Add a password so a reader has to type it before the PDF opens. The file is uploaded, and the server encrypts it with AES-256 using that same string for both the reader and the owner.
The password is required. It must be at least 4 characters and at most 128. You type it once for this tool, and that one string is what encryptPDF stores for the user password and the owner password. The page asks for the open password. The reader types that password to open the file.
This is a server tool, so the PDF leaves the browser for encryption and comes back locked. Free uploads allow 12 MB and eight a day. Pro raises the cap to 100 MB. The privacy policy says uploads and outputs are deleted after processing, typically within one hour and no later than 24 hours. Keep the password somewhere you will remember, because the locked file expects that same string.
Protect PDF Cluster
Add Password to PDF: a file that asks before it opens
Upload a PDF and set a password the reader must type before it opens. The server encrypts the file with AES-256.
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One password that opens the PDF
The server writes the password you choose as both the user password and the owner password. The reader types it to open the file.
A password the reader types to open the file
You set one required password, from 4 to 128 characters. The server applies it with AES-256 and uses that same string for the user password and the owner password. Someone who receives the PDF types it to open the file. Remember the string, because the download expects it.
Uploaded, then encrypted on the server
Adding a password is a server job. The PDF is uploaded, encrypted, and returned. Free files can be up to 12 MB, eight times a day. Pro raises the cap to 100 MB. The privacy policy says uploads and outputs are deleted after processing, typically within one hour and no later than 24 hours.
The lock is the open password
The control on this page is the password required to open the PDF. You are setting that open password, shared by the reader and the owner entry. Keep a copy of the wording in your own notes. After the download, test it once by opening the file and typing the password.
How it works
- 1
Upload the PDF
This page encrypts on the server, so the file is uploaded. Free runs allow 12 MB and eight a day. Pro allows 100 MB. Use a PDF you are allowed to lock, and keep your own unlocked copy.
- 2
Enter a password
The password is required, at least 4 characters and at most 128. That same string becomes the user password and the owner password under AES-256. Store it somewhere you can find later.
- 3
Download and try the lock
Open the downloaded PDF and type the password. The reader must type it to open the file. The privacy policy covers deletion after processing, typically within one hour and no later than 24 hours.
Use cases
A report you send to one person
Lock the PDF with a password you share through a separate channel. The reader types it to open the file. AES-256 uses that same string for reader and owner.
A draft you want closed until review
Upload the draft, set a password of 4 to 128 characters, and download the locked copy. Test the open step before you send it. Keep the unlocked original on your side.
A form that should stay closed in email
A password on the PDF means the attachment stays closed until the reader types it. Free files are up to 12 MB, eight a day. Pro files can be up to 100 MB.
Problems we solve
The password was rejected as too short
Use at least 4 characters and at most 128. The field is required. The same string is written for the user password and the owner password, so one password is the whole lock.
I need the file to open only for the right person
Share the password apart from the PDF. The reader types it to open the file. The server applied AES-256 with that string. Test the download once before you send it.
Related guide
Trust & privacy
AES-256 with one shared password string
The server encrypts the uploaded PDF and stores the same password for the user and the owner. Length is 4 to 128 characters, and the password is required. The reader types it to open the file.
Server limits and the privacy policy
Free protection allows 12 MB and eight runs a day. Pro raises the cap to 100 MB. The privacy policy says uploads and outputs are deleted after processing, typically within one hour and no later than 24 hours.