C# 中的 PDF 安全性：加密、權限與保護

using IronPdf;

var pdf = PdfDocument.FromFile("input.pdf");

// User password required to open/view the PDF
pdf.SecuritySettings.UserPassword = "view-access-2024";

// Owner password required to modify security settings
pdf.SecuritySettings.OwnerPassword = "admin-master-key";

// Disable printing for users without owner password
pdf.SecuritySettings.AllowUserPrinting = IronPdf.Security.PdfPrintSecurity.NoPrint;

// Disable copy/paste of content
pdf.SecuritySettings.AllowUserCopyPasteContent = false;

pdf.SaveAs("output-secured.pdf");

Imports IronPdf

Dim pdf = PdfDocument.FromFile("input.pdf")

' User password required to open/view the PDF
pdf.SecuritySettings.UserPassword = "view-access-2024"

' Owner password required to modify security settings
pdf.SecuritySettings.OwnerPassword = "admin-master-key"

' Disable printing for users without owner password
pdf.SecuritySettings.AllowUserPrinting = IronPdf.Security.PdfPrintSecurity.NoPrint

' Disable copy/paste of content
pdf.SecuritySettings.AllowUserCopyPasteContent = False

pdf.SaveAs("output-secured.pdf")

using IronPdf;
using IronPdf.Security;

Imports IronPdf
Imports IronPdf.Security

using IronPdf;
using IronPdf.Security;

// Allow low-resolution printing only (150 DPI)
var pdf1 = PdfDocument.FromFile("input.pdf");
pdf1.SecuritySettings.OwnerPassword = "admin-key-2024";
pdf1.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.PrintLowQuality;
pdf1.SaveAs("output-low-res-print.pdf");

// Disable printing completely
var pdf2 = PdfDocument.FromFile("input.pdf");
pdf2.SecuritySettings.OwnerPassword = "secret-admin-key";
pdf2.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.NoPrint;
pdf2.SaveAs("output-no-print.pdf");

// Allow full high-quality printing
var pdf3 = PdfDocument.FromFile("input.pdf");
pdf3.SecuritySettings.OwnerPassword = "owner-key";
pdf3.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights;
pdf3.SaveAs("output-full-print.pdf");

Imports IronPdf
Imports IronPdf.Security

' Allow low-resolution printing only (150 DPI)
Dim pdf1 = PdfDocument.FromFile("input.pdf")
pdf1.SecuritySettings.OwnerPassword = "admin-key-2024"
pdf1.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.PrintLowQuality
pdf1.SaveAs("output-low-res-print.pdf")

' Disable printing completely
Dim pdf2 = PdfDocument.FromFile("input.pdf")
pdf2.SecuritySettings.OwnerPassword = "secret-admin-key"
pdf2.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.NoPrint
pdf2.SaveAs("output-no-print.pdf")

' Allow full high-quality printing
Dim pdf3 = PdfDocument.FromFile("input.pdf")
pdf3.SecuritySettings.OwnerPassword = "owner-key"
pdf3.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.FullPrintRights
pdf3.SaveAs("output-full-print.pdf")

using IronPdf;

var pdf = PdfDocument.FromFile("input.pdf");

// Owner password required for copy/paste restrictions
pdf.SecuritySettings.OwnerPassword = "content-protection-key";

// Prevent users from selecting and copying text or images
pdf.SecuritySettings.AllowUserCopyPasteContent = false;

pdf.SaveAs("output-no-copy.pdf");

Imports IronPdf

Dim pdf = PdfDocument.FromFile("input.pdf")

' Owner password required for copy/paste restrictions
pdf.SecuritySettings.OwnerPassword = "content-protection-key"

' Prevent users from selecting and copying text or images
pdf.SecuritySettings.AllowUserCopyPasteContent = False

pdf.SaveAs("output-no-copy.pdf")

using IronPdf;
using IronPdf.Security;

// Prevent any content modifications
var pdf1 = PdfDocument.FromFile("input.pdf");
pdf1.SecuritySettings.OwnerPassword = "contract-admin-2024";
pdf1.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit;
pdf1.SaveAs("output-locked.pdf");

