EXHIBIT 32.1 ------------ CERTIFICATION OF CHIEF EXECUTIVE OFFICER Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (18 U.S.C. ss. 1350) Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (18 U.S.C. ss. 1350), the undersigned, Corey M. Horowitz, Chief Executive Officer and Chairman of Network-1 Security Solutions, Inc., a Delaware corporation (the "Company"), does hereby certify to his knowledge, that: The Annual Report of Form 10-KSB for the year ended December 31, 2003 of the Company (the "Report") fully complies with the requirements of Section 13(a) or 15(d) of the Securities Act of 1934, and the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. /s/ Corey M. Horowitz ------------------------------------ Chief Executive Officer and Chairman April 13, 2004 CERTIFICATION OF CHIEF FINANCIAL OFFICER Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (18 U.S.C. ss. 1350) Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (18 U.S.C. ss. 1350), the undersigned, David C. Kahn, Chief Financial Officer of Network-1 Security Solutions, Inc., a Delaware corporation (the "Company"), does hereby certify to his knowledge, that: The Annual Report of Form 10-KSB for the year ended December 31, 2003 of the Company (the "Report") fully complies with the requirements of Section 13(a) or 15(d) of the Securities Act of 1934, and the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. s/David C. Kahn ------------------------------------ Chief Financial Officer April 13, 2004