Local File Encryptor & Decryptor
Last Updated: June 28, 2026
100% Client-Side Encryption
Your files and passwords never leave your browser. All cryptographic operations execute locally.
Drop your files here
or click to browse. Single or batch — any file type supported.
Local File Encryptor & Decryptor
Protect your files with AES-256-GCM encryption before uploading to the cloud. All encryption happens in your browser — files, passwords, and keys never leave your device.
Files (0)
No files added. Drop files above.
Operation
Password
Lost password = permanently lost data. FreeDeskTools cannot recover passwords.
If decryption fails, the password may be incorrect or the file may be corrupted.
Key Derivation
PBKDF2Progress
Reading file...Security Dashboard
Processing Report
Session Metrics
Privacy Audit & Trust Verification
All cryptographic operations execute locally in your browser using the Web Cryptography API. No files, passwords, keys, or metadata ever leave your device.
Secure file encryption and decryption tool. Uses AES-256-GCM with PBKDF2 key derivation. All cryptographic operations in your browser. No uploads, no servers, no data leaks.
How To Use
Follow these simple steps to get started with local file encryptor & decryptor.
Upload your file
Drag and drop any file or click to browse. File info and SHA-256 hash are displayed.
Choose operation
Select Encrypt to password-protect or Decrypt to unlock. Encrypted files auto-select decrypt mode.
Set password and options
Enter a strong password. Adjust PBKDF2 iterations. The strength meter guides you.
Download the result
Click Encrypt/Decrypt. The processed file downloads automatically with a full processing report.
Real-World Examples
Practical situations where local file encryptor & decryptor helps solve real problems.
Cloud Backup Privacy
Encrypt sensitive documents, financial records, and personal files before uploading to cloud storage services like Google Drive, Dropbox, or iCloud.
Secure File Sharing
Encrypt files with a strong password before sending via email, messaging apps, or file transfer services.
Local Data Protection
Password-protect sensitive files on your local machine. Only you can decrypt them with the correct password.
Why Use This Tool
Discover how this tool can improve your workflow and productivity.
AES-256-GCM Encryption
Industry-standard authenticated encryption using the Web Cryptography API. Your files are encrypted with AES-256 in Galois/Counter Mode, providing both confidentiality and integrity verification.
100% Browser Processing
All cryptographic operations execute locally in your browser. Files, passwords, and keys never leave your device.
PBKDF2 Key Derivation
Passwords are strengthened using PBKDF2 with SHA-256 and configurable iterations. Salt and IV are randomly generated for each encryption.
Self-Describing Format
Encrypted files use a custom container format with magic bytes and metadata. Auto-detection on re-upload selects decrypt mode.
Common Use Cases
Practical scenarios where this tool can help you get things done.
Cloud Backup Privacy
Encrypt sensitive documents, financial records, and personal files before uploading to cloud storage services like Google Drive, Dropbox, or iCloud.
Secure File Sharing
Encrypt files with a strong password before sending via email, messaging apps, or file transfer services.
Local Data Protection
Password-protect sensitive files on your local machine. Only you can decrypt them with the correct password.
Tool Summary
Quick facts about this tool at a glance.
What Is Local File Encryptor & Decryptor?
A Local File Encryptor & Decryptor is a browser-based encryption tool that protects files using AES-256-GCM authenticated encryption with PBKDF2 key derivation — processed locally in a Web Worker via the Web Cryptography API with zero uploads and a self-describing encrypted container format.
About This Tool
File Encryption and Privacy
File encryption transforms readable data into an unreadable format using a cryptographic algorithm and a secret key. Only someone with the correct key can decrypt the data back to its original form. This is fundamentally different from encoding (like Base64) which can be reversed without a key.
AES-256-GCM: The Gold Standard
AES (Advanced Encryption Standard) is the globally recognized encryption standard adopted by the U.S. government and used worldwide. With a 256-bit key, AES-256 provides the highest level of security. GCM (Galois/Counter Mode) adds authenticated encryption — it not only encrypts the data but also provides integrity verification so that tampering with the ciphertext is detected during decryption.
Why Browser-Based Encryption?
