Runs in your browser · nothing uploaded

Encrypt a File with a Password — Free & In-Browser

Password-protect any file before you email or share it. AES-256-GCM with a PBKDF2-derived key, performed locally by your browser — no upload, no signup. Free.

Loading tool…

More tools

All free, all private — everything runs in your browser.

FilesPro

Bulk File Encryptor

Batch-encrypt many files with a single password into one downloadable .sealbox archive, and restore them all at once. AES-256-GCM per file, performed locally — no upload. SealBox Pro.

Text

Text Encryptor

Turn any message into a shareable encrypted string and back. AES-256-GCM with PBKDF2 key derivation, performed locally by your browser. No upload, free.

TextPro

Encrypted Notes Vault

Keep private notes encrypted with a master password, stored only on your device. The master password derives an AES-256-GCM key and is never stored. 100% client-side. SealBox Pro.

Keys

AES Encryption Tool

Encrypt or decrypt with your own AES-128/256 key and IV in GCM or CBC mode. A raw, explicit bench for learning and development — runs entirely in your browser.

Keys

RSA Keypair Generator

Generate an RSA-OAEP keypair in your browser and export the public and private keys as PEM files. 2048, 3072, or 4096 bits. No upload, no server, free.

Keys

PBKDF2 Key Deriver

Derive a cryptographic key from a password with PBKDF2-HMAC-SHA256. Tunable iterations, random or custom salt, hex or base64 output. Runs in your browser.

How to use File Encryptor

  1. 1Pick the file you want to protect (it is read locally — nothing is uploaded).
  2. 2Enter a strong password. It is never stored or transmitted; if you forget it, the file cannot be recovered.
  3. 3Click Encrypt — your browser derives an AES-256 key with PBKDF2 and encrypts the file with AES-256-GCM.
  4. 4Acknowledge the unrecoverable-password warning and download the .sealbox encrypted file, then share it and the password through separate channels.
  5. 5To decrypt: pick the .sealbox file, enter the same password, and the original file is restored and downloaded.

File Encryptor FAQ

Is my file uploaded anywhere?
No. The file is read into your browser's memory, encrypted there with the Web Crypto API (AES-256-GCM), and written back out as a download. There is no server, no upload, and no network request — you can verify this in your browser's DevTools Network tab.
What happens if I forget the password?
Nothing can recover it — by design. The key is derived from your password with PBKDF2 and the ciphertext is authenticated with AES-GCM, so a wrong password simply fails to decrypt. There is no backdoor, reset link, or copy of your password anywhere. Store it safely before you share the encrypted file.
Which encryption is used?
AES-256-GCM, an authenticated cipher: it provides confidentiality and verifies integrity on decryption, so tampered files are rejected rather than silently decrypted to garbage. The 256-bit key is derived from your password with PBKDF2-SHA256 (600,000 iterations) and a random 16-byte salt; a fresh random 12-byte IV is used for every encryption.