Document:

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                                                                     EXHIBIT 4.2

NEITHER THIS WARRANT NOR THE SHARES ISSUABLE UPON EXERCISE HEREOF HAVE BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT")
                                                              --------------
OR ANY OTHER APPLICABLE SECURITIES LAWS IN RELIANCE UPON AN EXEMPTION FROM THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND SUCH OTHER SECURITIES LAWS.
NEITHER THIS WARRANT NOR THE SHARES ISSUABLE UPON EXERCISE HEREOF MAY BE SOLD,
PLEDGED, TRANSFERRED, ENCUMBERED OR OTHERWISE DISPOSED OF EXCEPT PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR IN A TRANSACTION
WHICH IS EXEMPT FROM REGISTRATION UNDER THE PROVISIONS OF THE SECURITIES ACT AND
ANY APPLICABLE STATE LAWS.

                          COMMON STOCK PURCHASE WARRANT

               To Purchase ____________ Shares of Common Stock of
                                 VALICERT, INC.

THIS CERTIFIES that, for value received, _______________ (the "Holder"), is
                                                               ------
entitled, upon the terms and subject to the limitations on exercise and the
conditions hereinafter set forth, at any time on or after November 14, 2001 (the
"Initial Exercise Date") and on or prior to the earlier of (i) the close of
 ---------------------
business on November 14, 2006 or (ii) a Change of Control (as defined in Section
13) (the "Termination Date") but not thereafter, to subscribe for and purchase
          ----------------
from ValiCert, Inc., a corporation incorporated in the State of Delaware (the
"Company"), up to ______________ shares (the "Warrant Shares") of Common Stock,
 -------                                      --------------
$0.001 par value per share, of the Company (the "Common Stock"). The per share
                                                 ------------
exercise price of Common Stock (the "Exercise Price") under this Warrant shall
                                     --------------
be equal to $3.49452, which is one hundred and twenty percent (120%) of the
Purchase Price (as defined in the Purchase Agreement referenced below). The
Exercise Price and the number of Warrant Shares for which the Warrant is
exercisable shall be subject to adjustment as provided herein. In the event of
any conflict between the terms of this Warrant and the Common Stock Purchase
Agreement dated as of November 14, 2001 pursuant to which this Warrant has been
issued (the "Purchase Agreement"), the Warrant shall control. Capitalized terms
             ------------------
used and not otherwise defined herein shall have the meanings set forth for such
terms in the Purchase Agreement.

     1.     Title to Warrant. Prior to the Termination Date and subject to
            ----------------
compliance with applicable laws, this Warrant and all rights hereunder are
transferable, subject to Section 7 herein, in whole or in part, at the office or
agency of the Company by the Holder in person or by duly authorized attorney,
upon surrender of this Warrant together with the Assignment Form annexed hereto
properly endorsed.

     2.     Authorization of Shares. The Company covenants that all Warrant
            -----------------------
Shares which may be issued upon the exercise of the purchase rights represented
by this Warrant will, upon exercise of the purchase rights represented by this
Warrant and payment in accordance with Section 3 hereof, be duly authorized,
validly issued, fully paid and nonassessable and free from all taxes, liens and
charges in respect of the issue thereof (other than taxes in respect of any
transfer occurring contemporaneously with such issue).

                                       1

<PAGE>

     3.     Exercise of Warrant.

            (a) Except as provided in Section 4 herein, exercise of the purchase
     rights represented by this Warrant may be made at any time or times on or
     after the Initial Exercise Date and on or before the close of business on
     the Termination Date by the surrender of this Warrant and the Notice of
     Exercise Form annexed hereto duly executed, at the office of the Company
     (or such other office or agency of the Company as it may designate by
     notice in writing to the registered Holder at the address of such Holder
     appearing on the books of the Company) and upon payment of the Exercise
     Price of the shares thereby purchased by wire transfer or cashier's check
     drawn on a United States bank, the Holder shall be entitled to receive a
     certificate for the number of Warrant Shares so purchased. This Warrant
     shall be deemed to have been exercised and such certificate or certificates
     shall be deemed to have been issued, and Holder or any other person so
     designated to be named therein shall be deemed to have become a holder of
     record of such shares for all purposes, as of the date the Warrant has been
     exercised by payment to the Company of the Exercise Price and all taxes
     required to be paid by the Holder, if any, pursuant to Section 5 prior to
     the issuance of such shares, have been paid.

            (b) Notwithstanding any provisions herein to the contrary, if the
     fair market value of one share of the Company's Common Stock is greater
     than the Exercise Price (at the date of calculation as set forth below), in
     lieu of exercising this Warrant for cash, the Holder may elect to receive
     shares equal to the value (as determined below) of this Warrant (or the
     portion thereof being canceled) by surrender of this Warrant at the
     principal office of the Company together with the properly endorsed Notice
     of Exercise Form and notice of such election in which event the Company
     shall issue to the Holder a number of shares of Common Stock computed using
     the following formula:

                                  X = Y (A-B)
                                      -------
                                         A

         Where    X  =     the number of shares of Common Stock to be issued to
                           the Holder

                  Y  =     the number of shares of Common Stock purchasable
                           under the Warrant or, if only a portion of the
                           Warrant is being exercised, the portion of the
                           Warrant being canceled (at the date of such
                           calculation)

                  A  =     the fair market value of one share of the Company's
                           Common Stock (at the date of such calculation)

                  B  =     Exercise Price (as adjusted to the date of such
                           calculation)

     For purposes of the above calculation, fair market value of one share of
     Common Stock shall be the VWAP on the day prior to the day which the
                               ----
     Warrant is exercised.

            (c) In the event of any exercise of the rights represented by this
     Warrant in compliance with this Section 3(a) or 3(b), the Company shall, or
     shall cause its transfer agent to, within two (2) Trading Days of the
     Company's receipt of the Exercise Price (in the event the Warrant is
     exercised pursuant to this Section 3(a)) and this Warrant (or an
     indemnification undertaking or other form of security reasonably
     satisfactory to the Company

                                       2

<PAGE>

     with respect to this Warrant in the case of its loss, theft or destruction)
     either (A) at the Holder's request, credit such aggregate number of shares
     of Common Stock to which the Holder shall be entitled upon such exercise to
     the holder's or its designee's balance account with The Depository Trust
     Company ("DTC") through its Deposit Withdrawal Agent Commission system,
     provided that (i) Transfer Agent is participating in DTC Fast Automated
     Securities Transfer Program, (ii) the Holder is eligible to receive shares
     through DTC, and (iii) the certificates for the Common Stock do not bear a
     legend thereon, or (B) issue and deliver to the address as specified in the
     Notice of Exercise Form, a certificate or certificates in such
     denominations as may be requested by the holder in the Notice of Exercise
     Form, registered in the name of the Holder or its designee, for the number
     of shares of Common Stock to which the Holder shall be entitled upon such
     exercise. If this Warrant shall have been exercised in part, the Company
     shall, at the time of delivery of the certificate or certificates
     representing Warrant Shares, deliver to Holder a new Warrant evidencing the
     rights of Holder to purchase the unpurchased Warrant Shares called for by
     this Warrant, which new Warrant shall in all other respects be identical
     with this Warrant.

