Can the PDF set password be cracked?

First, let's look at a real-world example: You previously set a password for a PDF document, but you didn't record it at the time, or it was automatically thrown into the recycle bin in your memory over time. Now that you open it, you can only stare at the "Please enter password" dialog box? At this point, many people's first solution is to search for free password removal tools online, and then wait a minute! Have you ever considered that if someone with ulterior motives got hold of your file today, wanted to obtain the PDF content, or even did something detrimental to you, would that be okay? Of course, websites that provide password removal tools don't care about that; after all, their role is just as a tool, and the user's motivation isn't the key point. In other words, this is a question we should consider: Why do we use passwords to protect PDFs? If someone who doesn't know the password can easily crack it, is there any point in setting a password?

Technical Analysis and Suggestions

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

In other words, if you set a complex unlocking password, that is, "the one who tied the knot must untie it," no one in the world can help you except you, and there is no way to reset it, because that is the original intention of setting a password, isn't it? Instead of blaming the PDF design for not allowing you to remove your password, 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": open password requires you to enter a password to open the document; The permission password allows anyone to freely open the document, but it restricts certain operations on the PDF, such as printing, editing, and page adjustments. Unlocking a password is a simple function, supported by most PDF software and websites that provide PDF services. However, permission passwords are more complex and usually require downloading specialized software.

Here are our suggestions:

1. To prevent your password from being cracked, please set a password with a complex structure and a long length.

2. Remember to write down your password somewhere when you set it, so that no one can save you if you forget it (a password management tool is recommended).

3. If you really need to remove your password, please avoid using free websites of unknown origin. Also, pay attention to whether the website has SSL protection and clauses explaining the rights and obligations of both parties. Otherwise, the files you upload may be published or auctioned on the dark web one day.

If you have forgotten your password and need to retrieve it, you can use our Document Password Recovery Master to recover it.  You can also use us to test whether your password is secure enough.