I forgot the signatures. Those are done via Schnorr scalar math, similar to ECDSA but less computationally expensive and always produce a neat 64 byte long signature, on top of the 32 byte hash (ID) of the event, which is generated by normalizing its structure into a uniform, json array format with a first field being an integer 0 followed by a comma, and no whitespace except spaces inside the JSON strings (json standard).
There, that's the most concise version of the distinctive details of how Nostr cryptography works. It's the same as bitcoin Musig2 and Taproot signature algorithms, without the other complicated parts of those two protocols.
The only reason we didn't have schnorr signatures from the beginning of Bitcoin was because Schnorr patented it, and in response the government funded the development of ECDSA which is less efficient but not encumbered by patent claims. It took quite a long time for schnorr signatures to be added to bitcoin after the patent expired.