SELLER'S AGREEMENT


         THIS SELLER'S AGREEMENT  ("Agreement") is made as of September 8, 1997,
by and among:  CYLINK CORPORATION,  a California  corporation (the "Purchaser");
A.R.  DATA SECURITY  LTD., a limited  liability  company  organized and existing
under  the  laws  of the  State  of  Israel  (the  "Seller");  and  each  of the
shareholders  of the Seller,  all of which are  identified  on Schedule A hereto
(the "Parent Shareholders").

                                    RECITALS


         A. Contemporaneously with the execution and delivery of this Agreement,
the Purchaser is acquiring from the Seller (i) all of the issued and outstanding
shares of Algorithmic Research Ltd., a limited liability company organized under
the laws of the State of Israel (the  "Company"),  that are owned by the Seller,
and (ii) all of the issued and  outstanding  shares of Algart  Holdings  Ltd., a
limited  liability  company  organized  under  the laws of the  State of  Israel
("Holdings"),  pursuant to that certain Stock  Purchase  Agreement,  dated as of
September  7,  1997,  among the  Purchaser,  the  Company  and the  Seller  (the
"Purchase Agreement").

         B. As part of the  purchase  price for the  shares of the  Company  and
Holdings being acquired by the Purchaser pursuant to the Purchase Agreement, the
Purchaser  is  issuing  a total  of  2,593,169  shares  of  common  stock of the
Purchaser  (the  "Transaction  Shares"),  of which  1,272,300  shares  are being
deposited in escrow in accordance with the terms of the Purchase Agreement.

         C. The  Seller is in the  process  of a  voluntary  liquidation.  It is
contemplated  that,  in  connection  with the  liquidation  of the  Seller,  the
Transaction  Shares  held by the  Seller  will be  distributed  "in kind" by the
Seller to the Parent Shareholders.

         D. This Agreement is being executed and delivered  pursuant to Sections
4.6, 7.6 and 8.5 of the Purchase Agreement.

                                    AGREEMENT

         NOW,  THEREFORE,  in consideration of the mutual promises and covenants
hereinafter set forth, the parties hereto agree as follows:

         1. CERTAIN  DEFINITIONS.  All capitalized  terms used and not otherwise
defined herein shall have the meanings given to them in the Purchase  Agreement.
In  addition,  as used in this  Agreement,  the  following  terms shall have the
following respective meanings:


                                       1


                  "Affiliate" shall mean, with respect to any Person,  any other
Person controlling, controlled by or under common control with such Person.

                  A "Change in Control of the Purchaser" shall be deemed to have
occurred if: (a) any Person (other than Pittway  Corporation) or "group" (within
the meaning of Rule 13d-5 under the Exchange Act) becomes the "beneficial owner"
(within the meaning of Rule 13d-3 under the Exchange Act) of at least 50% of the
voting  securities  of the  Purchaser;  (b) a merger,  consolidation  or similar
transaction  involving  the  Purchaser  or any  affiliate  of the  Purchaser  is
effected,  and the  shareholders  of the  Purchaser  immediately  prior  to such
transaction  own  less  than  60%  of the  voting  securities  of the  surviving
corporation in such  transaction;  (c) assets  representing more than 50% of the
aggregate net book value of the  Purchaser's  assets  (exclusive of its wireless
communications  division)  are sold or  otherwise  transferred  to any Person or
Persons  (in a single  transaction  or a  series  of  transactions);  or (d) the
individuals  who, as of the date of this Agreement,  are members of the Board of
Directors  of the  Purchaser  (the  "Incumbent  Board")  cease for any reason to
constitute  at least  two-thirds  of the  Board of  Directors  of the  Purchaser
(provided,  however,  that if the election,  or  nomination  for election by the
Purchaser's shareholders, of any new director was approved by a vote of at least
two-thirds of the Incumbent Board, such new director shall, for purposes of this
Agreement, be considered as a member of the Incumbent Board).

                  A "Change in Control of the  Company"  shall be deemed to have
occurred if: (a) a Person  (other than the  Purchaser)  becomes the  "beneficial
owner" (within the meaning of Rule 13d-5 under the Exchange Act) of at least 50%
of the voting  securities of the Company (other than in connection with a Change
in Control of the Purchaser);  (b) the Purchaser  ceases to own more than 50% of
the outstanding shares of the Company;  or (c) assets representing more than 50%
of the aggregate  net book value of the  Company's  assets are sold or otherwise
transferred  to any Person or Persons  (in a single  transaction  or a series of
transactions).

                  "Commission"  shall  mean the  United  States  Securities  and
Exchange  Commission,  or any other federal agency at the time administering the
Securities Act.

                  "Exchange Act" shall mean the Securities Exchange Act of 1934,
as amended, or any similar federal statute, and the rules and regulations of the
Commission thereunder.

                  "First Restricted  Period" shall mean the period commencing on
the Closing Date and ending on the day that is 182 days after the Closing Date.

                  "Form  S-1,"  "Form S-3," "Form S-4" and "Form S-8" shall mean
(as the case may be) such form under the  Securities  Act as is in effect on the
date  hereof,  or any  successor  registration  form  to  such  form  under  the
Securities Act subsequently adopted by the Commission.

                                       2


                  "Fourth Restricted Period" shall mean the period commencing on
the second  anniversary  of the Closing  Date and ending on the day  immediately
preceding the third anniversary of the Closing Date.

                  "Holders"  shall  mean:  (a) each  Potential  Seller who holds
Registrable Shares; (b) each Permitted  Transferee who holds Registrable Shares;
and (c) each other Person  holding  Registrable  Shares to whom any rights under
this Agreement shall have been assigned in accordance with Section 7 hereof.

                  "Individual Parent Shareholders" shall mean Yossi Tulpan, Amos
Fiat and Yossi Cohen.

                  A  Parent  Shareholder's  "Percentage  Share"  shall  mean the
"Percentage Share" set forth opposite such Parent Shareholder's name on Schedule
A hereto.

                  "Permitted Transferee" shall mean: (a) any Parent Shareholder;
(b) any Affiliate,  shareholder,  spouse or lineal  descendant of the Seller, of
any  Parent  Shareholder  or  of  any  shareholder  of  any  Parent  Shareholder
(including,  without  limitation,  any corporation or other entity controlled by
any Parent Shareholder); (c) any administrator,  liquidator, executor, guardian,
curator or person acting in a similar capacity for any of the Persons  described
in clauses "(a)" and "(b)" of this sentence; and (d) any trustee of a trust, the
primary  beneficiary or beneficiaries of which are any of the Persons  described
in clauses "(a)," "(b)" and "(c)" of this sentence; provided, however, that Koor
Capital  Markets and Telrad  Holdings  Ltd.  shall not be deemed to be Permitted
Transferees  of any Restricted  Shares  transferred to them by (i) an Individual
Parent  Shareholder or (ii) a Permitted  Transferee who received such Restricted
Shares from an Individual Parent Shareholder.

                  "Person" shall mean any individual, corporation,  partnership,
limited  liability  company,  firm,  joint  venture,  association,   joint-stock
company, trust, unincorporated organization,  governmental or regulatory body or
other entity.

