Document:

<PAGE>

                                                                     EXHIBIT 4.2

THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON THE EXERCISE OF THIS
WARRANT 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.

                        WARRANT TO PURCHASE COMMON STOCK

                                       OF

                      ZIX CORPORATION, a Texas corporation

                         (void after September 18, 2006)

         This Warrant to Purchase Common Stock (this "Warrant") is issued as of
September 18, 2002 (the "Issue Date") and certifies that, for value received,
the Holder hereof (as defined below) is entitled to purchase the Warrant Stock
(as defined below) from Zix Corporation, a Texas corporation (the "Company"),
during the Exercise Period (as defined below), upon payment of the Exercise
Price (as defined below) and otherwise in accordance with the terms and subject
to the conditions set forth herein.

1.       Definitions. As used in this Warrant, the following terms have the
         meanings ascribed to them below:

         (a)      "Agreement" means the Securities Purchase Agreement, dated as
                  of the date hereof, by and among the Company and the investors
                  listed on Schedule A and Schedule B thereto.

         (b)      "Board" means the Board of Directors of the Company.

         (c)      "Common Stock" means the Common Stock, par value $0.01 per
                  share, of the Company.

         (d)      "Equity Security" means (i) Common Stock, (ii) any right or
                  option to purchase Common Stock, (iii) any obligation or
                  security convertible into or exchangeable for Common Stock and
                  (iv) any right or option to purchase any obligation or
                  security convertible into or exchangeable for Common Stock.

         (e)      "Exempt Issuance" means any issuance of Equity Securities (i)
                  pursuant to any employee benefit plan of the Company in effect
                  on the Issue Date; (ii) to officers, directors, employees or
                  consultants of the Company pursuant to the grant or exercise
                  of options that are granted pursuant to any employee benefit
                  plan approved by the shareholders of the Company after the
                  Issue Date to the extent that such issuance, together will all
                  other issuances to which this clause (ii) has

                                        1
<PAGE>

                  been applied, will not result in the issuance or potential
                  issuance of more than 4,000,000 shares of Common Stock (as
                  adjusted for any recapitalizations, stock splits or
                  combinations of the Common Stock or stock dividends on the
                  Common Stock to the extent paid in shares of Common Stock);
                  (iii) upon the conversion, exchange or exercise of any right,
                  option, obligation or security outstanding on the Issue Date,
                  provided that the terms of any such right, option, obligation
                  or security are not amended or otherwise altered on or after
                  the Issue Date; (iv) in connection with the sale and issuance
                  of shares of Series A Preferred, shares of Series B Preferred
                  and Senior Convertible Notes on the Issue Date (including (A)
                  the issuance of warrants to the initial purchasers of Series A
                  Preferred, Series B Preferred and Senior Convertible Notes and
                  (B) the conversion, redemption, exchange or exercise of such
                  Series A Preferred, Series B Preferred, Senior Convertible
                  Notes and warrants in accordance with their respective terms),
                  provided that the terms of any such securities are not amended
                  or otherwise altered on or after the Issue Date; (v) in
                  connection with any stock subdivision or stock dividend
                  described in Section 5(a) or any Recapitalization Event (as
                  defined in Section 5(c)); (vi) (A) to suppliers, customers or
                  strategic partners of the Company investing in connection with
                  a commercial relationship with the Company, the primary
                  purpose of which is not to raise capital, and (B) as
                  consideration for mergers or consolidations or acquisitions of
                  businesses or their tangible or intangible assets, other than
                  transactions in which cash or cash equivalents represent a
                  majority of the assets acquired, provided that the aggregate
                  number of shares of Common Stock that may be issued or
                  potentially issued under this clause (vi) may not exceed
                  400,000 shares (as adjusted for any recapitalizations, stock
                  splits or combinations of the Common Stock or stock dividends
                  on the Common Stock to the extent paid in shares of Common
                  Stock); (vii) in connection with leases; and (viii) to former
                  employees in satisfaction of severance obligations of the
                  Company.

         (f)      "Exercise Period" means the period commencing on the six (6)
                  month anniversary of the Issue Date and ending at 5:00 p.m.,
                  local time in Dallas, Texas, on September 18, 2006.

         (g)      "Exercise Price" means $4.51 per share of Warrant Stock,
                  subject to adjustment as described in Section 5 below.

         (h)      "Holder" means each person or other legal entity who validly
                  holds this Warrant (or any portion thereof) for so long as
                  this Warrant (or any portion thereof) is so held by them, the
                  initial Holder being [VARIES BY HOLDER].

         (i)      "Market Price" means $3.92 per share of Warrant Stock, subject
                  to adjustment as described in Section 5(a) below.

         (j)      "Senior Convertible Notes" means those certain Convertible
                  Notes, convertible into shares of Common Stock under certain
                  circumstances, issued on the Issue Date.

                                       2
<PAGE>

         (k)      "Series A Preferred" means the Series A Convertible Preferred
                  Stock, par value $1.00 per share, of the Company.

         (l)      "Series B Preferred" means the Series B Convertible Preferred
                  Stock, par value $1.00 per share, of the Company.

         (m)      "Warrant Stock" means [VARIES BY HOLDER] shares of Common
                  Stock, subject to adjustment as described in Section 5 below.

2.       Exercise of Warrant.

         (a)      Availability of Exercise. This Warrant may be exercised only
                  during the Exercise Period. During the Exercise Period, this
                  Warrant may be exercised by the Holder at any time, and from
                  time to time, to purchase all, or any portion, of the shares
                  of Warrant Stock for which this Warrant has not previously
                  been exercised. This Warrant will expire, and be of no further
                  force and effect, at the end of the Exercise Period without
                  regard to whether the Holder has purchased all of the shares
                  of Warrant Stock for which this Warrant is initially
                  exercisable.

