C# · 12月 26, 2021

c# – 使用iTextSharp锁定PDF以防编辑

我使用iTextSharp创建了一个C#程序,用于阅读PDF,附加社会DRM内容,然后保存文件.如何锁定这个新的PDF,进一步编辑?

我希望用户能够在不输入密码的情况下查看该文件,而我不介意选择/复制操作,但我记住删除社交DRM的能力.

解决方法 加密您的PDF文档.简单的HTTP处理程序工作示例让您开始: <%@ WebHandler Language=”C#” Class=”lockPdf” %>using System;using System.Web;using iTextSharp.text;using iTextSharp.text.pdf;public class lockPdf : IHttpHandler { public void ProcessRequest (HttpContext context) { HttpServerUtility Server = context.Server; HttpResponse Response = context.Response; Response.ContentType = “application/pdf”; using (Document document = new Document()) { PdfWriter writer = PdfWriter.GetInstance( document,Response.OutputStream ); writer.SetEncryption(// null user password => users can open document __without__ pasword null,// owner password => required to __modify__ document/permissions System.Text.Encoding.UTF8.GetBytes(“ownerPassword”),/* * bitwise or => see iText API for permission parameter: * http://api.itextpdf.com/itext/com/itextpdf/text/pdf/PdfWriter.html */ PdfWriter.ALLOW_PRINTING | PdfWriter.ALLOW_COPY,// encryption level also in documentation referenced above PdfWriter.ENCRYPTION_AES_128 ); document.open(); document.Add(new Paragraph(“hello world”)); } } public bool IsReusable { get { return false; } }}

内联评论应该是不言自明的.见PdfWriter documentation.

您还可以使用使用PdfEncryptor class的PdfReader对象加密PDF文档.换句话说,您还可以执行此操作(未测试):

PdfReader reader = new PdfReader(INPUT_FILE);using (MemoryStream ms = new MemoryStream()) { using (PdfStamper stamper = new PdfStamper(reader,ms)) { // add your content } using (FileStream fs = new FileStream( OUTPUT_FILE,FileMode.Create,FileAccess.ReadWrite)) { PdfEncryptor.Encrypt( new PdfReader(ms.ToArray()),fs,null,System.Text.Encoding.UTF8.GetBytes(“ownerPassword”),PdfWriter.ALLOW_PRINTING | PdfWriter.ALLOW_COPY,true ); } }