The Science of Codes: An Intro to Cryptography  Summary and Q&A
TL;DR
Encryption is the process of encoding information using a cipher and a key, but no code is truly unbreakable due to the use of rules. Frequency analysis and brute force techniques can often crack codes, while more sophisticated methods like the Vigenere cipher require longer texts for analysis. The Enigma machine used during World War II was eventually cracked by Alan Turing and his team through the use of cribs and finding patterns in the encrypted messages.
Questions & Answers
Q: What are the two main parts needed to encrypt a message?
The two main parts needed to encrypt a message are the cipher (rules for encoding) and the key (instructions to arrange those rules).
Q: How can codes be cracked using frequency analysis?
Frequency analysis involves looking for common words and letters in a message. By identifying patterns and matching them to known words, the code can be deciphered.
Q: What is the Vigenere cipher and how does it work?
The Vigenere cipher is a polyalphabetic cipher where the way the alphabet is scrambled changes throughout the message. It requires a key, and each letter of the message is encrypted using different scrambled alphabets based on the key.
Q: How did Alan Turing and his team crack the Enigma machine?
Alan Turing and his team cracked the Enigma machine by looking for common words and phrases (cribs) and analyzing the patterns in the encrypted messages. They used these clues to determine how the Enigma rotors were set up to encrypt the messages.
Summary & Key Takeaways

Encryption involves using a cipher and a key to encode information, but no code is truly unbreakable.

Different techniques like frequency analysis and brute force can often crack codes, with longer texts providing more clues.

The Vigenere cipher is a more sophisticated form of encryption that requires longer texts and can still be cracked using frequency analysis.

The Enigma machine used during World War II was eventually cracked by Alan Turing and his team using cribs and finding patterns in the encrypted messages.