diff --git a/src/validator-docs/Rules/Ddd.php b/src/validator-docs/Rules/Ddd.php
index b4589d5..aeffd5e 100644
--- a/src/validator-docs/Rules/Ddd.php
+++ b/src/validator-docs/Rules/Ddd.php
@@ -8,7 +8,7 @@ final class Ddd
 {
     public function validateDdd($attribute, $ddd): bool
     {
-        if (preg_match('/([1-9]{2}+)/', $ddd, $matches) <= 0) {
+        if (preg_match('/^[1-9]{2}$/', (string) $ddd, $matches) <= 0) {
             return false;
         }
 
@@ -30,6 +30,6 @@ public function validateDdd($attribute, $ddd): bool
             range(91, 99)
         );
 
-        return in_array($dddExtracted, $dddExisting);
+        return in_array($dddExtracted, $dddExisting, true);
     }
 }
diff --git a/tests/TestValidator.php b/tests/TestValidator.php
index 2a870b4..17fbd18 100644
--- a/tests/TestValidator.php
+++ b/tests/TestValidator.php
@@ -337,9 +337,21 @@ public function ddd()
             ['errado' => 'ddd']
         );
 
+        $incorrectWithThreeDigits = Validator::make(
+            ['errado' => '011'],
+            ['errado' => 'ddd']
+        );
+
+        $incorrectWithAlphaNumeric = Validator::make(
+            ['errado' => '11a'],
+            ['errado' => 'ddd']
+        );
+
         $this->assertTrue($correct->passes());
 
         $this->assertTrue($incorrect->fails());
+        $this->assertTrue($incorrectWithThreeDigits->fails());
+        $this->assertTrue($incorrectWithAlphaNumeric->fails());
     }
 
     /** @test **/