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                                                                    EXHIBIT 4.23


                            FIRST AMENDMENT TO LEASE
                            ------------------------

     THIS FIRST AMENDMENT TO LEASE ("Amendment") is made as of November 1, 1999,
by and between PENINSULA OFFICE PARK ASSOCIATES, L.P., a California limited
liability company ("Landlord"), and TRINTECH, INC., a California corporation
("Tenant").

                                    Recitals
                                    --------

     A.  Landlord and Tenant entered into a Lease Agreement dated May 28, 1999
(the "Lease") by which Landlord leased to Tenant and Tenant leased from Landlord
Suite 220 (the "Existing Premises") containing approximately 7,250 rentable
square feet of office space on the 2nd floor of the building known as Peninsula
Office Park 5 located at 2755 Campus Drive, San Mateo, California (the
"Building").

     B.  The Term of the Lease is scheduled to expire July 31, 2004 (the
"Expiration Date").

     C.  Landlord and Tenant desire to amend the Lease to (i) provide for Tenant
to lease Suite 205 (the "Additional Space") containing approximately 4,059
rentable square feet of office space on the 2nd floor of the Building; and (ii)
make certain other changes in the Lease, all upon and subject to the terms and
conditions set forth in this Amendment. The approximate configuration and
location of the Additional Space is shown on Exhibit A.
                                             ---------

     NOW THEREFORE, in consideration of the foregoing recitals and the mutual
agreements of the parties herein, Landlord and Tenant agree as follows:

1.   Capitalized Terms. Capitalized terms not otherwise defined in this
     -----------------
     Amendment shall have the meaning given them in the Lease.


2.   Leasing of Additional Space. Landlord leases to Tenant and Tenant leases
     ---------------------------
     from Landlord the Additional Space for a term commencing the earlier the
     date Landlord delivers possession of the Additional Space to Tenant
     following the date Landlord obtains possession of the Additional Space from
     the Existing Tenant (as hereinafter defined), or (b) March 15, 2000 (the
     "Additional Space Commencement Date"), and unless sooner terminated,
     expiring on the Expiration Date.


3.   Existing Tenant. Tenant acknowledges and agrees that the Additional Space
     ---------------
     is leased and occupied by an existing tenant (the "Existing Tenant") in
     accordance with a lease which expires February 29, 2000. Landlord agrees to
     use good faith efforts to regain possession of the Additional Space from
     the Existing Tenant and to deliver possession of the Additional Space to
     Tenant following expiration of the lease with the Existing Tenant. Landlord
     shall not be liable for any claims, damages or liabilities

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     if Landlord is unable to deliver possession of the Additional Space to
     Tenant following expiration of the lease with the Existing Tenant.

4.   Premises following the Additional Space Commencement Date. Commencing on
     ---------------------------------------------------------
     the Additional Space Commencement Date and continuing through the
     Expiration Date, except as a provision herein applies only to the
     Additional Space, the Additional Space shall be included in the "Premises"
     for all purposes under the Lease (and the "Premises" shall consist of both
     the Existing Premises and the Additional Space, totaling approximately
     11,309 rentable square feet of office space).

5.   Base Rent for Additional Space.  In addition to the Base Rent payable by
     ------------------------------
     Tenant to Landlord for the Existing Premises, commencing on the Additional
     Space Commencement Date and continuing until the Expiration Date, Tenant
     shall pay the following Base Rent for the Additional Space:

           Months following
           ----------------
           Additional Space
           ----------------
           Commencement Date:           Base Rent:
           ------------------           ----------

           Months 01 - 12:              $3.75 per rentable square foot per month
           Months 13 - 24:              $3.85 per rentable square foot per month
           Months 25 - 36:              $3.95 per rentable square foot per month
           Months 37 - 48:              $4.05 per rentable square foot per month
           Months 49 - Expiration Date: $4.15 per rentable square foot per month

6.   Condition of Additional Space.  Tenant has inspected and examined the
     -----------------------------
     Additional Space and has elected to lease the Additional Space on a
     strictly "AS IS" basis, with "all faults", and with no responsibility upon
     Landlord to demolish, clean, repair, or reconstruct the Additional Space or
     to remove any personal property, improvements or materials therefrom prior
     to or after delivery of the Additional Space. Tenant shall be solely
     responsible for making any alterations or improvements to the Additional
     Space required or desired by Tenant, subject to and in accordance with the
     provisions of Article 6 -Alterations - of the Lease, which Alterations may
     be made by Tenant at any time after the Additional Space Commencement Date
     using Webcor Builders ("Webcor") as general contractor. Tenant shall
     contract directly with Webcor for any such Alterations. Landlord shall
     contribute up to $18,265.50 ("Landlord's Allowance") toward the cost of the
     design (including preparation of plans), construction and installation of
     the Alterations in the Additional Space. Landlord shall pay Landlord's
     Allowance to Tenant within thirty (30) days following (a) the date Tenant
     notifies Landlord that the Alterations have been completed in accordance
     with the plans and specifications approved by Landlord, (b) Landlord has
     inspected the Alterations to verify that such Alterations have been
     completed in accordance with such approved plans and specifications, and
     (c) Tenant provides Landlord written evidence that Tenant has paid in full
     the costs of such Alterations, and that no lien will be filed by any
     contractor, subcontractor or supplier in connection with such Alterations.

