Definition string_of_list_byte (s : list byte) : string
  := string_of_list_ascii (List.map ascii_of_byte s).Definition list_byte_of_string (s : string) : list byte
  := List.map byte_of_ascii (list_ascii_of_string s).

Lemma string_of_list_byte_of_string s : string_of_list_byte (list_byte_of_string s) = s.