         (b)      Procedure for Exercise. Whenever the Holder desires to
                  exercise this Warrant for the purchase of any or all of the
                  shares of the Warrant Stock, the Holder must deliver to the
                  Company, at its principal office, (i) this Warrant, (ii) a
                  Notice of Exercise, in the form attached hereto as Attachment
                  1, duly completed and executed by the Holder, (iii) an
                  Investor Representation Statement in form and substance
                  reasonably satisfactory to the Company and covering the
                  matters set forth in Section 3.2 through Section 3.10,
                  inclusive, of the Agreement, unless the Warrant Stock is then
                  registered for resale under the Securities Act of 1933, as
                  amended, and (iv) payment in full of the Exercise Price in
                  cash, wire transfer or by certified check for the shares of
                  Warrant Stock being purchased. An exercise of this Warrant
                  will be deemed effective immediately prior to the close of
                  business on the date on which all required deliveries have
                  been made and, thereafter, the Holder, or its duly-appointed
                  nominee, will be treated for all purposes as the holder of
                  record of the shares of Warrant Stock purchased pursuant to
                  such exercise.

         (c)      Deliveries by the Company. As promptly as practicable after an
                  exercise of this Warrant, but in any event within three (3)
                  business days thereafter, the Company will issue and deliver
                  to the Holder, or its duly-appointed nominee, a certificate or
                  certificates for the number of full shares of Warrant Stock
                  issuable upon such exercise. If this Warrant is exercised for
                  less than the total number of shares of Warrant Stock then
                  issuable upon exercise, the Company will also execute and
                  deliver to the Holder a new warrant, dated the Issue Date,
                  evidencing the right of the Holder to purchase the balance of
                  the Warrant Stock purchasable hereunder on the same terms and
                  conditions as set forth herein.

                                       3
<PAGE>

3.       Cashless Exercise / Conversion.

         (a)      Right to Convert. At any time during the Exercise Period that
                  the Warrant Stock is not registered and available for resale
                  pursuant to a registration statement in accordance with the
                  Registration Rights Agreement (as defined in the Agreement),
                  including during an Allowed Delay (as defined in the
                  Registration Rights Agreement), the Holder may convert all or
                  any portion of this Warrant that is then exercisable into
                  Warrant Stock pursuant to this Section 3, in lieu of
                  exercising this Warrant pursuant to Section 2.

         (b)      Procedure for Conversion. Whenever the Holder desires to
                  convert this Warrant into shares of Warrant Stock pursuant to
                  this Section 3, the Holder must deliver to the Company, at its
                  principal office, (i) this Warrant and (ii) a Notice of
                  Conversion, in the form attached hereto as Attachment 2, duly
                  completed and executed by the Holder, specifying the portion
                  of the Warrant to be converted. The portion of this Warrant
                  that is converted will be immediately canceled. This Warrant,
                  to the extent converted, will be deemed to have been converted
                  immediately prior to the close of business on the date on
                  which all required deliveries have been made and, thereafter,
                  the Holder, or its duly-appointed nominee, will be treated for
                  all purposes as the holder of record of the shares of Warrant
                  Stock issuable pursuant to such conversion.

         (c)      Conversion Formula. The number of shares of Warrant Stock to
                  be issued to the Holder upon any conversion of this Warrant
                  pursuant to this Section 3 will be computed using the
                  following formula:

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

        Where     X =      the number of shares of Warrant Stock to be issued to
                           the Holder for the portion of the Warrant being
                           converted.

                  P =      the portion of the Warrant being converted expressed
                           as a decimal.

                  Y =      the total number of shares of Warrant Stock issuable
                           upon exercise of the Warrant in full.

                  A =      the Fair Market Value of one share of Warrant Stock
                           as of the last business day immediately prior to the
                           date the notice of conversion is received by the
                           Company.

                  B =      the Exercise Price on the date of conversion.

         (d)      Deliveries by the Company. As promptly as practicable after a
                  conversion of this Warrant, but in any event within three (3)
                  business days thereafter, the Company will issue and deliver
                  to the Holder, or its duly-appointed nominee, a certificate or

                                       4
<PAGE>

                  certificates for the number of full shares of Warrant Stock
                  issuable upon such conversion. If the Warrant is converted for
                  less than the total number of shares of Warrant Stock then
                  issuable upon exercise, the Company will also execute and
                  deliver to the Holder a new warrant, dated the Issue Date,
                  evidencing the right of the Holder to purchase the balance of
                  the Warrant Stock purchasable hereunder on the same terms and
                  conditions set forth herein.

4.       Fractional Shares. No fractional shares of Warrant Stock will be
         issuable upon the exercise or conversion of this Warrant and the number
         of shares of Warrant Stock issued upon any exercise or conversion will
         be rounded down to the nearest whole share. Instead of issuing any
         fractional shares of Warrant Stock that would otherwise be issuable
         upon any exercise or conversion of this Warrant, the Company will pay a
         cash amount in respect of such fractional interest equal to the
         fractional interest multiplied by the Exercise Price on the date of
         exercise or conversion.

5.       Adjustments and Notices.

         (a)      Subdivision, Stock Dividends or Combinations. If the Company
                  subdivides the outstanding shares of Common Stock or issues a
                  dividend in the form of Common Stock with respect to Common
                  Stock, the Exercise Price and the Market Price in effect
                  immediately prior to such subdivision or the issuance of such
                  dividend will each be proportionately decreased, and the
                  number of shares of Warrant Stock purchasable upon the full
                  exercise of this Warrant immediately prior to such subdivision
                  or issuance of dividend will be proportionately increased,
                  effective at the close of business on the date of such
                  subdivision or dividend. If the Company combines the
                  outstanding shares of Common Stock, the Exercise Price and
                  Market Price in effect immediately prior to such combination
                  will each be proportionately increased, and the number of
                  shares of Warrant Stock purchasable upon the full exercise of
                  this Warrant immediately prior to such combination will be
                  proportionately decreased, effective at the close of business
                  on the date of such combination. This Section 5(a) will
                  similarly apply to successive subdivisions, dividends in
                  Common Stock and combinations.

