Encrypted workbooks cannot be viewed as PDFs on IOS 13

Similar to iOS 13 and Password Protected PDFs - #3 by amani7

When rendering a password protected excel workbook to PDF users on IOS13 are unable to view the pdf or in some cases can seem a clipped version of the pdf. This is consistently reproducible and when removing the password shows no issue. The issue is also non-existent on previous versions of IOS.

This is the code used to encrypt:

protected PdfSaveOptions AddEncryption(Workbook workbook, bool userLocked) {
    var options = new PdfSaveOptions { };
    var properties = workbook.Worksheets.CustomDocumentProperties;
    if (properties.Contains("password")) {
        var pass = properties["password"].ToString();
        options.SecurityOptions = new Aspose.Cells.Rendering.PdfSecurity.PdfSecurityOptions();
        if (!string.IsNullOrWhiteSpace(pass)) {
            if (userLocked) {
                options.SecurityOptions.UserPassword = pass;
                options.SecurityOptions.OwnerPassword = pass;
            } else {
                options.SecurityOptions.OwnerPassword = pass;
            options.SecurityOptions.ExtractContentPermission = false;
            options.SecurityOptions.PrintPermission = false;
    return options;

We think it should be related to some change in IOS because the file works in previous versions. However, we need to look into it more. We have logged the issue in our database for investigations. Once, we will have some news for you, we will update you in this topic.

This issue has been logged as

CELLSNET-47042 - Encrypted workbooks cannot be viewed as PDFs on IOS 13

We have found a similar discussion on Appleā€™s communities. Seems that it is the problem on the Apple side.