For the man who uses PDF documents would have encountered that some PDF files are locked, which means, they cannot be copied, printed or even opened. And the reason is what I want to talk about today: about PDF password.
Generally speaking, there are two types of pdf passwords to PDF files. One is open password and the other is user password. The two kinds of protection are used for different situations: the former prevents people from viewing documents while the latter makes copying and printing unavailable.
Also known as open password. If you were familiar with this kind of password, it is possible to unlock PDF file quickly. Or if not, things would become complicated, as there is no easy way to rip PDF password. Many PDF apps which claim have to use some universal methods such as Brute Force Attack and Dictionary Search, but you have to bear the unbearably slow speed. Imagine it, your computer runs for a whole day to remove user password. What a time-wasting work. That's terrible, isn't it?
Usually, we need to ask the publisher for the open password to unlock it. However, sometimes, it is impossible, because we could not find the author message. Of course, PDF Password Recovery can manage it. You need to make it legitimate previously.
It is a sort of PDF restriction rather than a type of password. Many people use it out of consideration of copyright. They want to their work retained as what they were in the beginning. Or they hate copycats. However, people who are authorized may still face such a problem. Fortunately, you can find many PDF Password Crackers are made to crack owner password and they really work very well.
There is much software available for owner password. The most common used is PDF Password Remover, which would make restricted PDF documents unrestricted quickly.
In conclusion, these two kinds of PDF password are both useful for copyright protection. You can use any one of them to requirements. And you can set both open password and user password to the same PDF document.