`sig
val c : int
val m : int
val encrypt : string -> string -> string
val encrypt_mstrings :
string -> Netxdr_mstring.mstring list -> Netxdr_mstring.mstring list
val decrypt : string -> string -> string
val decrypt_mstrings :
string -> Netxdr_mstring.mstring list -> Netxdr_mstring.mstring list
val tests : (string * string * string) list
val run_tests : unit -> bool
val run_mtests : unit -> bool
end`