对编辑锁PDF使用iTextSharp的

Question

我创建使用iTextSharp的用于读取PDF，附加社会DRM内容，然后保存文件C＃程序。如何锁定这个新的PDF进一步编辑？

我希望用户能够查看该文件，而无需输入密码，我不介意选择/复制操作，但我很介意去除DRM社会的能力。

Answer 1

加密PDF文档。简单HTTP Handler工作例子，让你开始：

<%@ 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; } } 
} 

内注释应该是不言自明的。请参阅PdfWriter documentation。

您也可以使用使用PdfEncryptor class一个PdfReader对象加密PDF文档。换句话说，你也可以做这样的事情（未经测试）：

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 
    ); 
    } 
}