Advanced Encryption Standard (AES-256) using Cipher Block Chaining (CBC) mode with cipher-text stealing. Write any sized text message (must be greater than 16 characters) into the decoded block. If message is less than 16 characters, just add spaces. Place your 256-bit hexadecimal key into the key block. Hit encode button to receive an encoded output in the encoded block. To decode, just reverse the process. Converts message input using UTF-8. You could use this with my Curve25519 elliptic curve cryptography file exchange. My curve25519 could generate a shared key which could be shared with someone over the internet. Once the other person's shared key is received, it could be used with your private key to generate the key need for AES encryption. The other person could also compute the same key using his private key and the shared key you provided to decode your message.