Document:

<PAGE>
                                                                     EXHIBIT 4.1

                               OCEAN ENERGY, INC.

                              OFFICERS' CERTIFICATE

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

                                   EVIDENCING
                          4.375% SENIOR NOTES DUE 2007

                        Officers' Certificate to Trustee

         Robert K. Reeves, Executive Vice President, General Counsel and
Secretary, and Winston M. Talbert, Vice President and Treasurer of Ocean Energy,
Inc., a Delaware corporation (the "Company"), pursuant to Sections 2.1 and 2.3
of the Senior Indenture, dated as of September 28, 2001, (the "Indenture") among
the Company, Ocean Energy, Inc. (a Louisiana corporation), as guarantor (the
"Guarantor"), and The Bank of New York, as trustee (the "Trustee"), in
connection with the offering of $400,000,000 aggregate principal amount of the
Company's 4.375% Senior Notes due 2007 (the "Senior Notes"), each hereby
certifies that, to the best of his knowledge, after reasonable investigation:

         1. The Board of Directors (the "Board") has established the form of the
Senior Notes pursuant to Section 2.1 of the Indenture, and such form is set
forth in the specimen of the Senior Notes attached as Exhibit A.

         2. The Executive Committee of the Board has established the terms of
the Senior Notes pursuant to Section 2.3 of the Indenture, and such terms are
set forth in Exhibit B.

         IN WITNESS WHEREOF, the undersigned have duly executed this Officers'
Certificate as of the 20th day of September, 2002.

                                            OCEAN ENERGY, INC.

                                            By:
                                               ---------------------------------
                                            Name: Robert K. Reeves
                                            Title: Executive Vice President,
                                                   General Counsel and Secretary

                                            By:
                                               ---------------------------------
                                            Name: Winston M. Talbert
                                            Title: Vice President and Treasurer
<PAGE>
                                                                       EXHIBIT A

         THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITORY OR A
NOMINEE OF A DEPOSITORY. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART
FOR SECURITIES IN DEFINITIVE REGISTERED FORM, THIS SECURITY MAY NOT BE
TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITARY TO THE NOMINEE OF THE DEPOSITARY
OR BY A NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE
DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR
A NOMINEE OF SUCH SUCCESSOR DEPOSITARY.

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY OR
ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME
AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

                               OCEAN ENERGY, INC.

                           4.375% Senior Note due 2007

NO. 001                                            CUSIP NO.  67481EAB2

         OCEAN ENERGY, INC., a corporation duly organized and existing under the
laws of the State of Delaware (herein called the "Company," which term includes
any successor Person under the Indenture hereinafter referred to), for value
received, hereby promises to pay to Cede & Co., or registered assigns, the
principal sum of FOUR HUNDRED MILLION DOLLARS on October 1, 2007, and to pay
interest thereon from September 20, 2002 or from the most recent interest
payment date to which interest has been paid or duly provided for, semiannually
in arrears on April 1 and October 1 in each year, commencing April 1, 2003, at
the rate of 4.375% per annum, until the principal hereof is fully paid or made
available for full payment. The interest so payable, and punctually paid or duly
provided for, on any interest payment date will, as provided in such Indenture,
be paid to the Person in whose name this Note is registered at the close of
business on the March 15 or September 15 (whether or not a Business Day), as the
case may be, next preceding such interest payment date (a "Regular Record
Date"). Notwithstanding the foregoing, if and to the extent the Company shall
default in the payment of the interest due on such interest payment date, any
such interest not so punctually paid or duly provided for will forthwith cease
to be payable to the Holder on such Regular Record Date and such defaulted
interest shall instead be paid to the Person in whose name this Note is
registered (a) at the close of business on a subsequent record date (which shall
be not less than five Business Days prior to the date of payment of such
defaulted interest) established by notice given by mail by or on
<PAGE>

behalf of the Company to the Holders of Notes not less than 15 days preceding
such subsequent record date or (b) as determined by such other procedure as is
mutually acceptable to the Company and the Trustee, all as more fully described
in the Indenture.

         Payment of the principal of (and premium, if any) and interest on this
Note shall be made at the Corporate Trust Office of the Trustee in New York, New
York, or at such other office or agency of the Company as it may designate for
such purpose pursuant to the Indenture hereinafter referred to, in such
immediately available funds of the United States of America as at the time of
payment are legal tender for payment of public and private debts.

         Reference is hereby made to the further provisions of this Note set
forth below, which further provisions shall for all purposes have the same
effect as if set forth in this place.

         Unless the certificate of authentication hereon has been executed by
the Trustee referred to below by manual signature of an authorized officer, this
Note shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.

Dated: September 20, 2002

                                            OCEAN ENERGY, INC.

                                            By:
                                               ---------------------------------
                                                 Winston M. Talbert
                                                 Vice President and Treasurer

ATTEST:

------------------------------------
Robert K. Reeves
Secretary

                                       2
<PAGE>

                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

         This is one of the Securities of the series designated herein referred
to in the within-mentioned Indenture.

                                            THE BANK OF NEW YORK
                                            as Trustee

                                            By:
                                               ---------------------------------
                                                      Authorized Officer

                                       3
<PAGE>

                              [REVERSE OF SECURITY]

         This Note is one of a duly authorized issue of Securities of the
Company (such issue being herein called the "Notes"), issued and to be issued in
one or more series under the Senior Indenture, dated as of September 28, 2001
(herein, together with the Board Resolution establishing the terms of the Notes,
called the "Indenture"), among the Company, Ocean Energy, Inc. (a Louisiana
corporation), as guarantor (herein called the "Guarantor") and The Bank of New
York, as Trustee (herein called the "Trustee," which term includes any
additional successor trustee under the Indenture), to which Indenture and all
indentures supplemental thereto reference is hereby made for a statement of the
respective rights, limitation of rights, duties and immunities thereunder of the
Company, the Guarantor, the Trustee and the Holders of the Notes and of the
terms upon which the Notes are, and are to be, authenticated and delivered.
Capitalized terms used but not defined herein are defined in the Indenture and
used herein with the same meanings ascribed to them therein. This Note is a
Global Security representing the entire principal amount of the series
designated on the face hereof, limited in aggregate principal amount to
$400,000,000 except as set forth in the Indenture; provided, however, that the
Company may, without the consent of the holders of the Notes issue additional
notes under the Indenture, having the same ranking and the same interest,
maturities and other terms as the Notes. Any such additional notes may, together
with the Notes, constitute a single series under the Indenture and have the same
CUSIP number as the Notes.

         The Guarantor will guarantee the Company's obligations on the Notes
subject to and in accordance with the terms of the Indenture.

         As further described in the Indenture, the Notes shall be redeemable in
whole or in part, at the Company's option at any time, at a redemption price
equal to the greater of (1) 100% of the principal amount of such Notes to be
redeemed or (2) the sum of the present values of the Remaining Scheduled
Payments on such Notes, discounted to the redemption date on a semiannual basis
(assuming a 360-day year consisting of twelve 30-day months) at the Treasury
Rate plus 25 basis points, plus accrued interest on the principal amount being
redeemed to the redemption date.

         As further described in the Indenture, upon the occurrence of a Change
of Control Triggering Event, the Company shall be obligated to make an offer to
purchase all of the then outstanding Notes (a "Change of Control Offer"), and
shall purchase, on a Business Day (the "Change of Control Purchase Date") not
more than 70 nor less than 30 days following the Change of Control Triggering
Event, all of the then outstanding Notes validly tendered pursuant to such
Change of Control Offer, at a purchase price (the "Change of Control Purchase
Price") equal to 101% of the principal amount thereof plus accrued and unpaid
interest, if any, to the Change of Control Purchase Date.

         The Notes shall not be subject to a sinking fund requirement.

         The Indenture contains provisions for defeasance of the entire
indebtedness of the Notes upon compliance by the Company with certain conditions
set forth therein.

                                       1
<PAGE>

         If an Event of Default with respect to the Notes shall occur and be
continuing, the unpaid principal of the Notes may be declared due and payable in
the manner and with the effect provided in the Indenture.

         The Indenture contains provisions permitting the Company and the
Trustee with the consent of the Holders of not less than a majority in aggregate
principal amount of the Notes then Outstanding under the Indenture and affected
thereby, evidenced as provided in the Indenture, to execute supplemental
indentures adding any provisions to or changing in any manner or eliminating any
of the provisions of the Indenture or of any supplemental indenture or modifying
in any manner the rights of the Holders of the Notes. It is also provided in the
Indenture that the Holders of a majority in aggregate principal amount of the
Notes then Outstanding may on behalf of the Holders of all of the Notes waive
any past default or Event of Default under the Indenture and its consequences
except a default in the payment of the principal of or interest on any of the
Notes. Any such consent or waiver by the Holder of this Note (unless revoked as
provided in the Indenture) shall be conclusive and binding upon such Holder and
upon all future Holders and owners of this Note and any Notes which may be
issued in exchange or substitution herefor, irrespective of whether or not any
notation thereof is made upon this Note or such other Notes.

         No reference herein to the Indenture and no provision of this Note or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of and interest on this Note at
the place, at the respective times, and at the rates and in the coin or currency
herein provided.

         As set forth in, and subject to, the provisions of the Indenture, no
Holder of any Note shall have any right to institute any proceeding with respect
to the Indenture or for any remedy thereunder, unless such Holder shall have
previously given to the Trustee written notice of default and the continuance
thereof, as provided in the Indenture, and unless the Holders of not less than
25% in principal amount of the Notes then Outstanding shall have made written
request, and offered reasonable indemnity, to the Trustee to institute such
proceeding as trustee, and the Trustee shall have failed to institute such
proceeding within 60 days; provided, however, that such limitations shall not
without the consent of such Holder impair the right of a Holder hereof to
institute suit for the enforcement of payment of the principal of or interest on
this Note on or after the respective due dates expressed herein.

         This Note shall be exchangeable for Notes registered in the names of
Persons other than the Depositary with respect to such series or its nominee
only as provided in this paragraph. This Note shall be so exchangeable if (i)
such Depositary notifies the Company that it is unwilling, unable or ineligible
to continue as Depositary for this Note and a successor Depositary is not
appointed by the Company within 90 days or (ii) the Company executes and
delivers to the Trustee a written order providing that this Note shall be so
exchangeable. Notes so issued in exchange for this Note shall be of the same
series and of like tenor, in authorized denominations and in the aggregate
having the same unpaid principal amount as this Note and registered in such
names as such Depositary shall direct. Individual Notes so issued will be issued
in registered form and denominations, unless otherwise specified by the Company,
of $1,000 and integral multiples thereof.

                                       2
<PAGE>

         As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this Note is registrable in the security register
maintained for that purpose, upon surrender of this Note for registration of
transfer at the office or agency of the Company in any place where the principal
of (and premium, if any) and interest on this Note are payable, duly endorsed
by, or accompanied by a written instrument of transfer in form satisfactory to
the Company and the Trustee duly executed by, the Holder hereof or its attorney
duly authorized in writing, and thereupon on or more new Notes of this series,
and of like tenor, of authorized denominations and for the same aggregate unpaid
principal amount, shall be issued to the designated transferee or transferees.
At the date of the original issuance of this Note, such office or agency of the
Company is maintained by the Trustee at its Corporate Trust Office, 101 Barclay
Street, Floor 8 West, New York, New York.

