diff --git a/phpseclib/File/ASN1.php b/phpseclib/File/ASN1.php
index 12392c2f..30f9e4d2 100644
--- a/phpseclib/File/ASN1.php
+++ b/phpseclib/File/ASN1.php
@@ -909,7 +909,7 @@ abstract class ASN1
                     if ($mapping['type'] == self::TYPE_SET) {
                         sort($value);
                     }
-                    $value = implode($value, '');
+                    $value = implode('', $value);
                     break;
                 }