C# / VB 获取PDF文档的数字签名信息

古城微笑少年丶 2022-12-28 01:57 219阅读 0赞

文档中的数字签名具有不可否认性，可有效防伪防篡改。对文档中已有的数字签名信息，可通过一定方法获取，下面通过程序代码介绍如何来实现。程序中，使用了[***Spire.PDF.dll***][Spire.PDF.dll]***，版本：6.11.6***，可自行在官网下载包，或者通过*[Nuget][]*下载。下载后，在程序中添加引用dll文件。如下添加引用效果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl_size_16_color_FFFFFF_t_70][]

完成dll文件添加引用后，可参考如下代码来操作:

**\[C\#\]**

using Spire.Pdf;
    using Spire.Pdf.Graphics;
    using Spire.Pdf.Security;
    using Spire.Pdf.Widget;
    using System;
    using System.Drawing;
    
    namespace GetSignature
    {
        class Program
        {
            static void Main(string[] args)
            {
    
                //创建PdfDocument实例
                PdfDocument pdf = new PdfDocument();
                //加载含有签名的PDF文件
                pdf.LoadFromFile("数字签名.pdf");
    
                //获取域集合
                PdfFormWidget pdfFormWidget = (PdfFormWidget)pdf.Form;
                PdfFormFieldWidgetCollection pdfFormFieldWidgetCollection = pdfFormWidget.FieldsWidget;
    
                //遍历域
                for (int i = 0; i < pdfFormFieldWidgetCollection.Count; i++)
                {
                    //判定是否为签名域
                    if (pdfFormFieldWidgetCollection[i] is PdfSignatureFieldWidget)
                    {
                        //获取签名域
                        PdfSignatureFieldWidget signatureFieldWidget = (PdfSignatureFieldWidget)pdfFormFieldWidgetCollection[i];
                        //获取签名
                        PdfSignature signature = signatureFieldWidget.Signature;
                        String location = signature.LocationInfo;
                        String reason = signature.Reason;
                        String data = signature.Date.ToString();
    
                        Console.WriteLine("签名位置信息：" + location + "\n" +
                                "签名原因：" + reason + "\n" +
                                "签名日期：" + data + "\n" +
                                "文档中的签名坐标：X = " + signatureFieldWidget.Location.X + "  Y = " + signatureFieldWidget.Location.Y);
                        Console.ReadLine();
                    }
                }
    
            }
        }
    }

**\[VB.NET\]**

Imports Spire.Pdf
    Imports Spire.Pdf.Graphics
    Imports Spire.Pdf.Security
    Imports Spire.Pdf.Widget
    Imports System.Drawing
    
    Namespace GetSignature
    	Class Program
    		Private Shared Sub Main(args As String())
    
    			'创建PdfDocument实例
    			Dim pdf As New PdfDocument()
    			'加载含有签名的PDF文件
    			pdf.LoadFromFile("数字签名.pdf")
    
    			'获取域集合
    			Dim pdfFormWidget As PdfFormWidget = DirectCast(pdf.Form, PdfFormWidget)
    			Dim pdfFormFieldWidgetCollection As PdfFormFieldWidgetCollection = pdfFormWidget.FieldsWidget
    
    			'遍历域
    			For i As Integer = 0 To pdfFormFieldWidgetCollection.Count - 1
    				'判定是否为签名域
    				If TypeOf pdfFormFieldWidgetCollection(i) Is PdfSignatureFieldWidget Then
    					'获取签名域
    					Dim signatureFieldWidget As PdfSignatureFieldWidget = DirectCast(pdfFormFieldWidgetCollection(i), PdfSignatureFieldWidget)
    					'获取签名
    					Dim signature As PdfSignature = signatureFieldWidget.Signature
    					Dim location As [String] = signature.LocationInfo
    					Dim reason As [String] = signature.Reason
    					Dim data As [String] = signature.[Date].ToString()
    
    					Console.WriteLine("签名位置信息：" + location + vbLf + "签名原因：" + reason + vbLf + "签名日期：" + data + vbLf + "文档中的签名坐标：X = " + signatureFieldWidget.Location.X + "  Y = " + signatureFieldWidget.Location.Y)
    					Console.ReadLine()
    				End If
    			Next
    
    		End Sub
    	End Class
    End Namespace

数字签名信息获取结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl_size_16_color_FFFFFF_t_70 1][]

**相关阅读推荐：**

*  [C\# 删除PDF中的数字签名][C_ _PDF]
 *  [C\# 给PDF添加时间戳][C_ _PDF 1]
 *  [C\# 在PDF中添加签名域][C_ _PDF 2]

[Spire.PDF.dll]: https://www.e-iceblue.cn/Downloads/Spire-PDF-NET.html
[Nuget]: http://www.nuget.org/packages/Spire.PDF/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl_size_16_color_FFFFFF_t_70]: /images/20221120/251363ff02b74d3c9dedb487a29265a3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl_size_16_color_FFFFFF_t_70 1]: /images/20221120/55bfffe6bcc141f982606314222e8d1f.png
[C_ _PDF]: https://blog.csdn.net/Eiceblue/article/details/52860239
[C_ _PDF 1]: https://blog.csdn.net/Eiceblue/article/details/88575015
[C_ _PDF 2]: https://blog.csdn.net/Eiceblue/article/details/52549943