                  "Potential  Sellers"  shall  mean the  Seller  and the  Parent
Shareholders.

                  "Purchaser  Common Stock" shall mean the common  stock,  $0.01
par value per share, of the Purchaser;  provided, however, that if the Purchaser
Common  Stock  is  converted  into or  exchanged  for  other  securities  of the
Purchaser  or of any other  Person  (pursuant  to a merger  or  recapitalization
involving the Purchaser or  otherwise),  then, for purposes of Section 4 hereof,
"Purchaser Common Stock" shall refer to such other securities.

                  "Registrable  Shares" shall mean: (a) the Transaction  Shares;
and (b) any securities issued with respect to, in exchange for or in replacement
of any of the  Transaction  Shares  (whether by way of a stock dividend or stock
split,  in connection  with a combination of shares,  recapitalization,  merger,
consolidation or other reorganization or similar event or 

                                       3


otherwise);  provided,  however,  that shares of Purchaser Common Stock shall be
treated as  Registrable  Shares only if and so long as such shares are held by a
Holder.

                  "Registration  Expenses" shall mean: (a) all expenses,  except
Selling  Expenses,  incurred  in  connection  with a  registration  pursuant  to
Sections  4.1,  4.2  and  4.4  hereof,   including,   without  limitation,   all
registration,  qualification  and  filing  fees,  printing  expenses,  fees  and
disbursements  of counsel for the Purchaser and Blue Sky fees and expenses;  and
(b)  reasonable  fees  and  disbursements   (not  to  exceed  $100,000  for  all
registrations  effected pursuant to this Agreement) of a single U.S. counsel and
a  single  Israeli  counsel  for  the  Holders  who  are   participating   in  a
registration.

                  The terms "register," "registered" and "registration" refer to
a registration  effected by preparing and filing a  registration  statement with
the Commission  and the  declaration  or ordering of the  effectiveness  of such
registration statement.

                  "Regulation S" shall mean  Regulation S promulgated  under the
Securities Act.

                  "Restriction Expiration Date" shall mean the earliest to occur
of: (a) the fourth anniversary of the Closing Date; (b) the date of commencement
of a tender or exchange offer relating to at least 50% of the outstanding shares
of  Purchaser  Common  Stock;  (c) the date on which a Change in  Control of the
Purchaser  occurs;  (d) the date on which a Change  in  Control  of the  Company
occurs;  (e) the date of  execution of any binding  letter of intent,  contract,
agreement or understanding  contemplating  or otherwise  relating to an event of
the  type  referred  to in  clause  "(c)" of this  sentence;  or (f) the date of
occurrence of any material  breach or default by the  Purchaser  with respect to
any of its  obligations  under Section 2 or 4 of this  Agreement or Article V of
the Purchase Agreement,  which breach or default is not cured within twenty (20)
days after notice thereof is given to the Purchaser.

                  "Restricted  Periods" shall mean the First,  Second, Third and
Fourth Restricted Periods.

                  "Restricted  Shares" shall mean only those Transaction  Shares
that are held by the Seller,  the Escrow  Agent (in its  capacity as such),  any
Parent  Shareholder  or  any  Permitted  Transferee;   provided,  however,  that
notwithstanding  anything to the  contrary  contained in this  Agreement:  (a) a
Transaction  Share shall cease to be a  Restricted  Share (and shall cease to be
subject to the restrictions contained in this Agreement) upon the earlier of (i)
the  Restriction  Expiration  Date, or (ii) the sale of such  Transaction  Share
pursuant to Section 3.1(a),  3.1(b),  3.1(c),  3.1(d) or 3.1(f) hereof;  and (b)
upon the occurrence of a Special Termination Event with respect to an Individual
Parent  Shareholder,  all  Transaction  Shares  held by such  Individual  Parent
Shareholder, and all Transaction Shares held by any Permitted Transferee to whom
such Individual Parent Shareholder has transferred any Transaction Shares, shall
cease to be Restricted Shares (and shall cease to be subject to the restrictions
contained in this Agreement).

                                       4



                  "Rule  144"  shall  mean  Rule  144   promulgated   under  the
Securities  Act,  or  any  similar  or  analogous  rule  promulgated  under  the
Securities Act.

                  "Second Restricted Period" shall mean the period commencing on
the day immediately  following the last day of the First  Restricted  Period and
ending on the day  immediately  preceding the first  anniversary  of the Closing
Date.

                  "Securities  Act" shall mean the  Securities  Act of 1933,  as
amended,  or any similar federal  statute,  and the rules and regulations of the
Commission thereunder.


                  "Selling  Expenses"  shall  mean all  underwriting  discounts,
selling  commissions  and stock  transfer  taxes  applicable  to the  securities
registered  by the  Holders  and  (except as  otherwise  specified  above in the
definition of "Registration Expenses") all fees and disbursements of counsel for
any Holder.

                  A "Special  Termination  Event" with respect to an  Individual
Parent  Shareholder  shall be deemed to have occurred if: (a) the  employment of
such  Individual  Parent  Shareholder  with the Company or any of the  Company's
Affiliates  shall have been  terminated  by the Company or any of the  Company's
Affiliates  (other  than  for  reasons  described  in  sub-paragraph  6.3 of the
Employment   Agreement   between  the  Company   and  such   Individual   Parent
Shareholder);  or (b) such  Individual  Parent  Shareholder  shall  have died or
become disabled.

                  "Special   Qualifying  Block  Trade"  shall  mean  a  sale  of
Restricted  Shares that: (a) is made in a block trade at a price of at least $15
per share;  and (b) is designated by the Seller of such Restricted  Shares (in a
written notice given to the Purchaser within 120 days following such sale) to be
a "Special Qualifying Block Trade"; provided, however, that at any time prior to
the second  anniversary of the Closing Date,  any Potential  Seller may (without
the  consent or  approval  of the  Purchaser  or any other  Person)  rescind its
designation of any such sale as a "Special Qualifying Block Trade."

                  "Third Restricted  Period" shall mean the period commencing on
the first  anniversary  of the  Closing  Date and ending on the day  immediately
preceding the second anniversary of the Closing Date.

         2.       TRANSFERABILITY OF TRANSACTION SHARES.

                  Except  as   expressly   provided  in  this   Agreement,   the
Transaction Shares (and any other securities issued with respect to, in exchange
for or in  replacement  of  any  of the  Transaction  Shares)  shall  be  freely
tradeable and  transferable,  and the Purchaser  shall take or cause to be taken
all actions necessary to ensure that the Transaction  Shares (and any such other
securities) can legally be sold, publicly and otherwise,  within and outside the
United States,  without any  restriction or limitation of any nature;  provided,
however,  that, in the event that applicable U.S. federal  securities laws shall
limit the  ability  of any  Holder to sell any of the  

