.


                                SERVICE AGREEMENT

             THIS AGREEMENT made and entered into as of May 1, 1999;


BETWEEN:

                              DR. SCOTT A. VANSTONE
                              10140 Pineview Trail
                                  P.O. Box 490
                             Campbellville, Ontario
                                     LOP 1B0
                           (the "Chief Cryptographer")

                                                               OF THE FIRST PART

                                     -and-


                                 CERTICOM CORP.
                     200 Matheson Boulevard West, Suite 200
                          Mississauga, Ontario L5R 3L7
                               (the "Corporation")

                                                              OF THE SECOND PART


THIS AGREEMENT  WITNESSES that in  consideration of the covenants and agreements
herein contained the parties hereto agree as follows:

1.       Services

1.1      Description

          (a)      The Chief Cryptographer will provide the following services:

                   (i)     provision  of and  responsibility  for  research  and
                           development,   in  the   leadership   role  of  Chief
                           Cryptographer,   of  cryptographic   and  information
                           security   systems  on  an  exclusive  basis  to  the
                           Corporation;

                   (ii)    provision  of  technical  support for  marketing  and
                           strategy development;

                   (iii)   provision of product development support;

                   (iv)    the  overseeing  and  training  of the  Corporation's
                           cryptographers;

                   (v)     the identification of strategic intellectual property
                           initiatives;

                                       -1-


<PAGE>


                   (vi)    provision of support for patent activity;

                   (vii)   responsibility for providing research and development
                           of   the    Corporation's    products   relating   to
                           cryptographic and security information systems; and

                   (viii)  such  other  services  as are  mutually  agreed  upon
                           between the Chief  Cryptographer  and the Corporation
                           from time to time.

          (b)      The Chief  Cryptographer  shall commit himself on a full-time
                   basis and provide  active service in person at the offices of
                   the  Corporation  or  such  other  appropriate  site  as  the
                   Corporation  may agree to for an  average  three (3) days per
                   week. At all times, the Chief Cryptographer will use his best
                   efforts  to  respond in a  reasonably  timely  fashion to all
                   e-mail and voicemail  messages relating to the services to be
                   provided by him under this Agreement.

          (c)      The parties  agree that they will discuss and mutually  agree
                   upon the extent of the Chief  Cryptographer's  involvement in
                   such  other  activities  and his  time  commitments  relating
                   thereto.

          (d)      Subject to shareholder approval,  the Chief Cryptographer may
                   be  appointed  as a  member  of the  Corporation's  board  of
                   directors  during  the  term of  this  Agreement  or,  in the
                   alternative,  may attend  meetings of such board of directors
                   as an observer.

1.2       Term and termination

          Unless  otherwise  terminated as provided for in this Agreement,  this
Agreement shall be for a term of five (5) years,  and may be renewed upon mutual
written consent of the parties for successive additional periods of one (1) year
each.  This  Agreement may be terminated by either party upon receipt of written
notice at least  ninety (90) days in advance of the annual  anniversary  date of
this Agreement.  Further, if either party is in breach of any of its obligations
under this  Agreement,  the other party may give notice in writing of the breach
to the  defaulting  party and request the latter to remedy such  breach.  If the
party in breach  fails to remedy the breach  within  thirty  (30) days after the
date of written  notice,  then the Agreement may be  terminated  immediately  by
written notice of termination given by the complaining party.

1.3       Non-Competition

          The Chief Cryptographer agrees that during the term of this Agreement,
and for twelve (12) months following the termination of this Agreement,  without
the prior written approval of the Chief Financial Officer of the Corporation, he
will not become  engaged,  directly or  indirectly  as an employee,  consultant,
partner,  principal,  agent,  proprietor,  shareholder  (other than a holding of
shares  listed on a stock  exchange  that does not exceed 2% of the  outstanding
shares so listed) or advisor, in a business in


                                       -2-


<PAGE>


          (a)      Canada;

          (b)      the United States; or

          (c)      anywhere else in the world where the Corporation  markets its
                   products or services during the term of this Agreement;

                   that

          (i)      develops or markets  software  competitive  with the software
                   owned or marketed by the Corporation, or

          (ii)     provides   consulting,   maintenance,   support  or  training
                   services   that  are   competitive   with   the   consulting,
                   maintenance,  support or  training  services  provided by the
                   Corporation,

provided if, with respect to the period after the termination of this Agreement,
such business has two or more  divisions  located at different  addresses,  then
this Section 1.3 will not prohibit the Chief Cryptographer from becoming engaged
in a division that neither  develops nor markets  software  competitive with the
software  owned or marketed by the  Corporation  nor provides  services that are
competitive with the services provided by the Corporation (provided further that
in such case all the other  obligations  of this  Agreement  shall  continue  to
apply). The Corporation recognizes that the Chief Cryptographer is the owner and
principal  of  SVI  Consulting  Inc.  and  that  the  corporation  excludes  SVI
Consulting Inc. from the terms of this non-compete clause.
                                                                            SAV.

2.        Remuneration

2.1       Fees

          The Corporation  shall pay to the Chief  Cryptographer  an amount that
will provide him with total annual  compensation  including  all amounts paid to
the Chief  Cryptographer  by the University of Waterloo,  other than  publishing
royalties, as follows:

   May 1, 1999 - April 30, 2000               $275,000.00;
   May 1, 2000 - April 30, 2001               $300,000.00;
   May 1, 2001 - April 30, 2002               $325,000.00;
   May 1, 2002 - April 30, 2003               $350,000.00;
   May 1, 2003 - April 30, 2004               $375,000.00.

