What is PDF Encryption?
Cryptographic protection that requires a password to open or modify a PDF — typically AES-128 or AES-256.
PDF encryption uses a user password (to open) and/or an owner password (to change permissions). Modern PDFs use AES-256; older RC4 encryption is considered weak. Encryption is separate from permissions — a file can be openable but have printing or editing blocked.
Also known as
- password-protected PDF
- encrypted PDF
Related terms
- PDF Permissions — Flags inside a PDF that limit actions like printing, copying, or editing — enforced by viewers, not cryptography.
- PDF Redaction — Permanently removing sensitive text or images from a PDF — not just covering them with a black box.
Category: Security