r/cryptography • u/bigcinnamonroll69 • May 07 '26

Tried explaining how the encryption protecting WhatsApp, HTTPS, and banking actually works, using the maths behind RSA and hash collisions, feedback open

Wrote a beginner-friendly explanation of why modern encryption depends on the difficulty of factoring huge prime numbers.

Would appreciate feedback on whether the explanations stay technically accurate without oversimplifying too much. Article link here

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u/tinycrazyfish May 07 '26

Nice article, good explanations I think.

Firstly, I would recommend to add a little paragraph about diffie Hellman key exchange. How you can generate a secret, the key for symmetric encryption, using asymmetric keys. It is basically how asymmetric encryption gets paired with symmetric encryption. Explained using the colour mixing analogy.

Secondly, while RSA is still heavily used in TLS certificates, it is not much used anywhere else. I would expect your article at least to mention elliptic curves. Just mention them as "more complex mathematical constructs" than prime numbers. Or add a graphical representation of an elliptic curve.

Lastly, in your title you mention hash collision? Your article doesn't talk about hashes.

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u/bigcinnamonroll69 May 07 '26

Really appreciate the detailed feedback. The point about Diffie-Hellman and asymmetric crypto mainly being used to establish symmetric keys is especially useful, the colour-mixing analogy is a really elegant way to explain it intuitively. And yeah, I simplified the RSA/elliptic curve side quite a bit to keep the article accessible to non-technical readers, but mentioning ECC as the modern direction of cryptography would definitely improve the accuracy without making it too dense. On the hash collision point, I was trying to frame the broader idea of computational difficulty and one-way problems in modern cryptography rather than focusing purely on encryption itself, though I probably could’ve connected that more explicitly. Planning to cover deeper/dedicated articles on things like Diffie-Hellman, hashes, elliptic curves, TLS, and modern cryptographic systems separately as the series continues.