diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventDecryptionExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventDecryptionExtensions.cs
index 27455f68..081eae28 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventDecryptionExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventDecryptionExtensions.cs
@@ -18,7 +18,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (string.IsNullOrEmpty(callbackJson)) throw new ArgumentNullException(callbackJson);
 
-            return client.FlurlJsonSerializer.Deserialize<WechatTenpayEvent>(callbackJson);
+            return client.JsonSerializer.Deserialize<WechatTenpayEvent>(callbackJson);
         }
 
         /// <summary>
@@ -57,7 +57,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 try
                 {
                     plainJson = Utilities.AESUtility.DecryptWithGCM(
-                        key: client.WechatMerchantV3Secret,
+                        key: client.Credentials.MerchantV3Secret,
                         iv: resource.Nonce,
                         aad: resource.AssociatedData,
                         cipherText: resource.CipherText
@@ -73,7 +73,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 throw new Exceptions.WechatTenpayEventDecryptionException("Unknown encrypt algorithm of the resource.");
             }
 
-            return client.FlurlJsonSerializer.Deserialize<T>(plainJson);
+            return client.JsonSerializer.Deserialize<T>(plainJson);
         }
     }
 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventVerificationExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventVerificationExtensions.cs
index 62534001..520ad71a 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventVerificationExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientEventVerificationExtensions.cs
@@ -35,13 +35,13 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (callbackSignature == null) throw new ArgumentNullException(nameof(callbackSignature));
             if (callbackSerialNumber == null) throw new ArgumentNullException(nameof(callbackSerialNumber));
 
-            if (client.WechatCertificateManager == null)
+            if (client.CertificateManager == null)
             {
-                throw new Exceptions.WechatTenpayResponseVerificationException($"You must set an instance of `{nameof(Settings.ICertificateManager)}` at first.");
+                throw new Exceptions.WechatTenpayResponseVerificationException($"You must set an instance of `{nameof(Settings.CertificateManager)}` at first.");
             }
             else
             {
-                string? certificate = client.WechatCertificateManager.GetCertificate(callbackSerialNumber);
+                string? certificate = client.CertificateManager.GetCertificate(callbackSerialNumber);
                 if (certificate == null)
                     throw new Exceptions.WechatTenpayResponseVerificationException("Cannot get certificate by the serial number, may not be stored.");
 
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteCombineTransactionExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteCombineTransactionExtensions.cs
index 91b89ac0..3f438ead 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteCombineTransactionExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteCombineTransactionExtensions.cs
@@ -29,7 +29,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.CombineMerchantId)) 
-                request.CombineMerchantId = client.WechatMerchantId;
+                request.CombineMerchantId = client.Credentials.MerchantId;
 
             if (request.SubOrderList != null)
             {
@@ -63,7 +63,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.CombineMerchantId))
-                request.CombineMerchantId = client.WechatMerchantId;
+                request.CombineMerchantId = client.Credentials.MerchantId;
 
             if (request.SubOrderList != null)
             {
@@ -95,7 +95,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.CombineMerchantId))
-                request.CombineMerchantId = client.WechatMerchantId;
+                request.CombineMerchantId = client.Credentials.MerchantId;
 
             if (request.SubOrderList != null)
             {
@@ -127,7 +127,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.CombineMerchantId))
-                request.CombineMerchantId = client.WechatMerchantId;
+                request.CombineMerchantId = client.Credentials.MerchantId;
 
             if (request.SubOrderList != null)
             {
@@ -183,7 +183,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 foreach (var subOrder in request.SubOrderList)
                 {
                     if (string.IsNullOrEmpty(subOrder.MerchantId))
-                        subOrder.MerchantId = client.WechatMerchantId;
+                        subOrder.MerchantId = client.Credentials.MerchantId;
                 }
             }
 
