public EncryptionOptions EncryptionOptions { get; set; }

Public Property EncryptionOptions As EncryptionOptions

using DevExpress.Docs.Pdf;
using DevExpress.Docs.Presentation;
using DevExpress.Docs.Presentation.Export;
using System.IO;

using (var presentation = new Presentation(File.ReadAllBytes(@"C:\Documents\Presentation.pptx"))) {
    var options = new PdfExportOptions();

    // Initialize encryption options with owner and user passwords:
    options.EncryptionOptions = new EncryptionOptions(
        ownerPassword: "ownerPassword",
        userPassword: "userPassword"
    );

    // Specify operation restrictions:
    options.EncryptionOptions.DataExtractionPermissions =
        DocumentDataExtractionPermissions.NotAllowed;
    options.EncryptionOptions.PrintPermissions =
        DocumentPrintPermissions.LowQuality;
    options.EncryptionOptions.ModificationPermissions =
        DocumentModificationPermissions.NotAllowed;

    // Specify encryption algorithm:
    options.EncryptionOptions.Algorithm = EncryptionAlgorithm.AES256;

    presentation.ExportToPdf(
        new FileStream(@"C:\Documents\Presentation.pdf", FileMode.Create, FileAccess.ReadWrite),
        options
    );
}

Imports DevExpress.Docs.Pdf
Imports DevExpress.Docs.Presentation
Imports DevExpress.Docs.Presentation.Export
Imports System.IO

Using presentation As New Presentation(File.ReadAllBytes("C:\Documents\Presentation.pptx"))
    Dim options As New PdfExportOptions()

    ' Initialize encryption options with owner and user passwords:
    options.EncryptionOptions = New EncryptionOptions(
        ownerPassword:="ownerPassword",
        userPassword:="userPassword"
    )

    ' Specify operation restrictions:
    options.EncryptionOptions.DataExtractionPermissions =
        DocumentDataExtractionPermissions.NotAllowed
    options.EncryptionOptions.PrintPermissions =
        DocumentPrintPermissions.LowQuality
    options.EncryptionOptions.ModificationPermissions =
        DocumentModificationPermissions.NotAllowed

    ' Specify encryption algorithm:
    options.EncryptionOptions.Algorithm = EncryptionAlgorithm.AES256

    presentation.ExportToPdf(
        New FileStream("C:\Documents\Presentation.pdf", FileMode.Create, FileAccess.ReadWrite),
        options
    )
End Using