     {
                         try
                         {
-                            if (client.PlatformCertificateManager is null)
-                            {
-                                result = ErroredResult.Fail(new Exception("The platform certificate manager is not initialized."));
-                                break;
-                            }
-
-                            CertificateEntry? entry = client.PlatformCertificateManager.GetEntry(strSerialNumber);
-                            if (!entry.HasValue)
-                            {
-                                result = ErroredResult.Fail(new Exception($"The platform certificate manager does not contain a certificate with serial number \"{strSerialNumber}\"."));
-                                break;
-                            }
-
                             bool valid = Utilities.RSAUtility.VerifyByCertificate(
-                                certificatePem: entry.Value.Certificate,
-                                messageData: GenerateMessageForSignature(timestamp: strTimestamp, nonce: strNonce, body: strContent),
-                                encodingSignature: new EncodedString(strSignature, EncodingKinds.Base64)
+                                certificatePem: certificate,
+                                messageData: message,
+                                encodingSignature: new EncodedString(signature, EncodingKinds.Base64)
                             );
                             if (valid)
                                 result = ErroredResult.Ok();
                             else
-                                result = ErroredResult.Fail(new Exception($"Signature does not match. Maybe \"{strSignature}\" is an illegal signature."));
+                                result = ErroredResult.Fail(new Exception($"Signature does not match. Maybe \"{signature}\" is an illegal signature."));
                         }
                         catch (Exception ex)
                         {
@@ -49,32 +84,19 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                     }
                     break;
 
-                case Constants.SignSchemes.WECHATPAY2_SM2_WITH_SM3:
+                case SignSchemes.WECHATPAY2_SM2_WITH_SM3:
                     {
                         try
                         {
-                            if (client.PlatformCertificateManager is null)
-                            {
-                                result = ErroredResult.Fail(new Exception("The platform certificate manager is not initialized."));
-                                break;
-                            }
-
-                            CertificateEntry? entry = client.PlatformCertificateManager.GetEntry(strSerialNumber);
-                            if (!entry.HasValue)
-                            {
-                                result = ErroredResult.Fail(new Exception($"The platform certificate manager does not contain a certificate with serial number \"{strSerialNumber}\"."));
-                                break;
-                            }
-
                             bool valid = Utilities.SM2Utility.VerifyWithSM3ByCertificate(
-                                certificatePem: entry.Value.Certificate,
-                                messageData: GenerateMessageForSignature(timestamp: strTimestamp, nonce: strNonce, body: strContent),
-                                encodingSignature: new EncodedString(strSignature, EncodingKinds.Base64)
+                                certificatePem: certificate,
+                                messageData: message,
+                                encodingSignature: new EncodedString(signature, EncodingKinds.Base64)
                             );
                             if (valid)
                                 result = ErroredResult.Ok();
                             else
-                                result = ErroredResult.Fail(new Exception($"Signature does not match. Maybe \"{strSignature}\" is an illegal signature."));
+                                result = ErroredResult.Fail(new Exception($"Signature does not match. Maybe \"{signature}\" is an illegal signature."));
                         }
                         catch (Exception ex)
                         {
@@ -85,17 +107,12 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 
                 default:
                     {
-                        result = ErroredResult.Fail(new Exception($"Unsupported signing scheme: \"{strSignScheme}\"."));
+                        result = ErroredResult.Fail(new Exception($"Unsupported signing scheme: \"{scheme}\"."));
                     }
                     break;
             }
 
             return result;
         }
-
-        private static string GenerateMessageForSignature(string timestamp, string nonce, string body)
-        {
-            return $"{timestamp}\n{nonce}\n{body}\n";
-        }
     }
 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Interceptors/WechatTenpayRequestSigningInterceptor.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Interceptors/WechatTenpayRequestSigningInterceptor.cs
index 59312caf..2927abc4 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Interceptors/WechatTenpayRequestSigningInterceptor.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Interceptors/WechatTenpayRequestSigningInterceptor.cs
@@ -8,6 +8,7 @@ using Flurl.Http;
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Interceptors
 {
     using SKIT.FlurlHttpClient.Internal;
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Constants;
 