     4.     No Fractional Shares or Scrip. No fractional shares or scrip
            -----------------------------
representing fractional shares shall be issued upon the exercise of this
Warrant. As to any fraction of a share which Holder would otherwise be entitled
to purchase upon such exercise, the Company shall pay a cash adjustment in
respect of such final fraction in an amount equal to such fraction multiplied by
the Exercise Price.

     5.     Charges, Taxes and Expenses. Issuance of certificates for Warrant
            ---------------------------
Shares shall be made without charge to the Holder for any issue or transfer tax
or other incidental expense in respect of the issuance of such certificate, all
of which taxes and expenses shall be paid by the Company, and such certificates
shall be issued in the name of the Holder or in such name or names as may be
directed by the Holder; provided, however, that in the event certificates for
                        -----------------
Warrant Shares are to be issued in a name other than the name of the Holder,
this Warrant when surrendered for exercise shall be accompanied by the
Assignment Form attached hereto duly executed by the Holder; and the Company may
require, as a condition thereto, the payment of a sum sufficient to reimburse it
for any transfer tax incidental thereto.

     6.     Closing of Books. The Company will not close its stockholder books
            ----------------
or records in any manner which prevents the timely exercise of this Warrant.

     7.     Transfer, Division and Combination.
            ----------------------------------

            (a) Subject to compliance with any applicable securities laws,
     transfer of this Warrant and all rights hereunder, in whole or in part,
     shall be registered on the books of the Company to be maintained for such
     purpose, upon surrender of this Warrant at the principal office of the
     Company, together with a written assignment of this Warrant substantially
     in the form attached hereto duly executed by the Holder or its agent or
     attorney and funds sufficient to pay any transfer taxes payable upon the
     making of such transfer. Upon such surrender and, if required, such
     payment, the Company shall execute and deliver a new Warrant or Warrants in
     the name of the assignee or assignees and in the denomination or
     denominations specified in such instrument of assignment, and shall issue
     to the assignor a new Warrant evidencing the portion of this Warrant not so
     assigned, and this Warrant shall promptly be cancelled. A

                                       3

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     Warrant, if properly assigned, may be exercised by a new holder for the
     purchase of Warrant Shares without having a new Warrant issued.

            (b) This Warrant may be divided or combined with other Warrants upon
     presentation hereof at the aforesaid office of the Company, together with a
     written notice specifying the names and denominations in which new Warrants
     are to be issued, signed by the Holder or its agent or attorney. Subject to
     compliance with Section 7(a), as to any transfer which may be involved in
     such division or combination, the Company shall execute and deliver a new
     Warrant or Warrants in exchange for the Warrant or Warrants to be divided
     or combined in accordance with such notice.

            (c) The Company shall prepare, issue and deliver at its own expense
     (other than transfer taxes) the new Warrant or Warrants under this Section
     7.

            (d) The Company agrees to maintain, at its aforesaid office, books
     for the registration and the registration of transfer of the Warrants.

     8.     No Rights as Stockholder until Exercise. This Warrant does not
            ---------------------------------------
entitle the Holder to any voting rights or other rights as a stockholder of the
Company prior to the exercise hereof. Upon the surrender of this Warrant and the
payment of the aggregate Exercise Price or by means of a cashless exercise, the
Warrant Shares so purchased shall be and be deemed to be issued to such Holder
as the record owner of such shares as of the close of business on the later of
the date of such surrender or payment.

     9.     Loss, Theft, Destruction or Mutilation of Warrant. The Company
            -------------------------------------------------
covenants that upon receipt by the Company of evidence reasonably satisfactory
to it of the loss, theft, destruction or mutilation of this Warrant or any stock
certificate relating to the Warrant Shares, and in case of loss, theft or
destruction, of indemnity or security reasonably satisfactory to it (which shall
not include the posting of any bond), and upon surrender and cancellation of
such Warrant or stock certificate, if mutilated, the Company will make and
deliver a new Warrant or stock certificate of like tenor and dated as of such
cancellation, in lieu of such Warrant or stock certificate.

     10.    Saturdays, Sundays, Holidays, etc. If the last or appointed day for
            ---------------------------------
the taking of any action or the expiration of any right required or granted
herein shall be a Saturday, Sunday or a legal holiday, then such action may be
taken or such right may be exercised on the next succeeding day not a Saturday,
Sunday or legal holiday.

     11.    Adjustments of Exercise Price and Number of Warrant Shares. The
            ----------------------------------------------------------
number and kind of securities purchasable upon the exercise of this Warrant and
the Exercise Price shall be subject to adjustment from time to time upon the
happening of any of the following: In case the Company shall (i) pay a dividend
in shares of Common Stock or make a distribution in shares of Common Stock to
holders of its outstanding Common Stock, (ii) subdivide its outstanding shares
of Common Stock into a greater number of shares, (iii) combine its outstanding
shares of Common Stock into a smaller number of shares of Common Stock, or (iv)
issue any shares of its capital stock in a reclassification of the Common Stock,
then the number of Warrant Shares purchasable upon exercise of this Warrant

                                       4

<PAGE>

immediately prior thereto shall be adjusted so that the Holder shall be entitled
to receive the kind and number of Warrant Shares or other securities of the
Company which it would have owned or have been entitled to receive had such
Warrant been exercised in advance thereof. Upon each such adjustment of the kind
and number of Warrant Shares or other securities of the Company which are
purchasable hereunder, the Holder shall thereafter be entitled to purchase the
number of Warrant Shares or other securities resulting from such adjustment at
an Exercise Price per Warrant Share or other security obtained by multiplying
the Exercise Price in effect immediately prior to such adjustment by the number
of Warrant Shares purchasable pursuant hereto immediately prior to such
adjustment and dividing by the number of Warrant Shares or other securities of
the Company resulting from such adjustment. An adjustment made pursuant to this
paragraph shall become effective immediately after the effective date of such
event retroactive to the record date, if any, for such event.

