Hash

A mathematical operation known as a hash transforms an input of any length into an encrypted output of a certain length. Therefore, its unique hash will always be the same size regardless of the original quantity of data or file size involved.

Since hash functions are “one-way” (like a meat grinder; you can’t put the ground beef back into a steak), they cannot be used to “reverse-engineer” the input from the hashed output. However, if you apply the same function to the same data, the hash will be the same, allowing you to verify that the data is the same—and hence, undamaged—provided you already know the hash.