                                        5


Transaction  Shares,  the obligations of the Purchaser to cause such Transaction
Shares  to be freely  tradeable  and  transferrable  shall be  limited  to those
obligations of the Purchaser set forth in Section 4 hereof. Without limiting the
generality of the foregoing,  to the extent that any Holder  determines (in such
Holder's  reasonable  judgment)  that in  order  for such  Holder  to be able to
legally  sell  publicly  in  the  United  States  (without  any  restriction  or
limitation of any nature) any  Transaction  Shares that such Holder is otherwise
not  restricted  from  selling  pursuant to Section 3 hereof,  such Holder shall
notify the Purchaser of such determination and the Purchaser shall take or cause
to be taken the  actions  referred  to in  Sections  4.1 and 4.4  hereof (or the
actions  referred to in Section 4.8 hereof).  The Purchaser  agrees that it will
use  reasonable  efforts  to  furnish  to the  Potential  Sellers,  on or before
September  18,  1997,  a written  opinion of  Morrison  & Foerster  LLP or other
reputable U.S.  securities  counsel  (reasonably  satisfactory  to the Potential
Sellers  in form  and  substance)  that,  from and  after  the  forty-first  day
following the Closing Date, the sale of the Transaction  Shares by the Potential
Sellers will be exempt from  registration  under the  Securities Act and will be
exempt from (or otherwise not subject to) registration and  qualification  under
state  securities  laws;  provided,  however,  that the Purchaser  shall have no
obligation under this sentence if any of the  representations  and warranties of
the Seller contained in Section 2.33, 2.34 or 2.35 of the Purchase  Agreement is
inaccurate in any material respect.

         3.       RESALES OF RESTRICTED SHARES.

                  3.1      Resale Restrictions.

                           The Potential Sellers shall not be permitted to sell,
transfer or assign any Restricted Shares during the Restricted  Periods,  except
as follows:

                           (a)  During  the  Second   Restricted   Period,   the
Potential  Sellers may (without  being deemed to have breached  this  Agreement)
sell, transfer and/or assign a total of up to 218,000 Restricted Shares.

                           (b) During the Third Restricted Period, the Potential
Sellers  may  (without  being  deemed to have  breached  this  Agreement)  sell,
transfer and/or assign a total of up to 1,307,000  Restricted Shares,  minus the
number of Restricted  Shares that were sold by the Potential  Sellers during the
Second Restricted Period pursuant to Section 3.1(a) hereof.

                           (c) In addition to the Restricted  Shares that may be
sold,  transferred  and assigned by the Potential  Sellers  pursuant to Sections
3.1(a) and 3.1(b) hereof,  during the First, Second and Third Restricted Periods
(exclusive of the first 40 days of the First Restricted  Period),  the Potential
Sellers may (without being deemed to have breached this  Agreement) sell a total
of up to 250,000 Restricted Shares in Special Qualifying Block Trades; provided,
however,  that,  during the period  commencing on the Closing Date and ending on
the day  immediately  preceding the second  anniversary of the Closing Date, the
Purchaser  may,  on one  occasion,  prohibit  the sale of  Restricted  Shares in
Special  Qualifying  Block  Trades  (but  may not  prohibit

                                       6


any other  sale of  Restricted  Shares  except  as  expressly  provided  in this
Agreement)  (i) while the  Purchaser  is actively  engaged in a firm  commitment
underwritten  public offering of at least 1,000,000  shares of Purchaser  Common
Stock,  or (ii)  for a  period  of 30 days  following  the  consummation  by the
Purchaser  of a public sale of at least  1,000,000  shares of  Purchaser  Common
Stock pursuant to a firm  commitment  underwriting,  provided that the Purchaser
first  furnishes  to  the  Potential   Sellers  written  notice  and  reasonably
satisfactory  evidence  that  the  Purchaser  is  actively  engaged  in  such an
offering, or has so consummated such a sale.

                           (d)  During  the  Fourth   Restricted   Period,   the
Potential  Sellers may (without  being deemed to have breached  this  Agreement)
sell, transfer and/or assign up to 2,376,000 Restricted Shares, minus the number
of Restricted  Shares that were sold by the Potential  Sellers during the Second
and Third Restricted Periods pursuant to Sections 3.1(a) and 3.1(b) hereof.



                           (e) The Potential  Sellers may (without  being deemed
to have  breached this  Agreement)  sell,  transfer  and/or assign any number of
Restricted Shares to any Permitted  Transferee at any time and from time to time
during any Restricted Period, provided that any such Permitted Transferee agrees
in writing,  prior to the sale, transfer or assignment to him of such Restricted
Shares, to be bound by all of the applicable  provisions of this Agreement as to
all such Restricted Shares so sold, transferred or assigned to him.

                           (f) The Potential  Sellers may (without  being deemed
to have breached this Agreement) sell,  transfer and/or assign Restricted Shares
during any  Restricted  Period in accordance  with the provisions of Section 4.2
hereof.

                  3.2      Overall Monthly Limitation.

                           The number of  Restricted  Shares that may be sold by
the Potential  Sellers  pursuant to Sections 3.1(a),  3.1(b),  3.1(c) and 3.1(d)
hereof in any  particular  calendar  month during the period  commencing  on the
Closing Date and ending on the last day of the full calendar  month  immediately
preceding the fourth  anniversary of the Closing Date shall not exceed 8.711% of
the  aggregate  number  of  shares  of  Purchaser  Common  Stock  traded  on all
securities  exchanges  and  reported  through  Nasdaq  and any  other  automated
quotation system during the calendar month immediately preceding such particular
calendar month.

                  3.3      Percentage Share Limitation.

                           Each Individual  Parent  Shareholder  agrees that the
total number of Restricted  Shares sold by such  Individual  Parent  Shareholder
pursuant to Sections 3.1(a),  3.1(b), 3.1(c) and 3.1(d) hereof during the period
from the Closing Date through the end of the Fourth  Restricted  Period will not
exceed such Individual Parent Shareholder's Percentage Share of 2,376,000.

                                       7


                  3.4      Termination of Restrictions.

                           (a)   Notwithstanding   anything   to  the   contrary
contained  in this  Agreement,  all  restrictions  set forth in Section 3 hereof
(that have not  previously  terminated)  shall  terminate and cease to be of any
further force or effect upon the Restriction Expiration Date; provided, however,
that the rights  granted to the  Potential  Sellers and the other  Holders under
this  Agreement  (including  the  registration  rights  granted  under Section 4
hereof)  shall  survive  any such  termination  and  continue  in full force and
effect. Without limiting the generality of the foregoing,  the rights granted by
the Purchaser  pursuant to Section 4 hereof shall survive any merger  involving,
and any other Change in Control of, the Purchaser.

