Khan Academy: Journey Into Cryptography: Pseudorandom Number Generators

The perfect cipher

What is Cryptography? A story which takes us from Caesar to Claude Shannon.

Claude Shannon's idea of perfect secrecy: no amount of computational power can help improve your ability to break the one-time pad.

This video demonstrates how to evaluate an expression with two variables using substitution. [1:46]

How to understand & calculate probability visually.

Find out how does a codebreaker works?

Lear about the Caesar Cipher with this video.

Find out what is the difference between a coin flip and a blind guess.

An explanation of the first seven problems on the California Algebra I released test. [12:02]

This downloadable java simulation is an interactive linear congruent random number generator model. Students use paper and pencil to calculate the first few terms and then use the generator to check their calculations.