[loup-vaillant]

> By using libsodium, you're not rolling your own crypto.

That's debatable. Libsodium does not have a proper authenticated key exchange. The key exchange does the job somewhat, but it has worse security properties than a properly crafted interactive protocol.

Problem is, designing your own key exchange protocol is more delicate than most construction. I know, I designed my own, and made several serious mistakes in the process (one of which voided an important security property).

Granted, rolling your own constructions is generally less error prone than rolling your own primitive. But it still shouldn't be done without at least having followed and fully understood an introductory course in cryptography (I recommend https://www.crypto101.io/). I mean, I did quite a bit more than that, and I still don't fully trust myself.