使用IRONPDF 如何給PDF文檔設置密碼 Curtis Chau 更新日期:6月 22, 2025 Download IronPDF NuGet 下載 DLL 下載 Windows 安裝程式 Start Free Trial Copy for LLMs Copy for LLMs Copy page as Markdown for LLMs Open in ChatGPT Ask ChatGPT about this page Open in Gemini Ask Gemini about this page Open in Grok Ask Grok about this page Open in Perplexity Ask Perplexity about this page Share Share on Facebook Share on X (Twitter) Share on LinkedIn Copy URL Email article Your business is spending too much on yearly subscriptions for PDF security and compliance. Consider IronSecureDoc, which provides solutions for managing SaaS services like digital signing, redaction, encryption, and protection, all for a one-time payment. Explore IronSecureDoc Documentation A PDF file is a document that has been created and saved in the "Portable Document Format". It is a popular digital file format supported by most word processors and computer operating systems. PDF files can be edited, printed, and shared just like any other document file type. PDF stands for "portable document format". PDF files are widely used nowadays. They can be found in many places, such as company websites, social media pages, and even on the internet. This is because PDFs are versatile and can store all types of information. However, with the rise of technology comes the rise of cybercrimes. That is why it is essential to protect PDF documents from unauthorized users who want to steal your data or leak confidential information about your company. Here are some benefits of protecting your PDF files: Prevent unauthorized access to sensitive information Prevent data leaks Protect intellectual property Ensure compliance with regulations A Different Type of Protection PDF files are a popular format for distributing documents. But, like any other file type, they can be susceptible to hacking and unauthorized access. There are several ways to protect PDF files from unauthorized access. Password Protection Digital Signature Protection Encryption Protection Watermark Protection Password Protection A common way to protect PDF files is by password protecting them. This is the most basic form of protection, and it's often the easiest for users to understand. The downside is that this protection can be hacked or bypassed by someone who has the right skillset. Encryption Protection Another option for protecting PDF files is encrypting them with an encryption key that only authorized people can access. This key should only be known by authorized people to ensure that no one else can decrypt the file without authorization. Offline Tools for the Password Protection of PDF Files: The best offline tools for protecting PDF files are: 1) Adobe Acrobat Pro DC The Adobe Acrobat software is a powerful tool that you can use to create, edit, and convert PDF files. You can also create forms and fill them out with information from the document. It also allows you to convert paper documents into PDFs so they can be shared online or emailed without having to worry about losing the formatting of your document. Let's look at how to protect our PDF file using Adobe Acrobat Pro DC. There are different ways to secure PDFs with passwords: Open a PDF File Open the PDF file you want to protect with Adobe Acrobat Reader. You can open files by using the shortcut Ctrl+O or drop files directly in the Adobe Acrobat application. Method 1 Click on the file menu and select properties. From the properties dialogue box, go to the Security tab. From the Security Method drop-down menu, select Password Security. It will open the password security settings. Check the "Require a password to open document" option. Enter the password you want to use and press the OK button. It will prompt you to retype the correct password to confirm the password. Enter the password again and press the OK button to apply changes. Press Ctrl+S to save the modified security settings. Method 2 Click on the file menu and select the "Protect Using Password" option from the drop-down menu. It will open a dialogue box. Select the "Viewing" option if you want to restrict viewing options without a password, or select the "Editing" option if you want to prevent editing. Online Tools for the Password Protection of PDF Files: The best way to lock PDFs with passwords is to use an online tool. Many tools are available on the internet for locking PDFs with passwords. The top three best online tools are: ILovePDF SmallPDF PDF2GO 1) ILovePDF ILovePDF is an online PDF tool that provides the facility to perform all PDF-related operations on one website. It is fully secured because it has an SSL certificate, meaning that no third party will access your documents. Let's see how we can protect PDF documents using the ILovePDF protect PDF feature. Go to the ILovePDF website. Click on "Select PDF File" and choose the file you want to protect with a password. Type the password and retype the password to confirm it. Click on Protect PDF. Your password-protected PDF will be ready to download. 