         Prior to due presentment of this Note for registration of transfer, the
Company, the Trustee and any agent of the Company or the Trustee may treat the
Person in whose name this Note is registered as the owner hereof for all
purposes, whether or not this Note be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary. All
payments made to or upon the order of such registered Holder shall, to the
extent of the sum or sums so paid, satisfy and discharge the liability for
moneys payable on this Note.

         Pursuant to a recommendation promulgated by the Committee on Uniform
Security Identification Procedures, the Company has caused a CUSIP number to be
printed on this Note as a convenience to the Holder hereof. No representation is
made as to the accuracy of such number and reliance may be placed only on the
other identifying information printed hereon.

         Interest on this Note shall be computed on the basis of a 360-day year
comprised of twelve 30-day months.

         THE INDENTURE AND THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

                                        3
<PAGE>

                                 ASSIGNMENT FORM

         I or we assign and transfer this Note to

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

--------------------------------------------------------------------------------
(Print or type name, address and zip code of assignee or transferee)

--------------------------------------------------------------------------------
(Insert Social Security or other identifying number of assignee or transferee)
and irrevocably appoint
                       ---------------------------------------------------------
agent to transfer this Note on the books of the Company.  The agent may
substitute another to act for him.

Dated:                                 Signed:
      ------------------------------          ----------------------------------
                                              (Sign exactly as name appears
                                              above or on the other side of this
                                              Note)

Signature Guarantee:
                    -----------------------------------------------------
                    Participant in a recognized Signature Guarantee
                    Medallion Program (or other signature guarantor
                    program reasonably acceptable to the Trustee)

                                       4
<PAGE>

                                                                       EXHIBIT B

         In addition to the terms provided in the Senior Indenture, dated as of
September 28, 2001, (the "Indenture") among Ocean Energy, Inc., a Delaware
corporation (the "Company"), Ocean Energy, Inc., a Louisiana corporation, as
guarantor (the "Guarantor"), and The Bank of New York, as trustee (the
"Trustee"), in connection with the offering of $400,000,000 aggregate principal
amount of the Company's 4.375% Senior Notes due 2007 (the "Senior Notes"), with
respect to Securities of a series issued thereunder, the terms of the Senior
Notes shall be as follows (with all capitalized terms not defined herein having
the respective meanings ascribed thereto in the Indenture):

                  (1) Principal Amount. The aggregate principal amount of the
         Senior Notes that may be authenticated and delivered under the
         Indenture shall initially be limited to $400,000,000 (except for
         Securities authenticated and delivered upon registration of transfer
         of, or in exchange for, or in lieu of, other Securities of the series
         pursuant to Section 2.8, 2.9, 2.11, 8.5 or 12.3 of the Indenture),
         provided, however, that the Company may, without the consent of the
         holders of the Senior Notes issue additional notes under the Indenture,
         having the same ranking and the same interest, maturities and other
         terms as the Senior Notes. Any such additional notes may, together with
         the Senior Notes, constitute a single series under the Indenture and
         have the same CUSIP number as the Senior Notes.

                  (2) Stated Maturity. The principal of the Senior Notes shall
         be payable in full on October 1, 2007, unless earlier redeemed in
         accordance herewith.

                  (3) Interest. The unpaid principal of the Senior Notes shall
         bear interest at the rate of 4.375% per annum from September 20, 2002
         or from the most recent interest payment date to which interest has
         been paid or duly provided for, which interest shall be calculated on
         the basis of a 360-day year comprised of twelve 30-day months.

                  (4) Interest Payment Dates. The interest payment dates with
         respect to the Senior Notes shall be April 1 and October 1 in each
         year, commencing April 1, 2003, and the regular record dates for
         interest payable on any such interest payment date shall be March 15 or
         September 15 (whether or not a Business Day), as the case may be, next
         preceding such interest payment date.

                  (5) Office of Payment. Principal of (and premium, if any) and
         interest on the Senior Notes shall be payable at the Corporate Trust
         Office of the Trustee in New York, New York, and the Senior Notes may
         be surrendered for registration of transfer or exchange at such
         Corporate Trust Office, and notices and demands to or upon the Company
         in respect of the Senior Notes and the Indenture may be served at such
         Corporate Trust Office.

                  (6) Paying Agent, etc. The Trustee shall initially act as
         paying agent, authenticating agent, transfer agent and security
         registrar with respect to the Senior Notes.

                  (7) Guarantee. The Guarantor will guarantee the Company's
         payment obligations on the Senior Notes subject to and in accordance
         with Article Thirteen of the
<PAGE>

         Indenture. The provisions of Section 3.8 of the Indenture shall be
         applicable to the Senior Notes.

                  (8) Redemption. The Senior Notes shall be redeemable in whole
         or in part, at the Company's option, at any time or from time to time,
         at a redemption price equal to the greater of (1) 100% of the principal
         amount of such Senior Notes to be redeemed or (2) the sum of the
         present values of the Remaining Scheduled Payments (as hereinafter
         defined) on such Senior Notes, discounted to the date fixed for
         redemption in accordance with Article Twelve of the Indenture (the
         "Redemption Date") on a semiannual basis (assuming a 360-day year
         consisting of twelve 30-day months) at the Treasury Rate (as
         hereinafter defined) plus 25 basis points, plus accrued interest on the
         principal amount being redeemed to the Redemption Date.

                  "Treasury Rate" means, with respect to any Redemption Date,
         the rate per annum equal to the semiannual equivalent yield to maturity
         of the Comparable Treasury Issue, assuming a price for the Comparable
         Treasury Issue (expressed as a percentage of its principal amount)
         equal to the Comparable Treasury Price for such Redemption Date.

                  "Comparable Treasury Issue" means the United States Treasury
         security selected by an Independent Investment Banker as having a
         maturity comparable to the remaining term of the Senior Notes to be
         redeemed that would be used, at the time of selection and in accordance
         with customary financial practice, in pricing new issues of corporate
         debt securities of comparable maturity to the remaining term of such
         Senior Notes.

                  "Independent Investment Banker" means one of the Reference
         Treasury Dealers appointed by the Trustee after consultation with the
         Company.

                  "Comparable Treasury Price" means, with respect to any
         Redemption Date, (1) the arithmetic average of the bid and ask prices
         for the Comparable Treasury Issue (expressed in each case as a
         percentage of its principal amount) on the third Business Day before
         such Redemption Date, as published in the daily statistical release (or
         any successor release) by the Federal Reserve Bank of New York and
         designated "Composite 3:30 p.m. Quotations for U.S. Government
         Securities" or (2) if such release (or any successor release) is not
         available or does not contain such prices on such Business Day, the
         arithmetic average of the Reference Treasury Dealer Quotations for such
         Redemption Date.

                  "Reference Treasury Dealer" means Goldman, Sachs & Co. or
         Merrill Lynch & Co. and their respective successors; provided, however,
         that if any such entity ceases to be a primary U. S. Government
         securities dealer in New York City (a "Primary Treasury Dealer"), the
         Company shall substitute therefor another Primary Treasury Dealer.

                  "Reference Treasury Dealer Quotations" means, with respect to
         each Reference Treasury Dealer and any Redemption Date, the arithmetic
         average, as determined by the Trustee, of the bid and ask prices for
         the Comparable Treasury Issue (expressed in each case as a percentage
         of its principal amount) quoted in writing to the Trustee by such

                                       3
<PAGE>

         Reference Treasury Dealer by 5:00 p.m. on the third Business Day before
         such Redemption Date.

                  "Remaining Scheduled Payments" means the remaining scheduled
         payments of the principal of the Senior Notes to be redeemed and
         interest thereon that would be due after the related Redemption Date
         but for such redemption; provided, however, that, if such Redemption
         Date is not an interest payment date, the amount of the next succeeding
         scheduled interest payment thereon will be reduced by the amount of
         interest accrued thereon to such Redemption Date.

                  (9) Change of Control Offer. (i) Upon the occurrence of a
         Change of Control Triggering Event, the Company shall be obligated to
         make an offer to purchase all of the then outstanding Senior Notes (a
         "Change of Control Offer"), and shall purchase, on a Business Day (the
         "Change of Control Purchase Date") not more than 70 nor less than 30
         days following the date of the Change of Control Triggering Event, all
         of the then outstanding Senior Notes validly tendered pursuant to such
         Change of Control Offer, at a purchase price (the "Change of Control
         Purchase Price") equal to 101% of the principal amount thereof plus
         accrued and unpaid interest, if any, to the Change of Control Purchase
         Date. The Change of Control Offer is required to remain open for at
         least 20 Business Days and until the close of business on the Change of
         Control Purchase Date.

                           (ii) Not later than the 30th day following the date
                  of the Change of Control Triggering Event, the Company shall
                  give to the Trustee and each Holder of the Senior Notes, in
                  the manner provided in Section 11.4 of the Indenture, a notice
                  (the "Change of Control Notice") stating:

                                    (A) that a Change of Control Triggering
                           Event has occurred and that such Holder has the right
                           to require the Company to repurchase such Holder's
                           Senior Notes, or portion thereof equal to an integral
                           multiple of $1,000, at the Change of Control Purchase
                           Price;

                                    (B) any information regarding such Change of
                           Control Triggering Event required to be furnished
                           pursuant to Rule 14e-1 under the Securities Exchange
                           Act of 1934 (the "Exchange Act") and any other
                           securities laws and regulations thereunder;

                                    (C) the Change of Control Purchase Date,
                           which shall be on a Business Day and no earlier than
                           30 days nor later than 70 days after the date of the
                           Change of Control Triggering Event;

                                    (D) that any Senior Note, or portion
                           thereof, not tendered or accepted for payment will
                           continue to accrue interest;

                                    (E) that unless the Company defaults in
                           depositing money with the paying agent in accordance
                           with paragraph (v) of this Section (9), or payment is
                           otherwise prevented, any Senior Note, or portion
                           thereof, accepted for payment pursuant to the Change
                           of Control Offer shall cease to accrue interest after
                           the Change of Control Purchase Date; and

                                       4
<PAGE>

                                    (F) the instructions a Holder must follow in
                           order to have its Senior Notes repurchased in
                           accordance with paragraph (iv) of this Section (9).

                           (iii) The Company will not be required to make a
                  Change of Control Offer upon a Change of Control Triggering
                  Event if a third party makes the Change of Control Offer at
                  the same purchase price, at the same times and otherwise in
                  substantial compliance with the requirements applicable to a
                  Change of Control Offer made by the Company and purchases all
                  Senior Notes validly tendered and not withdrawn under such
                  Change of Control Offer.