// Allow page organization only (rotate, reorder, delete pages)
var pdf2 = PdfDocument.FromFile("input.pdf");
pdf2.SecuritySettings.OwnerPassword = "form-admin-key";
pdf2.SecuritySettings.AllowUserEdits = PdfEditSecurity.EditPages;
pdf2.SaveAs("output-edit-pages.pdf");

// Allow all editing operations
var pdf3 = PdfDocument.FromFile("input.pdf");
pdf3.SecuritySettings.OwnerPassword = "draft-admin";
pdf3.SecuritySettings.AllowUserEdits = PdfEditSecurity.EditAll;
pdf3.SaveAs("output-editable.pdf");

Imports IronPdf
Imports IronPdf.Security

' Prevent any content modifications
Dim pdf1 = PdfDocument.FromFile("input.pdf")
pdf1.SecuritySettings.OwnerPassword = "contract-admin-2024"
pdf1.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit
pdf1.SaveAs("output-locked.pdf")

' Allow page organization only (rotate, reorder, delete pages)
Dim pdf2 = PdfDocument.FromFile("input.pdf")
pdf2.SecuritySettings.OwnerPassword = "form-admin-key"
pdf2.SecuritySettings.AllowUserEdits = PdfEditSecurity.EditPages
pdf2.SaveAs("output-edit-pages.pdf")

' Allow all editing operations
Dim pdf3 = PdfDocument.FromFile("input.pdf")
pdf3.SecuritySettings.OwnerPassword = "draft-admin"
pdf3.SecuritySettings.AllowUserEdits = PdfEditSecurity.EditAll
pdf3.SaveAs("output-editable.pdf")

using IronPdf;

var pdf = PdfDocument.FromFile("input.pdf");

// Owner password required for annotation restrictions
pdf.SecuritySettings.OwnerPassword = "legal-admin-2024";

// Prevent adding comments, highlights, or other markup
pdf.SecuritySettings.AllowUserAnnotations = false;

pdf.SaveAs("output-no-annotations.pdf");

Imports IronPdf

Dim pdf = PdfDocument.FromFile("input.pdf")

' Owner password required for annotation restrictions
pdf.SecuritySettings.OwnerPassword = "legal-admin-2024"

' Prevent adding comments, highlights, or other markup
pdf.SecuritySettings.AllowUserAnnotations = False

pdf.SaveAs("output-no-annotations.pdf")

using IronPdf;

// Open password-protected PDF
var password = "user-access-2024";
var pdf = PdfDocument.FromFile("protected.pdf", password);

// Work with the decrypted document
var text = pdf.ExtractAllText();

// Modify and save
pdf.SaveAs("output-processed.pdf");

// Note: For production, use secure password storage (environment variables, key vaults)

Imports IronPdf

' Open password-protected PDF
Dim password As String = "user-access-2024"
Dim pdf As PdfDocument = PdfDocument.FromFile("protected.pdf", password)

' Work with the decrypted document
Dim text As String = pdf.ExtractAllText()

' Modify and save
pdf.SaveAs("output-processed.pdf")

' Note: For production, use secure password storage (environment variables, key vaults)

using IronPdf;

var pdf = PdfDocument.FromFile("protected.pdf", "owner-password-2024");

pdf.SecuritySettings.RemovePasswordsAndEncryption();

pdf.SaveAs("output-unprotected.pdf");

Imports IronPdf

Dim pdf = PdfDocument.FromFile("protected.pdf", "owner-password-2024")

pdf.SecuritySettings.RemovePasswordsAndEncryption()

pdf.SaveAs("output-unprotected.pdf")

using IronPdf;
using System;
using System.IO;

string inputDir = "./input";
string outputDir = "./output";

Directory.CreateDirectory(outputDir);

var pdfFiles = Directory.GetFiles(inputDir, "*.pdf");
string password = "batch-process-2024";

foreach (var pdfPath in pdfFiles)
{
    try
    {
        PdfDocument pdf;
        try
        {
            pdf = PdfDocument.FromFile(pdfPath, password);
        }
        catch
        {
            pdf = PdfDocument.FromFile(pdfPath);
        }

        var text = pdf.ExtractAllText();

        pdf.SecuritySettings.RemovePasswordsAndEncryption();

        string fileName = Path.GetFileName(pdfPath);
        string outputPath = Path.Combine(outputDir, fileName);
        pdf.SaveAs(outputPath);
    }
    catch (Exception ex)
    {
        // Handle errors as needed
    }
}

