Source file nonce_storage.ml

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(* Open Source License                                                       *)
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type t = Seed_repr.nonce

type nonce = t

let encoding = Seed_repr.nonce_encoding

type error +=
  | Too_late_revelation
  | Too_early_revelation
  | Already_revealed_nonce
  | Inconsistent_nonce

let () =
  register_error_kind
    `Branch
    ~id:"nonce.too_late_revelation"
    ~title:"Too late nonce revelation"
    ~description:"Nonce revelation happens too late"
    ~pp:(fun ppf () ->
      Format.fprintf ppf "This nonce cannot be revealed anymore.")
    Data_encoding.unit
    (function Too_late_revelation -> Some () | _ -> None)
    (fun () -> Too_late_revelation) ;
  register_error_kind
    `Temporary
    ~id:"nonce.too_early_revelation"
    ~title:"Too early nonce revelation"
    ~description:"Nonce revelation happens before cycle end"
    ~pp:(fun ppf () ->
      Format.fprintf ppf "This nonce should not yet be revealed")
    Data_encoding.unit
    (function Too_early_revelation -> Some () | _ -> None)
    (fun () -> Too_early_revelation) ;
  register_error_kind
    `Branch
    ~id:"nonce.already_revealed"
    ~title:"Already revealed nonce"
    ~description:"Duplicated revelation for a nonce."
    ~pp:(fun ppf () -> Format.fprintf ppf "This nonce was already revealed")
    Data_encoding.unit
    (function Already_revealed_nonce -> Some () | _ -> None)
    (fun () -> Already_revealed_nonce) ;
  register_error_kind
    `Branch
    ~id:"nonce.inconsistent"
    ~title:"Inconsistent nonce"
    ~description:
      "The provided nonce is inconsistent with the committed nonce hash."
    ~pp:(fun ppf () ->
      Format.fprintf
        ppf
        "This nonce revelation is invalid (inconsistent with the committed \
         hash)")
    Data_encoding.unit
    (function Inconsistent_nonce -> Some () | _ -> None)
    (fun () -> Inconsistent_nonce)

(* Checks that the level of a revelation is not too early or too late wrt to the
   current context and that a nonce has not been already revealed for that level.
   Also checks that we are not past the nonce revelation period. *)
let get_unrevealed ctxt (level : Level_repr.t) =
  let current_level = Level_storage.current ctxt in
  match Cycle_repr.pred current_level.cycle with
  | None -> tzfail Too_early_revelation (* no revelations during cycle 0 *)
  | Some revealed_cycle -> (
      if Cycle_repr.(revealed_cycle < level.Level_repr.cycle) then
        tzfail Too_early_revelation
      else if
        Cycle_repr.(level.Level_repr.cycle < revealed_cycle)
        || Compare.Int32.(
             current_level.cycle_position
             >= Constants_storage.nonce_revelation_threshold ctxt)
      then tzfail Too_late_revelation
      else
        Storage.Seed.Nonce.get ctxt level >>=? function
        | Revealed _ -> tzfail Already_revealed_nonce
        | Unrevealed status -> return status)

let record_hash ctxt unrevealed =
  let level = Level_storage.current ctxt in
  Storage.Seed.Nonce.init ctxt level (Unrevealed unrevealed)

let check_unrevealed ctxt (level : Level_repr.t) nonce =
  get_unrevealed ctxt level >>=? fun unrevealed ->
  fail_unless
    (Seed_repr.check_hash nonce unrevealed.nonce_hash)
    Inconsistent_nonce

let reveal ctxt level nonce =
  Storage.Seed.Nonce.update ctxt level (Revealed nonce)

type unrevealed = Storage.Seed.unrevealed_nonce = {
  nonce_hash : Nonce_hash.t;
  delegate : Signature.Public_key_hash.t;
}

type status = Storage.Seed.nonce_status =
  | Unrevealed of unrevealed
  | Revealed of Seed_repr.nonce

let get = Storage.Seed.Nonce.get

type nonce_presence = No_nonce_expected | Nonce_expected of status

let check ctxt level =
  Storage.Seed.Nonce.find ctxt level >>=? function
  | None -> return No_nonce_expected
  | Some status -> return (Nonce_expected status)

let of_bytes = Seed_repr.make_nonce

let hash = Seed_repr.hash

let check_hash = Seed_repr.check_hash