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(*                                BELENIOS                                *)
(*                                                                        *)
(*  Copyright © 2012-2021 Inria                                           *)
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(*  This program is free software: you can redistribute it and/or modify  *)
(*  it under the terms of the GNU Affero General Public License as        *)
(*  published by the Free Software Foundation, either version 3 of the    *)
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(*  WITHOUT ANY WARRANTY; without even the implied warranty of            *)
(*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     *)
(*  Affero General Public License for more details.                       *)
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(*  You should have received a copy of the GNU Affero General Public      *)
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(*  <http://www.gnu.org/licenses/>.                                       *)
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(** Returns a challenge string, used to identify the captcha in
   following functions. *)
val create_captcha : unit -> string Lwt.t

(** Returns the image associated to a challenge. *)
val get_captcha : challenge:string -> (string * string) Lwt.t

val check_captcha : challenge:string -> response:string -> bool Lwt.t

module Make (Web_services : Web_services_sig.S) : sig end