Most encryption tools require downloading and installing software, which can be inconvenient, platform-specific, and potentially compromised. Browser-based encryption via the Web Cryptography API offers several advantages: no installation, platform independence, transparent and auditable code execution, immediate updates, and zero cost.
PBKDF2: Protecting Against Brute Force
PBKDF2 (Password-Based Key Derivation Function 2) makes password cracking computationally expensive by repeatedly hashing the password hundreds of thousands of times. Each iteration adds real computational cost, making even modest passwords significantly harder to crack. The key derivation process uses a random 128-bit salt generated for every encryption, ensuring unique keys even for identical passwords.
The FDEncrypt Container Format
The custom binary format includes: magic bytes ('FDEncrypt'), version, KDF type, 16-byte random salt, 12-byte IV, 4-byte iteration count, filename, MIME type, original size, ciphertext payload, and 16-byte GCM authentication tag. This enables auto-detection on re-upload and correct restoration of the original file.
Use Cases
Journalist Protection: Encrypt source documents and sensitive communications. If a device is seized, encrypted files remain unreadable.
Healthcare Compliance: Encrypt patient records and PHI before emailing or storing in cloud services.
Remote Work Security: Encrypt company documents and proprietary data when using personal devices or public Wi-Fi.
Legal Document Protection: Encrypt client communications and case files to maintain confidentiality.
Quick Summary
Enterprise-grade file encryption entirely in the browser. Uses the Web Cryptography API with AES-256-GCM authenticated encryption and PBKDF2-SHA256 key derivation (100K-2M iterations). FDEncrypt container format with magic bytes, random 128-bit salt, random 96-bit IV, filename and MIME preservation, 128-bit GCM auth tag. Auto-detection of encrypted files. Password strength meter, confirm-match validation, 24-char random password generator, show/hide toggle, copy-to-clipboard. Security dashboard, processing report with JSON/CSV export, session metrics, localStorage preferences. SHA-256 hash computation. All operations in a Web Worker with Transferable objects.
Related Concepts
Explore related terms and topics associated with local file encryptor & decryptor.
Frequently Asked Questions
Common questions about local file encryptor & decryptor.
How do I encrypt a file in my browser?
Upload any file, select Encrypt mode, enter a strong password (min 8 characters), confirm it, adjust PBKDF2 iterations if desired, and click 'Encrypt & Download'. The encrypted file downloads automatically.
Is AES-256-GCM secure?
Yes. AES-256-GCM is the same encryption standard used by governments, banks, and security professionals worldwide. It provides authenticated encryption with integrity verification.
Are my files uploaded to any server?
No. All encryption, decryption, hashing, and key derivation happen entirely in your browser using the Web Cryptography API. Your files never leave your device.
Can I decrypt files encrypted by this tool?
Yes. Upload the .encrypted file and it auto-detects as an encrypted package. Enter the password and click 'Decrypt & Download' to recover the original file.
What happens if I lose my password?
The password cannot be recovered. If you lose it, the encrypted data is permanently inaccessible. Store passwords in a password manager.
What is PBKDF2 and why do iterations matter?
PBKDF2 strengthens your password by deriving an encryption key through repeated hashing. More iterations make brute-force attacks exponentially harder.
What is the encrypted file format?
The FDEncrypt format includes magic bytes, version, salt, IV, iterations, filename, MIME type, original size, ciphertext, and GCM authentication tag.
Can I encrypt any file type?
Yes. Any file type is supported — documents, images, videos, audio, archives, PDFs, spreadsheets, and more.
How are encryption keys managed?
Keys are derived from your password using PBKDF2 with a random salt. The derived key exists only in memory during the operation and is immediately released.
Is this tool free to use?
Yes. Completely free with no usage limits, no signup, and no hidden costs.
Does this tool work on mobile?
Yes. Works on all modern mobile browsers that support the Web Cryptography API.
What is the difference between encrypt and decrypt mode?
Encrypt mode converts any file into an encrypted .encrypted package. Decrypt mode reverses this process. Encrypted files are auto-detected on upload.
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Reviewed by FreeDeskTools Editorial Team
Local File Encryptor & Decryptor has been reviewed for accuracy, usability, privacy, and browser-side performance. FreeDeskTools tools are designed to run locally whenever possible, helping users complete tasks quickly without unnecessary data collection.
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