                           (iv) Holders electing to have Senior Notes purchased
                  will be required to surrender such Senior Notes to the Company
                  at the address specified in the Change of Control Notice at
                  least five Business Days prior to the Change of Control
                  Purchase Date. Repurchases of Senior Notes in part may be
                  elected only for portions of Senior Notes having a principal
                  amount of $1,000 or an integral multiple thereof. Holders will
                  be entitled to withdraw their election if the Company
                  receives, not later than three Business Days prior to the
                  Change of Control Purchase Date, a telegram, telex, facsimile
                  transmission or letter setting forth the name of the Holder,
                  the certificate number(s) and principal amount of the Senior
                  Notes delivered for purchase by the Holder as to which his
                  election is to be withdrawn and a statement that such Holder
                  is withdrawing his election to have such Senior Notes
                  purchased. Holders whose Senior Notes are purchased only in
                  part will be issued new Senior Notes equal in principal amount
                  to the unpurchased portion of the Senior Notes surrendered.

                           (v) On the Change of Control Purchase Date, the
                  Company shall (A) accept for payment Senior Notes or portions
                  thereof tendered pursuant to a Change of Control Offer, (B)
                  deposit with the paying agent money sufficient to pay the
                  purchase price of all Senior Notes or portions thereof so
                  tendered, and (C) deliver or cause to be delivered to the
                  Trustee the Senior Notes so accepted. The paying agent shall
                  promptly mail or deliver to Holders of the Senior Notes so
                  tendered payment in an amount equal to the purchase price for
                  the Senior Notes, and the Company will promptly execute and
                  the Trustee will promptly authenticate and mail or make
                  available for delivery to such Holders a new Senior Note equal
                  in principal amount to any unpurchased portion of the Senior
                  Note which any such Holder did not surrender for purchase. The
                  Company shall announce the results of a Change of Control
                  Offer on or as soon as practicable after the Change of Control
                  Purchase Date.

                           (vi) The Company shall comply with Rule 14e-1 under
                  the Exchange Act and any other securities laws and regulations
                  thereunder to the extent such laws and regulations are
                  applicable, in the event that a Change of Control Triggering
                  Event occurs and the Company is required to purchase Senior
                  Notes as described above.

                                       5
<PAGE>

                           (vii) For all purposes of this Section (9), the
                  following terms shall have the respective meanings specified
                  below (except as otherwise expressly provided or unless the
                  context otherwise clearly requires):

                  "Change of Control" means the occurrence of any of the
         following events: (a) any "person" or "group" (as such terms are used
         in Sections 13(d) and 14(d) of the Exchange Act) is or becomes the
         "beneficial owner" (as defined in Rule 13d-3 under the Exchange Act),
         directly or indirectly, of more than 50% of the Company's total Voting
         Stock; (b) the Company is merged with or into or consolidated with
         another Person and, immediately after giving effect to the merger or
         consolidation, (A) less than 50% of the total voting power of the
         outstanding Voting Stock of the surviving or resulting Person is then
         "beneficially owned" (within the meaning of Rule 13d-3 under the
         Exchange Act) in the aggregate by (x) the Company's stockholders
         immediately prior to such merger or consolidation, or (y) if a record
         date has been set to determine the stockholders of the Company entitled
         to vote with respect to such merger or consolidation, the stockholders
         of the Company as of such record date and (B) any "person" or "group"
         (as defined in Section 13(d)(3) or 14(d)(2) of the Exchange Act), has
         become the direct or indirect "beneficial owner" (as defined in Rule
         13d-3 under the Exchange Act) of more than 50% of the total voting
         power of the Voting Stock of the surviving or resulting Person; (c)
         during any consecutive two-year period, individuals who at the
         beginning of such period constituted the Company's board of directors
         (together with any new directors whose election by such board of
         directors or whose nomination for election by the Company's
         stockholders was approved by a vote of a majority of the directors then
         still in office who were either directors at the beginning of such
         period or whose election or nomination for election was previously so
         approved) cease for any reason to constitute a majority of the
         Company's board of directors then in office; or (d) the liquidation or
         dissolution of the Company.

                  "Change of Control Triggering Event" means the first
         occurrence of both a Change of Control and a related Rating Decline.

                  "Investment Grade" means (i) with respect to Moody's, a rating
         of at least "Baa3" (or equivalent successor category); (ii) with
         respect to S&P, a rating of at least "BBB-" (or equivalent successor
         category); and (iii) with respect to another Rating Agency, a rating
         that is at least the equivalent of the category specified in clause (i)
         or (ii), as applicable, for the Rating Agency for which such Rating
         Agency has been substituted.

                  "Moody's" means Moody's Investors Service, Inc. or any
         successor to the rating agency business thereof.

                  "Rating Agency" means each of S&P and Moody's, or if S&P or
         Moody's or both shall not make a rating on the Senior Notes publicly
         available, a nationally recognized statistical rating agency or
         agencies, as the case may be, selected by the Company (as certified by
         a resolution of the Board of Directors of the Company), which shall be
         substituted for S&P or Moody's, or both, as the case may be.

                                       6
<PAGE>

                  "Rating Decline" means with respect to each of the two Rating
         Agencies there has been either (i) a reduction in the rating of the
         Senior Notes by such Rating Agency to a rating that is not Investment
         Grade or (ii) a withdrawal of the rating of the Senior Notes by such
         Rating Agency; provided, however, that any such reduction or withdrawal
         by a Rating Agency (x) occurs not later than the date 30 days following
         the date of public notice of the occurrence of a Change of Control and
         (y) is due to such Change of Control.

                  "S&P" means Standard & Poor's Services or any successor to the
         rating agency business thereof.

                  "Voting Stock" means any class or classes of capital stock
         pursuant to which the holders thereof have the general voting power
         under ordinary circumstances to elect at least a majority of the board
         of directors, managers or trustees of any Person (irrespective of
         whether or not, at the time, stock of any other class or classes shall
         have, or might have, voting power by reason of the happening of any
         contingency).

                  (10) No Sinking Fund. The Senior Notes shall not be subject to
         a sinking fund requirement.

                  (11) Denominations. The Senior Notes shall be issuable in
         denominations of $1,000 and integral multiples thereof.

                  (12) Defeasance. The Senior Notes shall be subject to
         defeasance as provided in Section 10.1(C) of the Indenture.

                  (13) Depositary. The Senior Notes shall be issued initially
         wholly in the form of Global Securities, and The Depository Trust
         Company shall be the initial Depositary with respect thereto.

                                       7<PAGE>
                                                                     EXHIBIT 4.1

                          SECURITIES PURCHASE AGREEMENT

                      SERIES A CONVERTIBLE PREFERRED STOCK

                     SERIES B CONVERTIBLE PREFERRED STOCK

                              COMMON STOCK WARRANTS

         THIS SECURITIES PURCHASE AGREEMENT (this "Agreement"), dated as of
September 16, 2002, is made by and between Zix Corporation, a Texas corporation
(the "Company"), the investors listed on Schedule A to this Agreement (each, a
"Series A Investor" and, collectively, the "Series A Investors"), and the
investors listed on Schedule B to this Agreement (each, a "Series B Investor"
and, collectively, the "Series B Investors"). The Series A Investors and the
Series B Investors are sometimes collectively referred to in this Agreement as
the "Investors."

         In consideration of the mutual representations, warranties, covenants
and agreements set forth in this Agreement, the Company and the Investors hereby
agree as follows:

                                   ARTICLE I.
                     PURCHASE AND SALE OF CERTAIN SECURITIES

         Section 1.1. Authorization of Preferred Stock. The Restated Articles of
Incorporation of the Company, filed with the Secretary of State of the State of
Texas on December 4, 2001 (as amended, the "Charter"), authorizes the Company to
issue 185,000,000 shares of its capital stock, divided into two classes: (a)
175,000,000 shares of Common Stock, par value $0.01 per share (the "Common
Stock"), and (b) 10,000,000 shares of Preferred Stock, par value $1.00 per share
(the "Preferred Stock"). The Charter authorizes the Board of Directors of the
Company (the "Board") to provide for the issuance of the Preferred Stock from
time to time in one or more series, to establish the number of shares to be
included in each series, and to fix the designations, powers, relative rights,
qualifications, preferences, limitations and restrictions of the shares of each
such series. Pursuant to a resolution duly adopted by the Board, the Company
will file, prior to the Closing (as defined in Section 7.1), with the Secretary
of State of the State of Texas, (i) a Statement of Designations of the Series A
Convertible Preferred Stock of Zix Corporation, in the form attached hereto as
Exhibit A (the "Series A Statement of Designations"), providing for the issuance
of a series of 819,886 shares of Preferred Stock designated as "Series A
Convertible Preferred Stock" (the "Series A Preferred"), having the powers,
relative rights, qualifications, preferences, limitations and restrictions as
set forth in the Series A Statement of Designations, and (ii) a Statement of
Designations of the Series B Convertible Preferred Stock of Zix Corporation in
the form attached hereto as Exhibit B (the "Series B Statement of
Designations"), providing for the issuance of a series of 1,304,815 shares of
Preferred Stock designated as "Series B Convertible Preferred Stock" (the
"Series B Preferred"), having the

                                       1
<PAGE>

powers, relative rights, qualifications, preferences, limitations and
restrictions as set forth in the Series B Statement of Designations.

         Section 1.2. Purchase and Sale of Series A Preferred. On the terms and
subject to the conditions set forth in this Agreement, at the Closing, the
Company will issue and sell to the Series A Investors, and the Series A
Investors will purchase from the Company, up to an aggregate of 819,886 shares
of the Series A Preferred for a purchase price of $3.92 per share. The number of
shares of Series A Preferred to be purchased by each Series A Investor and the
aggregate purchase price to be paid by each Series A Investor is set forth on
Schedule A.

         Section 1.3. Purchase and Sale of Series B Preferred. On the terms and
subject to the conditions set forth in this Agreement, at the Closing, the
Company will issue and sell to the Series B Investors, and the Series B
Investors will purchase from the Company, up to an aggregate of 1,304,815 shares
of the Series B Preferred for a purchase price of $3.60 per share. The number of
shares of Series B Preferred to be purchased by each Series B Investor and the
aggregate purchase price to be paid by each Series B Investor is set forth on
Schedule B.

         Section 1.4. Purchase and Sale of Warrants. On the terms and subject to
the conditions set forth in this Agreement, at the Closing, the Company will
issue and sell to the Series A Investors, and the Series A Investors will
purchase from the Company, warrants, in the form attached hereto as Exhibit C
(the "Warrants"), to purchase up to an aggregate of 288,244 shares of Common
Stock ("Warrant Shares") for a purchase price of $0.125 per Warrant Share. On
the terms and subject to the conditions set forth in this Agreement, at the
Closing, the Company will issue and sell to the Series B Investors, and the
Series B Investors will purchase from the Company, Warrants to purchase up to an
aggregate of 421,284 Warrant Shares for a purchase price of $0.125 per Warrant
Share. The number of Warrant Shares for which the Warrant issued and sold to
each Investor will be exercisable and the aggregate purchase price to be paid by
each Investor for the Warrant issued thereto is set forth on Schedule A or
Schedule B, as applicable.

