Can the PDF set password be cracked?

2024-04-08 13:48:51

Firstly, let's take a look at a real case: you used to set a password for a PDF document, but it was not recorded at the time, or was it automatically thrown into the resource recycling bin in your memory over time. Now, when you open it, you can only stare at the "Please enter password" dialog box? At this point, the first solution that many people think of is to search for free tools to remove passwords online, and then

Wait a minute! Have you ever thought that if a thoughtful person gets your file today, wants to access the PDF content, or even does something detrimental to you, is that okay? Of course, websites that provide password removal tools will not care so much, after all, their role is just a tool, and why the user's motivation is not the focus; That is to say, this is a question we should consider: What are we using passwords to protect PDFs for? If someone who doesn't know the password can easily crack it, is setting a password still meaningful?

Technical analysis and suggestions

Leaving aside the above topics, based on our experience as a veteran PDF developer, we can provide some useful information from a technical perspective. The first thing you need to know is that password removal tools on the internet all have "guessing password" programs behind them - if the length of the password is short and the structure is simple, such as 1111 or ABCD, it will increase the likelihood of being cracked; However, as (1) the length and complexity of the password, and (2) the number of encrypted bits increases, these simple password guessing programs become powerless unless you are willing to wait for ten thousand years (laughs).

That is to say, if you set a complex password, which means "you still need a ringmaster to unlock the ringmaster," there is no one else in the world who can help you, and there is no way to reset it, because this is the original intention of setting a password, isn't it? Instead of blaming the design of PDF for not allowing you to remove your password, it's better to blame yourself for not developing the habit of keeping records.

According to ISO public standards, PDF passwords are divided into two types: "open password" and "permission password": the open password requires you to enter a password to open the document; Permission passwords allow anyone to freely open documents, but they also restrict certain operations on PDFs, such as printing, editing, and page adjustments. Opening a password is a simple function that is supported by most PDF software and websites that provide PDF services, but the permission password is more complex and usually requires downloading specialized software to obtain it.

Here are our suggestions:

To prevent password cracking, please set passwords with complex structures and long lengths.

2. Remember to record your password somewhere when setting it, so that no one can really save you if you forget it (it is recommended to use password management tools).

3. If you really need to remove the password, please avoid using it for unknown free websites, and also pay attention to whether the website has SSL protection and clauses that explain the rights and obligations of both parties. Otherwise, the files you upload may one day be put on the dark web for public or auction.

If you forget your password and need to recover it, you can use our document password recovery master for recovery or we can help you test whether your password is secure enough  /en