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Unlock PDF - PDF Unlocker - How to remove password from PDF

Encrypt and decrypt PDF files with password protection using AES-256 encryption. Lock your sensitive documents or unlock previously protected PDFs instantly in your browser.

AES-256 Encryption Password Protect Free & Secure

Key Features

Strong AES-256 Encryption

Lock your PDFs with industry-standard AES-256 encryption in CBC mode. Your documents are protected with PBKDF2 key derivation and random salt for maximum security.

Instant Unlocking

Unlock previously encrypted PDFs instantly with the correct password. Automatic detection shows which files are locked or unlocked with clear status badges.

Bulk Processing

Lock or unlock multiple PDFs at once with the same password. Use "Lock All" or "Unlock All" buttons to process all files simultaneously.

Complete Privacy

Locked files cannot be opened in any PDF viewer - not Adobe Reader, not browsers, not mobile apps. Only this website can decrypt and unlock them.

Bulk ZIP Download

Download all processed PDFs as a single ZIP file. Perfect for batch operations - lock multiple files and download them in one compressed package.

Automatic Status Detection

Each PDF card shows a clear lock/unlock status badge. Locked files display a lock icon, unlocked files show an unlock icon for instant visual identification.

How to Lock & Unlock PDFs

1
Upload PDFs

Upload up to 5 PDF files by dragging & dropping or browsing. Each file can be up to 25MB. Locked files are automatically detected.

2
Choose Action

Click the lock or unlock button on each PDF card, or use "Lock All" / "Unlock All" to process all files with the same password.

3
Enter Password

Enter a strong password for locking or the existing password for unlocking. Remember: locked files only work on this site.

4
Download & Return to Unlock

Download your locked PDFs. When you need to access them, return to this website to unlock them with your password.

Why Choose Our PDF Lock & Unlock Tool?

  • No Registration Required - Start protecting PDFs immediately
  • AES-256 Encryption - Industry-standard military-grade protection
  • PBKDF2 Key Derivation - Secure password-based key generation
  • Random Salt & IV - Unique random values for each encryption
  • 100% Browser-Based - Files and passwords never leave your device
  • Bulk Operations - Lock or unlock all PDFs with one password
  • Auto-Detection - Instantly identifies locked vs unlocked files
  • ZIP Download - Download all processed PDFs in one file

Frequently Asked Questions

Our tool uses AES-256 encryption in CBC mode with PKCS7 padding. A random 16-byte salt and 16-byte IV are generated for each file. The encryption key is derived from your password using PBKDF2 with SHA-256 and 1000 iterations. The encrypted file includes a PDFE magic header for detection.

Return to this website and upload the locked PDF. Click the unlock button and enter the password that was used to lock it. The tool automatically detects encrypted files and shows a lock icon. If the password is incorrect, you'll get an error message.

No. Locked PDFs cannot be opened in Adobe Reader, Google Chrome, Microsoft Edge, Preview (Mac), mobile apps, or any other PDF viewer. They will appear as corrupted or unreadable files. You must return to this website to unlock them. This is by design - it ensures maximum security and prevents unauthorized access.

Yes! Your password is never stored, transmitted, or logged anywhere. All encryption and decryption happens entirely in your browser. The password is only used temporarily in memory to derive the encryption key and is cleared after processing.

Yes! Use the "Lock All" button to apply the same password to all unlocked PDFs. Or use "Unlock All" to unlock all locked PDFs with the same password. Each file gets its own unique salt and IV for security.

The tool automatically detects locked files. Locked files show a red lock badge, unlocked files show a green badge. If you try to open a locked file outside this site, it will appear corrupted and won't display any content.

There is no way to recover a forgotten password. The encryption is designed to be secure - without the correct password, the PDF cannot be decrypted. We strongly recommend storing passwords in a password manager and keeping backups of important unencrypted documents.

Yes! Our PDF Lock & Unlock tool is fully responsive and works on all devices - desktop, tablet, and mobile. Lock and unlock your PDFs on the go!

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