Guia Completo de Assinatura Digital de PDFs com C

Como faço para adicionar uma assinatura digital a um PDF com certificado?

Você pode aplicar uma assinatura digital a um documento PDF usando um arquivo de certificado digital (como .pfx ou .p12) para garantir a autenticidade e a integridade do documento. Este processo garante que o documento não tenha sido alterado desde a sua assinatura. Para uma visão geral completa dos recursos de assinatura digital, explore nosso guia abrangente sobre assinaturas digitais .

O IronPDF fornece uma API simples para essa finalidade, suportando várias maneiras de aplicar uma assinatura digital. O núcleo dessa funcionalidade gira em torno da classe PdfSignature, que encapsula o certificado e todos os metadados associados à assinatura.

Install-Package IronPdf

using IronPdf;
using IronPdf.Signing;
using System.Security.Cryptography.X509Certificates;

// Create a new PDF from an HTML string for demonstration.
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Signed Document</h1><p>This document has been digitally signed.</p>");

// Load the certificate from a .pfx file with its password.
// The X509KeyStorageFlags.Exportable flag is crucial for allowing the private key to be used in the signing process.
var cert = new X509Certificate2("IronSoftware.pfx", "123456", X509KeyStorageFlags.Exportable);

// Create a PdfSignature object using the loaded certificate.
var signature = new PdfSignature(cert);

// Apply the signature to the PDF document.
pdf.Sign(signature);

// Save the securely signed PDF document.
pdf.SaveAs("Signed.pdf");

using IronPdf;
using IronPdf.Signing;
using System.Security.Cryptography.X509Certificates;

// Create a new PDF from an HTML string for demonstration.
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Signed Document</h1><p>This document has been digitally signed.</p>");

// Load the certificate from a .pfx file with its password.
// The X509KeyStorageFlags.Exportable flag is crucial for allowing the private key to be used in the signing process.
var cert = new X509Certificate2("IronSoftware.pfx", "123456", X509KeyStorageFlags.Exportable);

// Create a PdfSignature object using the loaded certificate.
var signature = new PdfSignature(cert);

// Apply the signature to the PDF document.
pdf.Sign(signature);

// Save the securely signed PDF document.
pdf.SaveAs("Signed.pdf");

Imports IronPdf
Imports IronPdf.Signing
Imports System.Security.Cryptography.X509Certificates

' Create a new PDF from an HTML string for demonstration.
Private renderer = New ChromePdfRenderer()
Private pdf = renderer.RenderHtmlAsPdf("<h1>Signed Document</h1><p>This document has been digitally signed.</p>")

' Load the certificate from a .pfx file with its password.
' The X509KeyStorageFlags.Exportable flag is crucial for allowing the private key to be used in the signing process.
Private cert = New X509Certificate2("IronSoftware.pfx", "123456", X509KeyStorageFlags.Exportable)

' Create a PdfSignature object using the loaded certificate.
Private signature = New PdfSignature(cert)

' Apply the signature to the PDF document.
pdf.Sign(signature)

' Save the securely signed PDF document.
pdf.SaveAs("Signed.pdf")

using IronPdf;
using IronPdf.Signing;
using IronSoftware.Drawing;
using System;

// Load an existing PDF document to be signed.
var pdf = PdfDocument.FromFile("invoice.pdf");

// Create a PdfSignature object directly from the certificate file and password.
var signature = new PdfSignature("IronSoftware.pfx", "123456");

// Add detailed metadata to the signature for a comprehensive audit trail.
// These properties enhance the signature's credibility and provide context
signature.SignatureDate = DateTime.Now;
signature.SigningContact = "legal@ironsoftware.com";
signature.SigningLocation = "Chicago, USA";
signature.SigningReason = "Contractual Agreement";

// Add a secure timestamp from a trusted Time Stamp Authority (TSA).
// This provides cryptographic proof of the signing time.
signature.TimeStampUrl = new Uri("[http://timestamp.digicert.com](http://timestamp.digicert.com)");
signature.TimestampHashAlgorithm = TimestampHashAlgorithms.SHA256;