                           (b)   Notwithstanding   anything   to  the   contrary
contained in this  Agreement:  (i) upon the occurrence of a Special  Termination
Event with respect to an Individual  Parent  Shareholder,  all  restrictions set
forth in Section 3 hereof (that have not previously  terminated)  shall cease to
apply to such  Individual  Parent  Shareholder  and shall  cease to apply to any
Permitted  Transferee to whom such Individual Parent Shareholder has transferred
any Transaction  Shares;  (ii) any shares of Purchaser Common Stock sold by such
Individual  Parent  Shareholder  or any  such  Permitted  Transferee  after  the
occurrence  of a Special  Termination  Event shall not be taken into  account in
determining  the number of Restricted  Shares sold  pursuant to Section  3.1(a),
3.1(b), 3.1(c), 3.1(d) or 3.2 hereof; and (iii) for each Restricted Period after
the Restricted  Period in which a Special  Termination Event occurs with respect
to an Individual Parent Shareholder,  the aggregate maximum number of Restricted
Shares that can be sold by the  remaining  Parent  Shareholders  pursuant to the
applicable  provision  of  Section  3.1 shall be reduced by the number of shares
equal to such Individual Parent Shareholder's Percentage Share of the previously
applicable  aggregate  maximum  number of  Restricted  Shares that could be sold
under  said  provision  of  Section  3.1.  (Thus,  for  example,  if  a  Special
Termination Event occurs with respect to Yossi Tulpan (whose Percentage Share is
31.407%) in the Third Restricted  Period,  then the maximum number of Restricted
Shares that could be sold pursuant to Section  3.1(d) hereof by the other Parent
Shareholders  would be equal to 68.593% of the amount by which 2,376,000 exceeds
the number of Restricted Shares that were sold by the Potential Sellers pursuant
to Sections 3.1(a) and 3.1(b) hereof.)  Notwithstanding anything to the contrary
contained  in this  Agreement,  the  rights  granted  to the  Individual  Parent
Shareholders and their Permitted Transferees under this Agreement (including the
registration  rights  granted  under  Section 4 hereof)  shall  survive any such
termination and continue in full force and effect.

                  3.5      Hedging Transactions.

                           Nothing  contained in this  Agreement will operate to
limit the  ability  of any  Potential  Seller to lend any  Restricted  Shares in
connection  with, or otherwise  engage in,  conventional  "collar"-type or other
"hedging"  transactions at any time after the Closing;  provided,  however, that
(i) the  Potential  Sellers  shall not be permitted  to engage in any  "hedging"
transactions  with respect to their  Restricted  Shares during the 40-day period
commencing  as of the Closing Date if such  transactions  would  jeopardize  the
availability  of the  

                                       8


Regulation  S exemption  for the  issuance of the  Purchaser  Common Stock being
issued to the Seller at the Closing;  and (ii) nothing contained in this Section
3.5 shall be deemed to allow a Potential  Seller to sell or  otherwise  transfer
all of such Potential Seller's  beneficial  interest in his Restricted Shares if
such transfer would violate Section 3.1 hereof.

         4.       REGISTRATION.

                  4.1      Shelf/Demand Registration.

                           (a) If the Purchaser  shall not have delivered to the
Potential  Sellers,  on or prior to  September  18,  1997,  the written  opinion
referred  to in the last  sentence  of  Section 2 hereof,  the  Purchaser  shall
promptly (and in any event prior to September 22, 1997) file with the Commission
a  registration  statement  on  Form  S-3  (a  "Shelf  Registration  Statement")
providing for the sale of 468,000  Registrable  Shares,  and the Purchaser shall
use its reasonable efforts to cause such Shelf Registration  Statement to become
effective  no later than the date 40 days after the  Closing  Date and to remain
continuously  effective until the earlier of (i) the date on which the Potential
Sellers may sell all such Registrable  Shares publicly in the United States (and
otherwise) without any restriction or limitation of any nature, or (ii) the date
on which the  distribution  described  in the Shelf  Registration  Statement  is
complete.

                           (b) Any  Holder may  request  at any time  during the
sixty day period  immediately  preceding  the first day of the Third  Restricted
Period that the Purchaser  register  under the Securities Act all or any part of
the Registrable  Shares that may be sold during the Third Restricted  Period. If
the Purchaser receives such a request,  then, subject to Sections 4.1(d) and 4.8
hereof,  the  Purchaser  shall (i)  within 10 days  after  its  receipt  of such
request,  give written notice thereof to all other Holders,  and (ii) as soon as
practicable  after its receipt of such  request (but in any event within 30 days
after its receipt of such request),  effect a registration  under the Securities
Act of all Registrable Shares that (A) the Holders request to be registered, and
(B) may be sold during such Third Restricted  Period in accordance with Sections
3.1(b) and 3.1(c)  hereof.  The Purchaser  shall use its  reasonable  efforts to
cause such registration to remain  continuously  effective until the earliest of
(A) the day  immediately  preceding the second  anniversary of the Closing Date,
(B) the  date 30 days  after  delivery  to all  Holders  of a legal  opinion  or
"no-action"  letter  and other  documentation  satisfying  the  requirements  of
Section 4.8 hereof,  or (C) the date on which the  distribution  covered by such
registration is complete.

                           (c) Any  Holder may  request  at any time  during the
sixty day period  immediately  preceding the first day of the Fourth  Restricted
Period that the Purchaser  register  under the Securities Act all or any part of
the Registrable  Shares that may be sold during the Fourth Restricted Period. If
the Purchaser receives such a request,  then, subject to Sections 4.1(d) and 4.8
hereof,  the  Purchaser  shall (i)  within 10 days  after  its  receipt  of such
request,  give written notice thereof to all other Holders,  and (ii) as soon as
practicable  after its receipt of such  request (but in any event within 30 days
after its receipt of such request),  effect a registration  under the Securities
Act of all Registrable Shares that (A) the Holders request to be registered,

                                       9




and (B) may be sold during  such Fourth  Restricted  Period in  accordance  with
Section 3.1(d) hereof.  The Purchaser shall use its reasonable  efforts to cause
such registration to remain continuously  effective until the earlier of (A) the
date 30 days after  delivery  to all  Holders of a legal  opinion or "no action"
letter and other  documentation  satisfying  the  requirements  of  Section  4.8
hereof,  or (B) the date on which the distribution  covered by such registration
is complete.

                           (d)   Notwithstanding   anything   to  the   contrary
contained  in Section 4.1 hereof,  the  Purchaser  shall have no  obligation  to
effect  any  registration  pursuant  to  Section  4.1(b)  or 4.1(c)  unless  the
aggregate number of Registrable Shares requested to be registered shall be equal
to or greater than 100,000.

                  4.2      Purchaser Registration.

                           (a)  Notice of  Registration.  If at any time or from
time to time the Purchaser  shall  determine to effect a  registration  with the
Commission of any securities for its own account (other than on Form S-4 or Form
S-8) or for the account of any other Person, the Purchaser will:

                                    (i)  promptly  (and in any event at least 45
days prior to the filing of a  registration  statement  under the Securities Act
with respect to such securities) give to all Holders written notice thereof; and

                                    (ii) include in such  registration  (and any
related  registration or qualification  under Blue Sky laws), and in the related
underwriting  (if any) all  Registrable  Shares that the Holders request to have
included  in such  registration  (such  request to be in writing  and to be made
within 30 days after  receipt by all  Holders of such  written  notice  from the
Purchaser).