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingBusifavorExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingBusifavorExtensions.cs
index b3077726..a00911ae 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingBusifavorExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingBusifavorExtensions.cs
@@ -29,7 +29,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.BelongMerchantId))
-                request.BelongMerchantId = client.WechatMerchantId;
+                request.BelongMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "busifavor", "stocks");
@@ -313,7 +313,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Get, "marketing", "busifavor", "callbacks")
@@ -337,7 +337,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "busifavor", "callbacks");
@@ -360,10 +360,10 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.PayerMerchantId))
-                request.PayerMerchantId = client.WechatMerchantId;
+                request.PayerMerchantId = client.Credentials.MerchantId;
 
             if (string.IsNullOrEmpty(request.PayeeMerchantId))
-                request.PayeeMerchantId = client.WechatMerchantId;
+                request.PayeeMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "busifavor", "subsidy", "pay-receipts");
@@ -406,10 +406,10 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.PayerMerchantId))
-                request.PayerMerchantId = client.WechatMerchantId;
+                request.PayerMerchantId = client.Credentials.MerchantId;
 
             if (string.IsNullOrEmpty(request.PayeeMerchantId))
-                request.PayeeMerchantId = client.WechatMerchantId;
+                request.PayeeMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "busifavor", "subsidy", "return-receipts");
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingFavorExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingFavorExtensions.cs
index 80a48577..a21acb2c 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingFavorExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingFavorExtensions.cs
@@ -29,7 +29,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.BelongMerchantId))
-                request.BelongMerchantId = client.WechatMerchantId;
+                request.BelongMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "favor", "coupon-stocks")
@@ -53,7 +53,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.StockCreatorMerchantId))
-                request.StockCreatorMerchantId = client.WechatMerchantId;
+                request.StockCreatorMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "favor", "stocks", request.StockId, "start")
@@ -77,7 +77,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.StockCreatorMerchantId))
-                request.StockCreatorMerchantId = client.WechatMerchantId;
+                request.StockCreatorMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "favor", "stocks", request.StockId, "pause")
@@ -101,7 +101,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.StockCreatorMerchantId))
-                request.StockCreatorMerchantId = client.WechatMerchantId;
+                request.StockCreatorMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "favor", "stocks", request.StockId, "restart")
@@ -125,7 +125,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.StockCreatorMerchantId))
-                request.StockCreatorMerchantId = client.WechatMerchantId;
+                request.StockCreatorMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Get, "marketing", "favor", "stocks", request.StockId)
@@ -149,7 +149,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.StockCreatorMerchantId))
-                request.StockCreatorMerchantId = client.WechatMerchantId;
+                request.StockCreatorMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Get, "marketing", "favor", "stocks")
@@ -184,7 +184,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.StockCreatorMerchantId))
-                request.StockCreatorMerchantId = client.WechatMerchantId;
+                request.StockCreatorMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Get, "marketing", "favor", "stocks", request.StockId, "merchants")
@@ -210,7 +210,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.StockCreatorMerchantId))
-                request.StockCreatorMerchantId = client.WechatMerchantId;
+                request.StockCreatorMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Get, "marketing", "favor", "stocks", request.StockId, "items")
@@ -278,7 +278,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.StockCreatorMerchantId))
-                request.StockCreatorMerchantId = client.WechatMerchantId;
+                request.StockCreatorMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "favor", "users", request.OpenId, "coupons")
@@ -365,7 +365,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "marketing", "favor", "callbacks")
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingMediaExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingMediaExtensions.cs
index 73d6d7a2..544ab602 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingMediaExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingMediaExtensions.cs
@@ -44,7 +44,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 
             string boundary = "--BOUNDARY--" + DateTimeOffset.Now.Ticks.ToString("x");
             using var fileContent = new ByteArrayContent(request.FileBytes);
-            using var metaContent = new ByteArrayContent(Encoding.UTF8.GetBytes(client.FlurlJsonSerializer.Serialize(request)));
+            using var metaContent = new ByteArrayContent(Encoding.UTF8.GetBytes(client.JsonSerializer.Serialize(request)));
             using var httpContent = new MultipartFormDataContent(boundary);
             httpContent.Add(metaContent, $"\"{Constants.FormDataFields.FORMDATA_META}\"");
             httpContent.Add(fileContent, "\"file\"", $"\"{HttpUtility.UrlEncode(request.FileName)}\"");
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingPartnershipsExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingPartnershipsExtensions.cs
index a7b119b9..c27a8b8e 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingPartnershipsExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMarketingPartnershipsExtensions.cs
@@ -74,10 +74,10 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 .CreateRequest(request, HttpMethod.Get, "marketing", "partnerships");
 
