more setup

.gitignore

@@ -32,4 +32,6 @@ bao-*.tar
 npm-debug.log
 /assets/node_modules/
 
-.DS_Store
+.DS_Store
+
+**/*.secret.exs

config/dev.exs

@@ -63,3 +63,5 @@ config :phoenix, :stacktrace_depth, 20
 
 # Initialize plugs at runtime for faster development compilation
 config :phoenix, :plug_init_mode, :runtime
+
+import_config "dev.secret.exs"

docker-compose.yaml

@@ -0,0 +1,18 @@
+version: '3'
+
+services:
+  bao_postgres:
+    image: postgres:12.10
+    container_name: bao_postgres
+    environment:
+      - POSTGRES_USER=postgres
+      - POSTGRES_PASSWORD=postgres
+      - PGDATA=/var/lib/postgresql/data/pgdata
+    volumes:
+    - bao-postgres-volume:/var/lib/postgresql/data
+    restart: on-failure
+    ports:
+      - "5438:5432"
+
+volumes:
+  bao-postgres-volume:

lib/bao.ex

@@ -6,4 +6,25 @@ defmodule Bao do
   Contexts are also responsible for managing your data, regardless
   if it comes from the database, an external API or others.
   """
+
+  alias Bitcoinex.Secp256k1.PrivateKey
+
+  # point = get_point()
+
+  # scalar = get_scalar()
+
+  # TODO get once from env and store in memory
+  def get_scalar() do
+    {:ok, privkey} =
+      Application.fetch_env!(:bao, :private_key)
+      |> Base.decode16!(case: :lower)
+      |> :binary.decode_unsigned()
+      |> PrivateKey.new()
+    privkey
+  end
+
+  def get_point() do
+    {:ok, point} = PrivateKey.to_point(get_scalar())
+    point
+  end
 end

lib/bao/events.ex

@@ -8,18 +8,20 @@ defmodule Bao.Events do
 
   alias Bao.Events.Event
 
-  @doc """
-  Returns the list of events.
+  alias Bitcoinex.Secp256k1
 
-  ## Examples
+  # @doc """
+  # Returns the list of events.
 
-      iex> list_events()
-      [%Event{}, ...]
+  # ## Examples
 
-  """
-  def list_events do
-    Repo.all(Event)
-  end
+  #     iex> list_events()
+  #     [%Event{}, ...]
+
+  # """
+  # def list_events do
+  #   Repo.all(Event)
+  # end
 
   @doc """
   Gets a single event.
@@ -35,10 +37,10 @@ defmodule Bao.Events do
       ** (Ecto.NoResultsError)
 
   """
-  def get_event!(id), do: Repo.get!(Event, id)
+  # def get_event!(id), do: Repo.get!(Event, id)
 
-  def get_event_by_point!(point) do
-    # TODO
+  def get_event_pubkey_by_point!(point) do
+    Repo.get_by(EventPubkey, [point: point])
   end
 
   @doc """
@@ -53,12 +55,10 @@ defmodule Bao.Events do
       {:error, %Ecto.Changeset{}}
 
   """
-  def create_event(attrs \\ %{}) do
+  def create_event(attrs) do
     # create all pubkey entries
     # put len(pubkeys) in attrs
     # generate new event
-
-
     %Event{}
     |> Event.changeset(attrs)
     |> Repo.insert()
@@ -206,4 +206,14 @@ defmodule Bao.Events do
   def change_event_pubkey(%EventPubkey{} = event_pubkey, attrs \\ %{}) do
     EventPubkey.changeset(event_pubkey, attrs)
   end
+
+  def verify_event_signature(event_point, user_point, signature) do
+    sighash =
+      event_point
+      |> Base.decode16!( case: :lower)
+      |> :binary.decode_unsigned()
+    {:ok, user_pk} = Secp256k1.Point.lift_x(user_point)
+    {:ok, sig} = Secp256k1.Signature.parse_signature(signature)
+    Secp256k1.Schnorr.verify_signature(user_pk, sighash, sig)
+  end
 end

lib/bao/events/event.ex

@@ -2,52 +2,67 @@ defmodule Bao.Events.Event do
   use Ecto.Schema
   import Ecto.Changeset
 
+  alias Bao.Events.EventPubkey
+  alias Bao
 
   alias Bitcoinex.Script
   alias Bitcoinex.Utils, as: BtcUtils
   alias Bitcoinex.Secp256k1
 
+  @bao_scalar Bao.get_scalar().d
+
   schema "events" do
-    field :point, :string
     field :pubkey_ct, :integer
+    field :point, :string
     field :scalar, :string
-    field :state, :string
+    has_many :event_pubkeys, EventPubkey
 
     timestamps()
   end
 
   @doc false
   def changeset(event, attrs = %{"pubkeys" => pubkeys}) do
-    attrs = Map.put(attrs, "pubkey_ct", length(pubkeys))
+    attrs =
+      attrs
+      |> Map.put("pubkey_ct", length(pubkeys))
+      |> Map.put("point", calculate_event_point(pubkeys))
 
     event
-    |> cast(attrs, [:pubkey_ct, :state, :point, :scalar])
-    |> validate_required([:pubkey_ct, :state, :point, :scalar])
+    |> cast(attrs, [:pubkey_ct, :point])
+    |> validate_required([:pubkey_ct, :point])
     |> validate_length(:point, is: 33)
-    |> validate_length(:scalar, is: 32)
     |> validate_number(:pubkey_ct, greater_than: 0)
   end
 
