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Encrypt & Decrypt Text or Files
Lock text or a file with a password using AES encryption, and unlock it again.
Free tools that run in your browser. Nothing you type, open or create is uploaded to NerdBible or anyone else.
No file chosen.
Encryption uses AES-256-GCM through your browser's built in Web Crypto. The key is made from your password with PBKDF2 (SHA-256, 600,000 rounds) and a random salt, and every message gets a fresh random nonce, so encrypting the same text twice gives different results. GCM also detects any change to the encrypted text. There is no way to recover the content without the password: not here, and not anywhere else.
How to use it
- Enter a password. A long passphrase of four or more random words is strongest.
- For text, type or paste it and press Encrypt; copy the result, which starts with NBENC1:
- For a file, choose it and press Encrypt file to download a .nbenc copy.
- To read it again, use the same password with Decrypt or Decrypt file.
Questions
Is my text or file sent anywhere?
No. Everything is encrypted and decrypted by your browser on your device. The page works offline once it has loaded.
What if I forget the password?
The content is lost. The password is not stored anywhere and there is no back door, which is the point of encrypting it.
How do I send encrypted text to someone?
Send the encrypted text by one route, such as email, and the password by another, such as a phone call or a messaging app. Anyone with both can decrypt it on this page.
Is this compatible with other encryption tools?
The format is specific to this page: a version prefix, then the salt, nonce and AES-GCM ciphertext in base64. It uses standard algorithms, so it can be decrypted with any crypto library that knows the layout, but not by opening it in another app directly.
How strong is it?
AES-256-GCM is a current standard used by governments and banks. In practice the password is the weak point: a short or common password can be guessed, however strong the cipher.