diff --git a/requirements.txt b/requirements.txt
index 6919e25..e9940d6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 ecdsa==0.15
 gmssl==3.2.1
 requests==2.20.0
-protobuf==3.12.2
+protobuf==3.18.3
 pycryptodome==3.9.7
 ed25519==1.5
diff --git a/setup.py b/setup.py
index ad033df..406a335 100644
--- a/setup.py
+++ b/setup.py
@@ -4,7 +4,7 @@
     "ecdsa == 0.15",
     "gmssl == 3.2.1",
     "requests == 2.20.0",
-    "protobuf == 3.12.2",
+    "protobuf == 3.18.3",
     "pycryptodome == 3.9.7",
     "ed25519 == 1.5",
 ]