diff --git a/src/SAML2/Assertion.php b/src/SAML2/Assertion.php
index d20ac3914a..2e8a0acc2d 100644
--- a/src/SAML2/Assertion.php
+++ b/src/SAML2/Assertion.php
@@ -920,7 +920,10 @@ public function decryptAttributes(XMLSecurityKey $key, array $blacklist = []): v
             }
 
             if (!array_key_exists($name, $this->attributes)) {
-                $this->attributes[$name] = [];
+                $attr = new Attribute();
+                $attr->setName($name);
+
+                $this->attributes[$name] = $attr;
             }
 
             $this->parseAttributeValue($attribute, $name);