在 PDF 文件中添加签名

在 PDF 文件中添加数字签名

PdfFileSignature 类允许您在 PDF 文件中添加签名。您需要使用输入和输出 PDF 文件创建 PdfFileSignature 类的对象。您还需要创建一个 Rectangle 对象，以指定您希望添加签名的位置，并且为了设置外观，您可以使用 PdfFileSignature 对象的 SignatureAppearance 属性指定图像。Aspose.Pdf.Facades 还提供不同类型的签名，如 PKCS#1、PKCS#7 和 PKCS#7Detached。为了创建特定类型的签名，您需要使用证书文件和密码创建特定类的对象，如 PKCS1、PKCS7 或 PKCS7Detached。

一旦创建了特定签名类型的对象，您可以使用 PdfFileSignature 类的 Sign 方法对 PDF 进行签名，并将特定签名对象传递给该类。您还可以为此方法指定其他属性。最后，您需要使用 PdfFileSignature 类的 Save 方法保存签名后的 PDF。以下代码片段向您展示了如何在 PDF 文件中添加签名。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddPdfFileSignature()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_SecuritySignatures();

    using (var pdFileSignature = new Aspose.Pdf.Facades.PdfFileSignature())
    {
        // Bind PDF document
        pdFileSignature.BindPdf(dataDir + "input.pdf");

        // Create a rectangle for signature location
        System.Drawing.Rectangle rect = new System.Drawing.Rectangle(10, 10, 300, 50);
    
        // Set signature appearance
        pdFileSignature.SignatureAppearance = dataDir + "aspose-logo.png";

        // Create any of the three signature types
        var signature = new PKCS1(dataDir + "rsa_cert.pfx", "12345"); // PKCS#1

        pdFileSignature.Sign(1, "I'm document author", "[e-mail]", "Aspose Pdf Demo, Australia", true, rect, signature);
        // Save PDF document
        pdFileSignature.Save(dataDir + "DigitallySign_out.pdf");
    }
}

以下代码示例展示了用两个签名签署文档的能力。在我们的示例中，我们将第一个签名放在第一页，第二个签名放在第二页。您可以指定所需的页面。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddTwoSignature()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_SecuritySignatures();

    using (var pdFileSignature = new Aspose.Pdf.Facades.PdfFileSignature())
    {
        // Bind PDF document
        pdFileSignature.BindPdf(dataDir + "input.pdf");

        // Create a rectangle for 1st signature location
        System.Drawing.Rectangle rect1 = new System.Drawing.Rectangle(10, 10, 300, 50);

        // Create 1st signature object
        var signature1 = new Aspose.Pdf.Forms.PKCS1(dataDir + "rsa_cert.pfx", "12345"); // PKCS#1

        pdFileSignature.Sign(1, "I'm document author", "[e-mail]", "Aspose Pdf Demo, Australia", true, rect1, signature1);
        pdFileSignature.Save(dataDir + "DigitallySign_out.pdf");

        // Sign with 2nd signature
        // Bind PDF document
        pdFileSignature.BindPdf(dataDir + "DigitallySign_out.pdf");

        // Create a rectangle for 2nd signature location
        System.Drawing.Rectangle rect2 = new System.Drawing.Rectangle(10, 10, 300, 50);

        // Create 2nd signature object
        var signature2 = new Aspose.Pdf.Forms.PKCS1(dataDir + "rsa_cert.pfx", "12345"); // PKCS#1

        pdFileSignature.Sign(2, "I'm document reviewer", "[e-mail]", "Aspose Pdf Demo, Australia", true, rect2, signature2);

        // Save PDF document
        pdFileSignature.Save(dataDir + "DigitallySign2_out.pdf");
    }
}

对于需要签名的表单或 acroforms 文档，请参见以下示例。 您需要使用输入和输出 PDF 文件创建 PdfFileSignature 类的对象。使用 BindPdf 进行绑定。创建一个签名，并能够添加所需的属性。在我们的示例中，它们是 ‘Reason’ 和 ‘CustomAppearance’。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddPdfFileSignatureField()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_SecuritySignatures();

    using (var pdFileSignature = new Aspose.Pdf.Facades.PdfFileSignature())
    {
        // Bind PDF document
        pdFileSignature.BindPdf(dataDir + "input.pdf");

        // Create any of the three signature types
        var signature = new Aspose.Pdf.Forms.PKCS1(dataDir + "rsa_cert.pfx", "12345")
        {
            Reason = "Sign as Author",
            CustomAppearance = new Aspose.Pdf.Forms.SignatureCustomAppearance
            {
                FontSize = 6,
                FontFamilyName = "Calibri"
            }
        }; // PKCS#1
        
        pdFileSignature.Sign("Signature1", signature);
        // Save PDF document
        pdFileSignature.Save(dataDir + "DigitallySign_out.pdf");
    }
}

如果我们的文档有两个字段，签署它的算法与第一个示例类似。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddPdfFileSignatureField2()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_SecuritySignatures();

    using (var pdFileSignature = new Aspose.Pdf.Facades.PdfFileSignature())
    {
        // Bind PDF document
        pdfFileSignature.BindPdf(dataDir + "input.pdf");

        // Create any of the three signature types
        var signature1 = new Aspose.Pdf.Forms.PKCS1(dataDir + "rsa_cert.pfx", "12345")
        {
            Reason = "Sign as Author",
            CustomAppearance = new Aspose.Pdf.Forms.SignatureCustomAppearance
            {
                FontSize = 6
            }
        }; // PKCS#1
        pdFileSignature.Sign("Signature1", signature1);
        // Save PDF document
        pdFileSignature.Save(dataDir + "DigitallySign_out.pdf");
        // Bind PDF document
        pdFileSignature.BindPdf(dataDir + "DigitallySign_out.pdf");

        // Create any of the three signature types
        var signature2 = new Aspose.Pdf.Forms.PKCS1(dataDir + "rsa_cert.pfx", "12345")
        {
            Reason = "Sign as Reviwer",
            CustomAppearance = new SignatureCustomAppearance
            {
                FontSize = 6
            }
        }; // PKCS#1
        
        pdFileSignature.Sign("Signature2", signature2);
        // Save PDF document
        pdFileSignature.Save(dataDir + "DigitallySign2_out.pdf");
    }
}