         Section 1.5. Separate Agreements. The Company's agreement with each
Investor is a separate agreement, and the sale of Warrants and shares of Series
A Preferred or Series B Preferred, as the case may be, to each Investor is a
separate sale.

         Section 1.6. Use of Proceeds. The Company will use the proceeds from
the sale of the Series A Preferred, the Series B Preferred and the Warrants
(collectively, the "Securities") for working capital and other general corporate
purposes.

         Section 1.7. Additional Financing Transaction. Simultaneously with the
Closing, the Company will enter into a financing transaction (the "Additional
Financing Transaction"), pursuant to which the Company will sell certain
convertible notes (the "Notes") and warrants (together with the Notes, the
"Additional Securities") for an aggregate purchase price of $8,000,000.

                                       2
<PAGE>

                                   ARTICLE II.
                  REPRESENTATIONS AND WARRANTIES OF THE COMPANY

         As a material inducement to the Investors to enter into and perform
their respective obligations under this Agreement, the Company hereby represents
and warrants to the Investors that, except as set forth in the "Schedule of
Exceptions" attached hereto as Schedule C:

         Section 2.1. Organization. The Company is a corporation, duly
organized, validly existing and in good standing under the laws of the State of
Texas. The Company is duly qualified or authorized to do business as a foreign
corporation, and is in good standing, under the laws of each other jurisdiction
where the failure to be so qualified or authorized would have a material adverse
effect on the properties, assets, financial condition, business or operations of
the Company. The Company has full corporate power and authority to own, lease
and operate its properties and to conduct its business as presently conducted.

         Section 2.2. Enforceability. The Company has full corporate power and
authority to execute and deliver this Agreement, to perform its respective
obligations under this Agreement and to consummate the transactions contemplated
by this Agreement. The execution and delivery by the Company of this Agreement,
the performance by the Company of its obligations under this Agreement and the
consummation by the Company of the transactions contemplated by this Agreement
have been duly authorized by all necessary corporate action. This Agreement has
been duly and validly executed and delivered by the Company and constitutes the
legal, valid and binding obligation of the Company enforceable against the
Company in accordance with its terms, except (a) as such enforceability may be
limited by applicable bankruptcy, insolvency, reorganization, moratorium and
other laws of general application affecting enforcement of creditors' rights
generally, (b) as such enforceability may be limited by laws relating to the
availability of specific performance, injunctive relief or other equitable
remedies and (c) to the extent that the choice of law provisions contained in
this Agreement may be limited by applicable laws.

         Section 2.3. No Conflicts. The execution and delivery by the Company of
this Agreement, the performance by the Company of its obligations under this
Agreement and the consummation by the Company of the transactions contemplated
by this Agreement do not, and will not,

                  (a) violate any provision of applicable law;

                  (b) violate any provision of the Charter or Bylaws of the
         Company;

                  (c) require any consent, waiver, order, approval or
         authorization of, registration, qualification, declaration or filing
         with or notification to any government or governmental or regulatory
         body thereof, whether federal, state, local or foreign, or any agency,
         department or instrumentality thereof, or any court (each, a
         "Governmental Authority"), or any self-regulatory organization to which
         the Company or its securities are subject, or any other person or legal
         entity, other than (i) filings under federal and state securities laws
         and the filing of a Listing of Additional Shares with The Nasdaq

                                       3
<PAGE>

         Stock Market, and (ii) consents, waivers, approvals, authorizations,
         declarations, filings or notifications that have been obtained or will
         be obtained prior to the Closing;

                  (d) violate, conflict with, constitute a default under or
         breach (whether with the passage of time, the giving of notice or
         otherwise) any term, condition or provision of any (i) material
         contract to which the Company is a party or by which it or any of its
         assets or properties are bound or (ii) any order, injunction, judgment,
         decree, ruling, writ, assessment or arbitration award by a Governmental
         Authority of competent jurisdiction to which the Company or any of its
         material assets or properties are subject; or

                  (e) result in the creation of any security interest, mortgage,
         deed of trust, lien, charge or other encumbrance with respect to any
         material asset or property of the Company.

         Section 2.4. Capitalization.

                  (a) As of the date hereof, the authorized capital stock of the
         Company consists of (i) 175,000,000 shares of Common Stock, of which as
         of the date hereof, (A) 18,119,284 shares are issued and outstanding,
         (B) 6,589,583 shares are issuable and reserved for issuance upon the
         exercise of options granted pursuant to the Company's stock option,
         restricted stock and stock purchase plans, (C) 1,267,797 shares are
         reserved for issuance upon the exercise of options that are available
         for grant pursuant to the Company's stock option, restricted stock and
         stock purchase plans and (D) 3,235,279 shares are issuable and reserved
         for issuance pursuant to securities (other than the Securities, the
         Additional Securities and the options described in clause (B) and
         clause (C) above) exercisable or exchangeable for, or convertible into,
         shares of Common Stock and (ii) 10,000,000 shares of Preferred Stock,
         $1.00 par value, of which as of the date hereof, without giving effect
         to the transactions contemplated by this Agreement, no shares are
         issued and outstanding. All of such outstanding or issuable shares have
         been, or upon issuance will be, (x) validly issued and are, or will be,
         fully paid and nonassessable and (y) issued in accordance with all
         applicable federal and state securities laws.

                  (b) No shares of the Company's capital stock are subject to
         preemptive rights or any other similar rights or any liens or
         encumbrances suffered or permitted by the Company.

                  (c) Other than the Additional Securities, there are no
         outstanding debt instruments for borrowed money issued by the Company.

                  (d) Other than the Securities and the Additional Securities,
         there are no outstanding options, warrants, scrip, rights to subscribe
         to, calls or commitments of any character whatsoever relating to, or
         securities or rights convertible into or exercisable for, any shares of
         capital stock of the Company, or contracts, commitments, understandings
         or arrangements by which the Company is or may become bound to issue
         additional shares of capital stock of the Company or options, warrants,
         scrip, rights to subscribe to,

                                       4
<PAGE>

         calls or commitments of any character whatsoever relating to, or
         securities or rights convertible into or exercisable for, any shares of
         capital stock of the Company.

                  (e) There are no agreements or arrangements under which the
         Company is obligated to register the sale of any of its securities
         under the Securities Act of 1933, as amended (the "Securities Act"),
         other than the Registration Rights Agreement (as defined in Section
         4.2) and the registration rights agreement executed in connection with
         the Additional Financing Transaction.

                  (f) Other than the Securities and the Additional Securities,
         (i) there are no outstanding securities or instruments of the Company
         that contain any redemption or similar provisions, and (ii) there are
         no contracts, commitments, understandings or arrangements by which the
         Company is or may become bound to redeem a security of the Company.

                  (g) There are no securities or instruments containing
         anti-dilution or similar provisions that will be triggered by the
         issuance of the Securities as described in this Agreement.

                  (h) The Company does not have any stock appreciation rights or
         "phantom stock" plans or agreements or any similar plan or agreement.

                  (i) The Charter and Bylaws of the Company, as amended and as
         in effect on the date hereof, are filed as exhibits to the SEC
         Documents (as defined in Section 2.7).

                  (j) The Company is not a party to or subject to any agreement
         or understanding (and, to the Company's knowledge, there is no
         agreement or understanding) between any persons or entities that
         affects or relates to the voting or giving of written consents (i) with
         respect to any security of the Company or (ii) by a director of the
         Company.

         Section 2.5. Valid Issuance of Securities. The Series A Preferred has
the powers, relative rights, qualifications, preferences, limitations and
restrictions described in the Series A Statement of Designations. The Series B
Preferred has the powers, relative rights, qualifications, preferences,
limitations and restrictions described in the Series B Statement of
Designations. The issuance, sale and delivery of the Securities in accordance
with this Agreement, and the issuance and delivery of the shares of Common Stock
issuable upon conversion or exercise, as the case may be, of the Securities (the
"Conversion Common"), have been duly authorized by all necessary corporate
action on the part of the Company, and all shares of Series A Preferred, Series
B Preferred and Conversion Common have been duly reserved for issuance. The
shares of Series A Preferred and Series B Preferred purchased by the Investors
pursuant to this Agreement, when issued, sold and delivered against payment
therefor in accordance with the provisions of this Agreement, will be duly and
validly issued, fully paid and non-assessable, and will be free of restrictions
on transfer, other than restrictions on transfer under applicable state and
federal securities laws. The Conversion Common, when issued upon conversion of
the Series A Preferred in accordance with the Series A Statement of
Designations, or upon conversion of the Series B Preferred in accordance with
the Series B Statement of Designations, or upon exercise

                                       5
<PAGE>

of the Warrants in accordance with the terms thereof, as applicable, will be
duly and validly issued, fully paid and non-assessable, and will be free of
restrictions on transfer, other than restrictions on transfer under applicable
state and federal securities laws.

         Section 2.6. Securities Laws Compliance. Based in part on the
representations made by each of the Investors in Article III, (a) other than
filings under federal and state securities laws and the filing of a Listing of
Additional Shares with The Nasdaq Stock Market, no consent, approval, order or
authorization of, or registration, qualification, designation, declaration or
filing with, any Governmental Authority is required on the part of the Company
in connection with the offer, issuance, sale and delivery of the Securities (and
the Conversion Common issuable upon the conversion or exercise, as the case may
be, of the Securities) and (b) the offer, issuance, sale and delivery of the
Securities (and the Conversion Common issuable upon the conversion or exercise,
as the case may be, of the Securities) will be in compliance with the
registration requirements of applicable federal and state securities laws. The
Company covenants that neither the Company nor any authorized agent acting on
its behalf will take any action hereafter that would cause the loss of such
exemptions.

         Section 2.7. SEC Filings. The Company has filed all forms, reports and
documents required to be filed by the Company with the United States Securities
and Exchange Commission (the "SEC") as of the date hereof. Each Investor has had
access to true and complete copies of the following materials (collectively, the
"SEC Documents"): (a) the Company's Annual Report on Form 10-K/A, for the year
ended December 31, 2001, (b) the Company's Quarterly Report on Form 10-Q/A, for
the quarterly period ended March 31, 2002 and the Company's Quarterly Report on
Form 10-Q for the quarterly period ended June 30, 2002, and (c) the Company's
definitive proxy statement for its annual meeting of stockholders held in 2002.
As of their respective dates, the SEC Documents complied in all material
respects with the applicable requirements of the Securities Exchange Act of
1934, as amended (the "Exchange Act"), and the rules and regulations of the SEC
thereunder, and none of the SEC Documents contained any untrue statement of a
material fact or omitted 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. Since June 30, 2002, there has been no
material adverse change and no material adverse development in the business,
properties, assets, operations, results of operations, financial conditions or
prospects of the Company.

         Section 2.8. Litigation. There is no action, suit, proceeding, inquiry
or investigation before or by any court, public board, government agency,
self-regulatory organization or body pending against or affecting the Company,
the Common Stock or any of the Company's officers or directors in their
capacities as such. To the knowledge of the Company there is no action, suit,
proceeding, inquiry or investigation before or by any court, public board,
government agency, self-regulatory organization or body threatened against or
affecting the Company, the Common Stock or any of the Company's officers or
directors in their capacities as such. To the knowledge of the Company, none of
the directors or officers of the Company have been involved in
securities-related litigation during the past five (5) years.

