VirnetX Holding (VHC) 10-Q 2009 Q2 Quarterly report

EXHIBIT 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of VirnetX Holding Corporation (the “Company”,) on Form 10-Q for the quarter ended June 30, 2009 as filed with the Securities and Exchange Commission on August 10, 2009 (the “Report”,) I, William E. Sliney, Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to my knowledge:

(1)     The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2)     The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Company.

/s/ WILLIAM E. SLINEY

William E. Sliney

Chief Financial Officer

(Principal Accounting and Financial Officer)

Date: August 10, 2009