     internal class WechatTenpayRequestSigningInterceptor : HttpInterceptor
     {
@@ -38,7 +39,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Interceptors
             if (context.FlurlCall.HttpRequestMessage.Content is MultipartFormDataContent formdataContent)
             {
                 // NOTICE: multipart/form-data 文件上传请求的待签名参数需特殊处理
-                var httpContent = formdataContent.SingleOrDefault(e => Constants.FormDataFields.FORMDATA_META.Equals(e.Headers.ContentDisposition?.Name?.Trim('\"')));
+                var httpContent = formdataContent.SingleOrDefault(e => FormDataFields.FORMDATA_META.Equals(e.Headers.ContentDisposition?.Name?.Trim('\"')));
                 if (httpContent is not null)
                 {
                     body = await _AsyncEx.RunTaskWithCancellationTokenAsync(httpContent.ReadAsStringAsync(), cancellationToken).ConfigureAwait(false);
@@ -54,7 +55,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Interceptors
 
             switch (_scheme)
             {
-                case Constants.SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256:
+                case SignSchemes.WECHATPAY2_RSA_2048_WITH_SHA256:
                     {
                         try
                         {
@@ -67,7 +68,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Interceptors
                     }
                     break;
 
-                case Constants.SignSchemes.WECHATPAY2_SM2_WITH_SM3:
+                case SignSchemes.WECHATPAY2_SM2_WITH_SM3:
                     {
                         try
                         {
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateEntry.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateEntry.cs
index dfd38f17..8f98e8ea 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateEntry.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateEntry.cs
@@ -7,7 +7,14 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
     /// </summary>
     public partial struct CertificateEntry : IEquatable<CertificateEntry>
     {
+        /// <summary>
+        /// 证书算法类型：RSA。
+        /// </summary>
         public const string ALGORITHM_TYPE_RSA = "RSA";
+
+        /// <summary>
+        /// 证书算法类型：SM2。
+        /// </summary>
         public const string ALGORITHM_TYPE_SM2 = "SM2";
 
         /// <summary>
@@ -36,6 +43,14 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
         /// </summary>
         public DateTimeOffset ExpireTime { get; }
 
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="algorithmType"></param>
+        /// <param name="serialNumber"></param>
+        /// <param name="certificate"></param>
+        /// <param name="effectiveTime"></param>
+        /// <param name="expireTime"></param>
         [Newtonsoft.Json.JsonConstructor]
         [System.Text.Json.Serialization.JsonConstructor]
         public CertificateEntry(string algorithmType, string serialNumber, string certificate, DateTimeOffset effectiveTime, DateTimeOffset expireTime)
@@ -58,6 +73,11 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
             ExpireTime = expireTime;
         }
 
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="algorithmType"></param>
+        /// <param name="certificate"></param>
         public CertificateEntry(string algorithmType, string certificate)
         {
             if (string.IsNullOrEmpty(algorithmType))
@@ -95,12 +115,21 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
             }
         }
 
+        /// <summary>
+        /// 返回一个布尔值，该值指示当前证书是否可用。
+        /// </summary>
+        /// <returns></returns>
         public bool IsAvailable()
         {
             DateTimeOffset now = DateTimeOffset.Now;
             return EffectiveTime <= now && now < ExpireTime;
         }
 
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="other"></param>
+        /// <returns></returns>
         public bool Equals(CertificateEntry other)
         {
             return string.Equals(AlgorithmType, other.AlgorithmType) &&
@@ -108,6 +137,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
                    string.Equals(SerialNumber, other.SerialNumber);
         }
 
+        /// <inheritdoc/>
         public override bool Equals(object? obj)
         {
             if (ReferenceEquals(null, obj))
@@ -118,20 +148,23 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
             return Equals((CertificateEntry)obj);
         }
 
+        /// <inheritdoc/>
         public override int GetHashCode()
         {
-#if NETFRAMEWORK || NETSTANDARD2_0
-            return (AlgorithmType?.GetHashCode(), Certificate?.GetHashCode(), SerialNumber?.GetHashCode()).GetHashCode();
-#else
+#if NETCOREAPP || NET5_0_OR_GREATER
             return HashCode.Combine(AlgorithmType?.GetHashCode(), Certificate?.GetHashCode(), SerialNumber?.GetHashCode());
+#else
+            return (AlgorithmType?.GetHashCode(), Certificate?.GetHashCode(), SerialNumber?.GetHashCode()).GetHashCode();
 #endif
         }
 
+        /// <inheritdoc/>
         public static bool operator ==(CertificateEntry left, CertificateEntry right)
         {
             return left.Equals(right);
         }
 
+        /// <inheritdoc/>
         public static bool operator !=(CertificateEntry left, CertificateEntry right)
         {
             return !left.Equals(right);
@@ -140,11 +173,23 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
 
     partial struct CertificateEntry
     {
+        /// <summary>
+        /// 将指定的 <see cref="Models.QueryCertificatesResponse.Types.Certificate"/> 对象解析为 <see cref="CertificateEntry"/> 对象。
+        /// </summary>
+        /// <param name="algorithmType"></param>
+        /// <param name="certificate"></param>
+        /// <returns></returns>
         public static CertificateEntry Parse(string algorithmType, Models.QueryCertificatesResponse.Types.Certificate certificate)
         {
             return new CertificateEntry(algorithmType, certificate.SerialNumber, certificate.EncryptCertificate.CipherText, certificate.EffectiveTime, certificate.ExpireTime);
         }
 
