Hashing and hash functions
Functions mapping data to fixed-size hash values enabling fast lookup. Cryptographic hashes provide integrity verification. Collision resistance is essential property.
Formula
h(input) → fixed-length output
Real World
GitHub verifies every download by publishing SHA-256 hashes — if even one byte of a file is tampered with, the hash changes completely, alerting the user to a corrupted or malicious download.
Exam Focus
Name all three properties — deterministic, collision-resistant, and avalanche effect — and give a distinct example for each.
How well did you know this?