This page is meant to be a digression from my "{Protocol} Illustrated" pages (linked at the top of the X25519 page).
In all three of those pages (TLS 1.2, TLS 1.3, and QUIC) I've had to explain key exchange, and even describing as succinctly as possible it still interrupted the flow of the article (especially in TLS 1.3 and QUIC where it's the first operation performed).
To avoid doing a disservice to the key exchange process I broke its explanation out into this interactive page that lets you do your own toy exchange on the Curve25519 curve.
In all three of those pages (TLS 1.2, TLS 1.3, and QUIC) I've had to explain key exchange, and even describing as succinctly as possible it still interrupted the flow of the article (especially in TLS 1.3 and QUIC where it's the first operation performed).
To avoid doing a disservice to the key exchange process I broke its explanation out into this interactive page that lets you do your own toy exchange on the Curve25519 curve.