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     and that no lien will be filed by any contractor, subcontractor or supplier
     in connection with such Alterations.

7.   Tenant's Share. From and after the Additional Space Commencement Date,
     --------------
     Tenant's Share shall be 14.20%.

8.   Base Year. The Base Year for the Additional Space shall be calendar year
     ---------
     2000. The Base Year for the Existing Premises remains unchanged.

9.   Security Deposit. Upon Tenant's execution and delivery of this Amendment to
     ----------------
     Landlord, Tenant shall deliver $65,755.80 as an additional Security Deposit
     to be held by Landlord in accordance with the provisions of Section 4 of
     the Lease.

10.  Brokers. Tenant warrants and represents to Landlord that in the negotiating
     -------
     or making of this Amendment neither Tenant nor anyone acting on Tenant's
     behalf has dealt with any real estate broker or finder who might be
     entitled to a fee or commission from this Amendment. Tenant agrees to
     indemnify and hold Landlord harmless from any claim or claims, including
     costs, expenses and attorney's fees incurred by Landlord, asserted by any
     broker or finder for a fee or commission, based upon any dealings with or
     statements made by Tenant or its representatives. Landlord agrees to
     indemnify and hold Tenant harmless from and against any claim by third
     parties claiming by, through, or under Landlord for commissions due or
     alleged to be due in connection with this Agreement.

11.  Ratification of Lease.  Except as expressly amended by this Amendment, the
     ---------------------
     Lease remains in full force and effect without modification. The Lease and
     this Amendment are fully integrated and each reference to any provision of
     the Lease shall be deemed to refer to such provision of the Lease as it may
     be amended in this Amendment. The Lease and this Amendment constitute the
     entire agreement between Landlord and Tenant regarding the subject matters
     contained herein, and supersedes all prior or contemporaneous agreements,
     understandings, proposals and other representations by or between Landlord
     and Tenant, whether written or oral, all of which are merged herein. This
     Amendment shall become effective as a binding agreement only if and when
     Amendment executes this Amendment following execution by Tenant and
     delivers a fully executed copy to Tenant.

12.  Authority.  Each of the persons executing this Amendment on behalf of
     ---------
     Tenant warrants and represents that Tenant is a duly organized and validly
     existing entity, that Tenant has full right and authority to enter into
     this Amendment and that the persons signing on behalf of Tenant are
     authorized to do so and have the power to bind Tenant to this Amendment.

     IN WITNESS WHEREOF, Landlord and Tenant have entered into and executed this
Amendment as of date of this Amendment.

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TENANT:                             LANDLORD:

TRINTECH, INC.,                     PENINSULA OFFICE PARK
a California corporation            ASSOCIATES, L.P.,
                                    a California limited partnership

By: /s/ John McGuire                     By:  CORNERSTONE HOLDINGS, LLC,
    ----------------------               a Delaware limited liability
                                         General Partner
Name: /s/ John McGuire
      --------------------

Title: /s/ CEO
       -------------------


By: /s/ Eugene Tighe                    By:
    ----------------------                  ---------------------------

Name: Eugene Tighe                      Name:
      --------------------                    -------------------------

Title: Controller                       Title:
       -------------------                     -----------------------


(For corporate entities, signature by TWO corporate officers is required:  one
by (x) the chairman of the board, the president, or any vice president; and the
other by (y) the secretary, any assistant secretary, the chief financial
officer, or any assistant treasurer.)

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                                   EXHIBIT A
                                   ---------

                       ATTACHED TO AND FORMING A PART OF
                            FIRST AMENDMENT TO LEASE
                          DATED AS OF NOVEMBER 1, 1999
                                    BETWEEN
              PENINSULA OFFICE PARK ASSOCIATES, L.P., AS LANDLORD,
                                      AND
                    TRINTECH, INC., AS TENANT ("AMENDMENT")


                              THE ADDITIONAL SPACE
                              --------------------


                               [GRAPHICS HERE]



                                  Second Floor
--------------------------------------------------------------------------------
            Peninsula Office Park - 2755 Campus Drive, San Mateo, CA

                                                   INITIALS:

                                                   Landlord
                                                   Tenant

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