--- a/libpskc/build.c	
+++ a/libpskc/build.c	
@@ -510,7 +510,7 @@ pskc_build_xml (pskc_t * container, char **out, size_t * len)
 
   xmlDocSetRootElement (doc, keycont);
 
-  if (container->xmldoc)
+  if (container->xmldoc && container->xmldoc != container->original_xmldoc)
     xmlFreeDoc (container->xmldoc);
   container->xmldoc = doc;
   doc = NULL;
--- a/libpskc/internal.h	
+++ a/libpskc/internal.h	
@@ -103,7 +103,7 @@ struct pskc_key
 struct pskc
 {
   /* raw XML */
-  xmlDocPtr xmldoc;
+  xmlDocPtr xmldoc, original_xmldoc;
   /* Is there a Signature element in xmldoc? */
   int signed_p;
 
--- a/libpskc/parser.c	
+++ a/libpskc/parser.c	
@@ -677,6 +677,8 @@ pskc_done (pskc_t * container)
     return;
 
   xmlFreeDoc (container->xmldoc);
+  if (container->original_xmldoc != container->xmldoc)
+	  xmlFreeDoc (container->original_xmldoc);
 
   for (i = 0; i < container->nkeypackages; i++)
     {
@@ -717,7 +719,7 @@ pskc_parse_from_memory (pskc_t * container, size_t len, const char *buffer)
   if (xmldoc == NULL)
     return PSKC_XML_ERROR;
 
-  container->xmldoc = xmldoc;
+  container->original_xmldoc = container->xmldoc = xmldoc;
 
   root = xmlDocGetRootElement (xmldoc);
   parse_keycontainer (container, root, &rc);