Such amounts will be paid monthly in advance.

2.2       Compensation Disclosure

          The Chief  Cryptographer  will provide the  Corporation  with full and
timely  disclosure of his compensation  from the University of Waterloo in order
that the fees to be paid as outlined in Section 2.1 above may be calculated.


                                       -3-


<PAGE>


2.3       Stock Options

          During the term of this Agreement,  the Chief  Cryptographer  shall be
entitled to participate in the Corporation's 1997 Stock Option Plan ("1997 SOP")
and any additional stock option plans or stock purchase plans established by the
Corporation.  The grant of any options or other  benefits under such plans shall
be in the discretion of the Corporation,  however, the Corporation  acknowledges
that the contribution of each of the Chief  Cryptographer  and Philip C. Deck is
fundamental  to the success of the  Corporation  and  declares  that  subject to
satisfactory  performance,  it is the intention of the  Corporation to treat the
Chief Cryptographer and Philip C. Deck similarly under the foregoing plans.

2.4       Auto Allowance

          In  addition  to the  amounts  outlined  in  section  2.1,  the  Chief
Cryptographer will receive a monthly auto allowance in the amount of $800.

2.5       Expenses

          The Chief  Cryptographer shall be reimbursed at the Corporation's cost
for all authorized  travelling  and other  out-of-pocket  expenses  actually and
properly incurred by him in connection with his duties  hereunder.  For all such
expenses the Chief Cryptographer shall furnish to the Corporation statements and
vouchers as and when required by the Corporation.

2.6       Issuance of Shares

          In  the  event  of  a  take-over  bid,  an  amalgamation,  a  plan  of
arrangement or other form of business  transaction  pursuant to which holders of
Common  Shares  cease  to own at  least  33% of  the  voting  securities  of the
Corporation   or  surviving   entity   resulting  from  such   transaction   (an
"Acquisition"),  the Corporation  will issue to the Chief  Cryptographer  50,000
Common Shares. Such shares, if issued to the Chief  Cryptographer,  will vest as
to 16,667 of such shares on the first  anniversary  following the  completion of
the  Acquisition  and a further  16,666 of such shares on each of the second and
third  anniversary of the  completion of the  Acquisition.  Notwithstanding  the
foregoing,  in the event that this  Agreement is terminated  by the  Corporation
subsequent  to the  completion  of the  Acquisition,  then all of the  foregoing
shares that have not yet vested will vest  immediately  upon the  termination of
this Agreement.

 3.       Proprietary Rights Agreement

          The Chief  Cryptographer  confirms he has executed and is bound by the
Proprietary  Rights  Agreement   attached  hereto.  The  Chief   Cryptographer's
obligations  under such Proprietary  Rights Agreement shall continue both before
and after he has used any  Confidential  Information  for the  purposes  of such
Proprietary Rights Agreement and both before and after the services of the Chief
Cryptographer  with the Corporation cease, and shall continue until such time as
the Chief  Cryptographer  is expressly released  therefrom by the Corporation in
writing.  The obligations of the Chief  Cryptographer under this Agreement shall
be binding on the executors, administrators or other legal representatives


                                       -4-


<PAGE>


of the  Chief  Cryptographer.  Any  breach  by the  Chief  Cryptographer of this
Agreement or the above  Proprietary  Rights  Agreement  shall cause  irreparable
damage to the  Corporation  and any such breach shall entitle the Corporation to
immediate injunctive relief from a court of competent jurisdiction.

4.        Confidentiality

          All confidential  data and information  concerning the Corporation and
obtained by the Chief Cryptographer during the performance of his services under
this Agreement shall be maintained confidential by the Chief Cryptographer.

5.        Exclusive Contract

          Subject to what is hereinafter stated, the Chief Cryptographer  agrees
that it is a condition of the  Corporation  utilizing  the services of the Chief
Cryptographer,  that the Chief  Cryptographer shall not provide similar services
to any other person,  other than the performance of his duties as a Professor at
the University of Waterloo.  For the purposes of clarity,  it is agreed that the
Chief Cryptographer shall not provide services directly or indirectly during the
term of this Agreement to a competitor of the  Corporation in the  cryptographic
or information security systems fields or in any closely related field of study.
The Corporation  shall be entitled to retain the services of any persons without
restriction during the term of this Agreement.

6.        Assignment

          Neither this  Agreement nor any interest may be assigned in any manner
by either party.

7.        Entire Agreement

          This Agreement  constitutes the entire  agreement  between the parties
with respect to the subject  matter hereof and cancels and  supersedes any prior
understandings  and agreements  between the parties hereto with respect thereto.
There are no representations,  warranties,  forms,  conditions,  undertakings or
collateral agreements,  express,  implied or statutory between the parties other
than as expressly set forth in this Agreement.

8.        Governing Law

          This Agreement  shall be governed by and construed in accordance  with
the laws of the Province of Ontario and the laws of Canada applicable therein.


                                       -5-


<PAGE>




          IN WITNESS WHEREOF the parties have executed this Agreement.

                                 )
/s/ Bruce MacInnis               )         /s/ Scott A. Vanstone
---------------------------------)         -------------------------------------
Witness                          )         Dr. Scott A. Vanstone
Name: Bruce MacInnis             )
Address: 1513 Sturgeon Court     )
         Pickering, ON           )
         L1V 5P6                 )

                                           CERTICOM CORP.

                                           By: /s/ Philip C. Deck
                                              ----------------------------------
                                                   Philip C. Deck
                                                   Chief Executive Officer


                                       -6-