如何从受密码保护的PDF文件中删除打印保护？

Question

如何从受密码保护的PDF文件中删除打印保护？

Answer 1

当PDF文档可见但不可打印时，使用GNU / Linux时可以轻松解决。

为此，您必须使用两步程序：

1. 将pdf打印为postscript

2. 恢复正常的pdf文件

   $ pdftops [your_protected_pdf_document.pdf] out.ps
   
   $ pstopdf [out.ps] broken_protection_pdf_document.pdf 
   

它已经完成了。您的pdf文档不再有密码保护。

Answer 2

见答案：

pdftk and qpdf to reset PDF commenting security

复制自另一个答案（写作bei Kurt Pfeifle）

The command qpdf --decrypt input.pdf output.pdf removes 
the 'owner' password. But it does only work, if there is 
no 'user' password set.

Once the owner password is removed, the output.pdf should 
already have unset all security protection and have allowed 
commenting. Needless to run your extra pdftk ... command then... 
BTW, your allow paramenter in your pdftk call will not work the 
way you quoted your command. The allow permissions will only be
applied if you also...

    ...either specify an encryption strength
    ...or give a user or an owner password

Try the following to find out the detailed security settings of the file(s):

qpdf --show-encryption input.pdf
qpdf --show-encryption output.pdf

示例：

qpdf --decrypt crypted.pdf --password=myP@sswor!D uncrypted.pdf