         (b)      Discount Sale of Capital Stock. If the Company issues Common
                  Stock, any right or option to purchase Common Stock, or any
                  obligation or any shares of stock convertible into or
                  exchangeable for Common Stock, other than in an Exempt
                  Issuance, for a consideration per share of Common Stock (or
                  per share of Common Stock into which such right, option,
                  obligation or stock is exercisable, convertible or
                  exchangeable) that is less than the Exercise Price in effect
                  immediately prior to the time of such issuance, then,
                  immediately upon such issuance, the Exercise Price will be the
                  greater of the Market Price or the price, calculated to the
                  nearest cent, obtained by dividing:

                           (i)      an amount equal to the sum of (A) the
                                    then-existing Exercise Price multiplied by
                                    the number of shares of Common Stock
                                    outstanding immediately prior to such
                                    issuance (assuming the full exercise of

                                       5
<PAGE>

                                    all options, rights and warrants then
                                    exercisable for Company securities, the full
                                    exercise of this Warrant and the full
                                    conversion or exchange of all other
                                    obligations or securities that are then
                                    convertible or exchangeable for Common Stock
                                    at the rate of conversion or exchange then
                                    in effect) and (B) an amount equal to the
                                    aggregate consideration received by the
                                    Company upon such issuance;

                           by

                           (ii)     the number of shares of Common Stock
                                    outstanding immediately after such issuance
                                    (assuming the full exercise of all options,
                                    rights and warrants then exercisable for
                                    Company securities, the full exercise of
                                    this Warrant and the full conversion or
                                    exchange of all other obligations or
                                    securities that are then convertible or
                                    exchangeable for Common Stock at the rate of
                                    conversion or exchange then in effect).

                  This Section 5(b) will similarly apply to successive such
                  issuances.

         (c)      Reclassification, Exchange, Substitution, etc. If any capital
                  reorganization, reclassification, exchange, substitution or
                  other similar event results in a change of the rights,
                  preferences or other terms of the Common Stock (other than a
                  change in par value or a change resulting from a stock
                  dividend or a subdivision or combination of shares) (any of
                  the foregoing, a "Recapitalization Event"), the Company must,
                  as a condition to such event, execute and deliver to the
                  Holder a new warrant so that the Holder will have the right to
                  receive, at an aggregate exercise price equal to the aggregate
                  Exercise Price payable upon the full exercise of the
                  unexercised portion of this Warrant, and in lieu of the
                  Warrant Stock theretofore issuable upon the full exercise of
                  this Warrant, the kind and amount of shares of stock, other
                  securities, money and property that would have been receivable
                  by the Holder upon such event had the Holder exercised this
                  Warrant in full immediately prior to the effective time of
                  such event. Such new warrant will provide for adjustments that
                  are as nearly equivalent as may be practicable to the
                  adjustments provided for in this Section 5.

         (d)      Merger. As a condition precedent to the consummation of any
                  merger or consolidation involving the Company in which the
                  Company is not the surviving corporation, the successor or
                  purchasing corporation must execute and deliver to the Holder
                  a new warrant so that the Holder will have the right to
                  receive, at an aggregate exercise price equal to the aggregate
                  Exercise Price payable upon the full exercise of the
                  unexercised portion of this Warrant, and in lieu of the
                  Warrant Stock theretofore issuable upon the full exercise of
                  this Warrant, the kind and amount of shares of stock, other
                  securities, money and property that would have been receivable
                  by the Holder pursuant to such merger or consolidation had the
                  Holder exercised this Warrant in full immediately prior to the
                  effective time of

                                       6
<PAGE>

                  such merger or consolidation. If all holders of Common Stock
                  do not receive the same kind and amount of consideration
                  pursuant to such merger or consolidation, the Holder will have
                  the right to choose the kind and amount of consideration for
                  which the new warrant will be exercisable from among the
                  combinations of kind and amount of consideration offered to
                  any holder of Common Stock pursuant to such merger or
                  consolidation. Such new warrant will provide for adjustments
                  that are as nearly equivalent as may be practicable to the
                  adjustments provided for in this Section 5.

         (e)      No Impairment. The Company will not, by amendment of its
                  Articles of Incorporation or through a reorganization,
                  transfer of assets, consolidation, merger, dissolution, issue
                  or sale of securities or any other voluntary action, avoid or
                  seek to avoid the observance or performance of any of the
                  terms to be observed or performed under this Warrant by the
                  Company, but must at all times in good faith assist in
                  carrying out of all the provisions of this Warrant and in
                  taking all such action as may be necessary or appropriate to
                  protect the Holder's rights under this Warrant against
                  impairment; provided, however, that this Section 5(e) will not
                  apply to the issuance by the Company of the Senior Convertible
                  Notes, shares of Series A Preferred, shares of Series B
                  Preferred or warrants issued to the purchasers of the Senior
                  Convertible Notes, Series A Preferred and Series B Preferred.
                  If the Company takes any action other than as described above
                  that adversely affects the Holder's rights under this Warrant,
                  the Exercise Price will be adjusted downward in an equitable
                  manner.

         (f)      Notice. The Company will give the Holder written notice of any
                  event described in this Section 5 as soon as the Company has
                  actual knowledge of such event but in no event later than the
                  effective time of such event or such earlier time as may be
                  otherwise required pursuant to this Section 5. Such notice
                  will provide a brief summary of the event (including a
                  reference to the subsection of this Section 5 that describes
                  such event) and the Holder's rights as a result thereof and
                  will set forth, as and if applicable, the Exercise Price as
                  adjusted, the increased or decreased number of shares of
                  Warrant Stock purchasable upon the exercise of this Warrant,
                  and reasonable detail regarding the method of calculation of
                  each.

6.       Miscellaneous.

         (a)      No Shareholder Rights. This Warrant, by itself, as
                  distinguished from any shares of Warrant Stock purchased
                  hereunder, will not entitle the Holder to any of the rights of
                  a shareholder of the Company.

