certificate_list

   This is a sequence (chain) of certificates.  The sender's
   certificate MUST come first in the list.  Each following
   certificate MUST directly certify the one preceding it.  Because
   certificate validation requires that root keys be distributed
   independently, the self-signed certificate that specifies the root
   certificate authority MAY be omitted from the chain, under the
   assumption that the remote end must already possess it in order to
   validate it in any case.