using iTextSharp.text.pdf;

 using iTextSharp.text;

 using System.IO;

  　　　　/// <summary>

         /// 将去掉PDF的加密

         /// </summary>

         /// <param name="sourceFullName">源文件路径(如：D:\old.pdf)</param>

         /// <param name="newFullName">目标文件路径(如:D:\new.pdf)</param>

         private static void deletePDFEncrypt(string sourceFullName, string newFullName)

         {

             if (string.IsNullOrEmpty(sourceFullName) || string.IsNullOrEmpty(newFullName))

             {

                 throw new Exception("源文件路径或目标文件路径不能为空或null.");

             }

             //Console.WriteLine("读取PDF文档");

             try

             {

                 // 创建一个PdfReader对象

                 PdfReader reader = new PdfReader(sourceFullName);

                 PdfReader.unethicalreading = true;

                 // 获得文档页数

                 int n = reader.NumberOfPages;

                 // 获得第一页的大小

                 Rectangle pagesize = reader.GetPageSize();

                 float width = pagesize.Width;

                 float height = pagesize.Height;

                 // 创建一个文档变量

                 Document document = new Document(pagesize, , , , );

                 // 创建该文档

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

                 // 打开文档

                 document.Open();

                 // 添加内容

                 PdfContentByte cb = writer.DirectContent;

                 int i = ;

                 int p = ;

                 while (i < n)

                 {

                     document.NewPage();

                     p++;

                     i++;

                     PdfImportedPage page1 = writer.GetImportedPage(reader, i);

                     cb.AddTemplate(page1, 1f, , , 1f, , );

                 }

                 // 关闭文档

                 document.Close();

             }

             catch (Exception ex)

             {

                 throw new Exception(ex.Message);

             }

         }