diff --git a/module/Common/src/Util/StringUtilsTrait.php b/module/Common/src/Util/StringUtilsTrait.php
index 1c048251..87b77a2a 100644
--- a/module/Common/src/Util/StringUtilsTrait.php
+++ b/module/Common/src/Util/StringUtilsTrait.php
@@ -3,40 +3,44 @@ declare(strict_types=1);
 
 namespace Shlinkio\Shlink\Common\Util;
 
+use function random_int;
+use function sprintf;
+use function strlen;
+
 trait StringUtilsTrait
 {
-    protected function generateRandomString($length = 10)
+    private function generateRandomString($length = 10): string
     {
         $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
         $charactersLength = strlen($characters);
         $randomString = '';
         for ($i = 0; $i < $length; $i++) {
-            $randomString .= $characters[mt_rand(0, $charactersLength - 1)];
+            $randomString .= $characters[random_int(0, $charactersLength - 1)];
         }
 
         return $randomString;
     }
 
-    protected function generateV4Uuid()
+    private function generateV4Uuid(): string
     {
         return sprintf(
             '%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
             // 32 bits for "time_low"
-            mt_rand(0, 0xffff),
-            mt_rand(0, 0xffff),
+            random_int(0, 0xffff),
+            random_int(0, 0xffff),
             // 16 bits for "time_mid"
-            mt_rand(0, 0xffff),
+            random_int(0, 0xffff),
             // 16 bits for "time_hi_and_version",
             // four most significant bits holds version number 4
-            mt_rand(0, 0x0fff) | 0x4000,
+            random_int(0, 0x0fff) | 0x4000,
             // 16 bits, 8 bits for "clk_seq_hi_res",
             // 8 bits for "clk_seq_low",
             // two most significant bits holds zero and one for variant DCE1.1
-            mt_rand(0, 0x3fff) | 0x8000,
+            random_int(0, 0x3fff) | 0x8000,
             // 48 bits for "node"
-            mt_rand(0, 0xffff),
-            mt_rand(0, 0xffff),
-            mt_rand(0, 0xffff)
+            random_int(0, 0xffff),
+            random_int(0, 0xffff),
+            random_int(0, 0xffff)
         );
     }
 }