// Apply a visual appearance to the signature. (More on this in the next section)
signature.SignatureImage = new PdfSignatureImage("assets/visual-signature.png", 0, new Rectangle(350, 750, 200, 100));

// Sign the PDF document with the configured signature object.
pdf.Sign(signature);

// Save the final, signed PDF document.
pdf.SaveAs("DetailedSignature.pdf");

using IronPdf;
using IronPdf.Signing;
using IronSoftware.Drawing;
using System;

// Load an existing PDF document to be signed.
var pdf = PdfDocument.FromFile("invoice.pdf");

// Create a PdfSignature object directly from the certificate file and password.
var signature = new PdfSignature("IronSoftware.pfx", "123456");

// Add detailed metadata to the signature for a comprehensive audit trail.
// These properties enhance the signature's credibility and provide context
signature.SignatureDate = DateTime.Now;
signature.SigningContact = "legal@ironsoftware.com";
signature.SigningLocation = "Chicago, USA";
signature.SigningReason = "Contractual Agreement";

// Add a secure timestamp from a trusted Time Stamp Authority (TSA).
// This provides cryptographic proof of the signing time.
signature.TimeStampUrl = new Uri("[http://timestamp.digicert.com](http://timestamp.digicert.com)");
signature.TimestampHashAlgorithm = TimestampHashAlgorithms.SHA256;

// Apply a visual appearance to the signature. (More on this in the next section)
signature.SignatureImage = new PdfSignatureImage("assets/visual-signature.png", 0, new Rectangle(350, 750, 200, 100));

// Sign the PDF document with the configured signature object.
pdf.Sign(signature);

// Save the final, signed PDF document.
pdf.SaveAs("DetailedSignature.pdf");

Imports IronPdf
Imports IronPdf.Signing
Imports IronSoftware.Drawing
Imports System

' Load an existing PDF document to be signed.
Dim pdf = PdfDocument.FromFile("invoice.pdf")

' Create a PdfSignature object directly from the certificate file and password.
Dim signature = New PdfSignature("IronSoftware.pfx", "123456")

' Add detailed metadata to the signature for a comprehensive audit trail.
' These properties enhance the signature's credibility and provide context
signature.SignatureDate = DateTime.Now
signature.SigningContact = "legal@ironsoftware.com"
signature.SigningLocation = "Chicago, USA"
signature.SigningReason = "Contractual Agreement"

' Add a secure timestamp from a trusted Time Stamp Authority (TSA).
' This provides cryptographic proof of the signing time.
signature.TimeStampUrl = New Uri("http://timestamp.digicert.com")
signature.TimestampHashAlgorithm = TimestampHashAlgorithms.SHA256

' Apply a visual appearance to the signature. (More on this in the next section)
signature.SignatureImage = New PdfSignatureImage("assets/visual-signature.png", 0, New Rectangle(350, 750, 200, 100))

' Sign the PDF document with the configured signature object.
pdf.Sign(signature)

' Save the final, signed PDF document.
pdf.SaveAs("DetailedSignature.pdf")

Como posso adicionar uma representação visual a uma assinatura digital?

Embora uma assinatura digital esteja criptograficamente incorporada ao PDF, muitas vezes é útil ter uma representação visual na página. Pode ser o logotipo de uma empresa, uma assinatura manuscrita ou outros elementos gráficos. O IronPDF facilita a adição de uma imagem a um objeto PdfSignature.

Você pode carregar uma imagem de um arquivo ou de um fluxo de dados e posicioná-la com precisão em qualquer página do PDF. Os formatos de imagem suportados incluem PNG, JPEG, GIF, BMP, TIFF e WebP. Essa técnica é semelhante à forma como você pode inserir texto e imagens em documentos PDF.

using IronPdf.Signing;
using IronSoftware.Drawing;

// This example demonstrates various ways to add a visual image to a PDF signature.