+        /// <summary>
+        /// 将指定的 <see cref="Models.QueryCertificatesResponse.Types.Certificate"/> 对象解析为 <see cref="CertificateEntry"/> 对象。
+        /// </summary>
+        /// <param name="certificate"></param>
+        /// <returns></returns>
+        /// <exception cref="ArgumentException"></exception>
         public static CertificateEntry Parse(Models.QueryCertificatesResponse.Types.Certificate certificate)
         {
             string? algorithmType = default!;
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateManager.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateManager.cs
index 7f3a2a49..da81b120 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateManager.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateManager.cs
@@ -2,45 +2,84 @@ using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
 {
     /// <summary>
     /// 微信商户平台证书管理器接口。
     /// </summary>
-    public abstract class CertificateManager
+    public interface ICertificateManager
     {
         /// <summary>
         /// 获取存储的全部证书实体。
         /// </summary>
         /// <returns></returns>
-        public abstract IEnumerable<CertificateEntry> AllEntries();
+        IEnumerable<CertificateEntry> AllEntries();
 
         /// <summary>
         /// 添加一个证书实体。
         /// </summary>
         /// <param name="entry"></param>
-        public abstract void AddEntry(CertificateEntry entry);
+        void AddEntry(CertificateEntry entry);
 
         /// <summary>
         /// 根据证书序列号获取证书实体。
         /// </summary>
         /// <param name="serialNumber"></param>
         /// <returns></returns>
-        public abstract CertificateEntry? GetEntry(string serialNumber);
+        CertificateEntry? GetEntry(string serialNumber);
 
         /// <summary>
         /// 根据证书序列号移除证书实体。
         /// </summary>
         /// <param name="serialNumber"></param>
         /// <returns></returns>
-        public abstract bool RemoveEntry(string serialNumber);
+        bool RemoveEntry(string serialNumber);
+    }
+
+    /// <summary>
+    /// 微信商户平台证书管理器异步接口。
+    /// </summary>
+    public interface ICertificateManagerAsync : ICertificateManager
+    {
+        /// <summary>
+        /// 异步获取存储的全部证书实体。
+        /// </summary>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        Task<IEnumerable<CertificateEntry>> AllEntriesAsync(CancellationToken cancellationToken = default);
+
+        /// <summary>
+        /// 异步添加一个证书实体。
+        /// </summary>
+        /// <param name="entry"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        Task AddEntryAsync(CertificateEntry entry, CancellationToken cancellationToken = default);
+
+        /// <summary>
+        /// 异步根据证书序列号获取证书实体。
+        /// </summary>
+        /// <param name="serialNumber"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        Task<CertificateEntry?> GetEntryAsync(string serialNumber, CancellationToken cancellationToken = default);
+
+        /// <summary>
+        /// 异步根据证书序列号移除证书实体。
+        /// </summary>
+        /// <param name="serialNumber"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        Task<bool> RemoveEntryAsync(string serialNumber, CancellationToken cancellationToken = default);
     }
 
     /// <summary>
     /// 一个基于内存实现的 <see cref="CertificateManager"/>。
     /// </summary>
-    public class InMemoryCertificateManager : CertificateManager
+    public sealed class InMemoryCertificateManager : ICertificateManager
     {
         private readonly ConcurrentDictionary<string, CertificateEntry> _dict;
 
@@ -49,20 +88,22 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
             _dict = new ConcurrentDictionary<string, CertificateEntry>(StringComparer.OrdinalIgnoreCase);
         }
 
-        public override IEnumerable<CertificateEntry> AllEntries()
+        /// <inheritdoc/>
+        public IEnumerable<CertificateEntry> AllEntries()
         {
-            return _dict.Values.Where(e => e.IsAvailable()).ToArray();
+            return _dict.Values.Where(static e => e.IsAvailable()).ToArray();
         }
 
-        public override void AddEntry(CertificateEntry entry)
+        /// <inheritdoc/>
+        public void AddEntry(CertificateEntry entry)
         {
-            _dict.TryRemove(entry.SerialNumber, out _);
-            _dict.TryAdd(entry.SerialNumber, entry);
+            _dict.AddOrUpdate(entry.SerialNumber, (_) => entry, (_, _) => entry);
         }
 
