PDF Encrypt / Unlock
Set a password to open a PDF, or remove the restriction if you know the password. Based on open-source qpdf, no login required, completely free.
🔐
点击选择，或把 PDF 拖到这里
为 PDF 添加打开密码（AES-256）
FAQ
Can it crack a PDF without knowing the password?
No. Unlocking requires the correct password; this tool only removes restrictions and does not perform any cracking.
What encryption strength is used?
AES-256 encryption is used to set an open password for PDFs.
Is the password secure?
The file and password are only used for immediate server processing and are deleted right after, with no retention.
Explore more AI tools and products