diff --git a/gluon/authapi.py b/gluon/authapi.py
index ddae855a..db2ae13f 100644
--- a/gluon/authapi.py
+++ b/gluon/authapi.py
@@ -988,7 +988,8 @@ class AuthAPI(object):
             requires = [requires]
         requires = list(filter(lambda t: isinstance(t, CRYPT), requires))
         if requires:
-            requires[0] = CRYPT(key=settings.hmac_key, min_length=0)
+            requires[0] = CRYPT(**requires[0].__dict__) # Copy the existing CRYPT attributes
+            requires[0].min_length = 0 # But do not enforce minimum length for the old password
 
         old_password = kwargs.get('old_password', '')
         new_password = kwargs.get('new_password', '')
diff --git a/gluon/tools.py b/gluon/tools.py
index 80b905ac..b063b6ea 100644
--- a/gluon/tools.py
+++ b/gluon/tools.py
@@ -3693,7 +3693,8 @@ class Auth(AuthAPI):
             requires = [requires]
         requires = list(filter(lambda t: isinstance(t, CRYPT), requires))
         if requires:
-            requires[0] = CRYPT(key=self.settings.hmac_key, min_length=0)
+            requires[0] = CRYPT(**requires[0].__dict__) # Copy the existing CRYPT attributes
+            requires[0].min_length = 0 # But do not enforce minimum length for the old password
         form = SQLFORM.factory(
             Field('old_password', 'password', requires=requires,
                   label=self.messages.old_password),