Execution, Authentication, Availability and Dating of the DefinitiveCertificates. The Definitive Certificates shall be executed on behalf of Fannie Mae by an authorized officer of Fannie Mae under the corporate seal of Fannie Mae, which may be in facsimile form and be imprinted or otherwise reproduced thereon, and shall be attested by the Secretary, Assistant Secretary, or a second authorized officer of Fannie Mae. The signature of any of these Persons on the Definitive Certificates may be manual or facsimile. A Definitive Certificate bearing the manual or facsimile signature of individuals who were at any time officers of Fannie Mae shall bind Fannie Mae, notwithstanding that such individuals or any of them have ceased to hold such offices prior to the authentication and delivery of such Certificate or did not hold such offices at the date of such Certificate. At any time and from time to time after the execution and delivery of this Trust Agreement, Fannie Mae may deliver the Definitive Certificates executed by Fannie Mae to the Certificate Registrar for authentication and the Certificate Registrar shall authenticate and make available such Certificates as provided in this Trust Agreement and not otherwise. No Definitive Certificates shall be entitled to any benefit under this Trust Agreement or be valid for any purpose, unless there appears on such Definitive Certificates a certificate of authentication substantially in the form provided for herein, executed by the Certificate Registrar by the manual or facsimile signature of one of its authorized signatories, and such certificate upon the Definitive Certificates shall be conclusive evidence, and the only evidence, that such Definitive Certificates has been duly authenticated and made available hereunder. The Definitive Certificates shall be dated the date of their authentication.