Imports IronPdf
Imports System
Imports System.IO

Dim inputDir As String = "./input"
Dim outputDir As String = "./output"

Directory.CreateDirectory(outputDir)

Dim pdfFiles = Directory.GetFiles(inputDir, "*.pdf")
Dim password As String = "batch-process-2024"

For Each pdfPath In pdfFiles
    Try
        Dim pdf As PdfDocument
        Try
            pdf = PdfDocument.FromFile(pdfPath, password)
        Catch
            pdf = PdfDocument.FromFile(pdfPath)
        End Try

        Dim text = pdf.ExtractAllText()

        pdf.SecuritySettings.RemovePasswordsAndEncryption()

        Dim fileName As String = Path.GetFileName(pdfPath)
        Dim outputPath As String = Path.Combine(outputDir, fileName)
        pdf.SaveAs(outputPath)
    Catch ex As Exception
        ' Handle errors as needed
    End Try
Next

using IronPdf;
using System;
using System.IO;
using System.Text.Json;

var handler = new SecureDocumentHandler();

handler.OpenClassifiedDocument(
    "classified.pdf",
    "classified-password",
    "john.doe@agency.gov",
    "192.168.1.100"
);

handler.LogPrintOperation(
    "classified.pdf",
    "john.doe@agency.gov",
    "192.168.1.100"
);


ic class PdfAuditLog

public DateTime Timestamp { get; set; }
public string Username { get; set; }
public string Operation { get; set; }
public string DocumentPath { get; set; }
public string IpAddress { get; set; }
public bool Success { get; set; }
public string Details { get; set; }


ic class SecureDocumentHandler

private readonly string auditLogPath = "./logs/audit.log";

public void OpenClassifiedDocument(string documentPath, string password, string username, string ipAddress)
{
    var auditEntry = new PdfAuditLog
    {
        Timestamp = DateTime.UtcNow,
        Username = username,
        Operation = "OPEN",
        DocumentPath = documentPath,
        IpAddress = ipAddress,
        Success = false,
        Details = ""
    };

    try
    {
        var pdf = PdfDocument.FromFile(documentPath, password);
        auditEntry.Success = true;
        auditEntry.Details = "Document opened successfully";
        LogAuditEntry(auditEntry);
    }
    catch (Exception ex)
    {
        auditEntry.Success = false;
        auditEntry.Details = $"Failed: {ex.Message}";
        LogAuditEntry(auditEntry);
        throw;
    }
}

public void LogPrintOperation(string documentPath, string username, string ipAddress)
{
    var auditEntry = new PdfAuditLog
    {
        Timestamp = DateTime.UtcNow,
        Username = username,
        Operation = "PRINT",
        DocumentPath = documentPath,
        IpAddress = ipAddress,
        Success = true,
        Details = "Document printed"
    };

    LogAuditEntry(auditEntry);
}

private void LogAuditEntry(PdfAuditLog entry)
{
    Directory.CreateDirectory(Path.GetDirectoryName(auditLogPath));
    string jsonEntry = JsonSerializer.Serialize(entry);
    File.AppendAllText(auditLogPath, jsonEntry + Environment.NewLine);
}

Imports IronPdf
Imports System
Imports System.IO
Imports System.Text.Json

Module Program
    Sub Main()
        Dim handler As New SecureDocumentHandler()

        handler.OpenClassifiedDocument(
            "classified.pdf",
            "classified-password",
            "john.doe@agency.gov",
            "192.168.1.100"
        )

        handler.LogPrintOperation(
            "classified.pdf",
            "john.doe@agency.gov",
            "192.168.1.100"
        )
    End Sub
End Module