         Section 2.9. Financial Statements. The financial statements of the
Company, including the notes thereto, included in the SEC Documents (the
"Financial Statements") present fairly, in all material respects, the
consolidated financial position of the Company as of their respective

                                       6
<PAGE>

dates and the results of the Company's operations and cash flows for the
respective periods (subject, in the case of unaudited statements, to normal,
year-end adjustments), complied as to form in all material respects with United
States generally accepted accounting procedures ("GAAP") and with the published
rules and regulations of the SEC with respect thereto, and have been prepared in
accordance with GAAP applied on a basis consistent throughout the periods
indicated and consistent with each other (except as may be indicated in the
notes thereto). There has been no material change in the Company's accounting
policies except as described in the notes to the Financial Statements.

         Section 2.10. Employee Relations. The Company is not involved in any
union labor dispute nor, to the knowledge of the Company, is any such dispute
threatened. None of the Company's employees is a member of a union that relates
to such employee's relationship with the Company, the Company is not a party to
a collective bargaining agreement, and the Company believes that its relations
with its employees are good. No executive officer (as defined in Rule 501(f) of
the Securities Act) has notified the Company that such officer intends to leave
the Company or otherwise terminate such officer's employment with the Company.
No executive officer, to the best knowledge of the Company, is, or is now
expected to be, in violation of any material term of any employment contract,
confidentiality, disclosure or proprietary information agreement,
non-competition agreement, or any other contract or agreement or any restrictive
covenant, and the continued employment of each such executive officer does not
subject the Company to any liability with respect to any of the foregoing
matters.

         Section 2.11. Intellectual Property Rights. The Company owns or
possesses adequate rights or licenses to use all trademarks, trade names,
service marks, service mark registrations, service names, patents, patent
rights, copyrights, inventions, licenses, approvals, governmental
authorizations, trade secrets and other intellectual property rights necessary
to conduct its business as now conducted and as presently proposed to be
conducted. None of the Company's trademarks, trade names, service marks, service
mark registrations, service names, patents, patent rights, copyrights,
inventions, licenses, approvals, governmental authorizations, trade secrets or
other intellectual property rights have expired or terminated, or are expected
to expire or terminate within two years from the date of this Agreement. The
Company does not have any knowledge of any infringement by the Company of
trademarks, trade names, service marks, service mark registrations, service
names, patents, patent rights, copyrights, inventions, licenses, trade secrets
or other intellectual property rights of others, or of any development of
similar or identical trade secrets or technical information by others. There is
no claim, action or proceeding being made or brought against, or to the
Company's knowledge, being threatened against, the Company regarding its
trademarks, trade names, service marks, service mark registrations, service
names, patents, patent rights, copyrights, inventions, licenses, approvals,
governmental authorization, trade secrets or other intellectual property rights,
or infringement of the intellectual property rights of others. The Company is
unaware of any facts or circumstances that might give rise to any of the
foregoing. The Company has taken reasonable security measures to protect the
secrecy, confidentiality and value of all of its intellectual properties. The
Company does not believe that it is or will be necessary to use any inventions
or works of authorship of its employees (or persons it currently intends to
hire) made outside of their employment by the Company.

                                       7
<PAGE>

         Section 2.12. Environmental Laws. The Company (a) is in compliance with
any and all applicable foreign, federal, state and local laws and regulations
relating to the protection of human health and safety, the environment or
hazardous or toxic substances or wastes, pollutants or contaminants
("Environmental Laws"), (b) has received all permits, licenses or other
approvals required of it under applicable Environmental Laws to conduct its
businesses and (c) is in compliance with all terms and conditions of any such
permit, license or approval, except where, in each of the three foregoing cases,
the failure to so comply would not have, either individually or in the
aggregate, a material adverse effect on the properties, assets, financial
condition, business or operations of the Company.

         Section 2.13. Permits. The Company has all written approvals, consents,
franchises, licenses, permits, certificates or other authorizations required by
applicable law ("Permits") necessary for the conduct of the Company's business,
as currently conducted, all such Permits are in full force and effect and the
Company is in compliance in all material respects with the requirements of all
such Permits. No loss or expiration of any Permit is pending, threatened or
reasonably foreseeable, other than expiration of Permits that may be renewed in
the ordinary course of business without lapsing.

         Section 2.14. Title. The Company has good and marketable title in fee
simple to all real property and good and marketable title to all personal
property owned by it that is material to the business of the Company, in each
case free and clear of all liens, encumbrances and defects except such as do not
materially affect the value of such property and do not interfere with the use
made and proposed to be made of such property by the Company. Any real property
and facilities held under lease by the Company are held by it under valid,
subsisting and enforceable leases with such exceptions as are not material and
do not interfere with the use made and proposed to be made of such property and
facilities by the Company. The properties and assets of the Company owned or
leased by the Company constitute all of the real property, personal property and
interests in real and personal property that are related to or reasonably
necessary for the operation of the business of the Company, as currently
conducted.

         Section 2.15. Placement Agent. The Company acknowledges that it has
engaged SoundView Technology Group as placement agent in connection with the
sale of the Securities, which placement agent may have formally or informally
engaged other agents on its behalf. The Company will be responsible for the
payment of any placement agent's fees or broker's commissions relating to or
arising out of the transactions contemplated hereby. The Company will pay, and
hold each Investor harmless against, any liability, loss or expense (including,
without limitation, attorneys' fees and out of pocket expenses) arising in
connection with any such claim.

                                       8
<PAGE>

                                  ARTICLE III.
                 REPRESENTATIONS AND WARRANTIES OF THE INVESTORS

         Each Investor hereby represents and warrants, severally and not
jointly, to the Company that:

         Section 3.1. Enforceability. Such Investor has full legal capacity,
power and authority to execute and deliver this Agreement, to perform his
respective obligations under this Agreement and to consummate the transactions
contemplated by this Agreement. This Agreement has been duly and validly
executed and delivered by such Investor and constitutes the legal, valid and
binding obligations of such Investor enforceable against him in accordance with
its terms, except (a) as such enforceability may be limited by applicable
bankruptcy, insolvency, reorganization, moratorium and other laws of general
application affecting enforcement of creditors' rights generally, (b) as such
enforceability may be limited by laws relating to the availability of specific
performance, injunctive relief or other equitable remedies and (c) to the extent
that the choice of law provisions contained in this Agreement may be limited by
applicable laws.

         Section 3.2. Investment Intent. Such Investor is acquiring the
Securities (and the Conversion Common issuable upon the conversion or exercise,
as the case may be, of the Securities) for investment for such Investor's own
account, not as a nominee or agent, and not with a view to, or for resale in
connection with, any distribution or public offering thereof, as defined in the
Securities Act.

         Section 3.3. Shares Not Registered. Such Investor understands and
acknowledges that the Securities sold pursuant to this Agreement will not be
registered under the Securities Act or qualified under any applicable blue sky
laws on the grounds that the offering and sale of securities contemplated by
this Agreement are exempt from registration under the Securities Act and exempt
from qualification pursuant to the applicable provisions of such blue sky laws,
and that the Company's reliance upon such exemptions is predicated upon such
Investor's representations set forth in this Agreement. Such Investor
acknowledges and understands that the Securities (and the Conversion Common
issuable upon the conversion or exercise, as the case may be, of the Securities)
must be held indefinitely unless it is subsequently registered under the
Securities Act and qualified under applicable blue sky laws or an exemption from
such registration and such qualification is available.

         Section 3.4. Knowledge and Experience. Such Investor (a) has such
knowledge and experience in financial and business matters as to be capable of
evaluating the merits and risks of such Investor's prospective investment in the
Securities, (b) has the ability to bear the economic risks (including the risk
of total loss) of such Investor's prospective investment, (c) has been furnished
with and has had access to such information as such Investor has considered
necessary to make a determination as to the purchase of the Securities together
with such additional information as is necessary to verify the accuracy of the
information supplied and (d) has not been offered the Securities by any form of
advertisement, article, notice, or other communication published in any
newspaper, magazine, or similar media or broadcast over television or radio, or
any seminar or meeting whose attendees have been invited by any such media. The
foregoing

                                       9
<PAGE>

does not, however, limit or modify the representations or warranties of the
Company set forth in Article II or the right of each Investor to rely thereon.

         Section 3.5. Accredited Investor. Such Investor is an "accredited
investor" within the meaning of Rule 501 promulgated by the Securities and
Exchange Commission ("SEC") under the Securities Act.

         Section 3.6. Rule 144. Such Investor acknowledges that he is aware of
Rule 144 promulgated under the Securities Act, which permits limited public
resales of securities acquired in a non-public offering, subject to the
satisfaction of certain conditions. Such Investor understands that under Rule
144, except as otherwise provided by section (k) of that Rule, the conditions
include, among other things: the availability of certain current public
information about the issuer, the resale occurring not less than one year after
the Investor has purchased and paid for the securities to be sold and
limitations on the amount of securities to be sold and the manner of sale. Such
Investor acknowledges and understands that the Company may not be satisfying the
current public information requirement of Rule 144 at the time he wishes to sell
the Securities (or the Conversion Common issuable upon the conversion or
exercise, as the case may be, of the Securities), and that, in such event, he
may be precluded from selling such stock under such rule, even if the one year
minimum holding period of such Rule has been satisfied. Such Investor
acknowledges that in the event all of the requirements of Rule 144 are not met,
registration under the Securities Act, compliance with Regulation A promulgated
by the SEC pursuant to the Securities Act or an exemption from registration will
be required for any disposition of the Securities (and the Conversion Common
issuable upon the conversion or exercise, as the case may be, of the
Securities). Such Investor understands that, although Rule 144 is not exclusive,
the SEC has expressed its opinion that persons proposing to sell restricted
securities received in a private offering other than in a registered offering or
pursuant to Rule 144 will have a substantial burden of proof in establishing
that an exemption from registration is available for such offers or sales and
that such persons and the brokers who participate in the transactions do so at
their own risk.

         Section 3.7. Holding Requirements. Such Investor understands that if
the Company does not have a registration statement covering the Securities (or,
as applicable, the Conversion Common issuable upon the conversion or exercise,
as the case may be, of the Securities) under the Securities Act, or a filing
pursuant to the exemption from registration under Regulation A of the Securities
Act covering the Securities (or, as applicable, the Conversion Common issuable
upon the conversion or exercise, as the case may be, of the Securities), in
effect when it desires to sell the Securities (or, as applicable, the Conversion
Common issuable upon the conversion or exercise, as the case may be, of the
Securities), such Investor may be required to hold the Securities and such
Conversion Common for an indeterminate period.

         Section 3.8. No Solicitation. Such Investor knows of no public
solicitation or advertisement of an offer in connection with the proposed
issuance and sale of the Securities.

