5 THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE UNAUDITED FINANCIAL STATEMENTS OF NETWORK-1 SECURITY SOLUTIONS, INC. FOR THE PERIOD ENDED JUNE 30, 1999 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS. 6-MOS DEC-31-1999 JAN-01-1999 JUN-30-1999 2,667,000 0 652,000 160,000 2,000 3,393,000 1,282,000 585,000 5,027,000 1,255,000 0 0 6,000 44,000 3,722,000 5,027,000 113,000 903,000 300,000 1,074,000 3,630,000 0 0 (3,707,000) 0 (3,707,000) 0 0 0 (3,707,000) (0.85) (0.85)