Add timestamp in node validation election

lib/archethic.ex

@@ -66,10 +66,11 @@ defmodule Archethic do
     welcome_node_key = Keyword.get(opts, :welcome_node_key, Crypto.first_node_public_key())
     contract_context = Keyword.get(opts, :contract_context, nil)
     forward? = Keyword.get(opts, :forward?, false)
+    ref_timestamp = DateTime.utc_now()
 
     cond do
       P2P.authorized_and_available_node?() and shared_secret_synced?() ->
-        validation_nodes = Mining.get_validation_nodes(tx)
+        validation_nodes = Mining.get_validation_nodes(tx, ref_timestamp)
 
         responses =
           %{already_locked?: already_locked?} =

lib/archethic/election.ex

@@ -23,10 +23,13 @@ defmodule Archethic.Election do
   """
   @spec validation_nodes_election_seed_sorting(Transaction.t(), DateTime.t()) :: binary()
   def validation_nodes_election_seed_sorting(tx = %Transaction{}, timestamp = %DateTime{}) do
-    tx_hash =
+    serialized_tx =
       tx
       |> Transaction.to_pending()
       |> Transaction.serialize()
+
+    tx_hash =
+      <<serialized_tx::bitstring, DateTime.to_unix(timestamp, :millisecond)::64>>
       |> Crypto.hash()
 
     Crypto.sign_with_daily_nonce_key(tx_hash, timestamp)

lib/archethic/mining.ex

@@ -80,9 +80,12 @@ defmodule Archethic.Mining do
   @doc """
   Elect validation nodes for a transaction
   """
-  def get_validation_nodes(tx = %Transaction{address: tx_address, validation_stamp: nil}) do
+  def get_validation_nodes(
+        tx = %Transaction{address: tx_address, validation_stamp: nil},
+        ref_timestamp
+      ) do
     current_date = DateTime.utc_now()
-    sorting_seed = Election.validation_nodes_election_seed_sorting(tx, current_date)
+    sorting_seed = Election.validation_nodes_election_seed_sorting(tx, ref_timestamp)
 
     node_list = P2P.authorized_and_available_nodes(current_date)
 
@@ -100,10 +103,11 @@ defmodule Archethic.Mining do
   @doc """
   Determines if the election of validation nodes performed by the welcome node is valid
   """
-  @spec valid_election?(Transaction.t(), list(Crypto.key())) :: boolean()
-  def valid_election?(tx, validation_node_public_keys)
+  @spec valid_election?(Transaction.t(), list(Crypto.key()), ref_timestamp :: DateTime.t()) ::
+          boolean()
+  def valid_election?(tx, validation_node_public_keys, ref_timestamp)
       when is_list(validation_node_public_keys) do
-    validation_nodes = get_validation_nodes(tx)
+    validation_nodes = get_validation_nodes(tx, ref_timestamp)
     validation_node_public_keys == Enum.map(validation_nodes, & &1.last_public_key)
   end
 

lib/archethic/mining/distributed_workflow.ex

@@ -218,9 +218,9 @@ defmodule Archethic.Mining.DistributedWorkflow do
         :internal,
         {:start_mining, tx, welcome_node, validation_nodes, contract_context},
         :idle,
-        data = %{node_public_key: node_public_key}
+        data = %{ref_timestamp: ref_timestamp, node_public_key: node_public_key}
       ) do
-    validation_time = DateTime.utc_now() |> DateTime.truncate(:millisecond)
+    validation_time = ref_timestamp |> DateTime.truncate(:millisecond)
 
     authorized_nodes = P2P.authorized_and_available_nodes(validation_time)
 

lib/archethic/p2p/message/start_mining.ex

@@ -64,7 +64,7 @@ defmodule Archethic.P2P.Message.StartMining do
       ) do
     with :ok <- check_ref_timestamp(ref_timestamp),
          :ok <- check_synchronization(network_chains_view_hash, p2p_view_hash),
-         :ok <- check_valid_election(tx, validation_nodes),
+         :ok <- check_valid_election(tx, validation_nodes, ref_timestamp),
          :ok <- check_current_node_is_elected(validation_nodes),
          :ok <- check_not_already_mining(tx.address),
          :ok <- Mining.request_chain_lock(tx) do
@@ -212,8 +212,8 @@ defmodule Archethic.P2P.Message.StartMining do
     end
   end
 
-  defp check_valid_election(tx, validation_nodes) do
-    if Mining.valid_election?(tx, validation_nodes) do
+  defp check_valid_election(tx, validation_nodes, ref_timestamp) do
+    if Mining.valid_election?(tx, validation_nodes, ref_timestamp) do
       :ok
     else
       {:error, :invalid_validation_nodes_election}