數字簽名確保簽名的文檔不能被除其作者之外的任何人更改。添加簽名是確保文檔內容真實性的最常見方法。PDF 文檔中的可視數字簽名可以顯示文本或圖像（例如手寫簽名）。本文從以下三個方面介紹如何使用Spire.PDF for .NET對PDF 進行數字簽名。

Spire.PDF for .NET 是一款獨立 PDF 控件，用于 .NET 程序中創建、編輯和操作 PDF 文檔。使用 Spire.PDF 類庫，開發人員可以新建一個 PDF 文檔或者對現有的 PDF 文檔進行處理，且無需安裝 Adobe Acrobat。

E-iceblue 功能類庫Spire 系列文檔處理組件均由中國本土團隊研發，不依賴第三方軟件，不受其他國家的技術或法律法規限制，同時適配國產操作系統如中科方德、中標麒麟等，兼容國產文檔處理軟件 WPS（如 .wps/.et/.dps 等格式

Spire.PDF for.net下載   Spire.PDF for java下載

安裝適用于 .NET 的 Spire.PDF

首先，您需要將 Spire.PDF for .NET 包中包含的 DLL 文件添加為 .NET 項目中的引用。DLL 文件可以從此鏈接下載或通過NuGet安裝。

PM> Install-Package Spire.PDF

使用文本對 PDF 進行數字簽名

以下是將純文本簽名添加到 PDF 文檔的步驟。

• 創建一個PdfDocument對象，并使用PdfDocument.LoadFromFile()方法加載示例 PDF 文件。
• 初始化PdfCertificate對象時加載 .pfx 證書文件。
• 創建一個PdfSignature對象，指定其在文檔中的位置和大小。
• 將簽名圖形模式設置為SignDetail，這將以純文本形式顯示簽名詳細信息。
• 通過PdfSignature對象下的屬性設置簽名詳細信息，包括姓名、聯系信息、原因、日期等。
• 將認證文檔的權限設置為ForbidChanges和AllowFormFill。
• 使用PdfDocument.SaveToFile()方法將文檔保存到另一個文件。

【C#】

using Spire.Pdf;
using Spire.Pdf.Security;
using System;
using System.Drawing;
using Spire.Pdf.Graphics;

namespace AddTextSignature
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument object
PdfDocument doc = new PdfDocument();

//Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf");

//Load the certificate
PdfCertificate cert = new PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx", "e-iceblue");

//Create a PdfSignature object and specify its position and size
PdfSignature signature = new PdfSignature(doc, doc.Pages[doc.Pages.Count-1], cert, "MySignature");
RectangleF rectangleF = new RectangleF(doc.Pages[0].ActualSize.Width - 340, 150, 290, 100);
signature.Bounds = rectangleF;
signature.Certificated = true;

//Set the graphics mode to sign detail
signature.GraphicsMode = GraphicMode.SignDetail;

//Set the signature content
signature.NameLabel = "Signer:";
signature.Name = "Gary";
signature.ContactInfoLabel = "Phone:";
signature.ContactInfo = "0123456";
signature.DateLabel = "Date:";
signature.Date = DateTime.Now;
signature.LocationInfoLabel = "Location:";
signature.LocationInfo = "USA";
signature.ReasonLabel = "Reason:";
signature.Reason = "I am the author";
signature.DistinguishedNameLabel = "DN:";
signature.DistinguishedName = signature.Certificate.IssuerName.Name;

//Set the signature font
signature.SignDetailsFont = new PdfTrueTypeFont(new Font("Arial Unicode MS",12f,FontStyle.Regular));

//Set the document permission to forbid changes but allow form fill
signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill;

//Save to file
doc.SaveToFile("TextSignature.pdf");
doc.Close();
}
}
}

【VB.NET】

Imports Spire.Pdf
Imports Spire.Pdf.Security
Imports System
Imports System.Drawing
Imports Spire.Pdf.Graphics

Namespace AddTextSignature
Class Program
Shared Sub Main(ByVal args() As String)
'Create a PdfDocument object
Dim doc As PdfDocument = New PdfDocument()

'Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf")

'Load the certificate
Dim cert As PdfCertificate = New PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx","e-iceblue")

'Create a PdfSignature object and specify its position and size
Dim signature As PdfSignature = New PdfSignature(doc,doc.Pages(doc.Pages.Count-1),cert,"MySignature")
Dim rectangleF As RectangleF = New RectangleF(doc.Pages(0).ActualSize.Width - 340,150,290,100)
signature.Bounds = rectangleF
signature.Certificated = True

