# Tag Info

7

One option would be to get them to select a one-time MAC of the form: $mac(m,k_0, k_1) = (k_0 \times m + k_1) \mod p$ You would select $p$ to be something like 29. $k_0$ and $k_1$ would be chosen at random from the values 0-29. $k_0$ has the additional restriction that it can't be 0. You can aid the computation by giving them a 29x29 matrix of all ...

7

No, I think a general understanding of what a cipher, hash, signature, MAC and a few other of these concepts will make it much easier to understand what cryptography is about. It's like some knowledge about cars can be very helpful, even if you don't get to be a mechanic. Especially understanding a bit about certificates and PKI is pretty useful, as it is ...

5

Perhaps you could do something with Visual Cryptography. Maybe something like: Gather a few low-resolution images (symbols or short text phrases), perhaps a few more images than you have kids Use visual cryptography to split each image into 2 random-looking images, and print each random-looking image on its own piece of transparency paper Shuffle the pile ...

4

You could challenge them to devise low-tech, physical zero-knowledge proofs (of knowledge) for games like "Where's Waldo?" and Sudoku, then show them some methods that really work and why. I've done this before with high school CS students and they seemed to really like it. For "Where's Waldo?" one can prepare a large sheet of paper (at least twice as big ...

3

This is an opinion-based question to a large extent, but I hope it doesn't get flagged as off-topic, because it's really pertinent, specially in the context of the Meta question that Biv linked. I agree with Maarten's answer, but I want to add a bit, based on my own personal experience. Cryptography is a very deep subject, in the sense that very simple ...

1

15-18 is an age where kids are looking for independence and question authority of adults. Cryptography is often horribly implemented, and can serve as a teaching tool of where professionals have gone wrong. So pick some real world blunders, and do some analysis on those blunders. There's enough cryptographic blunders that are easy enough for HS students ...

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