VS2010下asp.net 对现有的PDF文档进行加密(利用iTextSharp)

到2011年8月iTextSharp最新版本下载地址：

http://download.csdn.net/source/3514917

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using iTextSharp;

using iTextSharp.text;

using iTextSharp.text.pdf;

using System.IO;

using System.Diagnostics;

//加密代码

protected void Button1_Click(object sender, EventArgs e)

{

string PdfPath = AppDomain.CurrentDomain.SetupInformation.ApplicationBase;

PdfPath = PdfPath + "PDFFiles\\";

string PdfFIle = PdfPath + "008.PDF";

string sname = PdfFIle;//要加密的文件

string sname1 = PdfPath + "test.PDF";//加密后生成的文件

PdfReader reader = new PdfReader(sname);

int n = reader.NumberOfPages;

Document document = new Document(reader.GetPageSizeWithRotation(1));

PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(sname1, FileMode.Create));

writer.SetEncryption(PdfWriter.STRENGTH128BITS, "123456", null, PdfWriter.AllowPrinting);

document.Open();

PdfContentByte cb = writer.DirectContent;

PdfImportedPage page;

int rotation;

int i = 0;

// step 4: we add content

while (i < n)

{

i++;

document.SetPageSize(reader.GetPageSizeWithRotation(i));

document.NewPage();

page = writer.GetImportedPage(reader, i);

rotation = reader.GetPageRotation(i);

if (rotation == 90 || rotation == 270)

{

cb.AddTemplate(page, 0, -1f, 1f, 0, 0, reader.GetPageSizeWithRotation(i).Height);

}

else

{

cb.AddTemplate(page, 1f, 0, 0, 1f, 0, 0);

}

}

//

// step 5: we close the document

document.Close();

writer.Close();

}

说明：加密后的文件没有访问，但PDF阅读器左侧的总页数似乎有点问题，不影响使用。

有人解决的可以跟上。