Block cipher

A block cipher is a type of encryption method that takes a plaintext message (i.e. the message you want to encrypt) and scrambles it in a way that only you can understand. Think of it like a secret code that only you and the person you're sending the message to can understand. To make it work, the plaintext message is broken up into chunks called blocks. Then, a special key is used to scramble each block in a different way. Finally, all the blocks are put back together to make one secret message. It's like making a puzzle where the original picture is hidden until you put all the pieces together.