#pragma once
@module key

(*  The same type is used as key for all symmetric cryptography. *)
(*  In practice this is a 256 bit random string. *)
(*  The empty key is derived from 0:nat or empty:bits. *)
(*  *)
(*  A constructors for key are deliberately omitted to ensure *)
(*  that keys must *always* be chosen usint `k <-R key`. *)

(* TODO: Capture that key reuse is forbidden. *)
#include "prelude/bits.mpv"
#include "crypto/setup.mpv"

type key.
const key0:key.
fun k2b(key) : bits [typeConverter].
letfun key_new() =
  new k:key;
  k.