             if (request.Partner != null)
-                flurlReq.SetQueryParam("partner", client.FlurlJsonSerializer.Serialize(request.Partner));
+                flurlReq.SetQueryParam("partner", client.JsonSerializer.Serialize(request.Partner));
 
             if (request.AuthorizedData != null)
-                flurlReq.SetQueryParam("authorized_data", client.FlurlJsonSerializer.Serialize(request.AuthorizedData));
+                flurlReq.SetQueryParam("authorized_data", client.JsonSerializer.Serialize(request.AuthorizedData));
 
             if (request.Limit.HasValue)
                 flurlReq.SetQueryParam("limit", request.Limit.Value.ToString());
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMerchantMediaExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMerchantMediaExtensions.cs
index 2294389e..bce79cd4 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMerchantMediaExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMerchantMediaExtensions.cs
@@ -44,7 +44,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 
             string boundary = "--BOUNDARY--" + DateTimeOffset.Now.Ticks.ToString("x");
             using var fileContent = new ByteArrayContent(request.FileBytes);
-            using var metaContent = new StringContent(client.FlurlJsonSerializer.Serialize(request), Encoding.UTF8, "application/json");
+            using var metaContent = new StringContent(client.JsonSerializer.Serialize(request), Encoding.UTF8, "application/json");
             using var httpContent = new MultipartFormDataContent(boundary);
             httpContent.Add(metaContent, $"\"{Constants.FormDataFields.FORMDATA_META}\"");
             httpContent.Add(fileContent, "\"file\"", $"\"{HttpUtility.UrlEncode(request.FileName)}\"");
@@ -83,7 +83,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 
             string boundary = "--BOUNDARY--" + DateTimeOffset.Now.Ticks.ToString("x");
             using var fileContent = new ByteArrayContent(request.FileBytes);
-            using var metaContent = new ByteArrayContent(Encoding.UTF8.GetBytes(client.FlurlJsonSerializer.Serialize(request)));
+            using var metaContent = new ByteArrayContent(Encoding.UTF8.GetBytes(client.JsonSerializer.Serialize(request)));
             using var httpContent = new MultipartFormDataContent(boundary);
             httpContent.Add(metaContent, $"\"{Constants.FormDataFields.FORMDATA_META}\"");
             httpContent.Add(fileContent, "\"file\"", $"\"{HttpUtility.UrlEncode(request.FileName)}\"");
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMerchantServiceExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMerchantServiceExtensions.cs
index 2fd311c9..e54e2383 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMerchantServiceExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecuteMerchantServiceExtensions.cs
@@ -108,7 +108,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.ComplaintedMerchantId))
-                request.ComplaintedMerchantId = client.WechatMerchantId;
+                request.ComplaintedMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "merchant-service", "complaints-v2", request.ComplaintId, "response");
@@ -131,7 +131,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.ComplaintedMerchantId))
-                request.ComplaintedMerchantId = client.WechatMerchantId;
+                request.ComplaintedMerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "merchant-service", "complaints-v2", request.ComplaintId, "complete");
@@ -247,7 +247,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
 