Public Class PdfAuditLog
    Public Property Timestamp As DateTime
    Public Property Username As String
    Public Property Operation As String
    Public Property DocumentPath As String
    Public Property IpAddress As String
    Public Property Success As Boolean
    Public Property Details As String
End Class

Public Class SecureDocumentHandler
    Private ReadOnly auditLogPath As String = "./logs/audit.log"

    Public Sub OpenClassifiedDocument(documentPath As String, password As String, username As String, ipAddress As String)
        Dim auditEntry As New PdfAuditLog With {
            .Timestamp = DateTime.UtcNow,
            .Username = username,
            .Operation = "OPEN",
            .DocumentPath = documentPath,
            .IpAddress = ipAddress,
            .Success = False,
            .Details = ""
        }

        Try
            Dim pdf = PdfDocument.FromFile(documentPath, password)
            auditEntry.Success = True
            auditEntry.Details = "Document opened successfully"
            LogAuditEntry(auditEntry)
        Catch ex As Exception
            auditEntry.Success = False
            auditEntry.Details = $"Failed: {ex.Message}"
            LogAuditEntry(auditEntry)
            Throw
        End Try
    End Sub

    Public Sub LogPrintOperation(documentPath As String, username As String, ipAddress As String)
        Dim auditEntry As New PdfAuditLog With {
            .Timestamp = DateTime.UtcNow,
            .Username = username,
            .Operation = "PRINT",
            .DocumentPath = documentPath,
            .IpAddress = ipAddress,
            .Success = True,
            .Details = "Document printed"
        }

        LogAuditEntry(auditEntry)
    End Sub

    Private Sub LogAuditEntry(entry As PdfAuditLog)
        Directory.CreateDirectory(Path.GetDirectoryName(auditLogPath))
        Dim jsonEntry As String = JsonSerializer.Serialize(entry)
        File.AppendAllText(auditLogPath, jsonEntry & Environment.NewLine)
    End Sub
End Class

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

var pdf = PdfDocument.FromFile("input.pdf");

// Apply encryption
pdf.SecuritySettings.UserPassword = "view-classified-2024";
pdf.SecuritySettings.OwnerPassword = "admin-classified-2024";

// Digital signature requires external certificate file (certificate.pfx)
// In production: use certificates from trusted Certificate Authorities and secure hardware (HSM)
var certificate = new X509Certificate2("certificate.pfx", "cert-password");

var signature = new PdfSignature(certificate)
{
    SigningContact = "security@agency.gov",
    SigningReason = "Document Certification",
    SigningLocation = "Washington DC, USA"
};

pdf.Sign(signature);

pdf.SaveAs("output-signed-encrypted.pdf");

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

Dim pdf = PdfDocument.FromFile("input.pdf")

' Apply encryption
pdf.SecuritySettings.UserPassword = "view-classified-2024"
pdf.SecuritySettings.OwnerPassword = "admin-classified-2024"

' Digital signature requires external certificate file (certificate.pfx)
' In production: use certificates from trusted Certificate Authorities and secure hardware (HSM)
Dim certificate As New X509Certificate2("certificate.pfx", "cert-password")

Dim signature As New PdfSignature(certificate) With {
    .SigningContact = "security@agency.gov",
    .SigningReason = "Document Certification",
    .SigningLocation = "Washington DC, USA"
}

pdf.Sign(signature)

pdf.SaveAs("output-signed-encrypted.pdf")

using IronPdf;
using IronPdf.Rendering;

var pdf = PdfDocument.FromFile("input.pdf");

// Prevent JavaScript injection by disabling editing
pdf.SecuritySettings.OwnerPassword = "admin-secure-2024";
pdf.SecuritySettings.AllowUserEdits = IronPdf.Security.PdfEditSecurity.NoEdit;

pdf.SaveAs("output-hardened.pdf");

Imports IronPdf
Imports IronPdf.Rendering

Dim pdf = PdfDocument.FromFile("input.pdf")

' Prevent JavaScript injection by disabling editing
pdf.SecuritySettings.OwnerPassword = "admin-secure-2024"
pdf.SecuritySettings.AllowUserEdits = IronPdf.Security.PdfEditSecurity.NoEdit

pdf.SaveAs("output-hardened.pdf")