Code to invoke MIP SDK for SharePoint files

HomeController.cs

private void InvokeMIP()
{
	//this client id is for Azure AD app and NOT of SharePoint app
	private static readonly string clientId = ConfigurationManager.AppSettings["ida:ClientId"]; 
        private static readonly string appName = ConfigurationManager.AppSettings["app:Name"];
        private static readonly string appVersion = ConfigurationManager.AppSettings["app:Version"];
        private static readonly string mipData = ConfigurationManager.AppSettings["MipData"];
        private readonly string mipPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, mipData);
	try
	{
		SharePointContext spContext = SharePointContextProvider.Current.GetSharePointContext(HttpContext);

		Uri sharepointUrl = new Uri(spContext.SPHostUrl.AbsoluteUri.ToString());

		//fetch tenant id to be used in getting access token
		string tenantId = TokenHelper.GetRealmFromTargetUrl(sharepointUrl).ToString();

		// Set path to bins folder.
		var path = Path.Combine(
			  Directory.GetParent(Path.GetDirectoryName(new Uri(System.Reflection.Assembly.GetExecutingAssembly().CodeBase).LocalPath)).FullName,
			   Environment.Is64BitProcess ? "bin\\x64" : "bin\\x86");

		MIP.Initialize(MipComponent.File, path);

		ApplicationInfo appInfo = new ApplicationInfo()
		{
			ApplicationId = clientId,
			ApplicationName = appName,
			ApplicationVersion = appVersion
		};

		AuthDelegateImplementation authDelegate = new AuthDelegateImplementation(appInfo, tenantId);

		var profileSettings = new FileProfileSettings(mipPath, false, authDelegate, new ConsentDelegateImplementation(), appInfo, LogLevel.Trace);

		//create MIP File Profile
		var fileProfile = Task.Run(async () => await MIP.LoadFileProfileAsync(profileSettings)).Result;

		//create MIP Engine and add it to the file profile
		var engineSettings = new FileEngineSettings("", "", "en-US");
		engineSettings.Identity = new Identity("admin@tenant.com"); //important to paas a valid admin account here
		var fileEngine = Task.Run(async () => await fileProfile.AddEngineAsync(engineSettings)).Result;

		//client context to get file stream
		using (var clientContext = spContext.CreateUserClientContextForSPHost())
		{
			if (clientContext != null)
			{
				var list = clientContext.Web.Lists.GetByTitle("Documents");
				clientContext.Load(list, i => i.RootFolder);
				clientContext.ExecuteQuery();

				var listItem = list.GetItemById(1);
				clientContext.Load(listItem, l => l.File, l => l.File.ServerRelativeUrl);
				var fileData = listItem.File.OpenBinaryStream();
				clientContext.ExecuteQuery();

				if (fileData.Value != null)
				{
					var fileStream = fileData.Value;

					//create file handler with the stream from SharePoint
					var handler = Task.Run(async () => await fileEngine.CreateFileHandlerAsync(fileStream, listItem.File.ServerRelativeUrl, true)).Result;

					//if needed, can check the existing labels and protection details using below two lines
					var labelDetails = handler.Label;
					var protectionDetails = handler.Protection;

					LabelingOptions labelingOptions = new LabelingOptions()
					{
						AssignmentMethod = AssignmentMethod.Privileged, //because I am removing a high priority label
						IsDowngradeJustified = true,
						JustificationMessage = "Lowering label"
					};

					handler.DeleteLabel(labelingOptions);

					//output stream where new file will be stored
					Stream outputStream = new MemoryStream();
					var result = Task.Run(async () => await handler.CommitAsync(outputStream)).Result;

					//This is neccessary else you will get following error
					//Specified argument was out of the range of valid values.\r\nParameter name: bytesToCopy
					outputStream.Position = 0;

					//You can create a new file handler using output stream here
					//and use it to apply different label using newhandler.SetLabel() method
					//and then upload it to SharePoint too

					FileCreationInformation decryptedFile = new FileCreationInformation();
					decryptedFile.ContentStream = outputStream;
					decryptedFile.Url = "decrypted.docx"; //change this according to your need
					decryptedFile.Overwrite = true;
					var uploadedFile = list.RootFolder.Files.Add(decryptedFile);
					clientContext.Load(uploadedFile);
					clientContext.ExecuteQuery();
				}
			}
		}
	}
	catch(Exception ex)
	{

	}
}