             string boundary = "--BOUNDARY--" + DateTimeOffset.Now.Ticks.ToString("x");
             using var fileContent = new ByteArrayContent(request.FileBytes);
-            using var metaContent = new ByteArrayContent(Encoding.UTF8.GetBytes(client.FlurlJsonSerializer.Serialize(request)));
+            using var metaContent = new ByteArrayContent(Encoding.UTF8.GetBytes(client.JsonSerializer.Serialize(request)));
             using var httpContent = new MultipartFormDataContent(boundary);
             httpContent.Add(metaContent, $"\"{Constants.FormDataFields.FORMDATA_META}\"");
             httpContent.Add(fileContent, "\"file\"", $"\"{HttpUtility.UrlEncode(request.FileName)}\"");
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecutePayPartnerTransactionsExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecutePayPartnerTransactionsExtensions.cs
index 00c625ce..47652e6b 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecutePayPartnerTransactionsExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecutePayPartnerTransactionsExtensions.cs
@@ -29,7 +29,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "partner", "transactions", "app");
@@ -54,7 +54,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "partner", "transactions", "jsapi");
@@ -77,7 +77,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "partner", "transactions", "h5");
@@ -99,7 +99,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "partner", "transactions", "native");
@@ -126,7 +126,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Get, "pay", "partner", "transactions", "out-trade-no", request.OutTradeNumber)
@@ -155,7 +155,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Get, "pay", "partner", "transactions", "id", request.TransactionId)
@@ -184,7 +184,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "partner", "transactions", "out-trade-no", request.OutTradeNumber, "close");
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecutePayTransactionsExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecutePayTransactionsExtensions.cs
index dcc6b957..d79dc721 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecutePayTransactionsExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientExecutePayTransactionsExtensions.cs
@@ -28,7 +28,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "transactions", "app");
@@ -51,7 +51,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "transactions", "jsapi");
@@ -73,7 +73,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId)) 
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "transactions", "h5");
@@ -95,7 +95,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId)) 
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "transactions", "native");
@@ -121,7 +121,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId)) 
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Get, "pay", "transactions", "out-trade-no", request.OutTradeNumber)
@@ -148,7 +148,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId))
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Get, "pay", "transactions", "id", request.TransactionId)
@@ -175,7 +175,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (request is null) throw new ArgumentNullException(nameof(request));
 
             if (string.IsNullOrEmpty(request.MerchantId)) 
-                request.MerchantId = client.WechatMerchantId;
+                request.MerchantId = client.Credentials.MerchantId;
 
             IFlurlRequest flurlReq = client
                 .CreateRequest(request, HttpMethod.Post, "pay", "transactions", "out-trade-no", request.OutTradeNumber, "close");
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientParameterExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientParameterExtensions.cs
index 1b72e116..ab3b42f6 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientParameterExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientParameterExtensions.cs
@@ -43,7 +43,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             string nonce = Guid.NewGuid().ToString("N");
             string package = $"prepay_id={prepayId}";
             string sign = Utilities.RSAUtility.SignWithSHA256(
-                privateKey: client.WechatMerchantCertPrivateKey,
+                privateKey: client.Credentials.MerchantCertPrivateKey,
                 plainText: $"{appId}\n{timestamp}\n{nonce}\n{package}\n"
             );
 
@@ -72,7 +72,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
         /// <returns></returns>
         public static IDictionary<string, string> GenerateParametersForAppPayRequest(this WechatTenpayClient client, string appId, string prepayId)
         {
-            return GenerateParametersForAppPayRequest(client, merchantId: client.WechatMerchantId, appId: appId, prepayId: prepayId);
+            return GenerateParametersForAppPayRequest(client, merchantId: client.Credentials.MerchantId, appId: appId, prepayId: prepayId);
         }
 
         /// <summary>
@@ -98,7 +98,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             string timestamp = DateTimeOffset.Now.ToLocalTime().ToUnixTimeSeconds().ToString();
             string nonce = Guid.NewGuid().ToString("N");
             string sign = Utilities.RSAUtility.SignWithSHA256(
-                privateKey: client.WechatMerchantCertPrivateKey,
+                privateKey: client.Credentials.MerchantCertPrivateKey,
                 plainText: $"{appId}\n{timestamp}\n{nonce}\n{prepayId}\n"
             );
 
