ELI5: how sha256 work

SHA-256 is like a magical kitchen blender that takes any piece of information, chops and mixes it up, and turns it into a unique, fixed-size digital fingerprint.

Imagine you have a magical blender and a recipe notebook:

• The Blender: You can drop anything into it—a single word, a picture of your dog, or a giant encyclopedia.
• The Smoothie: When you press the button, the blender chops, mixes, and mashes the ingredients through 64 precise steps. It always pours out a special smoothie that is exactly the same size, no matter how much you put in at the start. In the computer world, this smoothie is a unique code made of 64 letters and numbers called a hash.

• It is a one-way street: It is super easy to blend strawberries and bananas into a pink smoothie. However, it is completely impossible to look at the smoothie and turn it back into whole, fresh fruit. You cannot reverse the process to guess the original secret.
• The magic recipe never changes: If you put the exact same recipe into the blender tomorrow, you will get the exact same smoothie every single time.
• The butterfly effect: If you change just one tiny grain of sugar in your recipe, the entire smoothie turns a completely different color, like bright blue. If someone secretly changes even a single comma in a document, the final code completely changes, instantly revealing that someone messed with it.