lock and unlock pdf - pdfsmith

Secure your documents with confidence using PDFSmith, a fast and privacy-first PDF security tool that lets you lock PDFs, unlock PDFs, add passwords, remove password protection, and change PDF passwords — all fully offline on your device.

No uploads. No cloud processing. Your files never leave your phone.

Unlock Password-Protected PDFs

Remove password protection from PDFs when you know the correct password

Instantly unlock PDFs for viewing, editing, or sharing

Password is required — PDFSmith does not bypass or crack encryption

Lock PDFs with a Password

Add a password to unprotected PDF files

Secure sensitive documents before sharing

Protect PDFs instantly with strong encryption


Fast, Offline & On-Device

100% offline PDF processing

No internet connection required

Instant results with no waiting


Privacy-First by Design

Files are processed entirely on your device

No uploads to servers

No data collection or tracking


Save & Share Easily

Save locked or unlocked PDFs instantly

Share securely using your device’s share options


Perfect For

Professionals handling confidential documents

Students and educators

Travelers and offline environments

Anyone who values privacy and control


Key Features

Lock PDF with password

Unlock PDF with password

Add password to PDF

Remove password from PDF (password required)

Offline PDF security

On-device PDF processing

PDFSmith delivers professional-grade PDF security — fast, private, and completely under your control.