         (b)      Reservation of Warrant Stock. At all times prior to the end of
                  the Exercise Period, the Company will reserve from its
                  authorized and unissued Common Stock a sufficient number of
                  shares to provide for the issuance of all shares of Warrant
                  Stock that may then be issued upon full exercise of this
                  Warrant. Issuance of this Warrant will constitute full
                  authority to the Company's officers who are charged with the
                  duty of executing stock certificates to execute and issue the
                  necessary

                                       7
<PAGE>

                  certificates for shares of Warrant Stock issuable upon the
                  exercise or conversion of this Warrant.

         (c)      Transfer of Warrant. This Warrant may be transferred or
                  assigned, in whole or in part, by the Holder provided that
                  such transfer or assignment is in compliance with any
                  restrictive legend set forth hereon. Such transfer will be
                  effected without charge to the Holder upon surrender of this
                  Warrant with a properly executed assignment to the Company, at
                  its principal office, and, thereafter, the Company will issue
                  a new warrant registered in the name of the transferee. If
                  this Warrant is being transferred in part, the Company will
                  issue new warrants, in each case evidencing the right to
                  purchase the appropriate number of shares of Warrant Stock,
                  registered in the names of the Holder and the transferee, as
                  applicable. Upon any transfer of all or any part of this
                  Warrant to any transferee, such transferee will be deemed the
                  "Holder" of such warrant, to the extent transferred, as such
                  term is used herein and will be deemed the owner hereof for
                  all purposes. Each Holder, by taking or holding this Warrant,
                  consents and agrees to be bound by the provisions of this
                  Warrant and consents and agrees that (i) this Warrant, when
                  endorsed in blank, will be deemed negotiable, (ii) the bearer
                  of this Warrant, when this Warrant is so endorsed, may be
                  treated by the Company (at the Company's option) and all other
                  persons dealing with this Warrant, any notice to the contrary
                  notwithstanding, as the absolute owner hereof for all
                  purposes, including the person entitled to exercise all rights
                  represented by this Warrant and to transfer this Warrant on
                  the books of the Company; provided, however, that until any
                  transfer of this Warrant is made on the books of the Company,
                  the Company may treat the registered Holder as the owner of
                  this Warrant for all purposes.

         (d)      Transfer Taxes. Neither this Warrant, nor any portion hereof,
                  may be transferred or assigned, and no Warrant Stock issued
                  upon exercise or conversion of this Warrant will be issued in
                  a name other than the name of the Holder, unless the Company
                  has been paid the amount of transfer taxes or charges incident
                  thereto, if any.

         (e)      Loss, Theft, Destruction or Mutilation of Warrant. Upon
                  receipt by the Company of evidence reasonably satisfactory to
                  it of the loss, theft, destruction or mutilation of this
                  Warrant, and (i) in case of loss, theft or destruction, of
                  indemnity reasonably satisfactory to the Company and upon
                  reimbursement of the Company of all reasonable expenses
                  incidental thereto, and (ii) if mutilated, upon surrender and
                  cancellation of this Warrant, the Company will make and
                  deliver a new Warrant of like tenor (but with no additional
                  rights or obligations) and dated as of such cancellation, in
                  lieu of this Warrant.

         (f)      Headings. The headings in this Warrant are for purposes of
                  convenience and reference only, and will not be deemed to
                  constitute a part hereof.

                                       8
<PAGE>

         (g)      Saturdays, Sundays, Holidays, etc. If the last or appointed
                  day for the taking of any action or the expiration of any
                  right required or granted herein is a Saturday, Sunday or
                  legal holiday in the State of Texas, then such action may be
                  taken or such right may be exercised on the next succeeding
                  day that is not a Saturday, Sunday or legal holiday in the
                  State of Texas.

         (h)      Amendment and Waiver. Neither this Warrant nor any term hereof
                  may be changed or waived orally, but only by an instrument in
                  writing signed by the Company and the Holder.

         (i)      Notices. All notices and other communications from the Company
                  to the Holder will be delivered personally or mailed by first
                  class mail, postage prepaid, to the address furnished to the
                  Company in writing by the last Holder of this Warrant who
                  furnished an address to the Company in writing, and if mailed
                  will be deemed given five days after deposit in the United
                  States mail.

         (j)      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.

ISSUED: September 18, 2002

                                             ZIX CORPORATION

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

                                             Title:
                                                    ----------------------------

                                       9
<PAGE>

                                  ATTACHMENT 1

                               NOTICE OF EXERCISE

TO:      Zix Corporation
         2711 North Haskell Avenue
         Suite 2300, LB 36
         Dallas, Texas 75204-2960

         1. The undersigned hereby elects to purchase ___________________ shares
of the Common Stock, par value $0.01 per share, of Zix Corporation pursuant to
the terms of the attached Warrant, and tenders herewith payment of the purchase
price in full, together with all applicable transfer taxes, if any.

         2. Please issue a certificate or certificates representing said shares
of Common Stock in the name of the undersigned or in such other name as is
specified below:

                          -----------------------------
                                     (Name)

                          -----------------------------
                                    (Address)

-----------------------------------          -----------------------------------
              (Date)                               (Name of Warrant Holder)

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

                                             Title:
                                                   -----------------------------
                                                    (Title and signature of
                                                        authorized person)

<PAGE>

                                  ATTACHMENT 2

                              NOTICE OF CONVERSION

TO:      Zix Corporation
         2711 North Haskell Avenue
         Suite 2300, LB 36
         Dallas, Texas 75204-2960

         1. The undersigned hereby elects to acquire ____________________ shares
of the Common Stock, par value $0.01 per share, of Zix Corporation pursuant to
the terms of the attached Warrant, by conversion of __________ percent ( __%) of
the Warrant.

         2. Please issue a certificate or certificates representing said shares
of Common Stock in the name of the undersigned or in such other name as is
specified below:

                          -----------------------------
                                     (Name)

                          -----------------------------
                                    (Address)

-----------------------------------          -----------------------------------
              (Date)                               (Name of Warrant Holder)

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

                                             Title:
                                                   -----------------------------
                                                    (Title and signature of
                                                        authorized person)<PAGE>
                                                                     EXHIBIT 4.3

                          REGISTRATION RIGHTS AGREEMENT

  (SERIES A CONVERTIBLE PREFERRED STOCK) (SERIES B CONVERTIBLE PREFERRED STOCK)

         REGISTRATION RIGHTS AGREEMENT (this "AGREEMENT"), dated as of September
16, 2002, by and among Zix Corporation, a Texas corporation, with its
headquarters located at 2711 North Haskell Avenue, Suite 2300 LB36, Dallas,
Texas 75204 (the "COMPANY"), and each of the undersigned (the "INVESTORS").

