Concept · short entry

Hash

A fixed-length value, called a digest, computed from input. A cryptographic hash is designed to make recovering input from a digest impractical; guesses can still be tested.

Taught in

Encoding, hashing, and encryption 07 · Security
Identifying a hash 10 · Crypto and files

Also in

How to recognize an encoding 04 · Code
Passwords, hashes, and dumps 07 · Security
What a password cracker does 10 · Crypto and files

This is a short entry. The lessons above are where the idea is taught with evidence and checks.