diff --git a/LeadKitAdditions/LeadKitAdditions/Controllers/PassCode/View/BasePassCodeViewController.swift b/LeadKitAdditions/LeadKitAdditions/Controllers/PassCode/View/BasePassCodeViewController.swift
index 7a309f1..d74bedf 100644
--- a/LeadKitAdditions/LeadKitAdditions/Controllers/PassCode/View/BasePassCodeViewController.swift
+++ b/LeadKitAdditions/LeadKitAdditions/Controllers/PassCode/View/BasePassCodeViewController.swift
@@ -57,6 +57,7 @@ open class BasePassCodeViewController: UIViewController {
         fakeTextField.isSecureTextEntry = true
         fakeTextField.keyboardType = .numberPad
         fakeTextField.isHidden = true
+        fakeTextField.delegate = self
         self.view.addSubview(fakeTextField)
         return fakeTextField
     }()
@@ -237,3 +238,15 @@ extension BasePassCodeViewController: ConfigurableController {
     open func localize() {}
 
 }
+
+extension BasePassCodeViewController: UITextFieldDelegate {
+
+    func textField(_ textField: UITextField,
+                   shouldChangeCharactersIn range: NSRange,
+                   replacementString string: String) -> Bool {
+
+        let invalid = CharacterSet(charactersIn: "0123456789").inverted
+        return string.rangeOfCharacter(from: invalid, options: [], range: string.startIndex..<string.endIndex) == nil
+    }
+    
+}