         WHEREAS:

         A. In connection with the Securities Purchase Agreement by and among
the parties hereto of even date herewith (the "SECURITIES PURCHASE AGREEMENT"),
the Company has agreed, upon the terms and subject to the conditions contained
therein, to issue and sell to the Investors (i) shares of its Series A
Convertible Preferred Stock and its Series B Convertible Preferred Stock (the
"PREFERRED SHARES"), that are convertible into shares of the Company's common
stock, par value $0.01 per share (the "COMMON STOCK"), upon the terms and
subject to the limitations and conditions set forth in the Statements of
Designations filed with the Texas Secretary of State with respect to the
Preferred Shares; and (ii) warrants (the "WARRANTS") to acquire seven hundred
nine thousand five hundred twenty-eight (709,528) shares of Common Stock, upon
the terms and conditions and subject to the limitations and conditions set forth
in the Warrants, dated of even date herewith, issued pursuant to the Securities
Purchase Agreement; and

         B. To induce the Investors to execute and deliver the Securities
Purchase Agreement, the Company has agreed to provide certain registration
rights under the Securities Act of 1933, as amended, and the rules and
regulations thereunder, or any similar successor statute (collectively, the
"1933 ACT"), and applicable state securities laws;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants contained herein and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the Company and each
of the Investors hereby agree as follows:

                                   ARTICLE I.
                                   DEFINITIONS

         Section 1.1. As used in this Agreement, the following terms shall have
the following meanings:

                  (a) "INVESTORS" means the Investors and any transferee or
         assignee who agrees to become bound by the provisions of this Agreement
         in accordance with Section 9 hereof.

                  (b) "REGISTER," "REGISTERED," and "REGISTRATION" refer to a
         registration effected by preparing and filing a Registration Statement
         or Statements in compliance with the 1933 Act

                                       1
<PAGE>

         and pursuant to Rule 415 under the 1933 Act or any successor rule
         providing for offering securities on a continuous basis ("RULE 415"),
         and the declaration or ordering of effectiveness of such Registration
         Statement by the United States Securities and Exchange Commission (the
         "SEC").

                  (c) "REGISTRABLE SECURITIES" means (A) the Conversion Common
         (as defined in the Securities Purchase Agreement) and (B) any shares of
         capital stock issued or issuable as a dividend on or in exchange for or
         otherwise with respect to the Conversion Common.

                  (d) "REGISTRATION STATEMENT(s)" means a registration
         statement(s) of the Company under the 1933 Act.

         Section 1.2. Capitalized terms used herein and not otherwise defined
herein shall have the respective meanings set forth in the Securities Purchase
Agreement.

                                   ARTICLE II.
                                  REGISTRATION

         Section 2.1. MANDATORY REGISTRATION. The Company shall prepare, and, on
or prior to the date (the "FILING DATE") that is thirty (30) calendar days after
the Closing, file with the SEC a Registration Statement on Form S-3 (or, if Form
S-3 is not then available, on such form of Registration Statement as is then
available to effect a registration of the Registrable Securities, subject to the
consent of the holders of a majority-in-interest of the Registrable Securities,
which consent will not be unreasonably withheld, conditioned or delayed)
covering the resale of the Registrable Securities, which Registration Statement,
to the extent allowable under the 1933 Act and the rules and regulations
promulgated thereunder (including Rule 416), shall state that such Registration
Statement also covers such indeterminate number of additional shares of Common
Stock as may become issuable upon conversion of or otherwise pursuant to the
Preferred Shares and exercise of or otherwise pursuant to the Warrants (a) to
prevent dilution resulting from stock splits, stock dividends or similar
transactions or (b) by reason of changes in the exercise price of the Warrants
in accordance with the terms thereof. The number of shares of Common Stock
initially included in such Registration Statement shall be two million seven
hundred thirty-two thousand two hundred ninety-three (2,732,293), representing
the aggregate number of Conversion Common Shares initially issuable upon
conversion of the Preferred Shares and upon exercise of the Warrants. The
Registration Statement shall be provided to and subject to the approval of
(which approval will not be unreasonably withheld, conditioned or delayed) the
Investors and their counsel prior to its filing or other submission. The Company
shall use all commercially reasonable efforts to obtain effectiveness of the
Registration Statement as soon as practicable, but in any event not later than
the 105th day after the Closing (the "REGISTRATION DEADLINE").

         Section 2.2. UNDERWRITTEN OFFERING. If any offering pursuant to a
Registration Statement pursuant to Section 2.1 hereof involves an underwritten
offering, the Investors who hold a majority

                                       2
<PAGE>

in interest of the Registrable Securities subject to such underwritten offering
shall have the right to select one legal counsel and the right to select the
investment banker or bankers and manager or managers to administer the offering
(subject to the approval of the Company, which approval shall not be
unreasonably withheld, conditioned or delayed). In the event that any Investors
elect not to participate in such underwritten offering, the Registration
Statement covering all of the Registrable Securities shall contain appropriate
plans of distribution reasonably satisfactory to the Investors participating in
such underwritten offering and the Investors electing not to participate in such
underwritten offering (including, without limitation, the ability of
non-participating Investors to sell from time to time at any time during the
effectiveness of such Registration Statement).

