diff --git a/setup.py b/setup.py
index 5f42a4f..0f89527 100644
--- a/setup.py
+++ b/setup.py
@@ -23,7 +23,7 @@ setup(name="magic-wormhole",
                 "wormhole.test", "wormhole.util"],
       entry_points={"console_scripts":
                     ["wormhole = wormhole.scripts.runner:entry"]},
-      install_requires=["spake2", "pynacl", "requests", "argparse"],
+      install_requires=["spake2==0.2", "pynacl", "requests", "argparse"],
       test_suite="wormhole.test",
       cmdclass=commands,
       )