2) Smallpdf Smallpdf is a free online PDF editor that allows you to edit your PDF with easy steps. It has an easy user interface and is entirely secure. It can convert PDFs to a different format. You can sign documents using Smallpdf. Smallpdf is a web-based tool website with unique features for all PDF operations. You don't need to pay anything to use the special features. The software is entirely free to use, and it can be accessed from any device with internet access. Internet connection, therefore, becomes a key element to using this editor. Let's see how to add password protection to PDF documents using SmallPDF: Go to the Smallpdf website. Click on "Choose File" and select the PDF file you want to be protected. Write a password and retype it to confirm your password. Click on the "Encrypt PDF" button to encrypt the PDF document with a password. Your password-protected PDF will be ready to download. Download it by clicking on the "Download" button on the left sidebar. 3) Pdf2Go Pdf2Go is a web-based PDF tools website. Its easy interface and simple processes make it different from other websites. It has all the essential tools required to perform all types of PDF operations. It is entirely free. Let's see how we can protect PDFs using the Pdf2Go website: Go to the Pdf2Go Website. Click on "choose file" and select the desired file you wish to lock. When the PDF loads, enter the password and retype the password to confirm. If you want to restrict editing and copying, enter the permission password. Check the box for those restrictions you wish to be applied. Then, click on the "Apply" button. Your password-protected file will be ready to download. You can upload it to Google Drive and Dropbox. IronPDF: a C# Library IronPDF is a C# library that provides functions to perform various actions on PDF files. IronPDF allows you to work with PDF documents without installing any PDF software on your system. This is a fantastic feature in itself — you don't need to worry about interfering with the system settings you are working with. If you still have doubts, read the IronPDF Documentation on the IronPDF Website. If you are developing software and you need to perform operations on a PDF file, then IronPDF is an excellent choice for you. It works quickly and easily. You will have to import the IronPDF DLL file into the project or install it with NuGet Package Manager. There is a Free Trial Version that you can use for testing all the capabilities and functions you need. The trial version is free and doesn't require the entering of any payment method in order to be downloaded. You can easily protect your PDF file with the IronPDF library. It has many available functions such as MakePdfDocumentReadOnly(), etc. These functions help you protect your PDF files easily. You can also follow this IronPDF Security Tutorial to protect a PDF. IronPDF is the perfect tool for completing all your PDF-related tasks — quick, efficient, and easy to use. You can download a file project from this Project Download Link. 常見問題解答 如何在C#中為PDF文件新增密碼保護？ 您可以使用 IronPDF 的ProtectWithPassword()方法在 C# 中安全地為 PDF 文件設定密碼保護。此方法可確保只有擁有正確密碼的使用者才能存取 PDF 的內容。 使用 C# 函式庫進行 PDF 保護有哪些好處？ 使用 IronPDF 等 C# 庫進行 PDF 保護，可讓開發人員以程式設計方式應用密碼保護、加密和浮水印等安全功能，而無需額外的 PDF 軟體。 C# 函式庫如何幫助加密 PDF 文件？ IronPDF 提供諸如Encrypt()之類的方法，可為 PDF 文件添加加密，確保只有授權使用者才能解密並檢視內容。 IronPDF 提供了哪些方法可以設定 PDF 檔案為唯讀？ IronPDF 提供了MakePdfDocumentReadOnly()方法，可用於對 PDF 應用唯讀限制，防止任何未經授權的修改。 IronPDF的PDF保護功能是否有免費試用版？ 是的，IronPDF 提供免費試用版，讓您可以體驗其所有 PDF 保護功能，包括密碼保護和加密，而無需輸入任何付款資訊。 在選擇線上和離線PDF保護工具時，我應該考慮哪些因素？ 在選擇線上和離線 PDF 保護工具時，請考慮安全性（IronPDF 等離線工具提供強大的安全性）、易用性以及是否需要數位簽章和加密等附加功能等因素。 為什麼密碼保護是保護 PDF 檔案的基本方法？ 密碼保護至關重要，因為它提供了一層基本的安全保障，防止未經授權存取文件。但是，為了獲得更強的安全性，密碼保護應該與加密技術結合。 IronSecureDoc是什麼？它與PDF保護有何關係？ IronSecureDoc 是一種經濟高效的替代方案，可取代年度訂閱，提供一次性付款解決方案，用於管理 PDF 文件的數位簽章、編輯、加密和保護。 確保PDF安全性的最佳實務有哪些？ 確保 PDF 安全性的最佳實踐包括使用強密碼、套用加密、限制編輯和複製以及使用數位簽章。 IronPDF 等工具可以幫助以程式設計方式實現這些實踐。 是否有關於如何使用 IronPDF 實現 PDF 安全功能的文件？ 是的，IronPDF 提供了全面的文件和教程，介紹如何在 C# 中實現各種 PDF 安全功能，包括密碼保護和加密。 .NET 10 相容性：我可以在面向 .NET 10 的專案中使用 IronPDF 的密碼保護功能嗎？ 是的，IronPDF 完全相容於 .NET 10，並支援其所有密碼保護和安全功能。您無需額外設定即可在 .NET 10 專案中使用ProtectWithPassword()方法和SecuritySettings API。 Curtis Chau 立即與工程團隊聊天 技術作家 Curtis Chau 擁有卡爾頓大學計算機科學學士學位，專注於前端開發，擅長於 Node.js、TypeScript、JavaScript 和 React。Curtis 熱衷於創建直觀且美觀的用戶界面，喜歡使用現代框架並打造結構良好、視覺吸引人的手冊。除了開發之外，Curtis 對物聯網 (IoT) 有著濃厚的興趣，探索將硬體和軟體結合的創新方式。在閒暇時間，他喜愛遊戲並構建 Discord 機器人，結合科技與創意的樂趣。 相關文章 發表日期 11月 13, 2025 如何在 C# 中合併兩個 PDF 位元組數組 使用 IronPDF 在 C# 中合併兩個 PDF 位元組數組。學習如何透過簡單的程式碼範例，將來自位元組數組、記憶體流和資料庫的多個 PDF 文件合併在一起。 閱讀更多 發表日期 11月 13, 2025 如何在 ASP.NET MVC 中創建 PDF 檢視器 為 ASP.NET MVC 應用程式構建一個強大的 PDF 檢視器。顯示 PDF 文件，將視圖轉換為 PDF，使用 IronPDF 添加互動功能。 閱讀更多 發表日期 11月 13, 2025 如何建立 .NET HTML 轉 PDF 轉換器 學習如何在.NET中使用IronPDF將HTML轉換為PDF。 閱讀更多 C#讀取PDF文件：簡單教程如何移除PDF文件上的密碼
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