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseDecryptionExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseDecryptionExtensions.cs
index 409a3dba..dad862f7 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseDecryptionExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseDecryptionExtensions.cs
@@ -20,7 +20,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantCertPrivateKey))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantCertPrivateKey))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant private key.");
 
             if (!response.IsSuccessful())
@@ -37,7 +37,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                     try
                     {
                         accountValidationModel.AccountName = Utilities.RSAUtility.DecryptWithECB(
-                            client.WechatMerchantCertPrivateKey, 
+                            client.Credentials.MerchantCertPrivateKey, 
                             accountValidationModel.AccountName
                         );
                     }
@@ -52,7 +52,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                     try
                     {
                         accountValidationModel.AccountNumber = Utilities.RSAUtility.DecryptWithECB(
-                            client.WechatMerchantCertPrivateKey,
+                            client.Credentials.MerchantCertPrivateKey,
                             accountValidationModel.AccountNumber!
                         );
                     }
@@ -80,7 +80,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantCertPrivateKey))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantCertPrivateKey))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant private key.");
 
             if (!response.IsSuccessful())
@@ -97,7 +97,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                         try
                         {
                             downloadBillModel.EncryptKey = Utilities.RSAUtility.DecryptWithECB(
-                                client.WechatMerchantCertPrivateKey,
+                                client.Credentials.MerchantCertPrivateKey,
                                 downloadBillModel.EncryptKey
                             );
                         }
@@ -126,7 +126,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantCertPrivateKey))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantCertPrivateKey))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant private key.");
 
             if (!response.IsSuccessful())
@@ -139,7 +139,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                     try
                     {
                         response.PayerPhone = Utilities.RSAUtility.DecryptWithECB(
-                            client.WechatMerchantCertPrivateKey,
+                            client.Credentials.MerchantCertPrivateKey,
                             response.PayerPhone!
                         );
                     }
@@ -164,7 +164,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantV3Secret))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantV3Secret))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant secret.");
 
             if (!response.IsSuccessful())
@@ -181,7 +181,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                         try
                         {
                             certificateModel.EncryptCertificate.CipherText = Utilities.AESUtility.DecryptWithGCM(
-                                key: client.WechatMerchantV3Secret,
+                                key: client.Credentials.MerchantV3Secret,
                                 iv: certificateModel.EncryptCertificate.Nonce,
                                 aad: certificateModel.EncryptCertificate.AssociatedData,
                                 cipherText: certificateModel.EncryptCertificate.CipherText
@@ -216,7 +216,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantCertPrivateKey))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantCertPrivateKey))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant private key.");
 
             if (!response.IsSuccessful())
@@ -233,7 +233,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                         try
                         {
                             complaintModel.PayerPhone = Utilities.RSAUtility.DecryptWithECB(
-                                client.WechatMerchantCertPrivateKey,
+                                client.Credentials.MerchantCertPrivateKey,
                                 complaintModel.PayerPhone!
                             );
                         }
@@ -262,7 +262,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantCertPrivateKey))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantCertPrivateKey))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant private key.");
 
             if (!response.IsSuccessful())
@@ -279,7 +279,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                         try
                         {
                             guideModel.UserName = Utilities.RSAUtility.DecryptWithECB(
-                                client.WechatMerchantCertPrivateKey,
+                                client.Credentials.MerchantCertPrivateKey,
                                 guideModel.UserName
                             );
                         }
@@ -294,7 +294,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                         try
                         {
                             guideModel.UserMobile = Utilities.RSAUtility.DecryptWithECB(
-                                client.WechatMerchantCertPrivateKey,
+                                client.Credentials.MerchantCertPrivateKey,
                                 guideModel.UserMobile
                             );
                         }
@@ -323,7 +323,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantCertPrivateKey))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantCertPrivateKey))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant private key.");
 
