Security tools here focus on protecting text and working with tokens. The Encrypt Text tool encrypts a message with AES-256-GCM using a passphrase you choose, and the Decrypt Text tool reverses it. Decryption is built for text encrypted with this site's tool, so use the pair together. The JWT Encoder signs a JSON Web Token with HS256 from your own payload and secret, which is useful for testing an API during development.
Both encryption and signing happen locally in your browser, so your text, passphrase and secret are not sent to a server. The strength of the result still depends on you. A short or guessable passphrase makes strong encryption easy to break, and there is no way to recover text if you forget it. Share the passphrase through a different channel than the encrypted message.
Related tools live in other categories. The Password Generator and Password Strength Checker are listed under Text Tools, and the JWT Decoder and Hash Generator are listed under Developer Tools. Use the JWT Encoder for testing only, and do not paste real production secrets into any web page unless you fully trust the environment.