GenerateTestDocumentWithSecurity.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using iText.Kernel.Geom;
using iText.Kernel.Pdf;
using iText.Kernel.Pdf.Canvas.Draw;
using iText.Layout;
using iText.Layout.Element;
using iText.Layout.Properties;

namespace Tracker.Service.Helpers
{
	/// <summary>
	/// Enhanced PDF protection utility with improved security and flexibility
	/// </summary>
	public class PdfProtection
	{
		public Stream GenerateTestDocumentWithSecurity()
		{
			string ownerPassword = "OownerPassword123";

			var config = new PdfProtectionConfig()
			{
				UserPassword = string.Empty,
				OwnerPassword = string.Empty,
				Permissions = PdfPermissions.Print,
				Encryption = EncryptionLevel.AES256,
				GenerateRandomOwnerPassword = true,
				Title = "Protected Document",
				Content = "Este documento está protegido con contraseña."
			};

			MemoryStream memoryStream = new MemoryStream();

			byte[] userPasswordBytes = Encoding.UTF8.GetBytes(config.UserPassword);
			byte[] ownerPasswordBytes = Encoding.UTF8.GetBytes(ownerPassword);

			var writerProperties = new WriterProperties()
				.SetStandardEncryption(
					userPasswordBytes,
					ownerPasswordBytes,
					(int)config.Permissions,
					(int)config.Encryption
				);

			using (var pdfWriter = new PdfWriter(memoryStream, writerProperties))
			using (var pdfDocument = new PdfDocument(pdfWriter))
			{
				pdfWriter.SetCloseStream(false);

				var pageSize = PageSize.A4;

				pdfDocument.SetDefaultPageSize(pageSize);
				Document document = new Document(pdfDocument);

				// Set document metadata
				var info = pdfDocument.GetDocumentInfo();
				info.SetTitle(config.Title);
				info.SetCreator("PDF Protection Utility");
				info.SetProducer("iText 7");

				// Add content
				// Title
				var title = new Paragraph(config.Title)
					.SetTextAlignment(TextAlignment.CENTER)
					.SetFontSize(20)
					.SimulateBold()
					.SetMarginBottom(20);
				document.Add(title);

				// Separator line
				var line = new LineSeparator(new SolidLine());
				document.Add(line);

				// Content
				var content = new Paragraph(config.Content)
					.SetTextAlignment(TextAlignment.JUSTIFIED)
					.SetMarginTop(20)
					.SetMarginBottom(20);
				document.Add(content);

				// Security info
				var securityInfo = new Paragraph()
					.Add("Información de Seguridad:\n")
					.SimulateBold()
					.SetMarginTop(30);

				securityInfo.Add(new Text($"• Nivel de cifrado: {GetEncryptionLevelDescription(config.Encryption)}\n").SimulateBold());
				securityInfo.Add(new Text($"• Permisos: {GetPermissionsDescription(config.Permissions)}\n").SimulateBold());
				securityInfo.Add(new Text($"• Fecha de creación: {DateTime.Now:yyyy-MM-dd HH:mm:ss}\n").SimulateBold());

				document.Add(securityInfo);

				document.Close();
			}

			memoryStream.Position = 0;
			return memoryStream;
		}

		/// <summary>
		/// Configuration for PDF protection
		/// </summary>
		public class PdfProtectionConfig
		{
			public string UserPassword { get; set; } = string.Empty;
			public string OwnerPassword { get; set; } = string.Empty;
			public PdfPermissions Permissions { get; set; } = PdfPermissions.Print;
			public EncryptionLevel Encryption { get; set; } = EncryptionLevel.AES256;
			public bool GenerateRandomOwnerPassword { get; set; } = true;
			public string Title { get; set; } = "Protected Document";
			public string Content { get; set; } = "Este documento está protegido con contraseña.";
		}

		/// <summary>
		/// PDF permission flags that can be combined
		/// </summary>
		[Flags]
		public enum PdfPermissions
		{
			None = 0,
			Print = EncryptionConstants.ALLOW_PRINTING,
			PrintHighQuality = EncryptionConstants.ALLOW_PRINTING | EncryptionConstants.ALLOW_DEGRADED_PRINTING,
			Copy = EncryptionConstants.ALLOW_COPY,
			Modify = EncryptionConstants.ALLOW_MODIFY_CONTENTS,
			ModifyAnnotations = EncryptionConstants.ALLOW_MODIFY_ANNOTATIONS,
			FillForm = EncryptionConstants.ALLOW_FILL_IN,
			ScreenReaders = EncryptionConstants.ALLOW_SCREENREADERS,
			Assembly = EncryptionConstants.ALLOW_ASSEMBLY,
			All = Print | Copy | Modify | ModifyAnnotations | FillForm | ScreenReaders | Assembly
		}

		/// <summary>
		/// Encryption strength options
		/// </summary>
		public enum EncryptionLevel
		{
			Standard40Bit = EncryptionConstants.STANDARD_ENCRYPTION_40,
			Standard128Bit = EncryptionConstants.STANDARD_ENCRYPTION_128,
			AES128 = EncryptionConstants.ENCRYPTION_AES_128,
			AES256 = EncryptionConstants.ENCRYPTION_AES_256
		}

		private string GetEncryptionLevelDescription(EncryptionLevel level)
		{
			switch (level)
			{
				case EncryptionLevel.Standard40Bit:
					return "Estándar 40-bit (Baja)";
				case EncryptionLevel.Standard128Bit:
					return "Estándar 128-bit (Media)";
				case EncryptionLevel.AES128:
					return "AES 128-bit (Alta)";
				case EncryptionLevel.AES256:
					return "AES 256-bit (Muy Alta)";
				default:
					return "Desconocido";
			}
		}

		private string GetPermissionsDescription(PdfPermissions permissions)
		{
			if (permissions == PdfPermissions.None)
				return "Sin permisos";

			if (permissions == PdfPermissions.All)
				return "Todos los permisos";

			var permissionList = new List<string>();

			if (permissions.HasFlag(PdfPermissions.Print))
			{
				permissionList.Add("Imprimir");
			}
			if (permissions.HasFlag(PdfPermissions.Copy))
			{
				permissionList.Add("Copiar");
			}
			if (permissions.HasFlag(PdfPermissions.Modify))
			{
				permissionList.Add("Modificar");
			}
			if (permissions.HasFlag(PdfPermissions.ModifyAnnotations))
			{
				permissionList.Add("Anotar");
			}
			if (permissions.HasFlag(PdfPermissions.FillForm))
			{
				permissionList.Add("Rellenar formularios");
			}

			return string.Join(", ", permissionList);
		}
	}
}