     12.    Notice of Adjustment. Whenever the number of Warrant Shares or
            --------------------
number or kind of securities or other property purchasable upon the exercise of
this Warrant or the Exercise Price is adjusted, as herein provided, the Company
shall promptly, but in no event later than ten (10) days from the date of such
adjustment, mail by registered or certified mail, return receipt requested, to
the Holder notice of such adjustment or adjustments setting forth the number of
Warrant Shares (and other securities or property) purchasable upon the exercise
of this Warrant and the Exercise Price of such Warrant Shares (and other
securities or property) after such adjustment, setting forth a brief statement
of the facts requiring such adjustment and setting forth the computation by
which such adjustment was made.

     13.    Notices of Corporate Action. In the event of:
            ---------------------------

            (a) any taking by the Company of a record of the holders of any
     class of securities for the purpose of determining the holders thereof who
     are entitled to receive any dividend or other distribution, or any right to
     subscribe for, purchase or otherwise acquire any shares of stock of any
     class or any other securities or property, or to receive any other right,
     or

            (b) any capital reorganization of the Company, any reclassification
     or recapitalization of the capital stock of the Company or any Change of
     Control (defined below), or

            (c) any voluntary or involuntary dissolution, liquidation or
     winding-up of the Company,

the Company will mail to the Holder a notice specifying (i) the date or expected
date on which any such record is to be taken for the purpose of such dividend,
distribution or right and the amount and character of any such dividend,
distribution or right, (ii) the date or expected date on which any such
reorganization, reclassification, recapitalization, Change of Control,
dissolution, liquidation or winding-up is to take place and the time, if any
such time is to be fixed, as of which the holders of record of Common Stock (or
other securities) shall be entitled to exchange their shares of Common Stock (or
other securities) for the securities or other property deliverable upon such
reorganization, reclassification, recapitalization, Change of Control,
dissolution, liquidation or winding-up and (iii) that in the event of a Change
of Control, the Warrants are exercisable immediately prior to the consummation
of such Change of Control. Such notice

                                       5

<PAGE>

shall be delivered at least 15 days prior to the date therein specified. For the
purposes of this Warrant, the term "Change of Control" shall mean (i) the
                                    -----------------
consolidation of the Company with or merger of the Company with or into any
other person in which the Company is not the surviving corporation and after
which persons who were not stockholders of the Company immediately prior to such
merger or consolidation own immediately after such merger or consolidation 50%
or more of the voting power of the outstanding securities of each of the
continuing or surviving entity and any direct or indirect parent corporation of
such continuing or surviving entity, (ii) the sale of all or substantially all
of the assets of the Company to any other person, or (iii) any sale or transfer
of any capital stock of the Company after the date of this Agreement, following
which 50% of the combined voting power of the Company becomes beneficially owned
by one person or group acting together. For purposes of this definition, "group"
shall have the meaning as such term is used in Section 13(d)(1) under the
Exchange Act.

     14.    Registration. The Company is obligated to register the Warrant
            ------------
Shares for resale under the Securities Act pursuant to the Registration Rights
Agreement. The shares of Common Stock issuable upon exercise of this Warrant
shall constitute Registrable Shares (as such term is defined in the Registration
Rights Agreement). Each holder of this Warrant shall be entitled to all of the
benefits afforded to a holder of any such Registrable Shares under the
Registration Rights Agreement and such holder, by its acceptance of this
Warrant, agrees to be bound by and to comply with the terms and conditions of
the Registration Rights Agreement applicable to such holder as a holder of such
Registrable Shares.

     15.    Authorized Shares. The Company covenants that during the period the
            -----------------
Warrant is outstanding, it will reserve from its authorized and unissued Common
Stock a sufficient number of shares to provide for the issuance of the Warrant
Shares upon the exercise of any purchase rights under this Warrant. The Company
further covenants that its issuance of this Warrant shall constitute full
authority to its officers who are charged with the duty of executing stock
certificates to execute and issue the necessary certificates for the Warrant
Shares upon the exercise of the purchase rights under this Warrant. The Company
will take all such reasonable action as may be necessary to assure that such
Warrant Shares may be issued as provided herein without violation of any
applicable law or regulation, or of any requirements of the Principal Market
upon which the Common Stock may be listed.

     The Company shall not by any action, including, without limitation,
amending its certificate of incorporation or through any reorganization,
transfer of assets, consolidation, merger, dissolution, issue or sale of
securities or any other voluntary action, avoid or seek to avoid the observance
or performance of any of the terms of this Warrant, but will at all times in
good faith assist in the carrying out of all such terms and in the taking of all
such actions as may be necessary or appropriate to protect the rights of Holder
against impairment. Without limiting the generality of the foregoing, the
Company will (a) not increase the par value of any Warrant Shares above the
amount payable therefor upon such exercise immediately prior to such increase in
par value, (b) take all such action as may be necessary or appropriate in order
that the Company may validly and legally issue fully paid and nonassessable
Warrant Shares upon the exercise of this Warrant, and (c) obtain all such
authorizations, exemptions or consents from any public regulatory body having
jurisdiction thereof as may be necessary to enable the Company to perform its
obligations under this Warrant.

                                       6

<PAGE>

     Before taking any action which would result in an adjustment in the number
of Warrant Shares for which this Warrant is exercisable or in the Exercise
Price, the Company shall obtain all such authorizations or exemptions thereof,
or consents thereto, as may be necessary from any public regulatory body or
bodies having jurisdiction thereof.

     16.    Miscellaneous.

            (a) Jurisdiction. This Warrant shall constitute a contract under the
                ------------
     laws of California, without regard to its conflict of law, principles or
     rules.

            (b) Restrictions. The Holder acknowledges that the Warrant Shares
                ------------
     acquired upon the exercise of this Warrant, if not registered, will have
     restrictions upon resale imposed by state and federal securities laws.

            (c) Notices. Any notice, request or other document required or
                -------
     permitted to be given or delivered to the Holder by the Company shall be
     delivered in accordance with the notice provisions of the Purchase
     Agreement.

            (d) Limitation of Liability. No provision hereof, in the absence of
                -----------------------
     affirmative action by Holder to purchase Warrant Shares, and no enumeration
     herein of the rights or privileges of Holder, shall give rise to any
     liability of Holder for the purchase price of any Common Stock or as a
     stockholder of the Company, whether such liability is asserted by the
     Company or by creditors of the Company.

            (e) Successors and Assigns. Subject to applicable securities laws,
                ----------------------
     this Warrant and the rights and obligations evidenced hereby shall inure to
     the benefit of and be binding upon the successors of the Company and the
     successors and permitted assigns of Holder. The provisions of this Warrant
     are intended to be for the benefit of all Holders from time to time of this
     Warrant and shall be enforceable by any such Holder or holder of Warrant
     Shares.

