PdfTextEncodingObfuscator Class

In This Topic

Obfuscates text encodings in fonts of PDF document.

Object Model

Syntax

Visual Basic
C#
Managed Extensions for C++
C++/CLI

'Declaration

Public Class PdfTextEncodingObfuscator

public class PdfTextEncodingObfuscator

public __gc class PdfTextEncodingObfuscator

public ref class PdfTextEncodingObfuscator

Remarks

Obfuscation of text encoding consists from 2 steps:

Unicode codes of symbols are removed from font
Font program is changed randomly (glyphs are rearranged; not used glyphs are removed; duplicate glyphs are added; etc).

Text search and text extraction will be not possible after the text encoding obfuscation - extracted text will contain "garbage". PDF page view will not be changed after obfuscation, i.e. PDF page view before and after obfuscation are the same.

Current version supports obfuscation of TrueType, Type1 and Type3 fonts.
A System.NotSupportedException will be thrown whenever an unsupported font is encountered during obfuscation.
A System.InvalidOperationException will be thrown whenever an external font is encountered during obfuscation.

Important! - PDF document must be packed (Pack) after text encoding obfuscation otherwise the original encodings can be restored.

Example

Here is an example that shows how to obfuscate the encoding of embedded fonts in PDF document:

VB.NET


''' <summary>
''' Obfuscates encoding of all fonts of PDF document.
''' </summary>
''' <param name="pdfFilename">The filename of PDF document.</param>
''' <param name="resultFilename">The filename of resulting PDF document.</param>
Public Shared Sub ObfuscateEncodingOfAllFonts(pdfFilename As String, resultFilename As String)
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)
        ' create obfuscator
        Dim textEncodingObfuscator As New Vintasoft.Imaging.Pdf.PdfTextEncodingObfuscator()
        Try
            ' obfuscate all fonts
            textEncodingObfuscator.Obfuscate(document)
            ' pack and save document to new location
            document.Pack(resultFilename)
        Catch ex As System.Exception
            System.Console.WriteLine(ex.Message)
        End Try
    End Using
End Sub


/// <summary>
/// Obfuscates encoding of all fonts of PDF document.
/// </summary>
/// <param name="pdfFilename">The filename of PDF document.</param>
/// <param name="resultFilename">The filename of resulting PDF document.</param>
public static void ObfuscateEncodingOfAllFonts(string pdfFilename, string resultFilename)
{
    using (Vintasoft.Imaging.Pdf.PdfDocument document = new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename))
    {
        // create obfuscator
        Vintasoft.Imaging.Pdf.PdfTextEncodingObfuscator textEncodingObfuscator = 
            new Vintasoft.Imaging.Pdf.PdfTextEncodingObfuscator();
        try
        {
            // obfuscate all fonts
            textEncodingObfuscator.Obfuscate(document);
            // pack and save document to new location
            document.Pack(resultFilename);
        }
        catch (System.Exception ex)
        {
            System.Console.WriteLine(ex.Message);
        }
    }
}

Inheritance Hierarchy

System.Object
Vintasoft.Imaging.Pdf.PdfTextEncodingObfuscator

Requirements

Target Platforms: .NET 8; .NET 7; .NET 6; .NET Framework 4.8, 4.7, 4.6, 4.5, 4.0, 3.5

Reference

PdfTextEncodingObfuscator Members
Vintasoft.Imaging.Pdf Namespace

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