         Section 2.3. PIGGY-BACK REGISTRATIONS. Subject to the last sentence of
this Section 2.3, if at any time prior to the expiration of the Registration
Period (as defined in Section 3.1 below), the Company shall determine to file
with the SEC a Registration Statement relating to an offering for its own
account or the account of others under the 1933 Act of any of its equity
securities (other than (a) pursuant to that certain Registration Rights
Agreement, dated the date hereof, by and among the Company and certain
purchasers of Convertible Notes of the Company and (b) offerings on Form S-4 or
Form S-8 or their then equivalents relating to equity securities to be issued
solely in connection with any acquisition of any entity or business or equity
securities issuable in connection with stock option or other employee benefit
plans), the Company shall send to each Investor who is entitled to registration
rights under this Section 2.3 written notice of such determination and, if
within fifteen (15) calendar days after the effective date of such notice, such
Investor shall so request in writing, the Company shall include in such
Registration Statement all or any part of the Registrable Securities such
Investor requests to be registered, except that if, in connection with any
underwritten public offering for the account of the Company the managing
underwriter(s) thereof shall impose a limitation on the number of shares of
Common Stock which may be included in the Registration Statement because, in
such underwriter(s)' judgment, marketing or other factors dictate such
limitation is necessary to facilitate public distribution, then the Company
shall be obligated to include in such Registration Statement only such limited
portion of the Registrable Securities with respect to which such Investor has
requested inclusion hereunder as the underwriter shall permit. Any exclusion of
Registrable Securities shall be made pro rata among the Investors seeking to
include Registrable Securities in proportion to the number of Registrable
Securities sought to be included by such Investors; provided, however, that the
Company shall not exclude any Registrable Securities unless the Company has
first excluded all outstanding securities, the holders of which are not entitled
by contract to inclusion of such securities in such Registration Statement or
are not entitled to pro rata inclusion with the Registrable Securities; and
provided, further, however, that, after giving effect to the immediately
preceding proviso, any exclusion of Registrable Securities shall be made pro
rata with holders of other securities having the contractual right to include
such securities in the Registration Statement, other than the holders of
securities that are making the demand for registration with respect to which the
piggy-back registration rights are being exercised. No right to registration of
Registrable Securities under this Section 2.3 shall be construed to limit any
registration required under Section 2.1 hereof. If an offering in connection
with which an Investor is entitled to registration under this Section 2.3 is an
underwritten offering, then each Investor whose Registrable Securities are
included in such Registration Statement shall, unless otherwise agreed by

                                       3
<PAGE>

the Company, offer and sell such Registrable Securities in an underwritten
offering using the same underwriter or underwriters and, subject to the
provisions of this Agreement, on the same terms and conditions as other shares
of Common Stock included in such underwritten offering. Notwithstanding anything
to the contrary set forth herein, the registration rights of the Investors
pursuant to this Section 2.3 shall only be available in the event the Company
fails to timely file, obtain effectiveness or maintain effectiveness of any
Registration Statement to be filed pursuant to Section 2.1 in accordance with
the terms of this Agreement.

         Section 2.4. SHORT FORM REGISTRATION RIGHTS. In addition to the rights
contained in Section 2.1 and Section 2.3, at any time following the nine (9)
month anniversary of this Agreement, George W. Haywood ("HAYWOOD") will have the
right to request registration of up to one million three hundred thirty-three
thousand three hundred and thirty-three (1,333,333) shares of Common Stock and
A.R. Sanchez, Jr. ("SANCHEZ" and, together with Haywood, the "ADDITIONAL
REGISTRANTS") will have the right to request registration of up to six hundred
sixty-six thousand six hundred and sixty-seven (666,667) shares of Common Stock
(such two million (2,000,000) shares of Common Stock, collectively, the
"ADDITIONAL REGISTRABLE SECURITIES") on Form S-3 (or, if Form S-3 is not then
available, on such form of Registration Statement as is then available to effect
a registration of the Additional Registrable Securities, subject to the consent
of the Additional Registrants, which consent will not be unreasonably withheld,
conditioned or delayed) covering the resale of the Additional Registrable
Securities (an "ADDITIONAL REGISTRATION STATEMENT"). The Company will not be
required to effect more than one (1) Additional Registration Statement. A
request for an Additional Registration Statement may be made by either
Additional Registrant and must be in a written notice delivered to the Company
and the other Additional Registrant, return receipt requested, and must state
the number of shares of Additional Registrable Securities that such Additional
Registrant proposes to dispose of and the intended method of distribution of
such shares. The other Additional Registrant will promptly, but in no event more
than fifteen (15) business days following his actual receipt of such request for
an Additional Registration Statement, give written notice to the Company and the
Additional Registrant as to whether such Additional Registrant intends to
participate in such Additional Registration Statement and, if so, setting forth
the number of Additional Registrable Securities such Additional Registrant
proposes to dispose of and the intended method of distribution of such shares.
The Additional Registration Statement shall be prepared by the Company promptly
following the first Additional Registrant's request and provided to and subject
to the approval, which approval will not be unreasonably withheld, conditioned
or delayed, of the Additional Registrants and their respective counsel prior to
its filing or other submission. The Company shall use all commercially
reasonable efforts to obtain effectiveness of the Additional Registration
Statement as soon as practicable and keep the Additional Registration Statement
effective pursuant to Rule 415 at all times until such date as is the earlier of
(a) the date on which all of the Additional Registrable Securities have been
sold and (b) the date on which the Additional Registrable Securities (in the
opinion of Company's counsel) may be immediately sold to the public without
registration or restriction (including without limitation as to volume by each
holder thereof) under the 1933 Act (the "ADDITIONAL REGISTRATION PERIOD"). The
Additional Registration Statement (including any amendments or supplements
thereto and prospectuses contained therein) shall not contain any untrue
statement of a material fact or omit to state a material

                                       4
<PAGE>

fact required to be stated therein, or necessary to make the statements therein
not misleading. The Additional Registrable Securities will be treated as
"Registrable Securities," and the Additional Registration Statement will be
treated as a "Registration Statement," for all purposes of this Agreement,
except pursuant to Section 2.1, Section 2.2, Section 2.3, Section 3.1, Article
IX, Section 11.13 and any other section to the extent that it applies to an
underwritten offering, which articles and sections will not be applicable to any
registration pursuant to this Section 2.4.