            (f) Amendment. This Warrant may be modified or amended or the
                ---------
     provisions hereof waived with the written consent of the Company and the
     Holder.

            (g) Severability. Wherever possible, each provision of this Warrant
                ------------
     shall be interpreted in such manner as to be effective and valid under
     applicable law, but if any provision of this Warrant shall be prohibited by
     or invalid under applicable law, such provision shall be ineffective to the
     extent of such prohibition or invalidity, without invalidating the
     remainder of such provisions or the remaining provisions of this Warrant.

            (h) Headings. The headings used in this Warrant are for the
                --------
     convenience of reference only and shall not, for any purpose, be deemed a
     part of this Warrant.

                                       7

<PAGE>

     IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by
its officer thereunto duly authorized.

Dated: November    , 2001                   VALICERT, INC.
                ---

                                            By:
                                                --------------------------------

<PAGE>

                               NOTICE OF EXERCISE

To:      ValiCert, Inc.

     [_] The undersigned hereby elects to purchase ________ Warrant Shares (the
"Common Stock"), of ValiCert, Inc., a Delaware corporation, pursuant to the
 ------------
terms of the attached Warrant, and tenders herewith payment of the exercise
price in full, together with all applicable transfer taxes, if any.

     [_] The undersigned, registered Holder of the Warrant delivered herewith,
hereby irrevocably exercises such Warrant for, and purchases thereunder, shares
of the Common Stock of ValiCert, Inc., a Delaware corporation, as provided
below. Capitalized terms used herein, unless otherwise defined herein, shall
have the meanings given in the Warrant. The portion of the Exercise Price (as
defined in the Warrant) to be applied toward the purchase of Common Stock
pursuant to this Notice of Exercise is $_______, thereby leaving a remaining
Exercise Price (if any) equal to $________. Such exercise shall be pursuant to
the cashless exercise provisions of Section 3 of the Warrant; therefore, Holder
makes no payment with this Notice of Exercise. The number of shares to be issued
pursuant to this exercise shall be determined by reference to the formula in
Section 3 of the Warrant which, by reference to Section 3, requires the use of
the VWAP preceding the date of such election, which price is
$___________________. To the extent the foregoing exercise is for less than the
full Aggregate Price of the Warrant, a replacement Warrant representing the
remainder of the Aggregate Price (and otherwise of like form, tenor and effect)
shall be delivered to Holder along with the share certificate evidencing the
Common Stock issued in response to this Notice of Exercise.

     Please issue a certificate or certificates representing said Warrant Shares
in the name of the undersigned or in such other name as is specified below:

                           -------------------------------

The Warrant Shares shall be delivered to the following:

                           -------------------------------

                           -------------------------------

                           -------------------------------

                                  By:
                                     -------------------------------------------
                                     Name:
                                     Title:

                                  Date:
                                       -----------------------------------------

The execution to the foregoing Notice of Exercise must exactly correspond to the
name of the Holder on the Warrant.

<PAGE>

                                 ASSIGNMENT FORM

                    (To assign the foregoing warrant, execute
                   this form and supply required information.
                 Do not use this form to exercise the warrant.)

     FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced thereby
are hereby assigned to

                                                             whose address is
------------------------------------------------------------

--------------------------------------------------------------------------------

-------------------------------------------------------------------------------.

                                                 Dated:                ,
                                                        ---------------  -------

                   Holder's Signature:
                                       -----------------------------------------

                   Holder's Address:
                                     -------------------------------------------

Signature Guaranteed:
                      ----------------------------------------------------------

NOTE: The signature to this Assignment Form must correspond with the name as it
appears on the face of the Warrant, without alteration or enlargement or any
change whatsoever, and must be guaranteed by a bank or trust company. Officers
of corporations and those acting in an fiduciary or other representative
capacity should file proper evidence of authority to assign the foregoing
Warrant.<PAGE>

                                                                     EXHIBIT 4.3

                          REGISTRATION RIGHTS AGREEMENT

     THIS REGISTRATION RIGHTS AGREEMENT, dated as of November ___, 2001 is
between the purchasers listed on Schedule A hereto (each a "Purchaser" and
collectively, the "Purchasers"), and ValiCert, Inc., a Delaware corporation (the
"Company").

     WHEREAS, simultaneously with the execution and delivery of this Agreement,
the parties shall enter into the Common Stock Purchase Agreement, dated as of
the date hereof, (the "Purchase Agreement") pursuant to which the Purchasers
have committed to purchase up to $5,000,000 of the Company's Common Stock (terms
not defined herein shall have the meanings ascribed to them in the Purchase
Agreement) and Purchasers have the option to purchase up $1,250,000 of the
Company's Common Stock pursuant to the Common Stock Warrant; and

     WHEREAS, the execution and delivery of this Agreement and granting to each
Purchaser of the registration rights set forth herein with respect to the
Registrable Securities is required by the terms of the Purchase Agreement.

     NOW, THEREFORE, the parties hereto mutually agree as follows:

     Section 1.     Definitions.
                    -----------

          (a)       Registrable Securities. As used herein the term "Registrable
                    ----------------------
     Securities" means all Shares, Warrant Shares, and Penalty Warrant Shares
     (defined below), if any, that (i) have not been sold under the Registration
     Statement, (ii) have not been sold under circumstances under which all of
     the applicable conditions of Rule 144 (or any similar provision then in
     force) under the Securities Act ("Rule 144") are met, (iii) have not been
     otherwise transferred to persons who may trade such Registrable Securities
     without restriction under the Securities Act, and the Company has delivered
     a new certificate or other evidence of ownership for such Registrable
     Securities not bearing a restrictive legend, or (iv) may not be sold
     without any time, volume or manner limitations pursuant to Rule 144(k) (or
     any similar provision then in effect) under the Securities Act. In the
     event of any merger, reorganization, consolidation, recapitalization or
     other change in corporate structure affecting the Common Stock, such
     adjustment shall be deemed to be made in the definition of "Registrable
     Security" as is appropriate in order to prevent any dilution or enlargement
     of the rights granted pursuant to this Agreement.

          (b)       Holder. As used herein the term "Holder" means any person
                    ------
     owning or having the right to acquire Registrable Securities or any
     assignee thereof in accordance with Section 3 of this Agreement.

          (c)       Potential Material Event. As used herein the term "Potential
                    ------------------------
     Material Event" shall have the meaning ascribed to it in Section 3(j)
     hereof.

