diff --git a/re2o/login.py b/re2o/login.py
index 0b552239..d45fed5a 100644
--- a/re2o/login.py
+++ b/re2o/login.py
@@ -115,7 +115,7 @@ class CryptPasswordHasher(hashers.BasePasswordHasher):
         """
         assert encoded.startswith(self.algorithm)
         salt = hash_password_salt(encoded)
-        return constant_time_compare(crypt.crypt(password, salt),
+        return constant_time_compare(self.algorithm + crypt.crypt(password, salt),
                                      encoded)
 
     def safe_summary(self, encoded):