// Create a PdfSignature object.
var signature = new PdfSignature("IronSoftware.pfx", "123456");

// Define the position and size for the signature image on the first page (index 0).
// Rectangle parameters: x position, y position, width, height
var signatureRectangle = new Rectangle(350, 750, 200, 100);

// Option 1: Set the SignatureImage property directly.
// This is the most straightforward approach
signature.SignatureImage = new PdfSignatureImage("assets/visual-signature.png", 0, signatureRectangle);

// Option 2: Use the LoadSignatureImageFromFile method.
// This method provides the same functionality with a different syntax
signature.LoadSignatureImageFromFile("assets/visual-signature.png", 0, signatureRectangle);

// Option 3: Load an image from a stream. This is useful for images generated in memory.
// Perfect for scenarios where images are retrieved from databases or web services
AnyBitmap image = AnyBitmap.FromFile("assets/visual-signature.png");
using (var imageStream = image.ToStream())
{
    signature.LoadSignatureImageFromStream(imageStream, 0, signatureRectangle);
}

// After configuring the signature image, apply it to a PDF.
var pdf = PdfDocument.FromFile("invoice.pdf");
pdf.Sign(signature);
pdf.SaveAs("VisualSignature.pdf");

using IronPdf.Signing;
using IronSoftware.Drawing;

// This example demonstrates various ways to add a visual image to a PDF signature.

// Create a PdfSignature object.
var signature = new PdfSignature("IronSoftware.pfx", "123456");

// Define the position and size for the signature image on the first page (index 0).
// Rectangle parameters: x position, y position, width, height
var signatureRectangle = new Rectangle(350, 750, 200, 100);

// Option 1: Set the SignatureImage property directly.
// This is the most straightforward approach
signature.SignatureImage = new PdfSignatureImage("assets/visual-signature.png", 0, signatureRectangle);

// Option 2: Use the LoadSignatureImageFromFile method.
// This method provides the same functionality with a different syntax
signature.LoadSignatureImageFromFile("assets/visual-signature.png", 0, signatureRectangle);

// Option 3: Load an image from a stream. This is useful for images generated in memory.
// Perfect for scenarios where images are retrieved from databases or web services
AnyBitmap image = AnyBitmap.FromFile("assets/visual-signature.png");
using (var imageStream = image.ToStream())
{
    signature.LoadSignatureImageFromStream(imageStream, 0, signatureRectangle);
}

// After configuring the signature image, apply it to a PDF.
var pdf = PdfDocument.FromFile("invoice.pdf");
pdf.Sign(signature);
pdf.SaveAs("VisualSignature.pdf");

Imports IronPdf.Signing
Imports IronSoftware.Drawing

' This example demonstrates various ways to add a visual image to a PDF signature.

' Create a PdfSignature object.
Dim signature As New PdfSignature("IronSoftware.pfx", "123456")

' Define the position and size for the signature image on the first page (index 0).
' Rectangle parameters: x position, y position, width, height
Dim signatureRectangle As New Rectangle(350, 750, 200, 100)

' Option 1: Set the SignatureImage property directly.
' This is the most straightforward approach
signature.SignatureImage = New PdfSignatureImage("assets/visual-signature.png", 0, signatureRectangle)

' Option 2: Use the LoadSignatureImageFromFile method.
' This method provides the same functionality with a different syntax
signature.LoadSignatureImageFromFile("assets/visual-signature.png", 0, signatureRectangle)

' Option 3: Load an image from a stream. This is useful for images generated in memory.
' Perfect for scenarios where images are retrieved from databases or web services
Dim image As AnyBitmap = AnyBitmap.FromFile("assets/visual-signature.png")
Using imageStream = image.ToStream()
    signature.LoadSignatureImageFromStream(imageStream, 0, signatureRectangle)
End Using

' After configuring the signature image, apply it to a PDF.
Dim pdf As PdfDocument = PdfDocument.FromFile("invoice.pdf")
pdf.Sign(signature)
pdf.SaveAs("VisualSignature.pdf")

Este código demonstra três maneiras equivalentes de adicionar um componente visual a uma assinatura digital. Quer você tenha uma imagem no disco ou na memória, você pode facilmente carimbá-la no PDF como parte do processo de assinatura. Isso preenche a lacuna entre a segurança criptográfica invisível e a aprovação visível de documentos.

