11:11

Crack The Code! Substitution Ciphers

12:09

Secret Codes: A History of Cryptography (Part 1)

7:27

Judith Wolfe - Pros and Cons of Dualism

7:29

Caesar Cipher Code Wheel Activity (Encrypt and Decrypt Secret Messages)

19:18

Playfair Cipher

8:15

How the "Unbreakable" Vigenere Cipher Was Broken

33:05

Let's Crack Zodiac #23 - Dr Garlick's solution

28:28

Russell's Paradox - a simple explanation of a profound problem