diff --git a/src/AtmAdmin.cpp b/src/AtmAdmin.cpp
index a89f09b..56b2109 100644
--- a/src/AtmAdmin.cpp
+++ b/src/AtmAdmin.cpp
@@ -71,6 +71,12 @@ namespace AtmAdmin {
         std::cin >> newPin;
         Error::ignoreLine();
 
+        std::array<int, 4> pinDigits{};
+
+        for (size_t i{}; i != 4; i++) {
+            pinDigits[i] = (newPin[i] - '0');
+        }
+
         if (newPin.size() != 4) {
             errorReport("The pin has to be 4 numbers long.");
             return "invalid";
@@ -89,7 +95,24 @@ namespace AtmAdmin {
             }
         }
 
-        { // Start of bracket scope
+        // Checks for sequential numbers (examples: 1234, 6789)
+        { // START OF BRACKET SCOPE //
+            int sequentialCount {0};
+
+            for (size_t i{0}; i < 3; i++) {
+                if (pinDigits[i]+1 == pinDigits[i+1] or pinDigits[i]-1 == pinDigits[i+1])
+                    sequentialCount += 1;
+
+
+                if (sequentialCount == 3) {
+                    errorReport("Pin is too simple.");
+                    return "invalid";
+                }
+            }
+        } // END OF BRACKET SCOPE //
+
+        // Checks for too many duplicate numbers.
+        { // START OF BRACKET SCOPE //
             std::string tempPin = newPin;
             std::ranges::sort(tempPin.begin(), tempPin.end());
 
@@ -103,7 +126,7 @@ namespace AtmAdmin {
                 errorReport("Too many duplicate numbers.");
                 return "invalid";
             }
-        } // End of bracket scope
+        } // END OF BRACKET SCOPE //
 
        return newPin;
     }