                                       1

<PAGE>

     Section 2.     Restrictions on Transfer. Holders acknowledge and understand
                    ------------------------
that in the absence of an effective Registration Statement authorizing the
resale of the Registrable Securities, as provided herein, the Registrable
Securities are "restricted securities" as defined in Rule 144. Holders
understand that no disposition or transfer of the Registrable Securities may be
made by Holders in the absence of (i) compliance with applicable laws; (ii) an
opinion of counsel to the Purchaser, in form and substance reasonably
satisfactory to the Company that such transfer may be made without registration
under the Securities Act, or (iii) such registration.

     With a view to making available to Holders the benefits of Rule 144, the
Company agrees to:

          (a)       comply with the provisions of paragraph (c)(1) of Rule 144;
     and

          (b)       furnish to any Holder, so long as the Holder owns any
     Registrable Securities, forthwith upon request: (i) a written statement by
     the Company that it has complied with the reporting requirements of SEC
     Rule 144, the Securities Act and the Exchange Act, or that it qualifies as
     a registrant whose securities may be resold pursuant to Form S-3 (at any
     time after it so qualifies), (ii) a copy of the most recent annual or
     quarterly report of the Company and such other reports and documents so
     filed by the Company and (iii) such other information as may be reasonably
     requested in availing any Holder of any rule or regulation of the SEC which
     permits the selling of any such securities without registration or pursuant
     to such form.

          (c)       to file with the Commission in a timely manner all reports
     and other documents required to be filed by the Company pursuant to Section
     13 or 15(d) under the Exchange Act; and, if at any time it is not required
     to file such reports but in the past had been required to or did file such
     reports, it will, upon the request of the Purchaser, make available other
     information as required by, and so long as necessary to permit sales of,
     its Registrable Securities pursuant to Rule 144.

     Section 3.     Registration Rights With Respect to the Registrable
                    ---------------------------------------------------
Securities.
----------

          (a)       The Company agrees that it will prepare, file with, and
     cause to be declared effective by the Commission within ninety (90) days
     after the date of this Agreement (the "Registration Deadline"), a
     registration statement (on Form S-3 or other appropriate form of
     registration statement) under the Securities Act (the "Registration
     Statement"), at the sole expense of the Company (except as provided in
     Section 3(d) hereof), so as to permit a public offering and resale of the
     Registrable Securities under the Securities Act by the Holders; provided,
     however, that if the Registration Statement is subject to formal, written
     review by the SEC, then the Registration Deadline shall be extended by
     thirty (30) days. If the Company fails to meet the Registration Deadline,
     the Company shall issue to the Holders additional warrants for common stock
     (the "Penalty Warrants"), on substantially the same terms and conditions as
     the Common Stock Purchase Warrants; provided, however, that the number of
                                         --------  -------
     shares issuable upon exercise of the Penalty Warrants shall be, in the
     aggregate, 1,000 shares of Common Stock for each day after the ninetieth
     (90th) day or one hundred twentieth day (120th) day,

                                       2

<PAGE>

     whichever is applicable, that the Company fails to meet the Registration
     Deadline, and the Exercise Price of the Penalty Warrants shall be eight
     percent (8%) less than the Exercise Price of the Common Stock Purchase
     Warrants. A designee of the Holders shall instruct the Company as to the
     number of Penalty Warrant shares to be allocated to each Holder.

          (b)       The Company will notify Purchaser of the effectiveness of
     the Registration Statement within one Trading Day of such event .

          (c)       The Company will maintain the Registration Statement or
     post-effective amendment filed under this Section 3 hereof effective under
     the Securities Act until the earliest of (i) the date that all the
     Registrable Securities have been sold or otherwise disposed of pursuant to
     the Registration Statement, (ii) the date that all of the Registrable
     Securities have been otherwise transferred to persons who may trade such
     shares without restriction under the Securities Act, and the Company has
     delivered a new certificate or other evidence of ownership for such
     Registrable Securities not bearing a restrictive legend, or (iii) the one
     year anniversary date of this Agreement.

          (d)       All fees, disbursements and out-of-pocket expenses and costs
     incurred by the Company in connection with the preparation and filing of
     the Registration Statement under subparagraph 3(a) and in complying with
     applicable securities and Blue Sky laws (including, without limitation, all
     attorneys' fees of the Company) shall be borne by the Company. The Company
     shall not be responsible for payment of any other fees, including legal
     fees, of Purchaser.

          (e)       Holders and their counsel shall have the right, upon
     request, to review any comment letters from the SEC, and a reasonable
     period, not to exceed three (3) Trading Days, to review and comment upon
     the Selling Stockholder Table in the proposed Registration Statement, prior
     to its initial filing with the Commission. The Plan of Distribution section
     in the Registration Statement shall be substantially in the form attached
     hereto as Exhibit A.
               ---------

          (f)       The Company shall make reasonably available for inspection
     by Holders, any underwriter participating in any disposition pursuant to
     the Registration Statement, and any attorney, accountant or other agent
     retained by the Holders or any such underwriter all relevant financial and
     other records, pertinent corporate documents and properties of the Company
     and its subsidiaries, and cause the Company's officers, directors and
     employees to supply all information reasonably requested by the Holders or
     any such underwriter, attorney, accountant or agent in connection with the
     Registration Statement, in each case, as is customary for similar due
     diligence examinations; provided, however, that all records, information
                             --------  -------
     and documents that are designated in writing by the Company, in good faith,
     as confidential, proprietary or containing any material non-public
     information shall be kept confidential by Holders and any such underwriter,
     attorney, accountant or agent, unless (i) such disclosure is made pursuant
     to judicial process in a court proceeding (after first giving the Company
     an opportunity promptly to seek a protective order or otherwise limit the
     scope of the information sought to be

                                       3

<PAGE>

     disclosed), (ii) is required by law, (iii) such records, information or
     documents become available to the public generally or through a third party
     not in violation of an accompanying obligation of confidentiality, (iv)
     that is in the possession of the using or disclosing party prior to the
     time such information was obtained from the Company or that is
     independently acquired by the using or disclosing party without the aid,
     application or use of such other information; (v) that is obtained by the
     using or disclosing party in good faith without knowledge of any breach of
     a secrecy arrangement from a third party; or (vi) that is disclosed in
     connection with any bona-fide offer to purchase any shares in the Company,
     provided that the proposed transferor obtains an undertaking from the
     proposed transferee to keep such information confidential in accordance
     with the provision of this section prior to such disclosure. If the
     foregoing inspection and information gathering would otherwise disrupt the
     Company's conduct of its business, such inspection and information
     gathering shall, to the maximum extent possible, be coordinated on behalf
     of Holders and the other parties entitled thereto by one firm of counsel
     designed by and on behalf of the majority in interest of the Holders and
     other parties.

