diff --git a/requirements.bazel.txt b/requirements.bazel.txt
index cffce19e778..586c710f108 100644
--- a/requirements.bazel.txt
+++ b/requirements.bazel.txt
@@ -14,4 +14,5 @@ chardet==3.0.4
 certifi==2017.4.17
 idna==2.7
 googleapis-common-protos==1.5.5
-rsa>=3.1.4,!=4.1,!=4.1.1,!=4.2,<5
+# rsa 4.0 is the last version support Python 2
+rsa==4.0
diff --git a/requirements.txt b/requirements.txt
index 799e75bca41..2218991c3f3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,4 +5,5 @@ enum34>=1.0.4
 protobuf>=3.5.0.post1
 six>=1.10
 wheel>=0.29
-rsa>=3.1.4,!=4.1,!=4.1.1,!=4.2,<5
+# rsa 4.0 is the last version support Python 2
+rsa==4.0