Private text encryption
Encrypt text with AES-256. Locally.
Write or paste a private note, then save an encrypted file. Your text and passphrase stay on this device — no account or upload.
Your text and passphrase stay on this device. Processing happens in this browser.
0 / 16 · 4 is a solid floor for everyday accounts; 6+ for the things that guard everything else. passphrase generator.
How to encrypt text privately
- Write or paste your text, then choose a clear file name.
- Create a unique passphrase and keep it separate from the encrypted file.
- Download the .sbx file. Open it later only with the same passphrase.
Compatible with Encrypt a file
This makes the same .sbx format as Encrypt a file, so either tool can open the result. It uses AES-256-GCM with PBKDF2-HMAC-SHA-256 (600,000 iterations), a random 16-byte salt and a random 12-byte nonce.
Keep the passphrase separate
There is no recovery if you lose it. Use a unique long passphrase from the passphrase generator; do not send it in the same message as the encrypted file. If you regularly protect IDs, photos and documents, see how to protect IDs and financial documents.
Questions people ask
Is my text uploaded when I encrypt it?
No. Browser cryptography creates and opens the encrypted file on your device. Sealby does not receive the text or passphrase.
Can I recover a lost passphrase?
No. That is the trade-off for private encryption. Keep your passphrase somewhere safe and separate.
Enjoying this free tool?
Sealby is our free app for iPhone and iPad. It encrypts your private photos, videos and files right on your device. No account, and nothing readable ever leaves it.
iPhone & iPad · iOS 17+ · Free