         Section 2.5. ELIGIBILITY FOR FORM S-3. The Company represents and
warrants that, to the best of its knowledge, it meets the registrant eligibility
and transaction requirements for the use of Form S-3 for registration of the
sale by the Investors and the Company shall file all reports required to be
filed by the Company with the SEC in a timely manner so as to maintain such
eligibility for the use of Form S-3.

                                  ARTICLE III.
                           OBLIGATIONS OF THE COMPANY

         In connection with the registration of the Registrable Securities, the
Company shall have the following obligations:

         Section 3.1. The Company shall prepare promptly, and file with the SEC
as soon as practicable after the Closing (but in no event later than the Filing
Date), a Registration Statement with respect to the number of Registrable
Securities provided in Section 2.1, and thereafter use its commercially
reasonable efforts to cause such Registration Statement relating to Registrable
Securities to become effective as soon as possible after such filing, (but in no
event later than the Registration Deadline), and keep the Registration Statement
effective pursuant to Rule 415 at all times until such date as is the earlier of
(a) the date on which all of the Registrable Securities have been sold and (b)
the date on which the Registrable Securities (in the opinion of Company's
counsel) may be immediately sold to the public without registration or
restriction (including without limitation as to volume by each holder thereof)
under the 1933 Act (together with the Additional Registration Period, the
"REGISTRATION PERIOD"), which Registration Statement (including any amendments
or supplements thereto and prospectuses contained therein) shall not contain any
untrue statement of a material fact or omit to state a material fact required to
be stated therein, or necessary to make the statements therein not misleading.

         Section 3.2. The Company shall prepare and file with the SEC such
amendments (including post-effective amendments) and supplements to the
Registration Statements and the prospectus used in connection with the
Registration Statements as may be necessary to keep the Registration Statements
effective at all times during the Registration Period, and, during such period,
comply with the provisions of the 1933 Act with respect to the disposition of
all Registrable Securities of the Company covered by the Registration
Statements.

                                       5
<PAGE>

         Section 3.3. The Company shall furnish to each Investor whose
Registrable Securities are included in a Registration Statement and its legal
counsel (a) promptly after the same is prepared and publicly distributed, filed
with the SEC, or received by the Company, one copy of each Registration
Statement and any amendment thereto, each preliminary prospectus and prospectus
and each amendment or supplement thereto, and (b) such number of copies of a
prospectus, including a preliminary prospectus, and all amendments and
supplements thereto and such other documents as such Investor may reasonably
request in order to facilitate the disposition of the Registrable Securities
owned by such Investor. The Company will immediately notify each Investor of the
effectiveness of each Registration Statement or any post-effective amendment.
The Company will promptly respond to any and all comments received from the SEC,
with a view towards causing each Registration Statement or any amendment thereto
to be declared effective by the SEC as soon as practicable and shall file an
acceleration request as soon as practicable following the resolution or
clearance of all SEC comments or, if applicable, following notification by the
SEC that any such Registration Statement or any amendment thereto will not be
subject to review.

         Section 3.4. The Company shall use reasonable efforts to (a) register
and qualify the Registrable Securities covered by the Registration Statements
under such other securities or "BLUE SKY" laws of such jurisdictions in the
United States as each Investor may reasonably request, if an exemption from such
securities or blue sky laws is not otherwise available, (b) prepare and file in
those jurisdictions such amendments (including post-effective amendments) and
supplements to such registrations and qualifications as may be necessary to
maintain the effectiveness thereof during the Registration Period, (c) take such
other actions as may be necessary to maintain such registrations and
qualifications in effect at all times during the Registration Period, and (d)
take all other actions reasonably necessary or advisable to qualify the
Registrable Securities for sale in such jurisdictions; provided, however, that
the Company shall not be required in connection therewith or as a condition
thereto to (i) qualify to do business in any jurisdiction where it would not
otherwise be required to qualify but for this Section 3.4, (ii) subject itself
to general taxation in any such jurisdiction, (iii) file a general consent to
service of process in any such jurisdiction, or (iv) make any change in its
charter or bylaws, which in each case the Board of Directors of the Company
determines to be contrary to the best interests of the Company and its
shareholders.

         Section 3.5. In the event Investors who hold a majority-in-interest of
the Registrable Securities being offered in the offering select underwriters for
the offering, the Company shall enter into and perform its obligations under an
underwriting agreement, in usual and customary form, including, without
limitation, customary indemnification and contribution obligations, with the
underwriters of such offering.

         Section 3.6. As promptly as practicable after becoming aware of such
event, the Company shall notify each Investor of the happening of any event, of
which the Company has knowledge, as a result of which the prospectus included in
any Registration Statement, as then in effect, includes an untrue statement of a
material fact or omission to state a material fact required to be stated therein
or necessary to make the statements therein not misleading, and use its
commercially reasonable efforts promptly to prepare a supplement or amendment to
any Registration Statement to correct such

                                       6
<PAGE>

untrue statement or omission, and deliver such number of copies of such
supplement or amendment to each Investor as such Investor may reasonably
request; provided that, for not more than fifteen (15) consecutive trading days
(or a total of not more than thirty (30) trading days in any twelve (12) month
period), the Company may delay the disclosure of material non-public information
concerning the Company (as well as prospectus or Registration Statement
updating) the disclosure of which at the time is not, in the good faith opinion
of the Company, in the best interests of the Company (an "ALLOWED DELAY");
provided, further, that the Company shall promptly (a) notify the Investors in
writing of the existence of (but in no event, without the prior written consent
of an Investor, shall the Company disclose to such Investor any of the facts or
circumstances regarding) material non-public information giving rise to an
Allowed Delay and (b) advise the Investors in writing to cease all sales under
such Registration Statement until the end of the Allowed Delay. Upon expiration
of the Allowed Delay, the Company shall again be bound by the first sentence of
this Section 3.6 with respect to the information giving rise thereto.

         Section 3.7. The Company shall use its commercially reasonable efforts
to prevent the issuance of any stop order or other suspension of effectiveness
of any Registration Statement, and, if such an order is issued, to obtain the
withdrawal of such order at the earliest possible moment and to notify each
Investor who holds Registrable Securities being sold (or, in the event of an
underwritten offering, the managing underwriters) of the issuance of such order
and the resolution thereof.

