package class_group_vdf

  1. Overview
  2. Docs

Source file vdf.ml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
module type Vdf_sig = sig
  module Group : S.GROUP

  (** [prove_vdf discriminant form difficulty] *)
  val prove : Group.t -> Unsigned.UInt64.t -> Group.t * Group.t

  (** [verify_vdf discriminant form difficulty form form] *)
  val verify : Group.t -> Unsigned.UInt64.t -> Group.t -> Group.t -> bool
end

module Stubs = struct
  external prove :
    Bytes.t ->
    Unsigned.Size_t.t ->
    Bytes.t ->
    Unsigned.UInt64.t ->
    Bytes.t ->
    Bytes.t ->
    int = "caml_prove_bytecode_stubs" "caml_prove_stubs"

  external verify :
    Bytes.t ->
    Unsigned.Size_t.t ->
    Bytes.t ->
    Bytes.t ->
    Bytes.t ->
    Unsigned.UInt64.t ->
    int = "caml_verify_bytecode_stubs" "caml_verify_stubs"
end

module Make (CG : Class_group.Class_group_sig) : Vdf_sig = struct
  module Group = CG

  let discriminant_bytes = Utils.Integer.to_bytes CG.discriminant

  let prove challenge difficulty =
    let challenge_bytes = CG.to_bytes challenge in
    let result_bytes = Bytes.create CG.size_in_bytes in
    let proof_bytes = Bytes.create CG.size_in_bytes in
    let status =
      Stubs.prove
        discriminant_bytes
        CG.discriminant_size
        challenge_bytes
        difficulty
        result_bytes
        proof_bytes
    in
    let result = CG.of_bytes_exn result_bytes in
    let proof = CG.of_bytes_exn proof_bytes in
    match status with
    | x when x = 0 -> (result, proof)
    | x when x = 2 -> raise Utils.invalid_group_element
    | _ -> raise Utils.unknown_error

  let verify challenge difficulty result proof =
    let challenge_bytes = CG.to_bytes challenge in
    let result_bytes = CG.to_bytes result in
    let proof_bytes = CG.to_bytes proof in
    let status =
      Stubs.verify
        discriminant_bytes
        CG.discriminant_size
        challenge_bytes
        result_bytes
        proof_bytes
        difficulty
    in
    match status with
    | x when x = 0 -> false
    | x when x = 1 -> true
    | x when x = 2 -> raise Utils.invalid_group_element
    | _ -> raise Utils.unknown_error
end