          (g)       The Company shall qualify any of the Registrable Securities
     for sale in such states as a Holder reasonably designates and shall furnish
     indemnification in the manner provided in Section 6 hereof. However, the
     Company shall not be required to qualify in any state which will require an
     escrow or other restriction relating to the Company and/or the sellers, or
     which will require the Company to qualify to do business in such state or
     require the Company to file therein any general consent to service of
     process.

          (h)       The Company at its expense will supply Holders with copies
     of the Registration Statement and the final prospectus included therein
     (the "Prospectus") and other related documents in such quantities as may be
     reasonably requested by Holders.

          (i)       If at any time or from time to time after the effective date
     of the Registration Statement, the Company notifies Holders in writing of
     the existence of a Potential Material Event (as defined in Section 3(j)
     below), Holders shall not offer or sell any Registrable Securities pursuant
     to a Registration Statement, from the time of the giving of notice with
     respect to a Potential Material Event until Holder receives written notice
     from the Company that such Potential Material Event either has been
     disclosed to the public or no longer constitutes a Potential Material Event
     (the "Suspension Period"). The Company must give Purchaser notice of the
     existence of a Potential Material Event promptly upon knowledge that such
     an event exists and, where possible, at least two (2) days prior to the
     first day of a Suspension Period, if lawful to do so.

          (j)       "Potential Material Event" means any of the following: (i)
     the possession by the Company of material information that is not ripe for
     disclosure in a registration statement, as determined in good faith by the
     Chief Executive Officer or the Board of Directors of the Company; (ii) any
     material engagement or activity by the Company which would, in the good
     faith determination of the Chief Executive Officer or the Board of
     Directors of the Company, be adversely affected by disclosure in a

                                       4

<PAGE>

     registration statement at such time, which determination shall be
     accompanied by a good faith determination by the Chief Executive Officer or
     the Board of Directors of the Company that the Registration Statement would
     be materially misleading absent the inclusion of such information, or (iii)
     pursuant to applicable law, the Company is required to file a
     post-effective amendment to the Registration Statement because the Company
     experiences a fundamental change, must change the plan of distribution to
     the Prospectus, or must update the information included in the Prospectus
     pursuant to Section 10(a)(3) of Securities Act.

     Section 4.     Cooperation with Company. The Purchaser will cooperate with
                    ------------------------
the Company in all respects in connection with this Agreement, including timely
supplying all information reasonably requested by the Company (which shall
include all information regarding the Purchaser and proposed manner of sale of
the Registrable Securities required to be disclosed in the Registration
Statement) and executing and returning all documents reasonably requested in
connection with the registration and sale of the Registrable Securities in usual
and customary form.

     Section 5.     Registration Procedures. In addition to the requirements set
                    -----------------------
forth in Section 3, the Company shall (except as otherwise provided in this
Agreement), as expeditiously as possible, subject to each Holder's assistance
and cooperation as reasonably required:

          (a)       (i) prepare and file with the Commission such amendments and
     supplements to the Registration Statement and the Prospectus as may be
     necessary to keep such registration statement effective and to comply with
     the provisions of the Securities Act with respect to the sale or other
     disposition of all securities covered by such registration statement
     whenever the Purchaser of such Registrable Securities shall desire to sell
     or otherwise dispose of the same (including prospectus supplements with
     respect to the sales of securities from time to time in connection with a
     registration statement pursuant to Rule 415 promulgated under the
     Securities Act) and (ii) take all lawful action such that each of (A) the
     Registration Statement and any amendment thereto does not, when it becomes
     effective, contain an untrue statement of a material fact or omit to state
     a material fact required to be stated therein or necessary to make the
     statements therein not misleading and (B) the Prospectus, and any amendment
     or supplement thereto, does not at any time during the Effectiveness Period
     include an untrue statement of a material fact or omit to state 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;

          (b)       do any and all acts and things which may be reasonably
     necessary or advisable to enable Holders to consummate the resale or other
     disposition in such jurisdiction of the Registrable Securities, except that
     the Company shall not for any such purpose be required to qualify to do
     business as a foreign corporation in any jurisdiction wherein it is not so
     qualified or to file therein any general consent to service of process;

                                       5

<PAGE>

          (c)       list such Registrable Securities on the Principal Market,
     and any other exchange on which the Common Stock of the Company is then
     listed, if the listing of such Registrable Securities is then permitted
     under the rules of such exchange or the Nasdaq Stock Market;

          (d)       notify Holders at any time when the Prospectus is required
     to be delivered under the Securities Act, of the happening of any event of
     which it has knowledge as a result of which the Prospectus, as then in
     effect, includes an untrue statement of a material fact or omits to state a
     material fact required to be stated therein or necessary to make the
     statements therein not misleading in the light of the circumstances then
     existing, and the Company shall prepare and file a curative amendment or
     curative supplement under Section 5(a) as quickly as possible;

          (e)       as promptly as practicable after becoming aware of such
     event, notify the Purchaser (or, in the event of an underwritten offering,
     the managing underwriters) of the issuance by the Commission or any state
     authority of any stop order or other suspension of the effectiveness of the
     Registration Statement at the earliest possible time and take all lawful
     action to effect the withdrawal, rescission or removal of such stop order
     or other suspension;

          (f)       take all such other lawful actions reasonably necessary to
     expedite and facilitate the disposition by Holders of its Registrable
     Securities in accordance with the intended methods therefor provided in the
     Prospectus; and

          (g)       maintain a transfer agent for its Common Stock.

     Section 6.     Indemnification.
                    ---------------

          (a)       The Company agrees to indemnify and hold harmless each
     Holder and each person, if any, who controls the Holder within the meaning
     of the Securities Act ("Distributing Purchaser") against any losses,
     claims, damages or liabilities, joint or several (which shall, for all
     purposes of this Agreement, include, but not be limited to, all reasonable
     costs of defense and investigation and all reasonable attorneys' fees), to
     which Holder may become subject, under the Securities Act or otherwise,
     insofar as such losses, claims, damages or liabilities (or actions in
     respect thereof) arise out of or are based upon any untrue statement or
     alleged untrue statement of any material fact contained in the Registration
     Statement, or any related preliminary prospectus, the Prospectus or
     amendment or supplement thereto, or arise out of or are based upon the
     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 when made not misleading; provided, however, that the
     Company will not be liable in any such case to the extent that any such
     loss, claim, damage or liability arises out of or is based upon an untrue
     statement or alleged untrue statement or omission or alleged omission made
     in the Registration Statement, preliminary prospectus, the Prospectus or
     amendment or supplement thereto in reliance upon, and in conformity with,
     written information furnished to the Company by Holder specifically for use
     in the preparation thereof. This Section 6(a) shall not inure

                                       6

<PAGE>

     to the benefit of any Holder with respect to any person asserting such
     loss, claim, damage or liability who purchased the Registrable Securities
     which are the subject thereof if Holder failed to send or give a copy of
     the Prospectus to such person at or prior to the written confirmation to
     such person of the sale of such Registrable Securities, where Holder was
     obligated to do so under the Securities Act or the rules and regulations
     promulgated thereunder. This indemnity agreement will be in addition to any
     liability which the Company may otherwise have.

