Cryptography: The Science of Making and Breaking Codes

The video explores cryptography, starting with simple ciphers like the Caesar cipher and moving to more complex ones like the Vigenere cipher. It explains how frequency analysis can crack these codes and introduces the concept of one-time pad encryption as a truly secure method. The historical context of cryptography is discussed, including the Enigma machine used in WWII. The video concludes with modern encryption challenges in digital computing.

What is the main reason a Caesar cipher is easy to crack?

• It changes the alphabet randomly.

• It requires a computer to decode.

• It has only 25 possible shifts.

• It uses a complex key.

Which technique is used to decode messages by analyzing common patterns in a language?

• Brute force

• Frequency analysis

• Key swapping

• Random scrambling

In a Vigenere cipher, how is the alphabet scrambled?

• It is scrambled randomly for each letter.

• It changes based on a keyword.

• It remains the same throughout the message.

• It uses a fixed shift for all letters.

What is a key feature of a one-time pad encryption?

• The key is shorter than the message.

• The key is reused for multiple messages.

• The key is as long as the message.

• The key is based on a simple shift.

Why was the Enigma machine considered secure initially?

• It was only used by the German military.

• It used a monoalphabetic cipher.

• It required a physical key to operate.

• It scrambled the alphabet differently for each letter.

What was a major flaw in the Enigma machine's encryption?

• It could encode a letter as itself.

• It used a fixed key for all messages.

• It was too complex to operate.

• No letter could be encoded as itself.

How did Alan Turing's team manage to crack the Enigma code?

• By using a one-time pad.

• By using a more advanced Enigma machine.

• By analyzing repeated patterns and cribs.

• By intercepting the German key.