PDF Encrypt

📖 Tool Introduction

PDF Encrypt puts an open password on a document. Once encrypted, any reader will prompt for the password before showing content, and a wrong password means no access at all. That makes it suitable for sending contracts, quotations or identity documents over email, cloud drives or chat apps.

The tool implements the standard security handler defined by the PDF specification, using the V4 / R4 / AES-128 combination: every string and every content stream in the file is encrypted with AES-128-CBC, and each object gets its own derived key. This is the most widely compatible encryption level today, recognised by Acrobat, the built-in readers in Chrome and Edge, Preview, and mobile PDF apps.

You can set an open password and an owner password separately. The open password is required to view the file. The owner password governs later changes to the permission flags; leave it blank and it falls back to the open password. For most people, filling in just the open password is enough.

Encryption happens locally in your browser. Neither the PDF nor the password is uploaded, and nothing is written to local storage. The flip side is that there is no recovery path whatsoever: forget the password and the file cannot be restored.

The permission flags are left fully open, so whoever knows the password can still print, copy text and add comments. If your goal is to stop recipients from editing rather than from reading, use the permission workflow in your PDF editor instead, because this tool deliberately protects access and nothing else.

✨ Key Features

• Standard encryption: V4 / R4 / AES-128 as defined by the PDF specification, readable everywhere
• Real content encryption: every string and content stream is encrypted, not merely a prompt bolted on top
• Two passwords: open password and optional owner password, the latter defaulting to the former
• Batch processing: apply one password to several PDFs at once, each exported and downloadable separately
• Fully local: the file and the password stay in browser memory, never uploaded or written to disk
• Permissions intact: printing, copying and annotating stay allowed; only opening is restricted

🚀 How to Use

1. Pick PDFs in the upload area on the left or drag them in; several files at once is fine
2. Enter the open password on the right; the owner password may stay blank
3. Press start and wait for the progress bar to fill
4. Check how many files were encrypted in the result area, then download them
5. Open a downloaded file in your reader once to confirm that a password is now required

⚠️ Things to Note

• No password recovery: The password is stored nowhere and cannot be recovered, so make sure you remember it before encrypting
• Owner password default: Leaving the owner password blank makes it the same as the open password
• Encrypted files must be decrypted first: An already encrypted PDF must be decrypted before it can be encrypted again
• Opening only: This tool restricts opening only; it does not separately block printing or copying
• Restricted or damaged files may fail: Restricted or damaged PDFs may fail to encrypt, and failures are reported by file name