n DES key 
 * and an RSA key from keys manager.
 *
 * Returns 0 on success or a negative value if an error occurs.
 */
int 
encrypt_file(xmlSecKeysMngrPtr mngr, const char* xml_file, const char* key_name) {
    xmlDocPtr doc = NULL;
    xmlNodePtr encDataNode = NULL;
    xmlNodePtr keyInfoNode = NULL;
    xmlNodePtr encKeyNode = NULL;
    xmlNodePtr keyInfoNode2 = NULL;
    xmlSecEncCtxPtr encCtx = NULL;
    int res = -1;
    
    assert(mngr);
    assert(xml_file);
    assert(key_name);

    /* load templa