Use raw ballots for hashing

src/web/common.ml

@@ -93,7 +93,7 @@ let load_elections_and_votes dirname =
             Lwt_stream.map (fun x ->
               let v = Serializable_compat_j.ballot_of_string Serializable_builtin_j.read_number x in
               assert (Uuidm.equal uuid v.election_uuid);
-              v
+              x, v
             )
           ) else Lwt_stream.from_direct (fun () -> None)
         in
@@ -102,37 +102,3 @@ let load_elections_and_votes dirname =
       | None -> assert false
     ) else Lwt.return None
   )
-
-let concat s l f = String.concat s (List.map f (Array.to_list l))
-
-let hash_ballot v =
-  concat "//" v.answers (fun a ->
-    concat "|" a.choices (fun c ->
-      Printf.sprintf "%s,%s" (Z.to_string c.alpha) (Z.to_string c.beta)
-    ) ^
-    "#" ^
-    concat "|" a.individual_proofs (fun p ->
-      concat "/" p (fun pi ->
-        Printf.sprintf "%a,%a,%a,%a"
-          Z.sprint pi.dp_commitment.a
-          Z.sprint pi.dp_commitment.b
-          Z.sprint pi.dp_challenge
-          Z.sprint pi.dp_response
-      )
-    ) ^
-    "#" ^
-    concat "/" a.overall_proof (fun pi ->
-      Printf.sprintf "%a,%a,%a,%a"
-        Z.sprint pi.dp_commitment.a
-        Z.sprint pi.dp_commitment.b
-        Z.sprint pi.dp_challenge
-        Z.sprint pi.dp_response
-    )
-  ) ^
-  "#" ^ v.election_hash ^
-  "#" ^ (Uuidm.to_string v.election_uuid) |>
-  hashB
-
-let hash_user v =
-  Serializable_compat_j.string_of_user v |>
-  hashB

src/web/common.mli

@@ -7,8 +7,7 @@ type election_data = {
   public_data : Z.t election_public_data;
 }
 
-val load_elections_and_votes :
-  string -> (election_data * Z.t ballot Lwt_stream.t) Lwt_stream.t
+val hashB : string -> string
 
-val hash_ballot : Z.t ballot -> string
-val hash_user : user -> string
+val load_elections_and_votes :
+  string -> (election_data * (string * Z.t ballot) Lwt_stream.t) Lwt_stream.t

src/web/registration.ml

@@ -32,8 +32,8 @@ let () =
         lwt () = Ocsipersist.add elections_table uuid e in
         let uuid_underscored = String.map (function '-' -> '_' | c -> c) uuid in
         let table = Ocsipersist.open_table ("ballots_" ^ uuid_underscored) in
-        lwt () = Lwt_stream.iter_s (fun v ->
-          Ocsipersist.add table (Common.hash_ballot v) v
+        lwt () = Lwt_stream.iter_s (fun (r, v) ->
+          Ocsipersist.add table (Common.hashB r) v
         ) ballots in
         return ()
       ) |>
@@ -193,7 +193,7 @@ let () = Eliom_registration.Html5.register
            if
              Uuidm.equal uuid ballot.election_uuid &&
              E.check_ballot (Serializable_compat.ballot ballot)
-           then `Valid (Common.hash_ballot ballot)
+           then `Valid (Common.hashB raw_ballot)
            else `Invalid
          with e -> `Malformed
        in