<ARTICLE> 5 <RESTATED> <CIK> 0000932064 <NAME> SECURITY DYNAMICS TECHNOLOGIES INC. <MULTIPLIER> 1,000 <CURRENCY> US DOLLARS <PERIOD-TYPE> YEAR <FISCAL-YEAR-END> DEC-31-1997 <PERIOD-START> JAN-01-1997 <PERIOD-END> SEP-30-1997 <EXCHANGE-RATE> 1 <CASH> 36,988 <SECURITIES> 70,774 <RECEIVABLES> 20,257 <ALLOWANCES> 787 <INVENTORY> 2,744 <CURRENT-ASSETS> 137,663 <PP&E> 21,290 <DEPRECIATION> 5,823 <TOTAL-ASSETS> 161,059 <CURRENT-LIABILITIES> 27,669 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 380 <OTHER-SE> 129,978 <TOTAL-LIABILITY-AND-EQUITY> 161,059<F1> <SALES> 96,202 <TOTAL-REVENUES> 96,202 <CGS> 19,995 <TOTAL-COSTS> 84,875 <OTHER-EXPENSES> 0 <LOSS-PROVISION> 327 <INTEREST-EXPENSE> (3,976) <INCOME-PRETAX> 19,899 <INCOME-TAX> 7,508 <INCOME-CONTINUING> 12,391 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 12,391 <EPS-PRIMARY> 0.314 <EPS-DILUTED> 0.312 <FN> <F1>TOTAL LIABILITY AND EQUITY INCLUDES $3,032 MINORITY INTERESTS </FN>