C#和vb.net实现PDF|C#和vb.net实现PDF 添加可视化和不可见数字签名 C#和vb.net实现PDF添加可视化和不

1. 在VS程序中通过Nuget安装 Spire.PDF for .NET 版本7.8.2，安装步骤如下：
2.在VS程序中添加如下代码添加数字签名

2.1 添加可视化数字签名
2.2 添加不可见数字签名

本文通过C#程序代码展示如何给PDF文档添加可视化数字签名和不可见数字签名。可视化数字签名，即在PDF文档中的指定页面位置添加签名，包含相关文字信息和签名图片等；不可见数字签名，即添加签名时不在文档中指定签名位置，在文档正文中不显示相关数字签名信息。
这里签名是通过PdfOrdinarySignatureMaker类提供的的接口来实现签名，在添加可视化签名时，通过IPdfSignatureAppearance类提供的接口来设置签名的具体位置，签名图片等。
下面是具体实现方法和步骤，供参考。
【C#和vb.net实现PDF|C#和vb.net实现PDF 添加可视化和不可见数字签名】
1. 在VS程序中通过Nuget安装 Spire.PDF for .NET 版本7.8.2，安装步骤如下：鼠标右键点击“引用”，“管理Nuget包”

C#和vb.net实现PDF|C#和vb.net实现PDF 添加可视化和不可见数字签名

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点击“浏览”，在搜索框中输入“Spire.PDF ”,点击选择搜索到的包，点击“安装”。

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在弹出的窗口点击“OK”

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等待安装完成。安装结果如图：

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2.在VS程序中添加如下代码添加数字签名
2.1 添加可视化数字签名
C#

using Spire.Pdf; using Spire.Pdf.Graphics; using Spire.Pdf.Interactive.DigitalSignatures; using System.Drawing; using System.Security.Cryptography.X509Certificates; namespace VisibleDigitalSignature{class Program{static void Main(string[] args){//加载PDF测试文档PdfDocument pdf = new PdfDocument(); pdf.LoadFromFile("test.pdf"); //获取PDF文档中的第5页PdfPageBase page = pdf.Pages[4]; //在页面中的指定位置添加可视化签名X509Certificate2 x509 = new X509Certificate2("cer.pfx", "e-iceblue"); PdfOrdinarySignatureMaker signatureMaker = new PdfOrdinarySignatureMaker(pdf, x509); IPdfSignatureAppearance signatureAppearance = new PdfCustomSignatureAppearance(); signatureMaker.MakeSignature("signName_" , page, page.ActualSize.Width-240,page.ActualSize.Height-200,150,150, signatureAppearance); //保存文档pdf.SaveToFile("VisibleDigitalSignature.pdf", FileFormat.PDF); System.Diagnostics.Process.Start("VisibleDigitalSignature.pdf"); pdf.Close(); }public class PdfCustomSignatureAppearance : IPdfSignatureAppearance{public void Generate(PdfCanvas g){float fontSize = 15; PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", fontSize), true); float lineHeight = fontSize; g.DrawString("Sign Here:", font, PdfBrushes.Black, new PointF(0, 0)); g.DrawImage(PdfImage.FromFile("sign.png"), new PointF(20, 20)); }}}}

Vb.net

Imports Spire.PdfImports Spire.Pdf.GraphicsImports Spire.Pdf.Interactive.DigitalSignaturesImports System.DrawingImports System.Security.Cryptography.X509CertificatesNamespace VisibleDigitalSignatureClass ProgramPrivate Shared Sub Main(args As String())'加载PDF测试文档Dim pdf As New PdfDocument()pdf.LoadFromFile("test.pdf")'获取PDF文档中的第5页Dim page As PdfPageBase = pdf.Pages(4)'在页面中的指定位置添加可视化签名Dim x509 As New X509Certificate2("cer.pfx", "e-iceblue")Dim signatureMaker As New PdfOrdinarySignatureMaker(pdf, x509)Dim signatureAppearance As IPdfSignatureAppearance = New PdfCustomSignatureAppearance()signatureMaker.MakeSignature("signName_", page, page.ActualSize.Width - 240, page.ActualSize.Height - 200, 150, 150, _signatureAppearance)'保存文档pdf.SaveToFile("VisibleDigitalSignature.pdf", FileFormat.PDF)System.Diagnostics.Process.Start("VisibleDigitalSignature.pdf")pdf.Close()End SubPublic Class PdfCustomSignatureAppearanceImplements IPdfSignatureAppearancePublic Sub Generate(g As PdfCanvas)Dim fontSize As Single = 15Dim font As New PdfTrueTypeFont(New Font("Arial", fontSize), True)Dim lineHeight As Single = fontSizeg.DrawString("Sign Here:", font, PdfBrushes.Black, New PointF(0, 0))g.DrawImage(PdfImage.FromFile("sign.png"), New PointF(20, 20))End SubEnd ClassEnd ClassEnd Namespace

可视化数字签名效果：

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2.2 添加不可见数字签名
C#

using Spire.Pdf; using Spire.Pdf.Interactive.DigitalSignatures; using System.Security.Cryptography.X509Certificates; namespace InvisibleDigitalSignature{class Program{static void Main(string[] args){//初始化一个PdfDocument实例PdfDocument pdf = new PdfDocument(); //加载PDF文档pdf.LoadFromFile("test.pdf"); //添加签名X509Certificate2 x509 = new X509Certificate2("cer.pfx", "e-iceblue"); PdfOrdinarySignatureMaker signatureMaker = new PdfOrdinarySignatureMaker(pdf, x509); signatureMaker.MakeSignature("signName"); signatureMaker.SetLocation("Chengdu"); signatureMaker.SetReason("Edit limited"); //保存文档pdf.SaveToFile("result.pdf", FileFormat.PDF); System.Diagnostics.Process.Start("result.pdf"); }}}

Vb.net

Imports Spire.PdfImports Spire.Pdf.Interactive.DigitalSignaturesImports System.Security.Cryptography.X509CertificatesNamespace InvisibleDigitalSignatureClass ProgramPrivate Shared Sub Main(args As String())'初始化一个PdfDocument实例Dim pdf As New PdfDocument()'加载PDF文档pdf.LoadFromFile("test.pdf")'添加签名Dim x509 As New X509Certificate2("cer.pfx", "e-iceblue")Dim signatureMaker As New PdfOrdinarySignatureMaker(pdf, x509)signatureMaker.MakeSignature("signName")signatureMaker.SetLocation("Chengdu")signatureMaker.SetReason("Edit limited")'保存文档pdf.SaveToFile("result.pdf", FileFormat.PDF)System.Diagnostics.Process.Start("result.pdf")End SubEnd ClassEnd Namespace

不可见数字签名效果：