         Section 3.9. Residency. The residency of such Investor is correctly set
forth on Schedule A or Schedule B, as the case may be.

                                       10
<PAGE>

         Section 3.10. Investor Counsel. Such Investor acknowledges that he has
had the opportunity to review this Agreement, the schedules attached hereto and
the transactions contemplated by this Agreement with his own legal counsel. Such
Investor is relying solely on such counsel and not on the Company or any of its
agents for legal advice with respect to this investment or the transactions
contemplated by this Agreement.

         Section 3.11. Material Nonpublic Information. Such Investor
acknowledges that such Investor is aware of the provisions of Section 10(b) of
the Exchange Act and Rule 10b-5 promulgated by the SEC thereunder.

         Section 3.12. Short Swing Profits. Such Investor acknowledges that such
Investor is aware of the provisions of Section 16(b) of the Exchange Act and
that any profit realized by an officer, director or beneficial holder of ten
percent or more of the outstanding capital stock of the Company from any
purchase and sale, or any sale and purchase, of the Company's equity securities
within a six (6) month period must be disgorged by such officer, director or
holder to the Company.

         Section 3.13. Short Sales. During the period beginning ninety (90) days
prior to the date hereof and ending on the Closing date (or the date this
Agreement is terminated pursuant to Section 8.1), neither such Investor nor any
of its affiliates has engaged or will engage, directly or indirectly, in any
sales of Common Stock, including any "short sales" (as defined in Rule 3b-3
promulgated under the Exchange Act) of Common Stock or has established or will
establish an open "put equivalent position" (within the meaning of Rule 16a-1(h)
promulgated under the Exchange Act) with respect to the Common Stock. As of the
Closing, neither such Investor nor any of its affiliates has any short position
or put equivalent position.

                                   ARTICLE IV.
                        CERTAIN AGREEMENTS AND COVENANTS

         Section 4.1. Legends. Each Warrant and each certificate representing
shares of Series A Preferred, Series B Preferred or Conversion Common will bear
a legend substantially in the following form:

         "THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE STATE
         SECURITIES LAWS, AND MAY NOT BE SOLD OR TRANSFERRED WITHOUT COMPLIANCE
         WITH THE REGISTRATION OR QUALIFICATION PROVISIONS OF APPLICABLE FEDERAL
         AND STATE SECURITIES LAWS OR APPLICABLE EXEMPTIONS THEREFROM."

The foregoing legend will be removed from the certificates representing any
shares of Series A Preferred, Series B Preferred or Conversion Common, at the
request of the holder thereof, at such time as such shares become eligible for
resale without compliance with the registration or qualification provisions of
applicable federal and state securities laws.

                                       11
<PAGE>

         Section 4.2. Registration of Conversion Common. The Company will
provide certain registration rights under the Securities Act to the Investors
with respect to the shares of Conversion Common pursuant to a Registration
Rights Agreement in the form attached hereto as Exhibit D (the "Registration
Rights Agreement").

         Section 4.3. Shareholder Approval. As contemplated by Section
6(d)(vii)(E), Section 7(d)(ii) and Section 8(b) of the Series A Statement of
Designations and Section 8(b) of the Series B Statement of Designations, the
approval of the shareholders of the Company is required under Marketplace Rule
4350(i) of The Nasdaq Stock Market before the Company may issue Common Stock
upon certain conversions and redemptions of the Series A Preferred and the
Series B Preferred (the "Shareholder Approval"). The Company covenants that it
will (a) prepare and file with the SEC a proxy statement relating to the
Shareholder Approval on or before October 25, 2002, (b) use all reasonable
efforts to obtain the Shareholder Approval on or before February 28, 2003 and
(c) in any event, seek Shareholder Approval no later than the 2003 Annual
Meeting of Shareholders of the Company.

         Section 4.4. Certain Trading Restrictions.

                  (a) Restrictions. So long as any of the Additional Securities
         are outstanding, neither such Investor nor any of its affiliates will,
         directly or indirectly, engage in any transaction constituting a "short
         sale" (as defined in Rule 3b-3 promulgated under the Exchange Act) of
         shares of Common Stock or establish an open "put equivalent position"
         (within the meaning of Rule 16a-1(h) promulgated under the Exchange
         Act) with respect to the Common Stock (each a "Short Sale"), except on
         those days (each a "Permitted Day") on which the aggregate short
         position (including aggregate open "put equivalent positions") with
         respect to the Common Stock of such Investor and its affiliates prior
         to giving effect to any Short Sales by such Investor or its affiliates
         on such Permitted Day does not exceed such Investor's Permitted Share
         Position (as defined below) on such Permitted Day; provided, however,
         that such Investor and its affiliates will only be entitled to engage
         in transactions that constitute Short Sales on a Permitted Day to the
         extent that following such transaction, the aggregate short position
         (including aggregate open "put equivalent positions") with respect to
         the Common Stock of such Investor and its affiliates does not exceed
         such Investor's Permitted Share Position.

                  (b) Exceptions. The restriction on Short Sales set forth in
         Section 4.4(a) will not apply with respect to a Short Sale (and such
         Short Sale will be excluded for purposes of determining compliance with
         Section 4.4(a)) so long as such Investor or its affiliates delivers a
         conversion notice pursuant to Section 5(a) of the Series A Statement of
         Designations or Section 5(a) of the Series B Statement of Designations,
         as the case may be, or is deemed to have exercised or converted a
         Warrant pursuant to Section 2(b) or Section 3(b), as the case may be,
         of the Warrant, in any such case on or before 11:59 p.m. (New York
         time) on the business day following the day of such Short Sale and
         entitling the Holder to receive a number of shares of Common Stock at
         least equal to the number of shares of Common Stock sold or subject to
         such Short Sale.

                  (c) Other Transactions Permitted. Subject to Section 4.4(a)
         and applicable provisions of federal and state securities laws, the
         Company acknowledges and agrees

                                       12
<PAGE>

         that nothing in this Section 4.4 or elsewhere in this Agreement, the
         Securities or the Registration Rights Agreement prohibits any Investor
         (or any of its affiliates) from, and each Investor (and its affiliates)
         is permitted to, engage, directly or indirectly, in hedging
         transactions involving the Securities and the Common Stock (including,
         without limitation, by way of short sales, purchases and sales of
         options, swap transactions and synthetic transactions) at any time.

                  (d) Definition. For purposes of this Section 4.4, "Permitted
         Share Position" means, with respect to any date of determination, the
         number of shares of Common Stock issuable upon exercise of the Warrants
         held by the applicable Investor and its affiliates (without regard to
         any limitations on exercise) on such date.

         Section 4.5. Subordination Agreement. In the event that the Company
elects to issue to any Series A Investor a Subordinated Note (as defined in the
Series A Statement of Designations) or elects to issue to any Series B Investor
a Subordinated Note (as defined in the Series B Statement of Designations), in
the circumstances and as provided in the Series A Statement of Designations and
the Series B Statement of Designations, as applicable, each such Investor agrees
to, and hereby covenants that it will, execute (as the "subordinated lender")
and deliver to the Company and each holder of Notes a Subordination Agreement,
in the form attached hereto as Exhibit E, at the time of the issuance of such
Subordinated Note.

                                   ARTICLE V.
               CONDITIONS PRECEDENT TO EACH INVESTOR'S OBLIGATIONS

         The obligation of each Investor to consummate the purchase of the
Warrants and the shares of Series A Preferred or Series B Preferred, as the case
may be, to be purchased by such Investor hereunder at the Closing is, at the
option of such Investor, subject to the satisfaction of the following conditions
(any or all of which may be waived by such Investor at or prior to the Closing):

         Section 5.1. Representations, Warranties and Covenants.

                  (a) All representations and warranties of the Company
         contained in this Agreement and qualified by materiality must be true
         and correct, and all representations and warranties of the Company
         contained in this Agreement and not qualified by materiality must be
         true and correct in all material respects, in each case at and as of
         the Closing with the same effect as though those representations and
         warranties had been made again at and as of the Closing, except to the
         extent that certain of such representations and warranties are made as
         of or through a specified date (which representations and warranties
         must continue on the Closing to have been true and correct or true and
         correct in all material respects, as applicable, as of or through the
         specified date).

                  (b) The Company must have performed and complied, in all
         material respects, with all obligations and covenants required by this
         Agreement to be performed or complied with by it on or prior to the
         Closing.

                                       13
<PAGE>

                  (c) Such Investor must have received a certificate, executed
         by either the Chief Executive Officer or the General Counsel of the
         Company, dated as of the Closing, certifying that the conditions set
         forth in Section 5.1(a) and Section 5.1(b) have been satisfied.

         Section 5.2. Secretary's Certificate. The Company must have delivered
to such Investor a secretary's certificate, dated as of the Closing, certifying
as to (a) the Charter, as in effect at the Closing, certified as of a date
within ten (10) days of the Closing, by the Secretary of State of the State of
Texas, (b) the Bylaws of the Company, as in effect at the Closing, and (c)
resolutions of the Board of Directors of the Company authorizing the
transactions contemplated by this Agreement.

         Section 5.3. Certificates of Good Standing and Existence. The Company
must have delivered to such Investor certificates evidencing the existence and
good standing of the Company in the State of Texas, issued by the Secretary of
State of the State of Texas and the Texas Comptroller of Public Accounts, as
applicable, each as of a date within ten (10) days of the Closing.

         Section 5.4. Litigation. No legal proceeding may have been instituted
by or before any federal or state court or other Governmental Authority that has
or may have the effect of making illegal, impeding or otherwise restraining or
prohibiting any of the transactions contemplated by this Agreement.

         Section 5.5. Material Adverse Change. There must not have been a
material adverse change in the properties, assets, condition (financial or
otherwise), business, operations or prospects of the Company since June 30,
2002, other than the matters referred to in Section 2.7 of the Schedule of
Exceptions.

         Section 5.6. Consents. All consents, approvals, orders or
authorizations of Governmental Authorities and other persons and legal entities
necessary for the consummation of the transactions contemplated by this
Agreement must have been obtained and all notices to Governmental Authorities
and other persons and legal entities necessary for the consummation of the
transactions contemplated by this Agreement must have been given.

         Section 5.7. Nasdaq Assurance. The Company must have received
confirmation from The Nasdaq Stock Market that the issuance of shares of Series
B Preferred to one or more of the Series B Investors will not result in a
"change of control" for purposes of Marketplace Rule 4350(i)(1)(B) of The Nasdaq
Stock Market.

         Section 5.8. Legal Opinion. Such Investor must have received the
opinion of Hughes & Luce L.L.P., dated as of the Closing, in form, scope and
substance reasonably satisfactory to such Investor and in substantially the form
of Exhibit F attached hereto.

         Section 5.9. Subordination Agreement. The form of Exhibit E
(Subordination Agreement) must be in form and substance reasonably satisfactory
to the Investors, the Company and the purchasers of Additional Securities.

                                       14
<PAGE>

         Section 5.10. Closing Deliveries. The Company must have made each of
the Closing deliveries set forth in Section 7.3.

