-type alg() ::
          #jose_jwe_alg_ecdh_es{epk :: undefined | {ec_public_key(), map()},
                                apu :: undefined | binary(),
                                apv :: undefined | binary(),
                                wrap :: undefined | aes_gcm_kw | aes_kw | c20p_kw | xc20p_kw,
                                bits :: undefined | 128 | 192 | 256,
                                iv :: undefined | binary(),
                                tag :: undefined | binary()}.

-type ec_public_key() ::
          {#'ECPoint'{point :: term()},
           {namedCurve, Oid :: tuple()} |
           #'ECParameters'{version :: term(),
                           fieldID :: term(),
                           curve :: term(),
                           base :: term(),
                           order :: term(),
                           cofactor :: term()}} |
          term().