diff --git a/src/test/ntor_ref.py b/src/test/ntor_ref.py
index 767da57a9c7186e992e395a0f26ae14c7d1f0cdd..df065853f36be866e16a60fa988b976b0b42a7ce 100755
--- a/src/test/ntor_ref.py
+++ b/src/test/ntor_ref.py
@@ -322,7 +322,7 @@ def kdf_vectors():
     """
     import binascii
     def kdf_vec(inp):
-        k = kdf(inp, T_KEY, M_EXPAND, 100)
+        k = kdf_rfc5869(inp, T_KEY, M_EXPAND, 100)
         print(repr(inp), "\n\""+ binascii.b2a_hex(k)+ "\"")
     kdf_vec("")
     kdf_vec("Tor")