Como posso controlar as permissões do documento após a assinatura?

Ao assinar um documento, você pode querer especificar quais alterações, se houver, serão permitidas posteriormente. Por exemplo, você pode querer bloquear o documento completamente ou permitir que os usuários preencham apenas os campos do formulário. O IronPDF permite que você defina essas permissões usando a enumeração SignaturePermissions. Para obter informações mais avançadas sobre controle de permissões, consulte nosso guia sobre como definir senhas e permissões para PDFs .

Definir permissões de assinatura é uma parte fundamental da gestão do ciclo de vida de um documento. Isso garante que a integridade do documento seja mantida de acordo com as suas regras após a sua assinatura. Se um usuário realizar uma ação não permitida, a assinatura será invalidada.

using IronPdf.Signing;

// Load a PDF file with change tracking enabled.
// This enables incremental save functionality for revision management
var pdf = PdfDocument.FromFile("annual_census.pdf", ChangeTrackingModes.EnableChangeTracking);

// Placeholder for edits: You might add text, fill forms, or add annotations here.
// For example: pdf.Annotations.Add(new TextAnnotation(...));
// Or: pdf.Form["fieldName"].Value = "New Value";

// Sign the current state of the document using SignWithFile for convenience.
// We set permissions to allow further signatures and form filling.
pdf.SignWithFile(
    "assets/IronSignature.p12", 
    "password", 
    SignaturePermissions.AdditionalSignaturesAndFormFillingAllowed);

// Save the current state as a distinct revision within the PDF's history.
// This creates a snapshot that can be referenced later
PdfDocument pdfWithRevision = pdf.SaveAsRevision();

// Save the final PDF with its full revision history to a new file.
pdfWithRevision.SaveAs("annual_census_signed.pdf");

using IronPdf.Signing;

// Load a PDF file with change tracking enabled.
// This enables incremental save functionality for revision management
var pdf = PdfDocument.FromFile("annual_census.pdf", ChangeTrackingModes.EnableChangeTracking);

// Placeholder for edits: You might add text, fill forms, or add annotations here.
// For example: pdf.Annotations.Add(new TextAnnotation(...));
// Or: pdf.Form["fieldName"].Value = "New Value";

// Sign the current state of the document using SignWithFile for convenience.
// We set permissions to allow further signatures and form filling.
pdf.SignWithFile(
    "assets/IronSignature.p12", 
    "password", 
    SignaturePermissions.AdditionalSignaturesAndFormFillingAllowed);

// Save the current state as a distinct revision within the PDF's history.
// This creates a snapshot that can be referenced later
PdfDocument pdfWithRevision = pdf.SaveAsRevision();

// Save the final PDF with its full revision history to a new file.
pdfWithRevision.SaveAs("annual_census_signed.pdf");

Imports IronPdf.Signing

' Load a PDF file with change tracking enabled.
' This enables incremental save functionality for revision management
Dim pdf = PdfDocument.FromFile("annual_census.pdf", ChangeTrackingModes.EnableChangeTracking)

' Placeholder for edits: You might add text, fill forms, or add annotations here.
' For example: pdf.Annotations.Add(New TextAnnotation(...))
' Or: pdf.Form("fieldName").Value = "New Value"

' Sign the current state of the document using SignWithFile for convenience.
' We set permissions to allow further signatures and form filling.
pdf.SignWithFile(
    "assets/IronSignature.p12",
    "password",
    SignaturePermissions.AdditionalSignaturesAndFormFillingAllowed)