             if (!response.IsSuccessful())
@@ -334,7 +334,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 try
                 {
                     response.UserName = Utilities.RSAUtility.DecryptWithECB(
-                        client.WechatMerchantCertPrivateKey,
+                        client.Credentials.MerchantCertPrivateKey,
                         response.UserName
                     );
                 }
@@ -358,7 +358,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantCertPrivateKey))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantCertPrivateKey))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant private key.");
 
             if (!response.IsSuccessful())
@@ -369,7 +369,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 try
                 {
                     response.UserName = Utilities.RSAUtility.DecryptWithECB(
-                        client.WechatMerchantCertPrivateKey,
+                        client.Credentials.MerchantCertPrivateKey,
                         response.UserName
                     );
                 }
@@ -393,7 +393,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantCertPrivateKey))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantCertPrivateKey))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant private key.");
 
             if (!response.IsSuccessful())
@@ -404,7 +404,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 try
                 {
                     response.UserName = Utilities.RSAUtility.DecryptWithECB(
-                        client.WechatMerchantCertPrivateKey,
+                        client.Credentials.MerchantCertPrivateKey,
                         response.UserName
                     );
                 }
@@ -428,7 +428,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (string.IsNullOrEmpty(client.WechatMerchantCertPrivateKey))
+            if (string.IsNullOrEmpty(client.Credentials.MerchantCertPrivateKey))
                 throw new Exceptions.WechatTenpayResponseDecryptionException("Decrypt response failed, because of there is no merchant private key.");
 
             if (!response.IsSuccessful())
@@ -439,7 +439,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
                 try
                 {
                     response.UserName = Utilities.RSAUtility.DecryptWithECB(
-                        client.WechatMerchantCertPrivateKey,
+                        client.Credentials.MerchantCertPrivateKey,
                         response.UserName
                     );
                 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseVerificationExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseVerificationExtensions.cs
index b620accf..3df729bb 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseVerificationExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Extensions/WechatTenpayClientResponseVerificationExtensions.cs
@@ -23,16 +23,16 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             if (client == null) throw new ArgumentNullException(nameof(client));
             if (response == null) throw new ArgumentNullException(nameof(response));
 
-            if (client.WechatCertificateManager == null)
+            if (client.CertificateManager == null)
             {
-                throw new Exceptions.WechatTenpayResponseVerificationException($"You must set an instance of `{nameof(Settings.ICertificateManager)}` at first.");
+                throw new Exceptions.WechatTenpayResponseVerificationException($"You must set an instance of `{nameof(Settings.CertificateManager)}` at first.");
             }
             else
             {
                 if (response.WechatpayCertSerialNumber == null)
                     throw new Exceptions.WechatTenpayResponseVerificationException("Cannot read the serial number in headers of this response.");
 
-                string? certificate = client.WechatCertificateManager.GetCertificate(response.WechatpayCertSerialNumber);
+                string? certificate = client.CertificateManager.GetCertificate(response.WechatpayCertSerialNumber);
                 if (certificate == null)
                     throw new Exceptions.WechatTenpayResponseVerificationException("Cannot get certificate by the serial number, may not be stored.");
 
