From 8c98a259ada01d5506743adb1f818dba2866ad10 Mon Sep 17 00:00:00 2001
From: Benjamin Loison <benjamin_loison@users.noreply.gitea.lemnoslife.com>
Date: Thu, 8 Jun 2023 14:11:07 +0200
Subject: [PATCH] Fix #11: Attack by using a nonce multiple times

---
 verifier.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/verifier.py b/verifier.py
index dda765c..e2286d4 100755
--- a/verifier.py
+++ b/verifier.py
@@ -55,6 +55,15 @@ while True:
     with open(input('entries: ')) as f:
         entries = ast.literal_eval(f.read())
 
+    nonces = set()
+    for entry in entries:
+        if type(entry) == str:
+            break
+        if entry in nonces:
+            print('A given nonce was used several times!')
+            exit(1)
+        nonces.add(entry)
+
     merkleTreeLevels = [{} for _ in range(common.LEVELS)]
 
     for index in indexesRequest: