diff --git a/lib/openpgp.php b/lib/openpgp.php
index 9849d1e..f99c24f 100644
--- a/lib/openpgp.php
+++ b/lib/openpgp.php
@@ -648,6 +648,15 @@ class OpenPGP_OnePassSignaturePacket extends OpenPGP_Packet {
     }
     $this->nested = ord($this->read_byte());
   }
+
+  function body() {
+    $body = chr($this->version).chr($this->signature_type).chr($this->hash_algorithm).chr($this->key_algorithm);
+    for($i = 0; $i < strlen($this->key_id); $i += 2) {
+      $body .= chr(hexdec($this->key_id{$i}.$this->key_id{$i+1}));
+    }
+    $body .= chr((int)$this->nested);
+    return $body;
+  }
 }
 
 /**