         Section 5.11. Statements of Designations. The Company must have duly
filed the Series A Statement of Designations and the Series B Statement of
Designations with the Secretary of State of the State of Texas.

         Section 5.12. Minimum Investment. The aggregate purchase price tendered
by all of the Investors and the purchasers in the Additional Financing
Transaction for the Securities and the Additional Securities must be not less
than $15,000,000.

         Section 5.13. Additional Securities. The documents to be entered into
between the Company and the purchasers of the Additional Securities and relating
to the Additional Financing Transaction must be in form and substance reasonably
satisfactory to the Investors.

         Section 5.14. Securities Laws Filings. The Company must have made all
filings under all applicable federal and state securities laws necessary to
consummate the issuance of the Securities pursuant to this Agreement in
compliance with such laws.

         Section 5.15. Additional Matters. Such Investor must have received such
additional documents, instruments or items of information reasonably requested
by him in respect of any aspect or consequence of the transactions contemplated
by this Agreement. All corporate and other proceedings, and all documents,
instruments and other legal matters in connection with the transactions
contemplated by this Agreement or by the other agreements referred to in this
Agreement must be reasonably satisfactory in form and substance to such Investor
and his counsel.

                                   ARTICLE VI.
                CONDITIONS PRECEDENT TO THE COMPANY'S OBLIGATIONS

         The obligations of the Company to consummate the sale and issuance of
the Warrants and the shares of Series A Preferred or Series B Preferred, as the
case may be, to be sold and issued to an Investor hereunder at the Closing is,
at the option of the Company, subject to the satisfaction of the following
conditions (any or all of which may be waived by the Company at or prior to the
Closing):

         Section 6.1. Representations, Warranties and Covenants.

                  (a) All representations and warranties of such Investor
         contained in this Agreement must be true and correct in all material
         respects at and as of the Closing with the same effect as though those
         representations and warranties had been made again and as of the
         Closing.

                  (b) Such Investor must have performed and complied, in all
         material respects, with all obligations and covenants required by this
         Agreement to be performed or complied with by such Investor on or prior
         to the Closing.

                                       15
<PAGE>

         Section 6.2. Litigation. No legal proceeding may have been instituted
by or before any federal or state court or other Governmental Authority that has
or may have the effect of making illegal, impeding or otherwise restraining or
prohibiting any of the transactions contemplated by this Agreement.

         Section 6.3. Nasdaq Assurance. The Company must have received
confirmation from The Nasdaq Stock Market that the issuance of shares of Series
B Preferred to one or more of the Series B Investors will not result in a
"change of control" for purposes of Marketplace Rule 4350(i)(1)(B) of The Nasdaq
Stock Market.

         Section 6.4. Closing Deliveries. The Investor must have made each of
the Closing deliveries set forth in Section 7.4.

         Section 6.5. Minimum Investment. The aggregate purchase price tendered
by all of the Investors and the purchasers in the Additional Financing
Transaction for the Securities and the Additional Securities must be not less
than $15,000,000.

         Section 6.6. Additional Matters. The Company must have received such
additional documents, instruments or items of information reasonably requested
by it in respect of any aspect or consequence of the transactions contemplated
by this Agreement. All corporate and other proceedings, and all documents,
instruments and other legal matters in connection with the transactions
contemplated by this Agreement or by the other agreements referred to in this
Agreement must be reasonably satisfactory in form and substance to the Company
and its counsel.

                                  ARTICLE VII.
                                     CLOSING

         Section 7.1. Closing. This Agreement will be executed by each of the
parties hereto at or before 2:59 p.m., Central Daylight Time, on the date first
written above. The closing of the transactions contemplated by this Agreement
(the "Closing") will take place at the principal executive office of the Company
at 3:00 p.m., Central Daylight Time on September 16, 2002, or at such other
place and at such other time and date as may be mutually agreed upon by the
Company and the Investors; provided, however, that if all of the conditions to
the obligations of the parties set forth in Article V and Article VI have not
been satisfied or waived on or before September 16, 2002, the Closing will take
place promptly following the time at which all such conditions have been
satisfied or waived.

         Section 7.2. Proceedings at Closing. All proceedings to be taken and
all documents to be executed and delivered by all parties at the Closing will be
deemed to have been taken, executed and delivered simultaneously, and no
proceedings will be deemed taken nor any documents executed or delivered until
all have been taken, executed and delivered.

         Section 7.3. Deliveries by the Company at the Closing. At the Closing,
the Company will deliver (or cause to be delivered) to each Investor (a) a
Warrant to purchase the number of shares of Common Stock set forth adjacent to
such Investor's name on Schedule A or Schedule

                                       16
<PAGE>

B, as the case may be, executed by an authorized officer of the Company, (b) the
Registration Rights Agreement, executed by an authorized officer of the Company,
and (c) a stock certificate or certificates, registered in such Investor's name
and executed by authorized officers of the Company, representing the aggregate
number of shares of Series A Preferred or Series B Preferred, as the case may
be, purchased by such Investor pursuant to this Agreement.

         Section 7.4. Deliveries by the Investors at the Closing. At the
Closing, each Investor will deliver (or cause to be delivered) to the Company
(a) a counterpart signature page to the Registration Rights Agreement, executed
by such Investor, and (b) the aggregate purchase price payable to the Company
for the Warrants and the shares of Series A Preferred or Series B Preferred, as
the case may be, purchased by such Investor pursuant to this Agreement, by wire
transfer of immediately available funds in accordance with the Company's written
wiring instructions.

                                  ARTICLE VIII.
                                   TERMINATION

         Section 8.1. Termination. This Agreement will terminate in the event
that (a) the Company and each Investor agree in writing to terminate this
Agreement or (b) the Closing does not occur on or before September 20, 2002.

         Section 8.2. Effect of Termination. If this Agreement is terminated in
accordance with Section 8.1, and the transactions contemplated by this Agreement
are not consummated, this Agreement will become null and void and of no further
force and effect, except (a) for this Section 8.2 and (b) that the termination
of this Agreement for any cause will not relieve any party to this Agreement
from any liability that at the time of termination had already accrued to any
other party to this Agreement or that thereafter may accrue in respect of any
act or omission of such party prior to such termination.

                                   ARTICLE IX.
                                  MISCELLANEOUS

         Section 9.1. Entire Agreement; Schedules. This Agreement (including the
Schedules and Exhibits to this Agreement) represents, and is intended to be, a
complete statement of all of the terms and the arrangements between the parties
to this Agreement with respect to the matters provided for in this Agreement,
supersedes any and all previous oral or written and all contemporaneous oral
agreements, understandings, negotiations and discussions between the parties to
this Agreement with respect to those matters. The Schedules and Exhibits to this
Agreement are hereby incorporated and made a part hereof and are an integral
part of this Agreement.

         Section 9.2. Headings; References. The article and section headings of
this Agreement are for reference purposes only and are to be given no effect in
the construction or interpretation of this Agreement. Except as otherwise
specifically provided, any reference to any article,

                                       17
<PAGE>

section, exhibit or schedule will be deemed to refer to such article or section
of or exhibit or schedule to this Agreement.

         Section 9.3. GOVERNING LAW. THIS AGREEMENT WILL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS WITHOUT REFERENCE TO
THE PRINCIPLES OF CONFLICT OF LAWS OR ANY OTHER PRINCIPLE THAT COULD RESULT IN
THE APPLICATION OF THE LAWS OF ANY OTHER JURISDICTION.

         Section 9.4. Further Assurances. Each party to this Agreement hereby
covenants and agrees, without the necessity of any further consideration, to
execute and deliver any and all such further documents and take any and all such
other actions as may be necessary or appropriate to carry out the intent and
purposes of this Agreement and to consummate the transactions contemplated
hereby.

         Section 9.5. Expenses. Other than the payment by the Company of up to
$30,000 for the reasonable fees and out-of-pocket expenses incurred by the
Series A Investors, collectively, in connection with the negotiation and
documentation of the transactions contemplated by this Agreement, and the
payment by the Company of up to $30,000 for the reasonable fees and
out-of-pocket expenses incurred by the Series B Investors, collectively, in
connection with the negotiation and documentation of the transactions
contemplated by this Agreement, each of the parties to this Agreement will bear
its or his own expenses (including, without limitation, fees and disbursements
of its counsel, accountants, financial advisors and other experts), incurred by
it in connection with the preparation, negotiation, execution, delivery and
performance of this Agreement, each of the other documents and instruments
executed in connection with or contemplated by this Agreement and the
consummation of the transactions contemplated by this Agreement.

         Section 9.6. Notices. All notices and other communications under this
Agreement must be in writing and will be deemed given (a) when delivered
personally or by courier service, (b) on the fifth business day after being
mailed by certified mail, return receipt requested or (c) upon transmission and
confirmation of receipt by a facsimile operator if sent by facsimile, to the
parties at the following addresses or facsimile numbers (or to such other
address or facsimile number as such party may have specified by notice given to
the other party pursuant to this provision):

         If to a Series A Investor, to the address set forth for such Series A
Investor on Schedule A

         If to a Series B Investor, to the address set forth for such Series B
Investor on Schedule B

         If to the Company:         Zix Corporation
                                    2711 North Haskell Avenue
                                    Suite 2300, LB 36
                                    Dallas, Texas 75204-2960
                                    Facsimile:  (214) 515-7385
                                    Attention:  General Counsel

                                       18
<PAGE>

                             with a copy to:

                             Hughes & Luce, LLP
                             111 Congress Avenue, Suite 900
                             Austin, Texas 78701
                             Facsimile:  (512) 482-6859
                             Attention:  Bryan C. Wittman, Esq.

         Section 9.7. Severability. If any provision of this Agreement, as
applied to any party or to any circumstance, is held invalid, illegal or
unenforceable by any court of competent jurisdiction, (a) such provision, as
applied to such party or such circumstance, is hereby deemed modified to give
effect to the original written intent of the parties to the greatest extent
consistent with being valid and enforceable under applicable law, (b) the
application of such provision to any other party or to any other circumstance
will not be affected or impaired thereby and (c) the validity, legality and
enforceability of the remaining provisions of this Agreement will remain in full
force and effect.

         Section 9.8. Binding Effect: No Assignment. This Agreement will be
binding upon and inure to the benefit of the parties and their respective
successors and permitted assigns. Nothing in this Agreement will create or be
deemed to create any third party beneficiary rights in any person or other legal
entity not party to this Agreement. No assignment of this Agreement or of any
rights or obligations under this Agreement may be made by the Company (by
operation of law or otherwise) without the prior written consent of each of the
other parties to this Agreement and any attempted assignment without such
required consents will be void. The Securities and shares of the Conversion
Common may be transferred only in accordance with applicable law (including
state and federal securities laws).

