yongrenjie
commented
1 year ago Working on the cryptography branch.
Scribbles from the existing HackMD
- Thursday section (ca 1.5 hrs): Symmetric, substitution ciphers
- Monoalphabetic substitution cipher (i.e. Caesar cipher)
- Polyalphabetic substitution cipher (i.e. Vigenère cipher)
- Character and n-gram frequency analysis
- A link to information theory / entropy https://ep.liu.se/ecp/158/013/ecp19158013.pdf
- In popular culture: Sherlock Holmes — The Adventure of the Dancing Men, or the Zodiac Killer's letters
- Enigma machine (connection to Bletchley Park is obviously a positive). I think the full version is too complicated — I've never been able to wrap my head around it and it would definitely need to be simplified
- It might be worth discussing cribs, though (and these are relevant to the substitution ciphers above as well)
- The final activity could be some kind of escape room-like question, or maybe some kind of crime solving question. Maybe adapt Cluedo by replacing actual clues with encrypted text that leads you to the answer in fewer steps, but needs more effort to crack.
- Friday section (ca 1.5 hrs): Modern asymmetric encryption
- RSA
- This gets us into number theory (specifically modular arithmetic, Euclid's algorithm, Chinese remainder theorem)
- (Brief mention of quantum computing, Shor's algorithm? There's a definite bias here because this is close to my PhD work)
- Generally, I'm thinking of some kind of game where two people try to pass messages between each other and the rest try to crack it.
- My initial thought was to adapt Taboo: ordinarily you can't use the five forbidden words, but if you encrypt your message you can try to cheat (e.g. by passing a message like 'THE WORD IS X'), and the 'opposing' team can try to detect cheating by racing to crack the encryption.
- Obviously, we won't be using full 4096-bit RSA for this, we'll be using teensy-tiny prime numbers. I kind of expect that at the beginning the encryption team will win out, and as the decryption people get better they will start to win.
I'm thinking approx. 45 mins to 1 hr for the 'teaching' sections and 30 to 45 mins for the 'game' sections on both days.
It would be nice to give the kids ways to make visualisations which they can add into their final presentation.
Some nice resources:
- Five Ways to Crack a Vigenere Cipher With accompanying code.
- Cryptography As a Teaching Tool This article is very nice and has some concrete ideas.
- GCHQ's Turing challenge: https://www.gchq.gov.uk/information/turing-challenge
KatrionaGoldmann
Write a 1-2 pager describing the proposal for the cryptography challenge, see #1