                           (b)  Underwriting.  If the  registration of which the
Purchaser  gives  notice  is  for a  registered  public  offering  involving  an
underwriting, the Purchaser shall so advise the Holders as a part of the written
notice given pursuant to Section  4.2(a)(i)  hereof.  In such event the right of
any Holder to have Registrable  Shares included in the registration  pursuant to
this Section 4.2 shall be conditioned  upon such Holder's  participation in such
underwriting. All Holders proposing to distribute any Registrable Shares through
such underwriting  shall (together with the Purchaser and the other shareholders
of the  Purchaser  distributing  their shares of Purchaser  Common Stock through
such underwriting)  enter into an underwriting  agreement in customary form with
the  managing  underwriter  selected  for such  underwriting  by the  Purchaser.
Notwithstanding  any other  provision  of this  Section  4.2,  if such  managing
underwriter reasonably determines that marketing factors require a limitation of
the  number  of  shares  of  Purchaser  Common  Stock  to be  included  in  such
registration and underwriting, the managing underwriter may exclude or otherwise
limit the number of shares of  Purchaser  Common  Stock to be  included  in such
registration  and  underwriting  by  shareholders  of the Purchaser,  including,

                                       10


without limitation, the Holders, prior to the exclusion of any shares to be sold
pursuant to such  registration and underwriting by the Purchaser.  The number of
Registrable  Shares that may be included in the  registration  and  underwriting
shall be allocated among all the participating Holders and other shareholders of
the Purchaser participating in such registration and underwriting in proportion,
as nearly as practicable,  to the respective  numbers of Registrable Shares held
by such Holders  (and  requested  to be included in such  registration)  and the
number of shares of Purchaser Common Stock held by such other  shareholders (and
requested  to be  included  in such  registration)  at the  time of  filing  the
registration  statement.  To facilitate  the  allocation of shares in accordance
with the  above  provisions,  the  Purchaser  may  round  the  number  of shares
allocated to any Holder or shareholder to the nearest 100 shares.  If any Holder
disapproves  of the terms of any such  underwriting,  such  Holder  may elect to
withdraw  therefrom  by  written  notice  to  the  Purchaser  and  the  managing
underwriter.  Any securities  excluded or withdrawn from such underwriting shall
be withdrawn from such registration.

                           (c)   Restrictions   Not  Applicable.   None  of  the
restrictions  contained  in  Section  3  hereof  shall  apply  to  any  sale  of
Registrable Shares pursuant to a registration under this Section 4.2.

                           (d) Right to Terminate  Registration.  The  Purchaser
shall have the right to terminate or withdraw any  registration  initiated by it
under this Section 4.2 prior to the effectiveness of such registration,  whether
or  not  any  Holder  has  elected  to  include   Registrable   Shares  in  such
registration.

                           (e) No Other Grants of Registration  Rights.  Without
the prior written  consent of the  Potential  Sellers,  the Purchaser  shall not
grant to any Person any rights to have any shares of Purchaser  Common Stock, or
any securities  convertible  into or exchangeable for shares of Purchaser Common
Stock,  registered  under the  Securities Act on terms more favorable than those
set forth in this Agreement.

                  4.3 Expenses of Registration.  All Registration Expenses shall
be borne  exclusively by the Purchaser.  Unless  otherwise  stated,  all Selling
Expenses  relating to  Registrable  Shares shall be borne by the Holders of such
Registrable  Shares pro rata on the basis of the number of Registrable Shares so
sold.

                  4.4 Registration Procedures.  In the case of each registration
effected by the Purchaser pursuant to this Agreement,  the Purchaser will: (a) a
reasonable number of days prior to filing any registration statement, prospectus
or amendment or supplement  thereto with the Commission,  furnish a copy of such
registration  statement,  prospectus  or amendment or  supplement to each Holder
participating  in such  registration  for such  Holder's  review;  (b) keep each
Holder  advised  in  writing  as to the  initiation  of  each  registration  and
qualification and as to the completion  thereof;  and (c) at the Purchaser's own
expense and as expeditiously as possible:

                                       11



                           (i)   prepare   and  file  with  the   Commission   a
         registration statement on Form S-3 (in the case of a registration under
         Section  4.1(a)  hereof) and, in all other  cases,  on Form S-1 or Form
         S-3, as the Purchaser shall determine,  and use its reasonable  efforts
         to cause such registration statement to become and remain effective for
         such  period  as may be  specified  in  this  Agreement  or,  if not so
         specified,  such  period that shall end on the earlier of: (A) the date
         270 days after its effectiveness, or (B) the date upon which all of the
         securities covered thereby have been sold by the Holders;

                           (ii)  furnish to each  Holder  participating  in such
         registration  upon  request  such  reasonable  number  of copies of the
         registration  statement  (and  each  amendment  thereto),   preliminary
         prospectus and final  prospectus (and each supplement  thereto) as such
         Holder  may  reasonably  request  in order  to  facilitate  the  public
         offering of the  securities  covered  thereby,  including all documents
         incorporated  therein by reference  (whether  filed with the Commission
         before or after the registration  statement becomes  effective) and all
         exhibits thereto;

                           (iii) use its reasonable  efforts to (A) register and
         qualify (or obtain  appropriate  exemptions  for) the shares covered by
         such  registration  statement  under such other  securities or Blue Sky
         laws of such  states  and other  jurisdictions  as shall be  reasonably
         requested  by  the  Holders,   and  (B)  keep  such  registrations  and
         qualifications  in effect  for so long as each  registration  statement
         remains in effect;  provided,  however, that the Purchaser shall not be
         required  in  connection  therewith  or as a  condition  thereto to (1)
         qualify to do business in any such jurisdiction,  (2) subject itself to
         taxation  in any such  jurisdiction,  or (3) file a general  consent to
         service of process in any such jurisdiction;

                           (iv)  in  the  event  of  any   underwritten   public
         offering,  enter into and perform its obligations under an underwriting
         agreement (in usual and customary form) with the managing  underwriters
         of such offering;

                           (v)  prepare  and  file  with  the  Commission   such
         amendments  and  supplements  to such  registration  statement  and the
         prospectus  used in  connection  therewith  as may be necessary to keep
         such  registration  statement  effective for the applicable  period set
         forth  in  this  Agreement,  and  comply  with  the  provisions  of the
         Securities Act with respect to the disposition of all shares covered by
         such  registration  statement during such period in accordance with the
         intended  methods of  disposition  by the sellers  thereof set forth in
         such registration statement;

                           (vi)   cause   all   securities   covered   by   such
         registration  statement  to be listed on each  securities  exchange  or
         interdealer  quotation system of the National Association of Securities
         Dealers,  Inc. on which similar  securities issued by the Purchaser are
         then listed;
                                       12


                           (vii) provide a transfer  agent and registrar for all
         securities  covered by such  registration  statement not later than the
         effective date of such registration statement;

                           (viii)  notify  each  Holder  participating  in  such
         registration, promptly after the Purchaser receives notice thereof, (A)
         of the time when such registration statement has become effective,  and
         (B) at any time when a prospectus is required to be delivered under the
         Securities Act in connection with any registration statement (1) of the
         happening  of  any  event  as  a  result  of  which  such  registration
         statement,  such prospectus,  any prospectus supplement or any document
         incorporated  by reference in any of the  foregoing  contains an untrue
         statement  of a  material  fact or  omits to state  any  material  fact
         required  to be stated  therein  or  necessary  to make the  statements
         therein,  in the light of the circumstances  under which they are made,
         not  misleading  or (2) that the Purchaser is in possession of material
         information  that it deems  advisable not to disclose in a registration
         statement;

