怎么能有密码保护的PDF文件以编程方式打开？ [英] how can a password-protected PDF file be opened programmatically?

问题描述

使用Adobe IFilter的不提供给提供密码以打开一个密码保护的PDF文件夹机构，因此它不能被用来打开密码保护的文件。

The Adobe IFilter doesn't provide a mechanism to supply a password to open a password-protected PDF file, so it cannot be used to open password-protected files.

我想知道，是否有一个比较简单的方法以编程方式检索的PDF文件中的实际加密的数据，利用标准的加密API解密，然后使用解密的数据建立一个新的PDF文件？

I was wondering, is there a relatively straightforward way to programmatically retrieve the actual encrypted data inside the PDF file, decrypt it using a standard cryptography API, and then build a new PDF file with the decrypted data?

推荐答案

要打开密码保护的PDF文档，你将需要至少开发一个PDF解析器，解密和发电机。我不建议这样做，虽然。这是远不及一件容易的事来完成。

To open a password protected PDF you will need to develop at least a PDF parser, decryptor and generator. I wouldn't recommend to do that, though. It's nowhere near an easy task to accomplish.

使用的PDF库的一切帮助是非常简单的。你可能会想尝试 Docotic.Pdf库的任务（声明：我的供应商合作图书馆）。

With help of a PDF library everything is much simpler. You might want to try Docotic.Pdf library for the task (disclaimer: I work for the vendor of the library).

下面是给你的任务的例子：

Here is a sample for you task:

public static void unprotectPdf(string input, string output)
{
    bool passwordProtected = PdfDocument.IsPasswordProtected(input);
    if (passwordProtected)
    {
        string password = null; // retrieve the password somehow

        using (PdfDocument doc = new PdfDocument(input, password))
        {
            // clear both passwords in order
            // to produce unprotected document
            doc.OwnerPassword = "";
            doc.UserPassword = "";

            doc.Save(output);
        }
    }
    else
    {
        // no decryption is required
        File.Copy(input, output, true);
    }
}

Docotic.Pdf可以从PDF文件提取文本（格式化与否）一>。它可能是有用的索引（我想这是你是什么最多，因为你提到的Adobe的IFilter）

Docotic.Pdf can also extract text (formatted or not) from PDFs. It might be useful for indexing (I guess it's what you are up to because you mentioned Adobe IFilter)

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