SealBox

Encrypt files & messages entirely in your browser

Password-protect a file before you email it, encrypt a message to a shareable string, work an explicit AES bench, generate RSA keypairs, and derive PBKDF2 keys — one free, private hub. Runs in your browser — your files and secrets never leave your device.

Runs in your browser · nothing uploaded
✓ No upload✓ No signup✓ AES-256-GCM✓ Works offline

File Encryption

Password-protect any file with AES-256-GCM before you share it.

Files

File Encryptor

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.

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 Encryption

Encrypt messages into shareable ciphertext strings and back.

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 & Derivation

A raw AES bench, RSA keypair generation with PEM export, and PBKDF2 derivation.

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.

Updated 17 August 2026

What is SealBox?

SealBox is an encrypt and decrypt tool. Keys stay on your device.

  • Encryption runs in your browser.
  • Your files and passwords stay on your computer.
  • You do not need an account.

How to use it

  1. Pick a tool from the list.
  2. Choose a file or paste text. Enter a password.
  3. Download the encrypted result. Encryption uses Web Crypto in your browser.

FAQ

What is SealBox?

SealBox is a free encrypt and decrypt hub. AES-256-GCM and RSA tools run in your browser.

Do you upload files I encrypt?

No. Encryption uses Web Crypto on your device. We do not receive the plaintext.

What if I forget the password?

The data cannot be recovered. There is no reset. Keep the password in a password manager.

Do I need an account?

No. Open a tool and start.

Does it work offline?

Yes, after the first load.