AES Text/Message Encryption & Decryption tool
Encrypt or decrypt text securely in your browser using AES-256 encryption. The Black Swan AES Encryptor keeps your data private – no uploads, no tracking, just local protection.
Text / Message Encryptor (AES-256)
Encrypt or decrypt text locally in your browser using AES-256. No data leaves your device.
salt:iv:ciphertext. Use the same key to decrypt. For safety, share the encrypted message and key via different channels.How this AES encryptor works
This tool lets you encrypt and decrypt text in your browser using AES-256.
Everything happens locally in your browser – nothing is uploaded or stored on the server.
To read an encrypted message, you need both the encrypted text and the exact same key / passphrase.
If the key is lost or mistyped, the original message cannot be recovered.
The encrypted output is shown in this format:
salt:iv:ciphertext
You’ll see that in the Output box after encryption.
Step-by-step: encrypting a message
Choose Encrypt mode
At the top, use the blue toggle and make sure
Encrypt is selected.Enter your message
In Your text, type or paste the message you want to protect.Set a secret key / passphrase
Under Secret key / passphrase you can:Type your own key or passphrase (ideally long and unique), or
Click Generate to create a random key.
Encrypt the text
Click Encrypt text.The encrypted value will appear in the Output box in the format
salt:iv:ciphertext.
Copy what you need
Click Copy Message to copy the encrypted string.
Click Copy Key to copy the key / passphrase.
Encrypt is selected.Step-by-step: decrypting a message
Choose Decrypt mode
Use the toggle to select Decrypt.Paste the encrypted message
In Your text, paste the full encrypted string you received.
It must include all three parts separated by colons:
salt:iv:ciphertext.
Enter the key / passphrase
Type or paste the original key into the Secret key / passphrase field.
It must match exactly – including capitals, spaces and symbols.
Decrypt the text
Click Decrypt text.
If the key and format are correct, the original message will appear in the Output box.
You can then click Copy Message if you want to copy the decrypted text.
Decrypt.Buttons and what they do
Encrypt text / Decrypt text
Runs the selected operation using the text and key fields.Generate
Creates a new random key and fills it into the key box.Copy Key
Copies the key / passphrase from the key field.
Useful for sharing the key via a separate channel or saving it securely.Copy Message
Copies whatever is currently shown in the Output box
(encrypted string in Encrypt mode, or decrypted text in Decrypt mode).Clear
Clears the text box, key field, output and any error message.
Sharing the encrypted text and key safely
To keep things secure:
Never send the encrypted message and the key in the same place.
If someone gets both, they can read the message.Use different channels:
Send the encrypted message by email, ticket, or document.
Share the key separately – for example by SMS, phone call, or a different secure app.
Use one-time keys for sensitive messages and avoid reusing passphrases you use elsewhere (e.g. email or banking).
Store keys carefully if you’ll need to decrypt later – a password manager is ideal.
Error messages and common issues
You might see:
“Enter text first” – You clicked Encrypt / Decrypt with an empty text box.
“Enter or generate a key” – The key field is empty.
“Invalid format (expected salt:iv:ciphertext)” – The encrypted text isn’t complete or has been altered – check both colons and that nothing has been cut off.
Other errors during decryption often mean:
The key is wrong, or
The encrypted string was changed (extra spaces, line breaks, missing characters).
If either of those happens, the tool won’t be able to recover the original message.