          (b)       Each Holder agrees that it will indemnify and hold harmless
     the Company, and each officer, director of the Company or person, if any,
     who controls the Company within the meaning of the Securities Act, against
     any losses, claims, damages or liabilities (which shall, for all purposes
     of this Agreement, include, but not be limited to, all reasonable costs of
     defense and investigation and all reasonable attorneys' fees) to which the
     Company or any such officer, director or controlling person may become
     subject under the Securities Act or otherwise, insofar as such losses,
     claims, damages or liabilities (or actions in respect thereof) arise out of
     or are based upon any untrue statement or alleged untrue statement of any
     material fact contained in the Registration Statement, or any related
     preliminary prospectus, the Prospectus or amendment or supplement thereto,
     or arise out of or are based upon the omission or the alleged omission to
     state therein a material fact required to be stated therein or necessary to
     make the statements therein not misleading, but in each case only to the
     extent that such untrue statement or alleged untrue statement or omission
     or alleged omission was made in the Registration Statement, preliminary
     prospectus, the Prospectus or amendment or supplement thereto in reliance
     upon, and in conformity with, written information furnished to the Company
     by such Holder specifically for use in the preparation thereof. This
     indemnity agreement will be in addition to any liability which Holder may
     otherwise have. Notwithstanding anything to the contrary herein, Holder
     shall not be liable under this Section 6(b) for any amount in excess of the
     gross proceeds to such Holder as a result of the sale of Registrable
     Securities pursuant to the Registration Statement; provided however, that
     this provision shall not limit any rights or claims based on fraudulent or
     intentional misrepresentation, bad faith or willful misconduct.

          (c)       Promptly after receipt by an indemnified party under this
     Section 6 of notice of the commencement of any action, such indemnified
     party will, if a claim in respect thereof is to be made against the
     indemnifying party under this Section 6, notify the indemnifying party of
     the commencement thereof; but the omission so to notify the indemnifying
     party will not relieve the indemnifying party from any liability which it
     may have to any indemnified party except to the extent of actual prejudice
     demonstrated by the indemnifying party. In case any such action is brought
     against any indemnified party, and it notifies the indemnifying party of
     the commencement thereof, the indemnifying party will be entitled to
     participate in, and, to the extent that it may wish, jointly with any other
     indemnifying party similarly notified, assume the defense thereof, subject
     to the provisions herein stated and after notice from the indemnifying
     party to such indemnified party of its election so to assume the defense
     thereof, the indemnifying party will not be liable to such indemnified
     party under this Section 6 for any legal or other expenses subsequently
     incurred by such indemnified party in connection with the defense thereof

                                       7

<PAGE>

     other than reasonable costs of investigation, unless the indemnifying party
     shall not pursue the action to its final conclusion. The indemnified party
     shall have the right to employ separate counsel in any such action and to
     participate in the defense thereof, but the fees and expenses of such
     counsel shall not be at the expense of the indemnifying party if the
     indemnifying party has assumed the defense of the action with counsel
     reasonably satisfactory to the indemnified party; provided that if the
     indemnified party is a Holder, the fees and expenses of such counsel shall
     be at the expense of the indemnifying party if (i) the employment of such
     counsel has been specifically authorized in writing by the indemnifying
     party, or (ii) the named parties to any such action (including any
     impleaded parties) include both Holder and the indemnifying party and
     Holder shall have been advised by such counsel in writing that there may be
     one or more legal defenses available to the indemnifying party different
     from or in conflict with any legal defenses which may be available to
     Holder (in which case the indemnifying party shall not have the right to
     assume the defense of such action on behalf of Holder, it being understood,
     however, that the indemnifying party shall, in connection with any one such
     action or separate but substantially similar or related actions in the same
     jurisdiction arising out of the same general allegations or circumstances,
     be liable only for the reasonable fees and expenses of one separate firm of
     attorneys for Holder, which firm shall be designated in writing by Holder
     and be approved by the indemnifying party). No settlement of any action
     against an indemnified party shall be made without the prior written
     consent of the indemnified party, which consent shall not be unreasonably
     withheld.

     All fees and expenses of the indemnified party (including reasonable costs
of defense and investigation in a manner not inconsistent with this Section and
all reasonable attorneys' fees and expenses) shall be promptly paid to the
indemnified party, as incurred, within ten (10) Trading Days of written notice
thereof to the indemnified party; provided, however, that the indemnifying party
may require such indemnified party to undertake to reimburse all such fees and
expenses to the extent it is finally judicially determined that such indemnified
party is not entitled to indemnification hereunder.

     Section 7.     Contribution. In order to provide for just and equitable
                    ------------
contribution under the Securities Act in any case in which (i) the indemnified
party makes a claim for indemnification pursuant to Section 6 hereof but is
judicially determined (by the entry of a final judgment or decree by a court of
competent jurisdiction and the expiration of time to appeal or the denial of the
last right of appeal) that such indemnification may not be enforced in such case
notwithstanding the fact that the express provisions of Section 6 hereof provide
for indemnification in such case, or (ii) contribution under the Securities Act
may be required on the part of any indemnified party, then the Company and the
applicable Holder shall contribute to the aggregate losses, claims, damages or
liabilities to which they may be subject (which shall, for all purposes of this
Agreement, include, but not be limited to, all reasonable costs of defense and
investigation and all reasonable attorneys' fees), in either such case (after
contribution from others) on the basis of relative fault as well as any other
relevant equitable considerations. The relative fault shall be determined by
reference to, among other things, whether the untrue or alleged untrue statement
of a material fact or the omission or alleged omission to state a material fact
relates to information supplied by the Company on the one hand or the applicable
Holder on

                                       8

<PAGE>

the other hand, and the parties' relative intent, knowledge, access to
information and opportunity to correct or prevent such statement or omission.
The Company and Holder agree that it would not be just and equitable if
contribution pursuant to this Section 7 were determined by pro rata allocation
or by any other method of allocation which does not take account of the
equitable considerations referred to in this Section 7. The amount paid or
payable by an indemnified party as a result of the losses, claims, damages or
liabilities (or actions in respect thereof) referred to above in this Section 7
shall be deemed to include any legal or other expenses reasonably incurred by
such indemnified party in connection with investigating or defending any such
action or claim. No person guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the Securities Act) shall be entitled to
contribution from any person who was not guilty of such fraudulent
misrepresentation.