         Section 9.9. Amendments. This Agreement may be amended, supplemented or
modified, and any provision hereof may be waived, only by written instrument
making specific reference to this Agreement signed by each of the parties to
this Agreement. Except as otherwise provided in this Agreement, no action (other
than a waiver) taken pursuant to this Agreement, including, without limitation,
any investigation by or on behalf of any party, will be deemed to constitute a
waiver by the party taking such action of compliance with any representation,
warranty, covenant or agreement contained in this Agreement. The waiver by any
party to this Agreement of a breach of any provision of this Agreement will not
operate or be construed as a further or continuing waiver of such breach or as a
waiver of any other or subsequent breach. Except as otherwise expressly provided
in this Agreement, no failure on the part of any party to exercise, and no delay
in exercising, any right, power or remedy under this Agreement will operate as a
waiver thereof, nor will any single or partial exercise of such right, power or
remedy by such party preclude any other or further exercise thereof or the
exercise of any other right, power or remedy. All remedies under this Agreement
are cumulative and are not exclusive of any other remedies provided by
applicable law.

         Section 9.10. Counterparts. This Agreement may be executed in any
number of counterparts, each of which will be deemed an original, but all of
which together will constitute one and the same instrument.

             * * * REMAINDER OF PAGE INTENTIONALLY LEFT BLANK * * *

                                       19
<PAGE>

         IN WITNESS WHEREOF, the parties to this Agreement have executed this
instrument as of the date and year first above written.

COMPANY
Zix Corporation, a Texas corporation

<Table>
<S>                                                        <C>
/s/ Ronald A. Woessner
----------------------------------------------
By:        Ronald A. Woessner
Title:     S.V.P.

SERIES A INVESTORS                                         SERIES B INVESTORS

/s/ John A. Ryan                                           /s/ Cornelius Egan
----------------------------------------------             -----------------------------------------------
John A. Ryan                                               Cornelius Egan

/s/ David P. Cook                                          /s/ George W. Haywood
----------------------------------------------             -----------------------------------------------
David P. Cook                                              George W. Haywood

SANTIG LTD., a Texas limited partnership                   WHITE ROCK CAPITAL
      By:     Sanchez Management Corp,
              its general partner

/s/ Frank A. Guerra                                        /s/ Tom Barton
----------------------------------------------             -----------------------------------------------
By:      Frank A. Guerra                                   By:      Tom Barton
Title:   Executive Vice President                          Title:   President

1988 Spendthrift Trust

/s/ Frank A. Guerra
----------------------------------------------
By:      Frank A. Guerra
Title:   Trustee

/s/ A.R. Sanchez, Jr.
----------------------------------------------
A.R. Sanchez, Jr.
</Table>

                                       20
<PAGE>

                                   SCHEDULE A

                               SERIES A INVESTORS

<Table>
<Caption>
NAME, ADDRESS             NO. OF SHARES OF                SERIES A                NO. OF                  WARRANT
& FAX NO.                SERIES A PREFERRED            PURCHASE PRICE         WARRANT SHARES          PURCHASE PRICE
-------------            ------------------            --------------         --------------          --------------

<S>                      <C>                           <C>                    <C>                     <C>
SANTIG, LTD.                   252,273                   $988,913.62              88,691                $11,086.38
1920 Sandman
Laredo, Texas 78041
Attn:  Frank Guerra
Fax No.:  (956) 722-1017

1988 Spendthrift Trust         126,136                   $494,456.87              44,345                 $5,543.13
1920 Sandman
Laredo, Texas 78041
Attn:  Frank Guerra
Fax No.:  (956) 722-1017

A.R. Sanchez, Jr.              126,136                   $494,456.87              44,345                 $5,543.13
1920 Sandman
Laredo, Texas 78041
Attn:  Frank Guerra
Fax No.:  (956) 722-1017

John Ryan                      189,205                   $741,685.25              66,518                 $8,314.75
2711 N. Haskell Avenue
Suite 2300, LB 36
Dallas, Texas 75204
Fax No.:  (214) 515-7390

David P. Cook                  126,136                   $494,456.87              44,345                 $5,543.13
15 Downs Lake Circle
Dallas, Texas 75230
Fax No.:  (972) 960-2874
</Table>

<PAGE>

                                   SCHEDULE B

                               SERIES B INVESTORS

<Table>
<Caption>
NAME, ADDRESS             NO. OF SHARES OF                SERIES B                NO. OF                  WARRANT
& FAX NO.                SERIES B PREFERRED            PURCHASE PRICE         WARRANT SHARES          PURCHASE PRICE
-------------            ------------------            --------------         --------------          --------------

<S>                      <C>                           <C>                    <C>                     <C>
Cornelius Egan                 219,758                   $791,130.87              70,953                 $8,869.13
225 E. 7th Street
Penthouse B
New York, New York 10072
Fax No.:  (646) 414-4087

White Rock Capital             137,349                   $494,456.87              44,345                 $5,543.13
3131 Turtle Creek Blvd.
Suite 800
Dallas, Texas 75219
Attn:  Joe / Tom Barton
Fax No.:  (214) 526-0856

George W. Haywood              947,708                  $3,411,751.75             305,986               $38,248.25
c/o Cronin & Vris, LLP
380 Madison Avenue
24th Floor
New York, New York 10017
Fax No.:  (212) 883-1314

With a copy to Gary Moomjian
c/o Kaufman & Moomjian, LLC
50 Charles Lindbergh Blvd.
Suite 206
Mitchel Field, New York 11553
Fax No.:  (516) 222-5110
</Table>

<PAGE>

                                   SCHEDULE C

                             SCHEDULE OF EXCEPTIONS

                                  [AS ATTACHED]

<PAGE>

                                                               Execution Version

                   SCHEDULE C TO SECURITIES PURCHASE AGREEMENT

         All capitalized terms used but not otherwise defined in this Schedule C
have the meanings given them in the Securities Purchase Agreement by and among
Zix Corporation, a Texas corporation ("Company"), and each of the purchasers set
forth on the signature pages thereto (the "Buyers"), dated as of September 16,
2002 (the "Agreement"). Each of the disclosures set forth in this Schedule C are
made as an exception to or as required by the Agreement. Disclosure of any
matters in this Schedule C should not be construed as indicating that such
matter is necessarily required to be disclosed in order for any representation
or warranty in the Agreement to be true and correct to the extent required in
the Agreement. Disclosure of any matter in this Schedule C relating to (a) any
known or contingent liabilities; (b) the compliance or failure to comply with
any contracts or laws; and (c) any pending or threatened actions, or any
potential basis therefore, will not be deemed to be an admission or denial of
the matters relating thereto so disclosed or an assessment of the likelihood or
magnitude of the outcome thereof.

<PAGE>

                                                               Execution Version

                                   SECTION 2.4

                                 CAPITALIZATION

(d)

     1.   There are options outstanding to employees, directors, and consultants
          and former employees, directors, and consultants to purchase an
          aggregate 6,589,583 shares of the Company's common stock at an average
          exercise price per share of $8.75 (exercise prices range from $2.50 to
          $73.75 per share), with expiration dates through 2012, of which
          approximately 3,422,848 option shares are currently exercisable.

     2.   There are warrants outstanding held by approximately 68
          persons/entities, who were investors in the Company's May 2000 equity
          financing, to purchase an aggregate 3,055,557 shares of the Company's
          common stock on the following terms:

          a.   1,222,223 warrant shares with an exercise price of $12.00 per
               share, expiration of 4/30/04, 100% exercisable.

          b.   916,667 warrant shares with an exercise price of $57.60 per
               share, expiration of 4/30/10, 100% exercisable.

          c.   916,667 warrant shares with an exercise price of $7.00 per share,
               expiration of 4/29/03, 100% exercisable.

     3.   There are options outstanding to former third party vendors to
          purchase an aggregate 179,722 shares of the Company's common stock at
          prices ranging from $7.94 to $80.00, with expiration dates through
          2007.

     4.   The Convertible Notes (and related warrants) being issued on or about
          the date of the securities issuance to which this schedule relates are
          convertible into shares of the Company's common stock.

(e)  OBLIGATIONS TO REGISTER SECURITIES

     The following active Registration Statements were filed pursuant to
contractual or statutory registration rights obligations:

1.   Huizenga Investor Group
     $12.00 Warrants to purchase 1,222,223 shares of common stock
     Registration Statement on Form S-3 (No. 333-36556)

2.   Huizenga Investor Group
     $57.60 Warrants to purchase 916,667 shares of common stock

<PAGE>

                                                               Execution Version

     Registration Statement on Form S-3 (No. 333-36556)

3.   Huizenga Investor Group
     $7.00 Warrants to purchase 916,667 shares of common stock
     Registration Statement on Form S-3 (No. 333-83934)

4.   Tumbleweed Communications Corp.
     116,833 shares of common stock  [All shares sold.]
     Registration Statement on Form S-3 (No. 333-89052)

5.   Yahoo! Inc.
     625,000 shares of common stock
     Registration Statement on Form S-3 (No. 333-89056)  [All shares sold.]

6.   Henry Kuehne
     25,000 shares of common stock
     Registration Statement on Form S-3 (No. 333-33708)

7.   The Company has various registration statements on Form S-8 filed with
     the SEC covering the option grants to employees and consultants,
     referred to above.

8.   The Company is in the process of preparing for filing registration
     statement(s) with respect to 68,622 shares of its common stock to be
     issued to two former employees in connection with their separation from
     employment.

9.   The Company is in the process of preparing for filing registration
     statement(s) with respect to 104, 722 option shares, at exercise prices
     ranging from $7.94 - $80.00 per share, and 5,000 restricted shares held
     by various former consultants to the Company.

10.  A former consultant holds options to acquire 50,000 shares, at an
     exercise price of $25.00 per share, which are accompanied by demand
     registration rights.

11.  The Company is obligated to register the common stock shares into which
     the Convertible Notes (and related warrants) referenced above are
     convertible or exercisable.

<PAGE>

                                                               Execution Version

                                   SECTION 2.7

                                   SEC FILINGS

The Company did not prevail in its recently concluded (July 2002) lawsuit, as
plaintiff, against Visa U.S.A., Inc. and Visa International Service Association,
Inc.

<PAGE>

                                                               Execution Version

                                   SECTION 2.8

                                   LITIGATION

1.       The Company recently received an informal telephone inquiry from the
         Fort Worth SEC Enforcement Office relating to its accounting treatment
         of an aggregate of $4.25 million of guaranteed payments (of which
         $500,000 and $469,000, respectively, was recognized in 2001 and 2002)
         due the Company from Entrust, Inc. pursuant to a Marketing and
         Distribution Agreement, dated November 6, 2000, between the Company and
         Entrust, Inc.

2.       The Company's President and CEO, John A. Ryan, is a defendant (in his
         capacity as a director and officer) in a securities related lawsuit,
         which arose while he was an officer and director of Entrust, Inc.

<PAGE>

                                                               Execution Version

                                  SECTION 2.10

                               EMPLOYEE RELATIONS

The Company's former President and Chief Executive Officer and a director, David
P. Cook, recently resigned from his position as "Founder" and as a director of
the Company.

<PAGE>

                                                               Execution Version

                                  SECTION 2.14

                                      TITLE

The Company has pledged a $250,000 (plus accrued interest) certificate of
deposit to support a credit card processing agreement with Bank of America.

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00043-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00043-of-00352.parquet"}]]