Isn't P always the same? Or is it shared before the exchange?
Edit: just looked it up and the base point for curve25519 is x=9 so no point in recovering it.
Edit: just looked it up and the base point for curve25519 is x=9 so no point in recovering it.
In the early days of EC you were able to pick a custom base point, and then it was found that this could leak information in various ways. It’s not allowed in modern curves or implementations.