EXHIBIT 32.1 SECTION 1350 CERTIFICATION OF CHIEF EXECUTIVE OFFICER In connection with the Quarterly Report of CDSI Holdings Inc. (the "Company") on Form 10-QSB for the period ended March 31, 2008 as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, Richard J. Lampen, Chief Executive 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 results of operations of the Company. May 15, 2008 /s/ Richard J. Lampen ---------------------------------------- Richard J. Lampen Chairman and Chief Executive Officer