diff --git a/ydb/tests/library/harness/tls_tools.py b/ydb/tests/library/harness/tls_tools.py
index e8941fa50cc1..46af7fc63595 100644
--- a/ydb/tests/library/harness/tls_tools.py
+++ b/ydb/tests/library/harness/tls_tools.py
@@ -13,7 +13,7 @@
 def generate_selfsigned_cert(hostname):
     key = rsa.generate_private_key(
         public_exponent=65537,
-        key_size=1024,
+        key_size=2048,
         backend=default_backend()
     )