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateManager.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateManager.cs
new file mode 100644
index 00000000..24cb41b9
--- /dev/null
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/CertificateManager.cs
@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+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
+    {
+        /// <summary>
+        /// 根据证书序列号获取证书（cer 格式）。
+        /// </summary>
+        /// <param name="serialNumber"></param>
+        /// <returns></returns>
+        public abstract string? GetCertificate(string serialNumber);
+
+        /// <summary>
+        /// 设置证书序列号与证书（cer 格式）的映射关系。
+        /// </summary>
+        /// <param name="serialNumber"></param>
+        /// <param name="certificate"></param>
+        public abstract void SetCertificate(string serialNumber, string certificate);
+    }
+
+    /// <summary>
+    /// 一个基于内存实现的 <see cref="CertificateManager"/>。
+    /// </summary>
+    public class InMemoryCertificateManager : CertificateManager
+    {
+        public IDictionary<string, string> _dict;
+
+        public InMemoryCertificateManager()
+        {
+            _dict = new ConcurrentDictionary<string, string>();
+        }
+
+        public override string? GetCertificate(string serialNumber)
+        {
+            if (serialNumber == null) throw new ArgumentNullException(nameof(serialNumber));
+
+            return _dict[serialNumber];
+        }
+
+        public override void SetCertificate(string serialNumber, string certificate)
+        {
+            if (serialNumber == null) throw new ArgumentNullException(nameof(serialNumber));
+            if (certificate == null) throw new ArgumentNullException(nameof(certificate));
+
+            _dict[serialNumber] = certificate;
+        }
+    }
+}
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/Credentials.cs
new file mode 100644
index 00000000..e387724a
--- /dev/null
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/Credentials.cs
@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
+{
+    public class Credentials
+    {
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatTenpayClientOptions.MerchantId"/> 的副本。
+        /// </summary>
+        public string MerchantId { get; }
+
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatTenpayClientOptions.MerchantV3Secret"/> 的副本。
+        /// </summary>
+        public string MerchantV3Secret { get; }
+
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatTenpayClientOptions.MerchantCertSerialNumber"/> 的副本。
+        /// </summary>
+        public string MerchantCertSerialNumber { get; }
+
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatTenpayClientOptions.MerchantCertPrivateKey"/> 的副本。
+        /// </summary>
+        public string MerchantCertPrivateKey { get; }
+
+        internal Credentials(WechatTenpayClientOptions options)
+        {
+            if (options == null) throw new ArgumentNullException(nameof(options));
+
+            MerchantId = options.MerchantId;
+            MerchantV3Secret = options.MerchantV3Secret;
+            MerchantCertSerialNumber = options.MerchantCertSerialNumber;
+            MerchantCertPrivateKey = options.MerchantCertPrivateKey;
+        }
+    }
+}
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/ICertificateManager.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/ICertificateManager.cs
deleted file mode 100644
index 220bd3c0..00000000
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/ICertificateManager.cs
+++ /dev/null
@@ -1,28 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-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 interface ICertificateManager
-    {
-        /// <summary>
-        /// 根据证书序列号获取证书（cer 格式）。
-        /// </summary>
-        /// <param name="serialNumber"></param>
-        /// <returns></returns>
-        string? GetCertificate(string serialNumber);
-
-        /// <summary>
-        /// 设置证书序列号与证书（cer 格式）的映射关系。
-        /// </summary>
-        /// <param name="serialNumber"></param>
-        /// <param name="certificate"></param>
-        void SetCertificate(string serialNumber, string certificate);
-    }
-}
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/InMemoryCertificateManager.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/InMemoryCertificateManager.cs
deleted file mode 100644
index 7e9ce92d..00000000
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/Settings/InMemoryCertificateManager.cs
+++ /dev/null
@@ -1,37 +0,0 @@
-using System;
-using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings
-{
-    /// <summary>
-    /// 一个基于内存实现的 <see cref="ICertificateManager"/>。
-    /// </summary>
-    public class InMemoryCertificateManager : ICertificateManager
-    {
-        public IDictionary<string, string> _dict;
-
-        public InMemoryCertificateManager()
-        {
-            _dict = new ConcurrentDictionary<string, string>();
-        }
-
-        string? ICertificateManager.GetCertificate(string serialNumber)
-        {
-            if (serialNumber == null) throw new ArgumentNullException(nameof(serialNumber));
-
-            return _dict[serialNumber];
-        }
-
-        void ICertificateManager.SetCertificate(string serialNumber, string certificate)
-        {
-            if (serialNumber == null) throw new ArgumentNullException(nameof(serialNumber));
-            if (certificate == null) throw new ArgumentNullException(nameof(certificate));
-
-            _dict[serialNumber] = certificate;
-        }
-    }
-}
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClient.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClient.cs
index ef02b246..5d4ea92a 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClient.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClient.cs
@@ -20,37 +20,14 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
     public partial class WechatTenpayClient : WechatClientBase
     {
         /// <summary>
-        /// 获取当前客户端使用的微信商户号。
+        /// 获取当前客户端使用的微信商户平台凭证。
         /// </summary>
-        public string WechatMerchantId { get; }
+        public Settings.Credentials Credentials { get; }
 