' Save the current state as a distinct revision within the PDF's history.
' This creates a snapshot that can be referenced later
Dim pdfWithRevision As PdfDocument = pdf.SaveAsRevision()

' Save the final PDF with its full revision history to a new file.
pdfWithRevision.SaveAs("annual_census_signed.pdf")

// Load a PDF with a complex signature history.
var pdf = PdfDocument.FromFile("multi_signed_report.pdf");

// Verify all signatures across all revisions.
// This ensures document integrity throughout its entire history
bool allSignaturesValid = pdf.VerifySignatures();
Console.WriteLine($"All signatures are valid: {allSignaturesValid}");

// Roll back to the first revision (index 0).
// Useful for reviewing the original document state
if (pdf.RevisionCount > 1)
{
    PdfDocument firstRevision = pdf.GetRevision(0);
    firstRevision.SaveAs("report_first_revision.pdf");
}

// Create a completely unsigned version of the document.
// This removes all digital signatures while preserving content
pdf.RemoveSignatures();
pdf.SaveAs("report_unsigned.pdf");

// Load a PDF with a complex signature history.
var pdf = PdfDocument.FromFile("multi_signed_report.pdf");

// Verify all signatures across all revisions.
// This ensures document integrity throughout its entire history
bool allSignaturesValid = pdf.VerifySignatures();
Console.WriteLine($"All signatures are valid: {allSignaturesValid}");

// Roll back to the first revision (index 0).
// Useful for reviewing the original document state
if (pdf.RevisionCount > 1)
{
    PdfDocument firstRevision = pdf.GetRevision(0);
    firstRevision.SaveAs("report_first_revision.pdf");
}

// Create a completely unsigned version of the document.
// This removes all digital signatures while preserving content
pdf.RemoveSignatures();
pdf.SaveAs("report_unsigned.pdf");

Imports System

' Load a PDF with a complex signature history.
Dim pdf = PdfDocument.FromFile("multi_signed_report.pdf")

' Verify all signatures across all revisions.
' This ensures document integrity throughout its entire history
Dim allSignaturesValid As Boolean = pdf.VerifySignatures()
Console.WriteLine($"All signatures are valid: {allSignaturesValid}")

' Roll back to the first revision (index 0).
' Useful for reviewing the original document state
If pdf.RevisionCount > 1 Then
    Dim firstRevision As PdfDocument = pdf.GetRevision(0)
    firstRevision.SaveAs("report_first_revision.pdf")
End If

' Create a completely unsigned version of the document.
' This removes all digital signatures while preserving content
pdf.RemoveSignatures()
pdf.SaveAs("report_unsigned.pdf")

Como faço para inserir uma assinatura manuscrita em um PDF?

Às vezes, você não precisa da segurança criptográfica de uma assinatura digital, mas simplesmente deseja aplicar uma assinatura visual eletrônica, como uma assinatura manuscrita digitalizada. Isso geralmente é chamado de estampagem. O IronPDF pode fazer isso usando seus recursos Watermark ou Stamp. Para opções de marca d'água mais avançadas, explore nosso guia de marcas d'água personalizadas .

Vamos começar com um exemplo de fatura em PDF e uma imagem .png de uma assinatura manuscrita.

A fatura original em PDF antes da assinatura.

Aqui está a imagem de assinatura que aplicaremos:

Exemplo de imagem de assinatura manuscrita.

O código a seguir usa a propriedade Watermark para inserir esta imagem no canto inferior direito do PDF.

using IronPdf.Editing;

// Load the existing PDF document.
var pdf = PdfDocument.FromFile("invoice.pdf");

// Create an HtmlStamp containing our signature image.
// HtmlStamp allows us to position HTML content precisely on the page
var signatureStamp = new HtmlStamp("<img src='assets/signature.png'/>")
{
    // Configure the stamp's position and appearance.
    VerticalAlignment = VerticalAlignment.Bottom,
    HorizontalAlignment = HorizontalAlignment.Right,
    Margin = 10,  // Add some space from the edge.
    Opacity = 90  // Make it slightly transparent for a more authentic look.
};