                           (ix)  advise  each  Holder   participating   in  such
         registration,  promptly  after the Purchaser  shall  receive  notice or
         obtain  knowledge  thereof,  of the  issuance  of any stop order by the
         Commission suspending the effectiveness of such registration  statement
         or the initiation or threatening of any proceeding for such purpose and
         promptly use its reasonable efforts to prevent the issuance of any stop
         order or to obtain its withdrawal (at the earliest practicable date) if
         such stop order should be issued; and

                           (x) prior to the  effectiveness of such  registration
         statement and any post-effective  amendment thereto and at each closing
         of an underwritten offering,  (A) make such reasonable  representations
         and warranties to the Holders  participating in such registration,  and
         the  underwriters,  if any, with respect to the Registrable  Shares and
         the  registration  statement  as are  customarily  made by  issuers  to
         underwriters and selling  shareholders in underwritten  offerings,  (B)
         obtain  opinions of counsel to the Purchaser and updates thereof (which
         counsel and which  opinions  shall be  reasonably  satisfactory  to the
         underwriters,  if  any,  and to  Holders  who  hold a  majority  of the
         Registrable Shares being sold pursuant to such registration)  addressed
         to each  selling  Holder and the  underwriters,  if any,  covering  the
         matters  customarily  covered in opinions requested in public offerings
         and such other matters as may be  reasonably  requested by such Holders
         and  underwriters or their counsel,  (C) obtain  "comfort"  letters and
         updates  thereof  from the  Purchaser's  independent  certified  public
         accountants  addressed to the selling Holders and the underwriters,  if
         any,  such letters to be in customary  form and to cover matters of the
         type customarily covered in "comfort" letters given to underwriters and
         selling   shareholders  in  connection   with  secondary   underwritten
         offerings,  and (D) deliver such documents and  certificates  as may be
         reasonably  requested  by the Holders of a majority of the  Registrable
         Shares   being  sold   pursuant  to  such   registration   and  by  the
         underwriters,  if any, to evidence  compliance  with clause (A) of this
         clause  "(x)"  and  with  any  customary  conditions  contained  in the
         underwriting   agreement  or  other  agreement   entered  into  by  the
         Purchaser.



                                       13



                  4.5      Indemnification.

                           (a) The  Purchaser  will  indemnify  each  Holder who
holds  any   Registrable   Shares  that  are  included  in  a  registration   or
qualification  pursuant  to  this  Agreement  and  each  person  controlling  or
controlled by such Holder within the meaning of Section 15 of the Securities Act
against any expenses,  claims,  losses,  damages or  liabilities  (or actions in
respect thereof),  including any of the foregoing  incurred in settlement of any
litigation,  commenced or threatened,  arising out of or based on (i) any untrue
statement (or alleged  untrue  statement)  of a material  fact  contained in any
registration statement,  prospectus, offering circular or other document, or any
amendment or supplement  thereto,  used in connection with such  registration or
qualification,  or (ii) any  omission (or alleged  omission) to state  therein a
material fact required to be stated  therein or necessary to make the statements
therein,  in  light  of the  circumstances  under  which  they  were  made,  not
misleading,  or (iii) any violation by the Purchaser of the Securities  Act, the
Exchange  Act,  any  state or other  securities  laws or any rule or  regulation
promulgated  under such acts or laws  applicable  to the Purchaser in connection
with any such  registration or  qualification.  In addition,  the Purchaser will
reimburse each such Holder, and each person so controlling or controlled by such
Holder, for any legal or other expenses  reasonably  incurred,  as such expenses
are incurred, in connection with investigating, preparing to defend or defending
any such claim, liability or action; provided,  however, that the Purchaser will
not be liable to any such  Holder in any such case to the  extent  that any such
expense,  loss,  damage or  liability  arises  out of or is based on any  untrue
statement  of  a  material  fact  made  by  the  Purchaser  in  the   applicable
registration  statement  in  reliance  upon and in  conformity  with  inaccurate
information  furnished  in  writing  to the  Purchaser  by any  Holder or person
controlling  such  Holder  expressly  for  use  in the  applicable  registration
statement.

                           (b) Each Holder will, if  Registrable  Shares held by
such  Holder  are  included  in  the  shares  as  to  which  a  registration  or
qualification  is being  effected  pursuant  to this  Agreement,  indemnify  the
Purchaser and each person  controlling or controlled by the Purchaser within the
meaning  of Section 15 of the  Securities  Act  against  any  expenses,  claims,
losses, damages or liabilities (or actions in respect thereof) arising out of or
based on any untrue  statement of a material fact contained in any  registration
statement,  prospectus, offering circular or other document, or any amendment or
supplement thereto,  used in connection with such registration or qualification,
and will reimburse the  Purchaser,  and each person so controlling or controlled
by the Purchaser,  for any legal or other expenses reasonably incurred,  as such
expenses are incurred, in connection with investigating,  preparing to defend or
defending any such claim,  liability or action based on such untrue statement of
a material fact, in each case to the extent,  but only to the extent,  that such
untrue  statement of a material  fact is made in reliance upon and in conformity
with inaccurate information furnished in writing to the Purchaser by such Holder
or  person   controlling  such  Holder  expressly  for  use  in  the  applicable
registration  statement.  Notwithstanding  anything to the contrary contained in
this Section 4.5(b) or elsewhere in this Agreement, any obligation of any Holder
to indemnify or reimburse  any person  pursuant to this Section shall be several
and not joint and shall be  limited to the net amount of 

                                       14


proceeds received by such Holder from the sale of Registrable Shares pursuant to
the registration or qualification  in connection with which  indemnification  or
reimbursement has been sought.

                           (c) Each party entitled to indemnification under this
Section 4.5 (the "Indemnified Party") shall give notice to the party required to
provide   indemnification   (the  "Indemnifying   Party")  promptly  after  such
Indemnified Party has actual knowledge of any claim as to which indemnity may be
sought;  provided,  however,  that the failure of any Indemnified  Party to give
notice as  provided  herein  shall not  relieve  the  Indemnifying  Party of its
obligations  under  this  Section  4.5 unless  the  failure to give such  notice
materially prejudices the rights or defenses of the Indemnifying Party, in which
case the  Indemnifying  Party shall be relieved  of its  obligations  under this
Section 4.5 to the extent of such  prejudice.  In the event of the  assertion or
commencement of any claim or litigation for which indemnification may be sought,
the  Indemnifying  Party  shall have the right to assume the defense of any such
claim or  litigation  with  counsel  approved by the  Indemnified  Party  (whose
approval shall not be unreasonably  withheld),  and the Indemnified  Party shall
have the right to  participate  in such  defense at its own  expense;  provided,
however,  that the  Indemnifying  Party  shall not have the right to assume  the
defense of any matters as to which representation of both the Indemnifying Party
and the  Indemnified  Party  by the same  counsel  would  be  inappropriate  (as
reasonably  determined by the  Indemnified  Party based on the written advice of
counsel) due to actual or potential  differing interests between them, but shall
instead in such event pay the reasonable fees and costs of separate  counsel for
the Indemnified  Party. No Indemnifying  Party, in the defense of any such claim
or litigation,  shall,  except with the consent of each Indemnified Party (which
consent shall not be unreasonably  withheld) consent to entry of any judgment or
enter into any  settlement  which  does not  include  as an  unconditional  term
thereof the giving by the claimant or plaintiff to such  Indemnified  Party of a
release from all liability in respect to such claim or litigation.