         /// <summary>
-        /// 获取当前客户端使用的微信商户 API 证书序列号（用于请求签名）。
+        /// 获取当前客户端使用的微信商户平台证书管理器。
         /// </summary>
-        internal string WechatMerchantCertSerialNumber { get; }
-
-        /// <summary>
-        /// 获取当前客户端使用的微信商户 API 证书私钥（用于请求签名、响应数据解密）。
-        /// </summary>
-        internal string WechatMerchantCertPrivateKey { get; }
-
-        /// <summary>
-        /// 获取当前客户端使用的微信商户 API v3 密钥（用于事件数据解密）。
-        /// </summary>
-        internal string WechatMerchantV3Secret { get; }
-
-        /// <summary>
-        /// 获取当前客户端使用的微信商户平台证书存储器。
-        /// </summary>
-        internal Settings.ICertificateManager? WechatCertificateManager { get; }
-
-        /// <summary>
-        /// 获取当前客户端使用的 JSON 序列化器。
-        /// </summary>
-        internal ISerializer FlurlJsonSerializer
-        {
-            get { return FlurlClient.Settings?.JsonSerializer ?? new FlurlNewtonsoftJsonSerializer(); }
-        }
+        internal Settings.CertificateManager CertificateManager { get; }
 
         /// <summary>
         /// 用指定的配置项初始化 <see cref="WechatTenpayClient"/> 类的新实例。
@@ -60,11 +37,8 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 
-            WechatMerchantId = options.MerchantId;
-            WechatMerchantCertSerialNumber = options.MerchantCertSerialNumber;
-            WechatMerchantCertPrivateKey = options.MerchantCertPrivateKey;
-            WechatMerchantV3Secret = options.MerchantV3Secret;
-            WechatCertificateManager = options.CertificateManager;
+            Credentials = new Settings.Credentials(options);
+            CertificateManager = options.CertificateManager;
 
             FlurlClient.BaseUrl = options.Endpoints ?? WechatTenpayEndpoints.DEFAULT;
             FlurlClient.Headers.Remove("Accept");
@@ -76,7 +50,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
             FlurlClient.WithTimeout(TimeSpan.FromMilliseconds(options.Timeout));
 
             Interceptors.Add(new Interceptors.WechatTenpaySignInterceptor(
-                scheme: options.AuthScheme,
+                scheme: options.SignAlgorithm,
                 mchId: options.MerchantId,
                 mchCertSn: options.MerchantCertSerialNumber,
                 mchCertPk: options.MerchantCertPrivateKey
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClientOptions.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClientOptions.cs
index 9758de84..744e1799 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClientOptions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV3/WechatTenpayClientOptions.cs
@@ -36,7 +36,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
         /// 获取或设置微信支付 API 签名认证方式。
         /// <para>默认值：<see cref="Constants.SignAlgorithms.WECHATPAY2_SHA256_RSA2048"/></para>
         /// </summary>
-        public string AuthScheme { get; set; } = Constants.SignAlgorithms.WECHATPAY2_SHA256_RSA2048;
+        public string SignAlgorithm { get; set; } = Constants.SignAlgorithms.WECHATPAY2_SHA256_RSA2048;
 
         /// <summary>
         /// 获取或设置微信商户号。
@@ -59,9 +59,9 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV3
         public string MerchantCertPrivateKey { get; set; } = default!;
 
         /// <summary>
-        /// 获取或设置微信商户平台证书存储器。
+        /// 获取或设置微信商户平台证书管理器。
         /// <para>默认值：<see cref="Settings.InMemoryCertificateManager"/></para>
         /// </summary>
-        public Settings.ICertificateManager? CertificateManager { get; set; } = new Settings.InMemoryCertificateManager();
+        public Settings.CertificateManager CertificateManager { get; set; } = new Settings.InMemoryCertificateManager();
     }
 }