     Notwithstanding any other provision of this Section 7, in no event shall
any (i) Holder be required to undertake liability to any person under this
Section 7 for any amounts in excess of the dollar amount of the gross proceeds
to be received by the Holder from the sale of Holder's Registrable Securities
(after deducting any fees, discounts and commissions applicable thereto)
pursuant to any Registration Statement under which such Registrable Securities
are or were to be registered under the Securities Act and (ii) underwriter be
required to undertake liability to any person hereunder for any amounts in
excess of the aggregate discount, commission or other compensation payable to
such underwriter with respect to the Registrable Securities underwritten by it
and distributed pursuant to the Registration Statement.

     Section 8.     Restrictions on Registration. From the date hereof through a
                    ----------------------------
period of 20 days following the date that the Registration Statement is first
declared effective, the Company shall not file a registration statement for any
securities other than securities issued in connection with any stock option
plan, stock purchase plan, stock bonus plan or other plan for the benefit of
employees, officers or directors of the Company.

     Section 9.     Notices. All notices, demands, requests, consents,
                    -------
approvals, and other communications required or permitted hereunder shall be in
writing and, unless otherwise specified herein, shall be delivered as set forth
in the Purchase Agreement.

     Section 10.    Assignment. Subject to Section 2 hereof, (a) the rights of a
                    ----------
Holder may be assigned by a Holder to any other person, and (b) the provisions
of this Agreement shall inure to the benefit of, and be enforceable by, any such
transferee of any of the Registrable Securities other than through open-market
sales.

     Section 11.    Counterparts/Facsimile. This Agreement may be executed in
                    ----------------------
two or more counterparts, each of which shall constitute an original, but all of
which, when together shall constitute but one and the same instrument, and shall
become effective when one or more counterparts have been signed by each party
hereto and delivered to the other party. In lieu of the original, a facsimile
transmission or copy of the original shall be as effective and enforceable as
the original.

     Section 12.    Remedies and Severability. The remedies provided in this
                    -------------------------
Agreement are cumulative and not exclusive of any remedies provided by law. If
any term,

                                       9

<PAGE>

provision, covenant or restriction of this Agreement is held by a board of
arbitration or a court of competent jurisdiction to be invalid, illegal, void or
unenforceable, the remainder of the terms, provisions, covenants and
restrictions set forth herein shall remain in full force and effect and shall in
no way be affected, impaired or invalidated, and the parties hereto shall use
their best efforts to find and employ an alternative means to achieve the same
or substantially the same result as that contemplated by such term, provision,
covenant or restriction. It is hereby stipulated and declared to be the
intention of the parties that they would have executed the remaining terms,
provisions, covenants and restrictions without including any of those that may
be hereafter declared invalid, illegal, void or unenforceable.

     Section 13.    Conflicting Agreements. The Company shall not enter into any
                    ----------------------
agreement with respect to its securities that is inconsistent with the rights
granted to the purchasers of Registrable Securities in this Agreement or
otherwise prevents the Company from complying with all of its obligations
hereunder.

     Section 14.    Headings. The headings in this Agreement are for reference
                    --------
purposes only and shall not affect in any way the meaning or interpretation of
this Agreement.

     Section 15.    Governing Law. This Agreement will be governed by and
                    -------------
construed in accordance with the internal laws of the State of California
applicable to contracts made among residents of, and wholly to be performed
within, the State of California, without regard to principles of conflict of
laws or choice of laws.

                            [SIGNATURE PAGE FOLLOWS]

                                       10

<PAGE>

                [SIGNATURE PAGE TO REGISTRATION RIGHTS AGREEMENT]

     IN WITNESS WHEREOF, the parties hereto have caused this Registration Rights
Agreement to be duly executed, on this ____ day of November, 2001.

COMPANY:

VALICERT, INC.

By:
    ------------------------------------
Name:   Joseph (Yosi) Amram
Title:  President and CEO

Address:    339 N. Bernardo Avenue
            Mountain View, CA 94043

INVESTORS:

PALO ALTO INTERNET VALUE FUND, L.P.

By:     Palo Alto Investors, LLC, its General Partner

By:     Palo Alto Investors, Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

<PAGE>

               [SIGNATURE PAGE TO REGISTRATION RIGHTS AGREEMENT]

PALO ALTO CROSSOVER FUND, L.P.

By:     Palo Alto Investors, LLC, its General Partner

By:     Palo Alto Investors, Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

CREE & JENNIFER EDWARDS FAMILY TRUST

By:    Palo Alto Investors, LLC, Registered Investment Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

<PAGE>

               [SIGNATURE PAGE TO REGISTRATION RIGHTS AGREEMENT]

WILLIAM H. DRAPER, III RT

By:    Palo Alto Investors, LLC, Registered Investment Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

FRED M. GIBBONS

By:    Palo Alto Investors, LLC, Registered Investment Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

<PAGE>

               [SIGNATURE PAGE TO REGISTRATION RIGHTS AGREEMENT]

MICRO CAP PARTNERS, L.P.

By:     Palo Alto Investors, LLC, its General Partner

By:     Palo Alto Investors, Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

MICRO-MOUSSE PARTNERS, L.P.

By:     Palo Alto Investors, LLC, its General Partner

By:     Palo Alto Investors, Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

<PAGE>

               [SIGNATURE PAGE TO REGISTRATION RIGHTS AGREEMENT]

PAUL C. EDWARDS

By:    Palo Alto Investors, LLC, Registered Investment Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

UBTI FREE, L.P.

By:    Palo Alto Investors, LLC, its General Partner

By:    Palo Alto Investors, Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

<PAGE>

               [SIGNATURE PAGE TO REGISTRATION RIGHTS AGREEMENT]

WILLIAM C. EDWARDS RT

By:    Palo Alto Investors, LLC, Registered Investment Manager

By:
    ------------------------------------
       William L. Edwards, President

Address:

-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------

Tax ID:
        ---------------------------------------------------

<PAGE>

                                    EXHIBIT A
                                    ---------

                              Plan of Distribution

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