C#和vb.net實現(xiàn)PDF 添加可視化和不可見數(shù)字簽名

更新時間：2021年08月10日 08:38:12 作者：E-iceblue

本文通過C#程序代碼展示如何給PDF文檔添加可視化數(shù)字簽名和不可見數(shù)字簽名。文中通過示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

本文通過C#程序代碼展示如何給PDF文檔添加可視化數(shù)字簽名和不可見數(shù)字簽名。可視化數(shù)字簽名，即在PDF文檔中的指定頁面位置添加簽名，包含相關(guān)文字信息和簽名圖片等；不可見數(shù)字簽名，即添加簽名時不在文檔中指定簽名位置，在文檔正文中不顯示相關(guān)數(shù)字簽名信息。

這里簽名是通過PdfOrdinarySignatureMaker類提供的的接口來實現(xiàn)簽名，在添加可視化簽名時，通過IPdfSignatureAppearance類提供的接口來設(shè)置簽名的具體位置，簽名圖片等。

下面是具體實現(xiàn)方法和步驟，供參考。

1. 在VS程序中通過Nuget安裝 Spire.PDF for .NET 版本7.8.2，安裝步驟如下：

鼠標右鍵點擊“引用”，“管理Nuget包”

點擊“瀏覽”，在搜索框中輸入“Spire.PDF ”,點擊選擇搜索到的包，點擊“安裝”。

在彈出的窗口點擊“OK”

等待安裝完成。安裝結(jié)果如圖：

2.在VS程序中添加如下代碼添加數(shù)字簽名

2.1 添加可視化數(shù)字簽名

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)
        {
            //加載PDF測試文檔
            PdfDocument pdf = new PdfDocument();
            pdf.LoadFromFile("test.pdf");

            //獲取PDF文檔中的第5頁
            PdfPageBase page = pdf.Pages[4];

            //在頁面中的指定位置添加可視化簽名
            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);

            //保存文檔
            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.Pdf
Imports Spire.Pdf.Graphics
Imports Spire.Pdf.Interactive.DigitalSignatures
Imports System.Drawing
Imports System.Security.Cryptography.X509Certificates

Namespace VisibleDigitalSignature
    Class Program
        Private Shared Sub Main(args As String())
            '加載PDF測試文檔
            Dim pdf As New PdfDocument()
            pdf.LoadFromFile("test.pdf")

            '獲取PDF文檔中的第5頁
            Dim page As PdfPageBase = pdf.Pages(4)

            '在頁面中的指定位置添加可視化簽名
            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)

            '保存文檔
            pdf.SaveToFile("VisibleDigitalSignature.pdf", FileFormat.PDF)
            System.Diagnostics.Process.Start("VisibleDigitalSignature.pdf")
            pdf.Close()

        End Sub
        Public Class PdfCustomSignatureAppearance
            Implements IPdfSignatureAppearance
            Public Sub Generate(g As PdfCanvas)
                Dim fontSize As Single = 15
                Dim font As New PdfTrueTypeFont(New Font("Arial", fontSize), True)
                Dim lineHeight As Single = fontSize
                g.DrawString("Sign Here:", font, PdfBrushes.Black, New PointF(0, 0))
                g.DrawImage(PdfImage.FromFile("sign.png"), New PointF(20, 20))
            End Sub
        End Class

    End Class
End Namespace

可視化數(shù)字簽名效果：

2.2 添加不可見數(shù)字簽名

using Spire.Pdf;
using Spire.Pdf.Interactive.DigitalSignatures;
using System.Security.Cryptography.X509Certificates;

namespace InvisibleDigitalSignature
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化一個PdfDocument實例
            PdfDocument pdf = new PdfDocument();

            //加載PDF文檔
            pdf.LoadFromFile("test.pdf");

            //添加簽名
            X509Certificate2 x509 = new X509Certificate2("cer.pfx", "e-iceblue");
            PdfOrdinarySignatureMaker signatureMaker = new PdfOrdinarySignatureMaker(pdf, x509);
            signatureMaker.MakeSignature("signName");
            signatureMaker.SetLocation("Chengdu");
            signatureMaker.SetReason("Edit limited");            
           
            //保存文檔
            pdf.SaveToFile("result.pdf", FileFormat.PDF);
            System.Diagnostics.Process.Start("result.pdf");
        }
    }
}

Vb.net

Imports Spire.Pdf
Imports Spire.Pdf.Interactive.DigitalSignatures
Imports System.Security.Cryptography.X509Certificates

Namespace InvisibleDigitalSignature
    Class Program
        Private Shared Sub Main(args As String())
            '初始化一個PdfDocument實例
            Dim pdf As New PdfDocument()

            '加載PDF文檔
            pdf.LoadFromFile("test.pdf")

            '添加簽名
            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")

            '保存文檔
            pdf.SaveToFile("result.pdf", FileFormat.PDF)
            System.Diagnostics.Process.Start("result.pdf")
        End Sub
    End Class
End Namespace

不可見數(shù)字簽名效果：