From a46dbfe82655eb08072e8123d316b459c7aa4528 Mon Sep 17 00:00:00 2001
From: Youngjoon Lee <5462944+youngjoon-lee@users.noreply.github.com>
Date: Mon, 20 May 2024 16:54:32 +0900
Subject: [PATCH] add an option to turn off mixing

---
 mixnet/v2/sim/config.py   | 2 +-
 mixnet/v2/sim/config.yaml | 2 ++
 mixnet/v2/sim/node.py     | 3 +++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/mixnet/v2/sim/config.py b/mixnet/v2/sim/config.py
index ddd4c1f..5a58474 100644
--- a/mixnet/v2/sim/config.py
+++ b/mixnet/v2/sim/config.py
@@ -62,7 +62,7 @@ class MixnetConfig:
 
     def validate(self):
         assert self.num_nodes > 0
-        assert 0 < self.num_mix_layers <= self.num_nodes
+        assert 0 <= self.num_mix_layers <= self.num_nodes
         assert self.payload_size > 0
         assert self.message_interval > 0
         assert self.real_message_prob > 0
diff --git a/mixnet/v2/sim/config.yaml b/mixnet/v2/sim/config.yaml
index 76d26d8..36a37b2 100644
--- a/mixnet/v2/sim/config.yaml
+++ b/mixnet/v2/sim/config.yaml
@@ -4,6 +4,8 @@ simulation:
 
 mixnet:
   num_nodes: 100
+  # A number of mix nodes selected by a message sender through which the Sphinx message goes through
+  # If 0, the message is broadcast directly to all nodes without being Sphinx-encoded.
   num_mix_layers: 3
   # A size of a message payload in bytes (e.g. the size of a block proposal)
   payload_size: 320
diff --git a/mixnet/v2/sim/node.py b/mixnet/v2/sim/node.py
index b55a5ba..2d349c2 100644
--- a/mixnet/v2/sim/node.py
+++ b/mixnet/v2/sim/node.py
@@ -63,6 +63,9 @@ class Node:
         Creates a real or cover message
         @return:
         """
+        if self.config.mixnet.num_mix_layers == 0:  # if mixing is turned off
+            return self.build_payload()
+
         mixes = self.p2p.get_nodes(self.config.mixnet.num_mix_layers)
         public_keys = [mix.public_key for mix in mixes]
         # TODO: replace with realistic tx