Change to use the new method added to BCL (#481)

Author: shibayan

AppService.Acmebot/Functions/SharedActivity.cs

@@ -589,7 +589,7 @@ public async Task CheckIsReady([ActivityTrigger] (OrderDetails, IReadOnlyList<Ac
             }
 
             // 全てのエラーが connection か dns 関係の場合は Orchestrator からリトライさせる
-            if (problems.All(x => x.Type == "urn:ietf:params:acme:error:connection" || x.Type == "urn:ietf:params:acme:error:dns"))
+            if (problems.All(x => x.Type is "urn:ietf:params:acme:error:connection" or "urn:ietf:params:acme:error:dns"))
             {
                 throw new RetriableOrchestratorException("ACME validation status is invalid, but retriable error. It will retry automatically.");
             }

AppService.Acmebot/Internal/AcmeProtocolClientFactory.cs

@@ -106,15 +106,13 @@ byte[] HmacSignature(byte[] x)
         {
             var hmacKeyBytes = CryptoHelper.Base64.UrlDecode(_options.ExternalAccountBinding.HmacKey);
 
-            var hmac = (HMAC)(_options.ExternalAccountBinding.Algorithm switch
+            return _options.ExternalAccountBinding.Algorithm switch
             {
-                "HS256" => new HMACSHA256(hmacKeyBytes),
-                "HS384" => new HMACSHA384(hmacKeyBytes),
-                "HS512" => new HMACSHA512(hmacKeyBytes),
+                "HS256" => HMACSHA256.HashData(hmacKeyBytes, x),
+                "HS384" => HMACSHA384.HashData(hmacKeyBytes, x),
+                "HS512" => HMACSHA512.HashData(hmacKeyBytes, x),
                 _ => throw new NotSupportedException($"The signature algorithm {_options.ExternalAccountBinding.Algorithm} is not supported. (supported values are HS256 / HS384 / HS512)")
-            });
-
-            return hmac.ComputeHash(x);
+            };
         }
 
         var payload = JsonConvert.SerializeObject(acmeProtocolClient.Signer.ExportJwk());