diff --git a/DepotDownloader/ContentDownloader.cs b/DepotDownloader/ContentDownloader.cs
index 43254c22..6648a583 100644
--- a/DepotDownloader/ContentDownloader.cs
+++ b/DepotDownloader/ContentDownloader.cs
@@ -1163,7 +1163,7 @@ namespace DepotDownloader
                     neededChunks = Util.ValidateSteam3FileChecksums(fs, file.Chunks.OrderBy(x => x.Offset).ToArray());
                 }
 
-                if (neededChunks.Count() == 0)
+                if (neededChunks.Count == 0)
                 {
                     lock (depotDownloadCounter)
                     {
diff --git a/DepotDownloader/Steam3Session.cs b/DepotDownloader/Steam3Session.cs
index 483ee061..10380b40 100644
--- a/DepotDownloader/Steam3Session.cs
+++ b/DepotDownloader/Steam3Session.cs
@@ -211,9 +211,9 @@ namespace DepotDownloader
             };
 
             var request = new SteamApps.PICSRequest(appId);
-            if (AppTokens.ContainsKey(appId))
+            if (AppTokens.TryGetValue(appId, out var value))
             {
-                request.AccessToken = AppTokens[appId];
+                request.AccessToken = value;
             }
 
             WaitUntilCallback(() =>
@@ -656,7 +656,7 @@ namespace DepotDownloader
                     {
                         Console.Write("Please enter your 2 factor auth code from your authenticator app: ");
                         logonDetails.TwoFactorCode = Console.ReadLine();
-                    } while (String.Empty == logonDetails.TwoFactorCode);
+                    } while (string.Empty == logonDetails.TwoFactorCode);
                 }
                 else if (isAccessToken)
                 {
diff --git a/DepotDownloader/Util.cs b/DepotDownloader/Util.cs
index f35a43bf..9dd954ce 100644
--- a/DepotDownloader/Util.cs
+++ b/DepotDownloader/Util.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -115,12 +115,9 @@ namespace DepotDownloader
 
         public static byte[] SHAHash(byte[] input)
         {
-            using (var sha = SHA1.Create())
-            {
-                var output = sha.ComputeHash(input);
+            var output = SHA1.HashData(input);
 
-                return output;
-            }
+            return output;
         }
 
         public static byte[] DecodeHexString(string hex)
@@ -146,7 +143,7 @@ namespace DepotDownloader
 
         public static async Task InvokeAsync(IEnumerable<Func<Task>> taskFactories, int maxDegreeOfParallelism)
         {
-            if (taskFactories == null) throw new ArgumentNullException(nameof(taskFactories));
+            ArgumentNullException.ThrowIfNull(taskFactories);
             if (maxDegreeOfParallelism <= 0) throw new ArgumentException(nameof(maxDegreeOfParallelism));
 
             var queue = taskFactories.ToArray();