EXHIBIT 8.3

[Linklaters Letterhead]

One Silk Street

London EC2Y 8HQ

Telephone (44-20) 7456 2000

Facsimile (44-20) 7456 2222

Group 4 Fax (44-20) 7374 9318

DX Box Number 10 CDE

Direct Line 020 7456 5683

Direct Fax 020 7456 2256

dominic.winter@linklaters.com

ActivCard Corp.

6623 Dumbarton Circle

Fremont

California 94555

USA

ActivCard S.A.

24-28, avenue du Général de Gaulle

Suresnes

Cedex

France 92156

24 September 2002

Our Ref                 DAYW

Dear Sirs

We have acted as your special United Kingdom tax counsel in connection with the offer to exchange the common stock and American depositary shares of ActivCard S.A. for common stock of ActivCard Corp. (the “Exchange”).

We have been requested to provide this opinion in connection with the Form S-4 Registration Statement filed on 25 September 2002 in connection with the Exchange (the “Registration Statement”).

We have reviewed the Registration Statement and, in our opinion, the statements under the heading “United Kingdom taxation” in it are correct in all material respects, subject to the qualifications contained in those statements and in the section headed “Material income tax considerations”.

In giving this opinion, we have relied upon the truth and accuracy of the other statements made in the Registration Statement.

We express no opinion as to any statements or documents other than as specified in this letter.

We consent to the reference to our firm under the heading “Material income tax considerations” in the Registration Statement and to the reproduction and filing of this opinion as an exhibit to the Registration Statement.

Yours faithfully

/s/    Linklaters

Linklaters