diff --git a/framework/yii/helpers/SecurityBase.php b/framework/yii/helpers/SecurityBase.php
index 0ecad0f..5b192de 100644
--- a/framework/yii/helpers/SecurityBase.php
+++ b/framework/yii/helpers/SecurityBase.php
@@ -140,7 +140,7 @@ class SecurityBase
 	public static function generateRandomKey($length = 32)
 	{
 		if (function_exists('openssl_random_pseudo_bytes')) {
-			$key = strtr(base64_encode(openssl_random_pseudo_bytes($length, $strong)), array('+' => '_', '/' => '-', '=' => '.'));
+			$key = strtr(base64_encode(openssl_random_pseudo_bytes($length, $strong)), '+/=', '_-.');
 			if ($strong) {
 				return substr($key, 0, $length);
 			}