-        public override CertificateEntry? GetEntry(string serialNumber)
+        /// <inheritdoc/>
+        public CertificateEntry? GetEntry(string serialNumber)
         {
-            if (_dict.TryGetValue(serialNumber, out var entry))
+            if (_dict.TryGetValue(serialNumber, out CertificateEntry entry))
             {
                 if (entry.IsAvailable())
                     return entry;
@@ -73,7 +114,8 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
             return null;
         }
 
-        public override bool RemoveEntry(string serialNumber)
+        /// <inheritdoc/>
+        public bool RemoveEntry(string serialNumber)
         {
             return _dict.TryRemove(serialNumber, out _);
         }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/Credentials.cs
index 5e5c7051..ec046dfb 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/Credentials.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/Credentials.cs
@@ -2,7 +2,7 @@ using System;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
 {
-    public class Credentials
+    public sealed class Credentials
     {
         /// <summary>
         /// 初始化客户端时 <see cref="WechatTenpayClientOptions.MerchantId"/> 的副本。
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Utilities/__Internal/FileHttpContentBuilder.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Utilities/__Internal/FileHttpContentBuilder.cs
index d1e7d517..cbbff22e 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Utilities/__Internal/FileHttpContentBuilder.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Utilities/__Internal/FileHttpContentBuilder.cs
@@ -6,6 +6,8 @@ using System.Web;
 
 namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Utilities
 {
+    using SKIT.FlurlHttpClient.Wechat.TenpayV3.Constants;
+
     internal static class FileHttpContentBuilder
     {
         public static MultipartFormDataContent Build(string fileName, byte[] fileBytes, string fileContentType, string fileMetaJson, string formDataName = "file")
@@ -35,7 +37,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Utilities
             string boundary = "--BOUNDARY--" + DateTimeOffset.Now.Ticks.ToString("x");
             MultipartFormDataContent httpContent = new MultipartFormDataContent(boundary);
             httpContent.Headers.ContentType = MediaTypeHeaderValue.Parse($"multipart/form-data; boundary={boundary}");
-            httpContent.Add(metaContent, $"\"{Constants.FormDataFields.FORMDATA_META}\"");
+            httpContent.Add(metaContent, $"\"{FormDataFields.FORMDATA_META}\"");
             httpContent.Add(fileContent, $"\"{formDataName}\"", $"\"{HttpUtility.UrlEncode(fileName)}\"");
             return httpContent;
         }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClient.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClient.cs
index e02e32fc..b284c764 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClient.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClient.cs
@@ -20,7 +20,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
         /// <summary>
         /// 获取当前客户端使用的微信支付平台证书管理器。
         /// </summary>
-        public Settings.CertificateManager PlatformCertificateManager { get; }
+        public Settings.ICertificateManager PlatformCertificateManager { get; }
 
         /// <summary>
         /// 获取是否自动加密请求中的敏感信息字段。
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClientOptions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClientOptions.cs
index e5433d18..b20a82ac 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClientOptions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClientOptions.cs
@@ -82,6 +82,6 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
         /// 默认值：<see cref="Settings.InMemoryCertificateManager"/>
         /// </para>
         /// </summary>
-        public Settings.CertificateManager PlatformCertificateManager { get; set; } = new Settings.InMemoryCertificateManager();
+        public Settings.ICertificateManager PlatformCertificateManager { get; set; } = new Settings.InMemoryCertificateManager();
     }
 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/ExtendedSDK/Finance/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/ExtendedSDK/Finance/Settings/Credentials.cs
index 21396665..cc2ec9e1 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/ExtendedSDK/Finance/Settings/Credentials.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/ExtendedSDK/Finance/Settings/Credentials.cs
@@ -2,7 +2,7 @@ using System;
 
 namespace SKIT.FlurlHttpClient.Wechat.Work.ExtendedSDK.Finance.Settings
 {
-    public class Credentials
+    public sealed class Credentials
     {
         /// <summary>
         /// 初始化客户端时 <see cref="WechatWorkFinanceClientOptions.CorpId"/> 的副本。
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Settings/Credentials.cs
index 419c2f59..413030e9 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Settings/Credentials.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Settings/Credentials.cs
@@ -1,8 +1,8 @@
-using System;
+using System;
 
 namespace SKIT.FlurlHttpClient.Wechat.Work.Settings
 {
-    public class Credentials
+    public sealed class Credentials
     {
         /// <summary>
         /// 初始化客户端时 <see cref="WechatWorkClientOptions.CorpId"/> 的副本。