// Apply the stamp to all pages of the PDF.
// You can also specify specific page numbers if needed
pdf.ApplyStamp(signatureStamp);

// Save the modified PDF document.
pdf.SaveAs("official_invoice.pdf");

using IronPdf.Editing;

// Load the existing PDF document.
var pdf = PdfDocument.FromFile("invoice.pdf");

// Create an HtmlStamp containing our signature image.
// HtmlStamp allows us to position HTML content precisely on the page
var signatureStamp = new HtmlStamp("<img src='assets/signature.png'/>")
{
    // Configure the stamp's position and appearance.
    VerticalAlignment = VerticalAlignment.Bottom,
    HorizontalAlignment = HorizontalAlignment.Right,
    Margin = 10,  // Add some space from the edge.
    Opacity = 90  // Make it slightly transparent for a more authentic look.
};

// Apply the stamp to all pages of the PDF.
// You can also specify specific page numbers if needed
pdf.ApplyStamp(signatureStamp);

// Save the modified PDF document.
pdf.SaveAs("official_invoice.pdf");

Imports IronPdf.Editing

' Load the existing PDF document.
Dim pdf = PdfDocument.FromFile("invoice.pdf")

' Create an HtmlStamp containing our signature image.
' HtmlStamp allows us to position HTML content precisely on the page
Dim signatureStamp = New HtmlStamp("<img src='assets/signature.png'/>") With {
    ' Configure the stamp's position and appearance.
    .VerticalAlignment = VerticalAlignment.Bottom,
    .HorizontalAlignment = HorizontalAlignment.Right,
    .Margin = 10,  ' Add some space from the edge.
    .Opacity = 90  ' Make it slightly transparent for a more authentic look.
}

' Apply the stamp to all pages of the PDF.
' You can also specify specific page numbers if needed
pdf.ApplyStamp(signatureStamp)

' Save the modified PDF document.
pdf.SaveAs("official_invoice.pdf")

Como posso adicionar um campo de assinatura interativa a um PDF?

Para documentos que precisam ser assinados pelo usuário final em um visualizador de PDF como o Adobe Acrobat, você pode adicionar um campo de formulário de assinatura interativo. Isso cria uma área vazia e clicável que solicita ao usuário que aplique sua própria assinatura digital. Para um guia completo sobre formulários em PDF, consulte nosso tutorial sobre como criar formulários em PDF .

Você pode criar um SignatureFormField e adicioná-lo à coleção de formulários do PDF. Você tem controle preciso sobre sua localização e tamanho na página. Isso é particularmente útil para documentos que exigem múltiplas assinaturas ou quando você precisa coletar assinaturas de terceiros.

using IronPdf.Forms;
using IronSoftware.Drawing;

// Create a new PDF to add the signature field to.
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Please Sign Below</h1>");

// Define the properties for the signature form field.
string fieldName = "ClientSignature";  // Unique identifier for the field
int pageIndex = 0;  // Add to the first page (zero-indexed)
var fieldRect = new Rectangle(50, 200, 300, 100);  // Position: (x, y), Size: (width, height)

// Create the SignatureFormField object.
// This creates an interactive field that users can click to sign
var signatureField = new SignatureFormField(fieldName, pageIndex, fieldRect);

// Add the signature field to the PDF's form.
pdf.Form.Add(signatureField);

// Save the PDF with the new interactive signature field.
pdf.SaveAs("interactive_signature.pdf");

using IronPdf.Forms;
using IronSoftware.Drawing;

// Create a new PDF to add the signature field to.
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Please Sign Below</h1>");

// Define the properties for the signature form field.
string fieldName = "ClientSignature";  // Unique identifier for the field
int pageIndex = 0;  // Add to the first page (zero-indexed)
var fieldRect = new Rectangle(50, 200, 300, 100);  // Position: (x, y), Size: (width, height)