'Set the graphics mode to sign detail
signature.GraphicsMode = GraphicMode.SignDetail

'Set the signature content
signature.NameLabel = "Signer:"
signature.Name = "Gary"
signature.ContactInfoLabel = "Phone:"
signature.ContactInfo = "0123456"
signature.DateLabel = "Date:"
signature.Date = DateTime.Now
signature.LocationInfoLabel = "Location:"
signature.LocationInfo = "USA"
signature.ReasonLabel = "Reason:"
signature.Reason = "I am the author"
signature.DistinguishedNameLabel = "DN:"
signature.DistinguishedName = signature.Certificate.IssuerName.Name

'Set the signature font
signature.SignDetailsFont = New PdfTrueTypeFont(New Font("Arial Unicode MS",12f,FontStyle.Regular))

'Set the document permission to forbid changes but allow form fill
signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill

'Save to file
doc.SaveToFile("TextSignature.pdf")
doc.Close()
End Sub
End Class
End Namespace

使用圖像對 PDF 進行數字簽名

以下是將圖像簽名添加到 PDF 文檔的步驟。

• 創建一個PdfDocument對象，并使用PdfDocument.LoadFromFile()方法加載示例 PDF 文件。
• 初始化PdfCertificate對象時加載 .pfx 證書文件。
• 創建一個PdfSignature對象，指定其在文檔中的位置和大小。
• 將簽名圖形模式設置為SignImageOnly，這將僅顯示簽名圖像。
• 通過PdfSignature.SignImageSource屬性設置簽名圖像。
• 將認證文檔的權限設置為ForbidChanges和AllowFormFill。
• 使用PdfDocument.SaveToFile()方法將文檔保存到另一個文件。

【C#】

using Spire.Pdf;
using Spire.Pdf.Graphics;
using Spire.Pdf.Security;
using System.Drawing;

namespace AddImageSignature
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument object
PdfDocument doc = new PdfDocument();

//Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf");

//Load the certificate
PdfCertificate cert = new PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx", "e-iceblue");

//Create a PdfSignature object and specify its position and size
PdfSignature signature = new PdfSignature(doc, doc.Pages[doc.Pages.Count - 1], cert, "MySignature");
RectangleF rectangleF = new RectangleF(doc.Pages[0].ActualSize.Width - 200, 150, 130, 130);
signature.Bounds = rectangleF;
signature.Certificated = true;

//Set the graphics mode to image only
signature.GraphicsMode = GraphicMode.SignImageOnly;

//Set the sign image source
signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\verified.png");

//Set the signature font
signature.SignDetailsFont = new PdfTrueTypeFont(new Font("Arial Unicode MS", 12f, FontStyle.Regular));

//Set the document permission to forbid changes but allow form fill
signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill;

//Save to file
doc.SaveToFile("ImageSignature.pdf");
doc.Close();
}
}
}

【VB.NET】

Imports Spire.Pdf
Imports Spire.Pdf.Graphics
Imports Spire.Pdf.Security
Imports System.Drawing

Namespace AddImageSignature
Class Program
Shared Sub Main(ByVal args() As String)
'Create a PdfDocument object
Dim doc As PdfDocument = New PdfDocument()

'Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf")

'Load the certificate
Dim cert As PdfCertificate = New PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx","e-iceblue")

'Create a PdfSignature object and specify its position and size
Dim signature As PdfSignature = New PdfSignature(doc,doc.Pages(doc.Pages.Count - 1),cert,"MySignature")
Dim rectangleF As RectangleF = New RectangleF(doc.Pages(0).ActualSize.Width - 200,150,130,130)
signature.Bounds = rectangleF
signature.Certificated = True

'Set the graphics mode to image only
signature.GraphicsMode = GraphicMode.SignImageOnly

'Set the sign image source
signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\verified.png")

'Set the signature font
signature.SignDetailsFont = New PdfTrueTypeFont(New Font("Arial Unicode MS", 12f, FontStyle.Regular))

'Set the document permission to forbid changes but allow form fill
signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill

'Save to file
doc.SaveToFile("ImageSignature.pdf")
doc.Close()
End Sub
End Class
End Namespace

