mul : XCurvesParameter n -> Vect n Bits8 -> Vect n Bits8 -> Maybe (Vect n Bits8)
derive_public_key : XCurvesParameter n -> Vect n Bits8 -> Maybe (Vect n Bits8)
x25519 : XCurvesParameter 32
x448 : XCurvesParameter 56