// Create the SignatureFormField object.
// This creates an interactive field that users can click to sign
var signatureField = new SignatureFormField(fieldName, pageIndex, fieldRect);

// Add the signature field to the PDF's form.
pdf.Form.Add(signatureField);

// Save the PDF with the new interactive signature field.
pdf.SaveAs("interactive_signature.pdf");

Imports IronPdf.Forms
Imports IronSoftware.Drawing

' Create a new PDF to add the signature field to.
Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Please Sign Below</h1>")

' Define the properties for the signature form field.
Dim fieldName As String = "ClientSignature"  ' Unique identifier for the field
Dim pageIndex As Integer = 0  ' Add to the first page (zero-indexed)
Dim fieldRect As New Rectangle(50, 200, 300, 100)  ' Position: (x, y), Size: (width, height)

' Create the SignatureFormField object.
' This creates an interactive field that users can click to sign
Dim signatureField As New SignatureFormField(fieldName, pageIndex, fieldRect)

' Add the signature field to the PDF's form.
pdf.Form.Add(signatureField)

' Save the PDF with the new interactive signature field.
pdf.SaveAs("interactive_signature.pdf")

Ao abrir este PDF, o usuário verá um campo clicável que lhe permitirá concluir o processo de assinatura usando sua própria identidade digital. Você pode aprender mais sobre como criar e gerenciar formulários interativos em nosso guia prático sobre como criar formulários em PDF .

Um campo de assinatura interativo não assinado, adicionado programaticamente a um documento PDF.

Como faço para recuperar o nome do signatário de assinaturas verificadas?

Para obter o nome comum do proprietário do certificado que assinou uma assinatura, podemos usar a classe VerifiedSignature para acessar a propriedade SignerName. Abaixo segue um trecho de código que demonstra como realizar isso.

:path=/static-assets/pdf/content-code-examples/how-to/signing-find-signer-name.cs

using IronPdf;
using System;

// Import the Signed PDF report
var pdf = PdfDocument.FromFile("multi_signed_report.pdf");

// Using GetVerifiedSignatures() obtain a list of `VerifiedSignature` objects from the PDF
pdf.GetVerifiedSignatures().ForEach(signature =>
{
    // Print out the SignerName of each `VerifiedSignature` object
    Console.WriteLine($"SignatureName: {signature.SignerName}");
});

Imports IronPdf
Imports System

' Import the Signed PDF report
Dim pdf = PdfDocument.FromFile("multi_signed_report.pdf")

' Using GetVerifiedSignatures() obtain a list of `VerifiedSignature` objects from the PDF
pdf.GetVerifiedSignatures().ForEach(Sub(signature)
    ' Print out the SignerName of each `VerifiedSignature` object
    Console.WriteLine($"SignatureName: {signature.SignerName}")
End Sub)

Após importar o arquivo PDF assinado, utilizamos o método GetVerifiedSignatures para recuperar uma lista de objetos VerifiedSignature dentro do relatório e imprimir o SignerName para cada assinatura.

Observe que esse valor é extraído do Nome Distinto do Assunto (SubjectDN) do certificado e retornará nulo se o campo CN não estiver presente.

Quais são os próximos passos para assinar PDFs com o IronPDF?

Este guia demonstrou os recursos poderosos e flexíveis de assinatura de PDF do IronPDF. Seja para aplicar assinaturas digitais seguras com metadados detalhados, gerenciar revisões de documentos, carimbar assinaturas visuais ou criar formulários interativos, o IronPDF oferece uma API abrangente e fácil de usar para desenvolvedores.

Para continuar explorando, você pode baixar a biblioteca IronPDF for .NET e obter uma licença de avaliação gratuita para testar todos os seus recursos em seus projetos. Para técnicas mais avançadas de manipulação de documentos, incluindo a adição de anotações e o trabalho com campos de formulário, consulte nossa extensa documentação e tutoriais.

Pronto para ver o que mais você pode fazer? Confira nossa página de tutoriais aqui: Assinar e proteger PDFs