How can a computer make a random number?

Description:
A simple pseudorandom generator starts from a seed and follows a fixed rule. Watch this tiny example compute 7→4→5→10, replay the same sequence after a reset, and change its output when the seed changes.

The rule (5x+1) mod 16 is a deliberately predictable teaching toy. It is unsuitable for security. The separate final diagram shows why secure generators need suitable unpredictable input and cryptographic construction. Its noise wave is schematic, and the displayed public sample was obtained through an operating-system-backed secure API.

Sources:
NIST — Deterministic Random Bit Generators: https://csrc.nist.gov/pubs/sp/800/90/a/r1/final
NIST — Entropy Sources: https://csrc.nist.gov/pubs/sp/800/90/b/final
Python — Random: https://docs.python.org/3/library/random.html
Python — Secrets: https://docs.python.org/3/library/secrets.html

Original illustrative animation and synthetic narration created for Why It Runs. The opening is a stylized question graphic; its engagement counters are illustrative design elements.

#Shorts #Computers #RandomNumbers