diff --git a/src/Encryption.php b/src/Encryption.php
index b0670e7..21ccd57 100644
--- a/src/Encryption.php
+++ b/src/Encryption.php
@@ -251,7 +251,9 @@ private static function createInfo(string $type, ?string $context, ContentEncodi
     private static function createLocalKeyObject(): array
     {
         $keyResource = openssl_pkey_new([
-            'curve_name'       => 'prime256v1',
+            'ec' => [
+                'curve_name' => 'prime256v1'
+            ],
             'private_key_type' => OPENSSL_KEYTYPE_EC,
         ]);
         if (!$keyResource) {