PDF Encryption & Decryption

This code example demonstrates how to modify metadata, make the PDF read-only, configure permissions, and change the document encryption password using IronPDF's powerful C# .NET PDF library.

To begin, import an existing PDF document using the open method. This method can be utilized to open password-protected documents by specifying the password as the second parameter, offering robust handling of secured files.

To set new metadata information, start by creating a dictionary and add key-value pairs for metadata, such as the author and keywords. Utilize the overrideMetadata method in IronPDF to apply the new metadata to the PDF document effectively.

Next, remove passwords and encryption using the removePasswordsAndEncryption method provided by IronPDF, and configure the PDF to be read-only by setting a new password with the makePdfDocumentReadOnly method, ensuring the document's integrity and security.

Permissions for the PDF document are configured using an object named "permissions," which specifies whether certain actions, such as annotations, content extraction, form filling, and printing, are allowed or disallowed. Pass the permissions object to the setPermission method to precisely control the document's accessibility features.

Finally, change or set the document encryption password to "my-password," and save the modified PDF as "secured.pdf," showcasing IronPDF’s capability for secure document management in application development.

// Import the necessary namespace.
using IronPdf;

class PdfExample
{
    static void Main()
    {
        // Open an existing PDF document. If the document is password protected, provide the password.
        var pdf = IronPdf.PdfDocument.FromFile("existing.pdf", "document-password");

        // Initialize a dictionary to store metadata key-value pairs.
        var newMetadata = new Dictionary<string, string>
        {
            { "Author", "New Author" },
            { "Keywords", "PDF, Documentation, Example" }
        };

        // Apply the new metadata to the PDF document.
        pdf.OverrideMetadata(newMetadata);

        // Remove any existing passwords and encryption.
        pdf.RemovePasswordsAndEncryption();

        // Make the PDF document read-only by setting a read-only password.
        pdf.MakePdfDocumentReadOnly("read-only-password");

        // Define and set the permissions for the PDF document.
        var permissions = new PdfPermissions
        {
            AllowAnnotations = false,
            AllowContentExtraction = false,
            AllowFormFilling = true,
            AllowPrinting = false,
            AllowDocumentAssembly = false
        };
        pdf.SetPermissions(permissions);

        // Change the document encryption password.
        pdf.SaveAs("secured.pdf", "my-password"); // Save the modified PDF with a new security password.
    }
}

// Import the necessary namespace.
using IronPdf;

class PdfExample
{
    static void Main()
    {
        // Open an existing PDF document. If the document is password protected, provide the password.
        var pdf = IronPdf.PdfDocument.FromFile("existing.pdf", "document-password");

        // Initialize a dictionary to store metadata key-value pairs.
        var newMetadata = new Dictionary<string, string>
        {
            { "Author", "New Author" },
            { "Keywords", "PDF, Documentation, Example" }
        };

        // Apply the new metadata to the PDF document.
        pdf.OverrideMetadata(newMetadata);

        // Remove any existing passwords and encryption.
        pdf.RemovePasswordsAndEncryption();

        // Make the PDF document read-only by setting a read-only password.
        pdf.MakePdfDocumentReadOnly("read-only-password");

        // Define and set the permissions for the PDF document.
        var permissions = new PdfPermissions
        {
            AllowAnnotations = false,
            AllowContentExtraction = false,
            AllowFormFilling = true,
            AllowPrinting = false,
            AllowDocumentAssembly = false
        };
        pdf.SetPermissions(permissions);

        // Change the document encryption password.
        pdf.SaveAs("secured.pdf", "my-password"); // Save the modified PDF with a new security password.
    }
}

' Import the necessary namespace.
Imports IronPdf

Friend Class PdfExample
	Shared Sub Main()
		' Open an existing PDF document. If the document is password protected, provide the password.
		Dim pdf = IronPdf.PdfDocument.FromFile("existing.pdf", "document-password")

		' Initialize a dictionary to store metadata key-value pairs.
		Dim newMetadata = New Dictionary(Of String, String) From {
			{"Author", "New Author"},
			{"Keywords", "PDF, Documentation, Example"}
		}

		' Apply the new metadata to the PDF document.
		pdf.OverrideMetadata(newMetadata)

		' Remove any existing passwords and encryption.
		pdf.RemovePasswordsAndEncryption()

		' Make the PDF document read-only by setting a read-only password.
		pdf.MakePdfDocumentReadOnly("read-only-password")

		' Define and set the permissions for the PDF document.
		Dim permissions = New PdfPermissions With {
			.AllowAnnotations = False,
			.AllowContentExtraction = False,
			.AllowFormFilling = True,
			.AllowPrinting = False,
			.AllowDocumentAssembly = False
		}
		pdf.SetPermissions(permissions)

		' Change the document encryption password.
		pdf.SaveAs("secured.pdf", "my-password") ' Save the modified PDF with a new security password.
	End Sub
End Class