                           (d)  If the  indemnification  provided  for  in  this
Section 4.5 is held by a court of competent jurisdiction to be unavailable to an
Indemnified  Party with respect to any  expenses,  claims,  losses,  damages and
liabilities  referred  to  herein,  then  the  Indemnifying  Party,  in  lieu of
indemnifying  such Indemnified  Party hereunder,  shall contribute to the amount
paid or payable by such Indemnified Party as a result of such expenses,  claims,
losses,  damages or liabilities in such  proportion as is appropriate to reflect
not only the relevant benefits  received by the Indemnifying  Party but also the
relative fault of the Indemnifying  Party on the one hand and of the Indemnified
Party on the other in connection  with the  statements,  omissions or violations
that resulted in such expenses,  claims,  losses, damages or liabilities as well
as any  other  relevant  equitable  considerations.  The  relative  fault of the
Indemnifying Party and of the Indemnified Party shall be determined by reference
to,  among other  things,  whether any untrue or alleged  untrue  statement of a
material  fact or the omission to state a material  fact relates to  information
supplied by the Indemnifying  Party or by the Indemnified Party and the parties'
relative intent, knowledge,  access to information and opportunity to correct or
prevent such statement or omission;  provided,  however, that, in any such case,
no Person guilty of fraudulent  misrepresentation (within the meaning of Section
11(f) of the Securities  Act) will be entitled to  contribution  from any Person
who was not guilty of such fraudulent misrepresentation.


                                       15



                  4.6      Information Regarding Holder.

                           Each Holder whose Registrable  Shares are included in
any  registration  under this  Agreement  shall  furnish to the  Purchaser  such
information  regarding such Holder,  the Registrable  Shares held by such Holder
and the  distribution  proposed by such Holder as the Purchaser  may  reasonably
request in  writing,  to the extent  such  information  is required by law to be
disclosed in the applicable registration statement.

                  4.7      Termination of Registration Rights.

                           The rights  granted  pursuant to this Section 4 shall
terminate as to any Holder at such time as such Holder can immediately  sell all
of the  Registrable  Shares held by such Holder without  restriction  (under the
Securities Act or otherwise) in accordance with Rule 144.

                  4.8      Opinion of Counsel/"No Action" Correspondence.

                           In lieu of taking the actions referred to in Sections
4.1 and 4.4 hereof,  the Purchaser may, at its sole expense,  obtain and deliver
to a Holder who desires to effect a sale of  Registrable  Shares:  (a) a written
opinion of Morrison & Foerster LLP or other  reputable U.S.  securities  counsel
(reasonably  satisfactory  to such Holder in form and  substance)  that, or such
other evidence  (reasonably  satisfactory  in form and substance to such Holder)
indicating  that,  such  sale is  exempt  from (or  otherwise  not  subject  to)
registration and qualification under state securities laws; and (b) either (i) a
written  opinion of Morrison & Foerster LLP or other  reputable U.S.  securities
counsel (reasonably satisfactory in form and substance to such Holder) that such
sale is exempt from  registration  under the  Securities  Act, or (ii) a writing
executed by an authorized  representative  of the  Commission to the effect that
the Commission  would take no action with respect to such sale.  Nothing in this
Section 4.8 or elsewhere in this  Agreement  shall be deemed to require that any
Holder obtain an opinion of counsel or a writing executed by a representative of
the Commission in order to sell Registrable Shares.

         5.       RULE 144 REPORTING.

                  With a view to making available to the Holders the benefits of
certain rules and regulations of the Commission which may permit the sale of the
Registrable Shares to the public in the United States without registration,  the
Purchaser agrees that, so long as any Holder owns any Registrable Shares:

                  (a) the  Purchaser  will  make  and  keep  public  information
available (in accordance with Rule 144) at all times;

                                       16



                  (b) the Purchaser will file with the  Commission,  in a timely
manner,  all reports and other  documents  required to be filed by the Purchaser
under the Exchange Act; and

                  (c) the  Purchaser  will furnish to each Holder  promptly upon
request (i) a written  statement  by the  Purchaser  as to its  compliance  with
applicable  requirements of Rule 144 and of the Exchange Act, (ii) a copy of the
most recent annual or quarterly  report of the  Purchaser,  and (iii) such other
reports and documents as such Holder may reasonably  request in availing  itself
of any rule or regulation of the Commission  allowing it to sell any Registrable
Shares without registration.

         6.       GOVERNING LAW.

                  This  Agreement  and the legal  relations  between the parties
arising  hereunder  shall be governed by and  interpreted in accordance with the
laws  of  the  State  of  California  without  regard  to its  conflicts  of law
provisions.  Any dispute  arising out of or relating to this Agreement  shall be
resolved  through  binding  arbitration  under  the  Rules of  Conciliation  and
Arbitration  of the  International  Chamber  of  Commerce.  The  venue  for such
arbitration  proceedings shall be in London,  England. The arbitrator's fees and
other related expenses of any arbitration under this Agreement (such as expenses
for transcripts of the arbitration  proceedings) shall be borne by the Purchaser
and the  other  parties  to such  arbitration  in such  proportions  as shall be
determined by the arbitrator,  or if there is no such  determination,  then such
fees and other  expenses  shall be borne  one-half by the Purchaser and one-half
divided equally among the other parties to such arbitration. The resolution of a
dispute by the  arbitrator  shall be  conclusive  and  binding  upon the parties
hereto and  judgment  may be entered  thereon in any court  having  jurisdiction
thereof.  The  arbitrator  shall have the  authority  to make an award of actual
compensatory damages incurred by a party in connection with a dispute, but shall
have no right to grant  special,  punitive or  exemplary  damages or indirect or
consequential  damages or to grant any form of equitable relief (except that the
arbitrator  may,  as part of his award,  require  the  Purchaser  to perform its
registration and other obligations under this Agreement).

         7.       ASSIGNABILITY.

                  Except as otherwise  provided herein,  this Agreement shall be
binding  upon and shall  inure to the  benefit of the  parties  hereto and their
respective heirs,  successors and assigns. A Holder may assign, to any Permitted
Transferee  or other  Person to which  such  Holder  transfers  at least  10,000
Registrable Shares, such Holder's registration rights and other rights hereunder
with respect to such Registrable Shares.

         8.       ENTIRE AGREEMENT.

                  This Agreement  constitutes the full and entire  understanding
and  agreement  among the parties  regarding  the  matters set forth  herein and
supersedes all prior agreements and 

                                       17


understandings,  both written and oral, among or between any of the parties with
respect to the subject matter hereof.