-  defp calculate_event_hash(pubkeys) do
+  def calculate_event_hash(pubkeys) do
     # sort pubkeys, concatenate them, hash them, convert to point
     {:ok, scalar} =
       pubkeys
+      |> Enum.map(fn pk -> {:ok, point} = Secp256k1.Point.lift_x(pk); point end)
       |> Script.lexicographical_sort_pubkeys()
       |> Enum.reduce(<<>>, fn pk, acc -> acc <> Secp256k1.Point.x_bytes(pk) end)
       |> BtcUtils.double_sha256()
       |> :binary.decode_unsigned()
       |> Secp256k1.PrivateKey.new()
+    scalar
   end
 
-  defp calculate_event_scalar(%Secp256k1.PrivateKey{d: bao_scalar}, pubkeys) do
+  def calculate_event_scalar(pubkeys) do
     # the event_scalar is just the event_hash tweaked with the Bao's scalar
     event_hash = calculate_event_hash(pubkeys)
-    PrivateKey.new(event_hash + bao_scalar)
+    {:ok, scalar} = PrivateKey.new(event_hash + @bao_scalar)
+    Secp256k1.force_even_y(scalar)
   end
 
-  defp calculate_event_point(bao_point, pubkeys) do
+  def calculate_event_point(pubkeys) do
+    # TODO don't recalc this every time
+    bao_point = Secp256k1.PrivateKey.to_point(@bao_scalar)
     event_hash = calculate_event_hash(pubkeys)
-    {:ok, point} = Secp256k1.PrivateKey.to_point(event_hash)
+    point = Secp256k1.PrivateKey.to_point(event_hash)
+    # tweak event_hash_point with bao pubkey
     Secp256k1.Math.add(point, bao_point)
+    # force even
+    |> Secp256k1.Point.x_bytes()
+    |> Secp256k1.Point.lift_x()
   end
 end

lib/bao/events/event_pubkey.ex

@@ -7,7 +7,7 @@ defmodule Bao.Events.EventPubkey do
     field :signature, :string
     field :signed, :boolean, default: false
     field :signed_at, :utc_datetime
-    field :event_id, :id
+    belongs_to :event, Event
 
     timestamps()
   end

lib/bao/mailer.ex

@@ -1,3 +1,4 @@
 defmodule Bao.Mailer do
   use Swoosh.Mailer, otp_app: :bao
+  # TODO: delete
 end

lib/bao_web/controllers/event_controller.ex

@@ -11,9 +11,9 @@ defmodule BaoWeb.EventController do
   #   render(conn, "index.json", events: events)
   # end
 
-  def create(conn, %{"event" => event_params}) do
+  def create(conn, attrs = %{"pubkeys" => pubkeys}) do
     # TODO: Just return pubkeys & event_point
-    with {:ok, %Event{} = event} <- Events.create_event(event_params) do
+    with {:ok, %Event{} = event} <- Events.create_event(attrs) do
       conn
       |> put_status(:created)
       |> put_resp_header("location", Routes.event_path(conn, :show, event))
@@ -27,10 +27,13 @@ defmodule BaoWeb.EventController do
     render(conn, "show.json", event: event)
   end
 
-  def update(conn, %{"point" => point, "signature" => signature}) do
-    event = Events.get_event_by_point!(point)
+  def update(conn, %{"point" => user_point, "signature" => signature}) do
+    event = Events.get_event_by_point!(user_point)
+
+    # TODO error if this fails
+    true = Events.verify_event_signature(event.point, user_point, signature)
 
-    event_pk = Events.get_event_pubkey!(point)
+    event_pk = Events.get_event_pubkey!(user_point)
 
     with {:ok, _} <- EventPubkeys.update_event_pubkey(event_pk, %{"signature" => signature}) do
       # If successfully verified sig

lib/bao_web/router.ex

@@ -1,5 +1,5 @@
 defmodule BaoWeb.Router do
-  alias BaoWeb.EventController
+  # alias BaoWeb.EventController
   use BaoWeb, :router
 
   pipeline :api do

mix.exs

@@ -7,7 +7,6 @@ defmodule Bao.MixProject do
       version: "0.1.0",
       elixir: "~> 1.12",
       elixirc_paths: elixirc_paths(Mix.env()),
-      compilers: [:gettext] ++ Mix.compilers(),
       start_permanent: Mix.env() == :prod,
       aliases: aliases(),
       deps: deps()

priv/repo/migrations/20230316225510_create_events.exs

@@ -4,7 +4,6 @@ defmodule Bao.Repo.Migrations.CreateEvents do
   def change do
     create table(:events) do
       add :pubkey_ct, :integer
-      add :state, :string
       add :point, :string
       add :scalar, :string
 

priv/repo/migrations/20230316225902_create_event_pubkeys.exs

@@ -6,12 +6,12 @@ defmodule Bao.Repo.Migrations.CreateEventPubkeys do
       add :pubkey, :string
       add :signed, :boolean, default: false, null: false
       add :signature, :string
-      add :signed_at, :utc_datetime
       add :event_id, references(:events, on_delete: :nothing)
 
       timestamps()
     end
 
+    # TODO create index(:events_event_pubkeys, [:pubkey, :event_id])
     create index(:event_pubkeys, [:event_id])
   end
 end