Hashing

Hashing↗ is a process that runs data, a file, a message, or a password, through a mathematical function to produce a fixed-length string of characters called a hash. The same input always produces the same hash, but even a tiny change to the input produces a completely different result, and the process can't be reversed to reveal the original data.

Hashing is widely used to verify that a file hasn't been tampered with and to store passwords securely, since a service can check a login attempt against a stored hash without ever keeping the actual password. Adding a random value called a salt to each password before hashing further strengthens this protection.