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                                                                      EXHIBIT 23


                         INDEPENDENT AUDITOR'S CONSENT

To the Board of Directors and Stockholders of
     Security Dynamics Technologies, Inc. and Subsidiaries:

We consent to the incorporation by reference in Registration Statements Nos.
33-87916, 33-88506, 33-88508, 33-88510, 333-08939, 333-31793, 333-52255 and 
333-71075 of Security Dynamics Technologies, Inc. (the "Company") on Forms S-8
and Registration Statement No. 333-49949 of the Company of Form S-3 of our
reports dated January 27, 1999 (which report on consolidated financial
statements expresses an unqualified opinion and includes explanatory paragraphs
referring to the restatement of the consolidated financial statements for
pooling of interests in 1998 and a change in the Company's method of accounting
for option grants requiring stockholder approval in 1996), appearing in and
incorporated by reference in this Annual Report on Form 10-K of the Company for
the year ended December 31, 1998.



/s/ DELOITTE & TOUCHE LLP

Boston, Massachusetts
March 29, 1999