使用文本和圖像對 PDF 進行數字簽名

以下是使用文本和圖像對 PDF 文檔進行數字簽名的步驟。

• 創建一個PdfDocument對象，并使用PdfDocument.LoadFromFile()方法加載示例 PDF 文件。
• 初始化PdfCertificate對象時加載 .pfx 證書文件。
• 創建一個PdfSignature對象，指定其在文檔中的位置和大小。
• 將簽名圖形模式設置為SignImageAndSignDetail，這將同時顯示簽名圖像和詳細信息。
• 通過PdfSignature.SignImageSource屬性設置簽名圖像，并通過 PdfSignature 對象下的其他屬性設置簽名詳細信息，包括姓名、聯系信息、原因、日期等。
• 將認證文檔的權限設置為ForbidChanges和AllowFormFill。
• 使用PdfDocument.SaveToFile()方法將文檔保存到另一個文件。

【C#】

using Spire.Pdf;
using Spire.Pdf.Security;
using System;
using System.Drawing;
using Spire.Pdf.Graphics;

namespace AddTextAndImageSignature
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument object
PdfDocument doc = new PdfDocument();

//Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf");

//Load the certificate
PdfCertificate cert = new PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx", "e-iceblue");

//Create a PdfSignature object and specify its position and size
PdfSignature signature = new PdfSignature(doc, doc.Pages[doc.Pages.Count - 1], cert, "MySignature");
RectangleF rectangleF = new RectangleF(doc.Pages[0].ActualSize.Width - 320, 150, 260, 110);
signature.Bounds = rectangleF;
signature.Certificated = true;

//Set the graphics mode to image and sign detail
signature.GraphicsMode = GraphicMode.SignImageAndSignDetail;

//Set the signature content
signature.NameLabel = "Signer:";
signature.Name = "Gary";
signature.ContactInfoLabel = "Phone:";
signature.ContactInfo = "0123456";
signature.DateLabel = "Date:";
signature.Date = DateTime.Now;
signature.LocationInfoLabel = "Location:";
signature.LocationInfo = "USA";
signature.ReasonLabel = "Reason:";
signature.Reason = "I am the author";
signature.DistinguishedNameLabel = "DN:";
signature.DistinguishedName = signature.Certificate.IssuerName.Name;

//Set the signature image source
signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\handSignature.png");

//Set the signature font
signature.SignDetailsFont = new PdfTrueTypeFont(new Font("Arial Unicode MS", 12f, FontStyle.Regular));

//Set the document permission to forbid changes but allow form fill
signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill;

//Save to file
doc.SaveToFile("TextAndImageSignature.pdf");
doc.Close();
}
}
}

【VB.NET】

Imports Spire.Pdf
Imports Spire.Pdf.Security
Imports System
Imports System.Drawing
Imports Spire.Pdf.Graphics

Namespace AddTextAndImageSignature
Class Program
Shared Sub Main(ByVal args() As String)
'Create a PdfDocument object
Dim doc As PdfDocument = New PdfDocument()

'Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf")

'Load the certificate
Dim cert As PdfCertificate = New PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx","e-iceblue")

'Create a PdfSignature object and specify its position and size
Dim signature As PdfSignature = New PdfSignature(doc,doc.Pages(doc.Pages.Count - 1),cert,"MySignature")
Dim rectangleF As RectangleF = New RectangleF(doc.Pages(0).ActualSize.Width - 320,150,260,110)
signature.Bounds = rectangleF
signature.Certificated = True

'Set the graphics mode to image and sign detail
signature.GraphicsMode = GraphicMode.SignImageAndSignDetail

'Set the signature content
signature.NameLabel = "Signer:"
signature.Name = "Gary"
signature.ContactInfoLabel = "Phone:"
signature.ContactInfo = "0123456"
signature.DateLabel = "Date:"
signature.Date = DateTime.Now
signature.LocationInfoLabel = "Location:"
signature.LocationInfo = "USA"
signature.ReasonLabel = "Reason:"
signature.Reason = "I am the author"
signature.DistinguishedNameLabel = "DN:"
signature.DistinguishedName = signature.Certificate.IssuerName.Name

'Set the signature image source
signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\handSignature.png")

'Set the signature font
signature.SignDetailsFont = New PdfTrueTypeFont(New Font("Arial Unicode MS", 12f, FontStyle.Regular))

'Set the document permission to forbid changes but allow form fill
signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill

'Save to file
doc.SaveToFile("TextAndImageSignature.pdf")
doc.Close()
End Sub
End Class
End Namespace

以上便是如何使用文本或/和圖像對 PDF 進行數字簽名，如果您有其他問題也可以繼續瀏覽本系列文章，獲取相關教程，你還可以給我留言或者加入我們的官方技術交流群。

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