         9.       NOTICES, ETC.

                  Any notice required or permitted hereunder shall be in writing
and shall be deemed given (a) when delivered in person,  (b) three business days
after  delivery to an  "overnight"  courier,  or (c) 24 hours after  delivery by
facsimile transmission (if receipt of such



                                       18





facsimile is evidenced by a transmission  report or other reasonable evidence of
the successful and accurate transmission of such notice), in each case addressed
as follows:



                                                  
                  If to any Parent Shareholder:      At such Parent Shareholder's address as set
                                                     forth on Schedule A hereto



                                       19



                                                       
                  With a copy to:               Shinar, Shachor, Weissberger
                                                5 Beit Hillel Street, 3rd Floor
                                                Tel Aviv 67017, Israel
                                                Attn: Doron Shinar
                                                Fax: 972-3-562-1905

                  If to the Purchaser:          Cylink Corporation
                                                910 Hermosa Court
                                                Sunnyvale, CA 94086
                                                Attn: Robert B. Fougner
                                                Fax: 408-774-4952

                  With a copy to:               Morrison & Foerster LLP
                                                755 Page Mill Road
                                                Palo Alto, CA  94304
                                                Attn:  Michael C. Phillips
                                                Fax: 650-494-0792

Addresses may be changed (or in the case of a Holder,  added) by written  notice
given  pursuant to this  Section.  Any notice  given  hereunder  may be given on
behalf of a party by his counsel or other authorized representative.

         10.      COUNTERPARTS.

                  This Agreement may be executed in any number of  counterparts,
each of which shall be an original,  but all of which together shall  constitute
one instrument.


         11.      AMENDMENTS.

                  This Agreement may not be amended,  modified or  supplemented,
except by means of a written  amendment  signed  by all of the  parties  hereto;
provided,  however,  that the  provisions  of Section 4 hereof may be amended by
means of a written  amendment signed by the Purchaser,  on one hand, and Holders
representing  a majority  in interest of the  Registrable  Shares,  on the other
hand, so long as such amendment does not take away any registration right of any
Holder or reduce the amount of  reimbursable  costs to any Holder in  connection
with  any   registration   hereunder   without  the  consent  of  such   Holder.
Notwithstanding  the foregoing,  any Holder may from time to time enter into one
or more agreements amending, modifying or


                                       20




supplementing the provisions of this Agreement if such action does not adversely
affect the rights or interest of any other Holder. This Agreement is intended to
benefit,  and  may  be  enforced  by,  the  parties  hereto  and  the  Permitted
Transferees who receive Transaction Shares;  provided,  however,  that except as
set forth in this  Section  11,  this  Agreement  may be  amended,  modified  or
supplemented without the consent of any Permitted Transferee.

         12.      STOCK SPLITS, STOCK DIVIDENDS, ETC.

                  All numerical  references  (including dollar amounts) referred
to in this Agreement  shall be adjusted,  if  appropriate,  to reflect any stock
split,  stock  dividend,  combination  of  shares,   recapitalization,   merger,
consolidation  or other  reorganization  or similar  event  with  respect to the
Purchaser Common Stock.

         13.      LIQUIDATION OF THE SELLER; LIABILITY FOR BREACH.

                  Nothing  contained  in this  Agreement  shall be  construed or
shall operate to prevent the Seller from dissolving,  winding up, liquidating or
terminating  its  existence  at any  time  after  the  date of  this  Agreement.
Notwithstanding  anything to the contrary  contained in this  Agreement,  in the
event  of the  dissolution  or  liquidation  of the  Seller,  the  then  current
shareholder(s)  of the Seller and their  successors and assigns shall succeed to
and shall be entitled  to  exercise  and enforce all of the rights of the Seller
under this Agreement. In the event of a breach of this Agreement, the liability,
if any, of each Parent Shareholder shall be limited to such Parent Shareholder's
Percentage  Share of the  compensable  damages (if any) incurred by, and payable
to, the  Purchaser as a result of such breach.  Notwithstanding  anything to the
contrary  contained in this  Agreement  (and without  limiting the effect of the
preceding  sentence),  the total  cumulative  maximum  liability  of each Parent
Shareholder  for all  breaches  of this  Agreement  and the Parent  Shareholders
Indemnity  Agreement of even date herewith  shall be limited in the aggregate to
the  dollar  value  of the  assets  of the  Seller  distributed  to such  Parent
Shareholder by the Seller in the dissolution and liquidation of the Seller,  and
no Parent  Shareholder's  liability  hereunder and thereunder  shall exceed such
amount.

         14.      INTERPRETATION OF CERTAIN TERMS.

                  All  references  in this  Agreement to "$" or "dollars"  shall
mean U.S.  dollars,  and all  references in this  Agreement to "calendar  month"
shall be based on the Gregorian  calendar.  For purposes of this Agreement,  the
masculine  gender shall be deemed to including  the feminine and neuter  gender,
and the neuter  gender  shall be deemed to include the  masculine  and  feminine
genders.

                                       21





         This Agreement is hereby executed as of the date first above written.

                                       CYLINK CORPORATION


                                       By:  /s/ John V. Kalb, Jr.
                                          --------------------------------------
                                                John V. Kalb, Jr.
                                                Vice President, Strategy and
                                                Business Development

                                       ALGORITHMIC RESEARCH LTD.


                                       By:  /s/ Yossi Tulpan
                                          --------------------------------------
                                                Yossi Tulpan
                                                Chief Executive Officer

                                       By   /s/ Yossi Cohen
                                          --------------------------------------
                                                Yossi Cohen
                                                Chief Operating Officer

                                       A.R. DATA SECURITY LTD.


                                       By:  /s/ Yossi Tulpan
                                          --------------------------------------
                                                Yossi Tulpan

                                       By:  /s/ Yossi Cohen
                                          --------------------------------------
                                                Yossi Cohen

                                       By:  /s/ Amos Fiat
                                          --------------------------------------
                                                Amos Fiat

                                       By:  /s/ Oded Koritshoner
                                          --------------------------------------
                                                Oded Koritshoner

                                       By:  /s/ Zohar Tal
                                          --------------------------------------
                                                Zohar Tal


                                       22       





                                       PARENT SHAREHOLDERS:


                                       /s/ Yossi Tulpan      
                                       -----------------------------------------
                                           Yossi Tulpan

                                       /s/ Amos Fiat
                                       -----------------------------------------
                                           Amos Fiat

                                       /s/ Yossi Cohen
                                       -----------------------------------------
                                           Yossi Cohen

                                       KOOR CAPITAL MARKETS


                                       By:  /s/ Itzak  Chalamish
                                          --------------------------------------
                                                Itzak  Chalamish
                                                President

                                       By:  /s/ Yair Na'aman
                                          --------------------------------------
                                                Yair Na'aman
                                                Head of Finance Division

                                       TELRAD HOLDINGS LTD.


                                       By:  /s/ Oded Koritshoner
                                          --------------------------------------
                                                Oded Koritshoner
                                                Managing Director

                                       By:  /s/
                                          --------------------------------------


                                       23



                                   Schedule A

                               Parent Shareholders

Name and Address of Parent Shareholder                      Percentage Share
- --------------------------------------                      ----------------
                                                      
Yossi Tulpan                                                     31.407%
21 Bilu Street, Ness Tziona, Israel                   
                                                      
Amos Fiat                                                        31.407%
20 Shalom Ash Street, Tel Aviv, Israel                
                                                      
Yossi Cohen                                                      10.337%
19 Mordechai Kaplan Street, Holon, Israel             
                                                      
Koor Capital Markets                                              7.501%
19 Rothschild Boulevard, Tel Aviv, Israel             
                                                      
Telrad Holdings Ltd.                                             19.348%
19 Rothschild Boulevard, Tel Aviv, Israel