diff --git a/src/Data.java b/src/Data.java
index 27a46ef..8c5a40f 100644
--- a/src/Data.java
+++ b/src/Data.java
@@ -5,6 +5,9 @@ import java.nio.file.Paths;
 import java.sql.Array;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Scanner;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * Data is a class to edit files.
@@ -223,5 +226,70 @@ public class Data {
         }
         return rows;
     }
+
+    /**
+     * The method validates the user input
+     *
+     * @return boolean inputValid
+     * @author Kevin Maier
+     */
+    private boolean validateData(String password, String phoneNumber)
+    {
+        boolean inputValid = false;
+        boolean phoneNumberMatchFound;
+        boolean passwordMatchFound;
+        boolean phoneNumberValid = false;
+        boolean passwordValid = false;
+
+        Pattern phoneNumberPattern = Pattern.compile("[0-9]*");
+        Pattern passwordPattern = Pattern.compile("^[^a-zA-Z0-9].*[0-9]$");
+
+        Scanner reader = new Scanner(System.in);
+
+        while(password.isEmpty() || phoneNumber.isEmpty())
+        {
+            System.out.println("Login fehlgeschlagen. Eingabe ist leer, versuchen Sie es erneut.");
+            System.out.println("");
+            System.out.print("Telefonnummer: ");
+            phoneNumber = reader.nextLine();
+            System.out.print("Passwort: ");
+            password = reader.nextLine();
+        }
+
+        Matcher phoneNumberMatcher = phoneNumberPattern.matcher(phoneNumber);
+        Matcher passwordMatcher = passwordPattern.matcher(password);
+
+        phoneNumberMatchFound = phoneNumberMatcher.find();
+        passwordMatchFound = passwordMatcher.find();
+
+        while (!inputValid) {
+            if (!phoneNumberMatchFound || phoneNumber.length() != 15) {
+                System.out.println("Login fehlgeschlagen. Die eingegebene Handynummer ist nicht valide.");
+                System.out.println("");
+                System.out.print("Telefonnummer: ");
+                phoneNumber = reader.nextLine();
+                System.out.print("Passwort: ");
+                password = reader.nextLine();
+            } else {
+                phoneNumberValid = true;
+            }
+
+            if (!passwordMatchFound || password.length() < 6 || password.length() > 20) {
+                System.out.println("Login fehlgeschlagen. Das eingegebene Passwort ist nicht valide.");
+                System.out.println("");
+                System.out.print("Telefonnummer: ");
+                phoneNumber = reader.nextLine();
+                System.out.print("Passwort: ");
+                password = reader.nextLine();
+            } else {
+                passwordValid = true;
+            }
+
+            if (phoneNumberValid && passwordValid) {
+                inputValid = true;
+            }
+        }
+        return inputValid;
+    }
 }