diff --git a/src/customer.py b/src/customer.py
index c06ba55..cb65199 100644
--- a/src/customer.py
+++ b/src/customer.py
@@ -22,32 +22,25 @@ class Customer:
     def valid_key_entry(self, username, selected_keys) -> bool:
         if username not in self.users:
             raise ValueError(f"User '{username}' does not exist")
-
         numb_of_keys = self.cipher.keypad_size.numb_of_keys
         if not all(0 <= key_idx < numb_of_keys for key_idx in selected_keys):
             raise ValueError(f"Invalid key indices. Must be between 0 and {numb_of_keys - 1}")
-
         passcode_len = len(selected_keys)
         user = self.users[username]
-
         passcode_set_vals = user.cipher.decipher_mask(
             user.enciphered_passcode.mask, self.cipher.set_key, passcode_len)
         set_vals_idx = [self.cipher.get_set_index(set_val) for set_val in passcode_set_vals]
-
         presumed_property_idxs = []
         for idx in range(passcode_len):
             key_numb = selected_keys[idx]
             set_idx = set_vals_idx[idx]
             selected_prop_idx = user.user_keypad.get_prop_idx_by_keynumb_setidx(key_numb, set_idx)
             presumed_property_idxs.append(selected_prop_idx)
-
         if not user.cipher.compare_nkode(presumed_property_idxs, self.cipher,user.enciphered_passcode.code):
             return False
-
         if user.renew:
             user.refresh_passcode(presumed_property_idxs, self.cipher)
-
-        user.user_keypad.partial_keypad_shuffle()
+        user.user_keypad.split_shuffle()
         return True
 
     def renew_keys(self) -> bool:
diff --git a/src/user_keypad.py b/src/user_keypad.py
index 1405dd3..ffcb0b6 100644
--- a/src/user_keypad.py
+++ b/src/user_keypad.py
@@ -62,22 +62,12 @@ class UserKeypad:
         )
         self.keypad = dispersed_keypad.reshape(-1)
 
-    def partial_keypad_shuffle(self):
-        # TODO: this should be split shuffle
-        #numb_of_selected_sets = self.keypad_size.props_per_key // 2
-        ## randomly shuffle half the sets. if props_per_key is odd, randomly add one 50% of the time
-        #numb_of_selected_sets += choice([0, 1]) if (self.keypad_size.props_per_key & 1) == 1 else 0
-        #selected_sets = secure_fisher_yates_shuffle(list(range(self.keypad_size.props_per_key)))[:numb_of_selected_sets]
-        #user_keypad_matrix = self.keypad_matrix()
-        #shuffled_keys = secure_fisher_yates_shuffle(user_keypad_matrix)
-        #keypad_by_sets = []
-        #for idx, props in enumerate(matrix_transpose(shuffled_keys)):
-        #    if idx in selected_sets:
-        #        keypad_by_sets.append(secure_fisher_yates_shuffle(props))
-        #    else:
-        #        keypad_by_sets.append(props)
-        #self.keypad = matrix_to_list(matrix_transpose(keypad_by_sets))
-        pass
+    def split_shuffle(self):
+        prop_permutation = np.random.permutation(self.keypad_size.props_per_key)[: self.keypad_size.props_per_key // 2]
+        key_permutation = np.random.permutation(self.keypad_size.numb_of_keys)
+        keypad_view = self.keypad_matrix().copy()
+        keypad_view[:, prop_permutation] = keypad_view[key_permutation, :][:, prop_permutation]
+        self.keypad = keypad_view.reshape(-1)
 
     def property_adjacency_graph(self) -> dict[int, set[int]]:
         user_keypad_keypad = self.keypad_matrix()
diff --git a/test/test_user_keypad.py b/test/test_user_keypad.py
index b7deadf..f7bb7a6 100644
--- a/test/test_user_keypad.py
+++ b/test/test_user_keypad.py
@@ -5,7 +5,7 @@ from src.models import KeypadSize
 
 @pytest.fixture()
 def user_keypad():
-    return UserKeypad.create(keypad_size=KeypadSize(props_per_key=7, numb_of_keys=10))
+    return UserKeypad.create(keypad_size=KeypadSize(props_per_key=8, numb_of_keys=8))
 
 
 def test_dispersion(user_keypad):
@@ -17,19 +17,19 @@ def test_dispersion(user_keypad):
             assert (adj_graph.isdisjoint(post_dispersion_graph[prop]))
 
 
-#def test_shuffle_props(user_keypad):
-#    """there's no easy way to test this. At some point we'll have to run this code thousands of time to see if we get
-#    expected statistical outcomes like:
-#    - every property gets to every key with a uniform distribution
-#    - every property is adjacent to every other property with uniform distribution
-#    - the order in which the cipher move from key to key is random (i.e. the distance traveled is uniform)
-#    """
-#    pre_shuffle_keypad = user_keypad.keypad
-#    user_keypad.partial_keypad_shuffle()
-#    post_shuffle_keypad = user_keypad.keypad
-#    assert (not all(
-#        post_shuffle_keypad[idx] == pre_shuffle_keypad[idx] for idx in range(len(post_shuffle_keypad))
-#    ))
-#    assert (not all(
-#        post_shuffle_keypad[idx] != pre_shuffle_keypad[idx] for idx in range(len(post_shuffle_keypad))
-#    ))
+def test_shuffle_props(user_keypad):
+    """there's no easy way to test this. At some point we'll have to run this code thousands of time to see if we get
+    expected statistical outcomes like:
+    - every property gets to every key with a uniform distribution
+    - every property is adjacent to every other property with uniform distribution
+    - the order in which the cipher move from key to key is random (i.e. the distance traveled is uniform)
+    """
+    pre_shuffle_keypad = user_keypad.keypad.copy()
+    user_keypad.split_shuffle()
+    post_shuffle_keypad = user_keypad.keypad.copy()
+    assert (not all(
+        post_shuffle_keypad[idx] == pre_shuffle_keypad[idx] for idx in range(len(post_shuffle_keypad))
+    ))
+    assert (not all(
+        post_shuffle_keypad[idx] != pre_shuffle_keypad[idx] for idx in range(len(post_shuffle_keypad))
+    ))