AES‑256‑GCM online

How does the AES‑256‑GCM work?

What is this method?

Modern authenticated encryption with a key derived from your password. It detects a wrong password and any message modification.

How does it work step by step?

The password derives a 256-bit key, while a random salt and IV make every encryption unique. GCM encrypts and creates an authentication tag that detects modified data or an incorrect password.

Example and practical use

Enter a message and a strong password. Every encryption creates a fresh salt and IV, so the same text can produce a different valid ciphertext.

How to use the tool

Choose encryption or decryption, enter a message and set the parameters required by the AES‑256‑GCM. The result is calculated locally in your browser and can be copied or shared without sending the text to a server.

History of the cipher

AES was selected through a competition run by the US NIST and became a standard in 2001. GCM was developed later to combine encryption with detection of modified data.

Security and limitations

AES-256-GCM is modern authenticated encryption, but security also depends on a strong password and a safe way to give it to the recipient. Rebusownia does not store the password and never includes it in shared content.