With TX Text Control, you can protect documents from authoring by encrypting the document with a password and adding editable areas as exceptions for specific users. The next code snippet adds an editable region in a specific selection range for the user developer@textcontrol.com. The word Text is now editable for this specific user:

textControl1.Text = "TX Text Control";
EditableRegion region = new EditableRegion("developer@textcontrol.com", 10, 4, 4);
textControl1.EditableRegions.Add(region);

Protecting Documents

The following code can be used to protect and save the document:

textControl1.EditMode = EditMode.UsePassword | EditMode.ReadAndSelect;
textControl1.Save("encrypted-document.tx", TXTextControl.StreamType.InternalUnicodeFormat);

After loading the document, the UserNames property can be used to define a list of names that specify users who have access to editable areas. In this example, we grant access to the user developer@textcontrol.com:

@Html.TXTextControl().TextControl(settings => {
  settings.UserNames = new string[] { "developer@textcontrol.com" };
}).LoadText(sDocument, TXTextControl.Web.BinaryStreamType.InternalUnicodeFormat).Render()

Loading Secured Documents

But what if you want to load a secured document into a non-visual ServerTextControl and export the document to PDF?

Because the loaded document is protected and cannot be exported to PDF as is, the following code would fail:

using TXTextControl;

using (ServerTextControl tx = new ServerTextControl()) {
  tx.Create();

  // Load an encrypted document protected with a password
  tx.Load("encrypted-document.tx", StreamType.InternalUnicodeFormat);

  tx.Save("results.pdf", StreamType.AdobePDF);
}

Unlocking Secured Documents

There are two ways to solve this problem. The first way is to provide the password when loading the document to unlock it. This is done using the MasterPassword property passed in the Load method.

using TXTextControl;

using (ServerTextControl tx = new ServerTextControl()) {
    tx.Create();

    LoadSettings loadSettings = new LoadSettings()
    {
        MasterPassword = "123"
    };  

    // Load an encrypted document protected with a password
    tx.Load("encrypted-document.tx", StreamType.InternalUnicodeFormat, loadSettings);
    
    tx.Save("results.pdf", StreamType.AdobePDF);
}

Preserving Original Settings

However, if you want to preserve the original author's DocumentAccessPermissions, you can set the password when saving the PDF. The following code shows an advanced logic that uses the FilterExceptions when saving the document. If the document contains an encrypted password, an exception is thrown and the MasterPassword are used to pass the password to the Save method.

using TXTextControl;

using (ServerTextControl tx = new ServerTextControl()) {
    tx.Create();

    // Load an encrypted document protected with a password
    tx.Load("encrypted-document.tx", StreamType.InternalUnicodeFormat);

    // Trying to save the document as PDF
    try {
        tx.Save("results.pdf", StreamType.AdobePDF);
    }
    catch (FilterException exc) {
        // Check if the exception was thrown because of an encrypted password
        if (exc.Reason == FilterException.FilterError.EncryptedPassword)
        {
            // Provide the password to save the document
            SaveSettings saveSettings = new SaveSettings() {
                MasterPassword = "123"
            };

            // Save the document as PDF
            tx.Save("results.pdf", StreamType.AdobePDF, saveSettings);
        }
    }
}

Conclusion

With TX Text Control, you can protect documents from editing by encrypting the document with a password and adding editable areas as exceptions for certain users. This article shows how to protect documents and how to unlock protected documents for further processing and export to PDF.