         Section 3.8. The Company shall permit a single firm of counsel
designated by the holders of a majority-in-interest of the Registrable
Securities to review such Registration Statement, and all amendments and
supplements thereto (as well as all requests for acceleration or effectiveness
thereof (collectively, the "REGISTRATION DOCUMENTS")) at least four (4) business
days prior to their filing with the SEC, and not file (or send) any Registration
Documents in a form to which such counsel reasonably objects and will not
request acceleration of such Registration Statement without prior notice to such
counsel. The sections of such Registration Statement covering information with
respect to the Investors, the Investor's beneficial ownership of securities of
the Company or the Investors intended method of disposition of Registrable
Securities shall conform to the information provided to the Company by each of
the Investors.

         Section 3.9. The Company shall (a) cause all the Registrable Securities
covered by the Registration Statement to be listed on each national securities
exchange on which securities of the same class or series issued by the Company
are then listed, if any, if the listing of such Registrable Securities is then
permitted under the rules of such exchange, or (b) to the extent the securities
of the same class or series are not then listed or permitted to be listed on a
national securities exchange, secure the designation and quotation of all the
Registrable Securities covered by the Registration Statement on Nasdaq or, if
not eligible for Nasdaq on the Nasdaq SmallCap.

         Section 3.10. The Company shall provide a transfer agent and registrar,
which may be a single entity, for the Registrable Securities not later than the
effective date of the Registration Statement.

                                       7
<PAGE>

         Section 3.11. At the request of the holders of a majority-in-interest
of the Registrable Securities, the Company shall prepare and file with the SEC
such amendments (including post-effective amendments) and supplements to a
Registration Statement and any prospectus used in connection with the
Registration Statement as may be necessary in order to change the plan of
distribution set forth in such Registration Statement.

         Section 3.12. The Company shall not, and shall not agree to, allow the
holders of any securities of the Company to include any of their securities in
any Registration Statement under Section 2.1 or Section 2.4 hereof or any
amendment or supplement thereto under Section 3.2 hereof without the consent of
the holders of a majority-in-interest of the Registrable Securities or the
Additional Registrable Securities, as the case may be. In addition, the Company
shall not offer any securities for its own account or the account of others in
any Registration Statement under Section 2.1 or Section 2.4 hereof or any
amendment or supplement thereto under Section 3.2 hereof without the consent of
the holders of a majority-in- interest of the Registrable Securities or the
Additional Registrable Securities, as the case may be.

         Section 3.13. The Company shall take all other reasonable actions
necessary to expedite and facilitate disposition by the Investors of Registrable
Securities pursuant to a Registration Statement.

         Section 3.14. The Company shall comply with all applicable laws related
to a Registration Statement and offering and sale of securities and all
applicable rules and regulations of governmental authorities in connection
therewith (including without limitation the 1933 Act and the 1934 Act (as
defined below) and the rules and regulations promulgated by the SEC).

                                   ARTICLE IV.
                          OBLIGATIONS OF THE INVESTORS

         In connection with the registration of the Registrable Securities, the
Investors shall have the following obligations:

         Section 4.1. It shall be a condition precedent to the obligations of
the Company to complete the registration pursuant to this Agreement with respect
to the Registrable Securities of a particular Investor that such Investor shall
furnish to the Company such information regarding itself, the Registrable
Securities held by it and the intended method of disposition of the Registrable
Securities held by it as shall be reasonably required to effect the registration
of such Registrable Securities and shall execute such documents in connection
with such registration as the Company may reasonably request. At least ten (10)
days prior to the first anticipated filing date of the Registration Statement,
the Company shall notify each Investor of the information the Company requires
from each such Investor.

         Section 4.2. Each Investor, by such Investor's execution of this
Agreement, agrees to cooperate with the Company as reasonably requested by the
Company in connection with the

                                       8
<PAGE>

preparation and filing of the Registration Statements hereunder, unless such
Investor has notified the Company in writing of such Investor's election to
exclude all of such Investor's Registrable Securities from the Registration
Statements.

         Section 4.3. If the services of an underwriter are engaged, each
Investor agrees to enter into and perform such Investor's obligations under an
underwriting agreement, in usual and customary form, including, without
limitation, customary indemnification and contribution obligations, with the
managing underwriter of such offering and take such other actions as are
reasonably required in order to expedite or facilitate the disposition of the
Registrable Securities, unless such Investor has notified the Company in writing
of such Investor's election to exclude all of such Investor's Registrable
Securities from such Registration Statement.

         Section 4.4. Each Investor agrees that, upon receipt of any notice from
the Company of the happening of any event of the kind described in Section 3.6
or 3.7, such Investor will immediately discontinue disposition of Registrable
Securities pursuant to the Registration Statement covering such Registrable
Securities until such Investor's receipt of the copies of the supplemented or
amended prospectus contemplated by Section 3.6 or 3.7 and, if so directed by the
Company, such Investor shall deliver to the Company or destroy all copies in
such Investor's possession, of the prospectus covering such Registrable
Securities current at the time of receipt of such notice.

         Section 4.5. No Investor may participate in any underwritten
registration hereunder unless such Investor (a) agrees to sell such Investor's
Registrable Securities on the basis provided in any underwriting arrangements in
usual and customary form entered into by the Company, (b) completes and executes
all questionnaires, powers of attorney, indemnities, underwriting agreements and
other documents reasonably required under the terms of such underwriting
arrangements, and (c) agrees to pay its pro rata share of all underwriting
discounts and commissions and any expenses in excess of those payable by the
Company pursuant to Section 5 below.

         Section 4.6. The Investors shall comply with all applicable laws
related to a Registration Statement and offering and sale of securities and all
applicable rules and regulations of governmental authorities in connection
therewith (including without limitation the 1933 Act and the 1934 Act (as
defined below) and the rules and regulations promulgated by the SEC).

                                   ARTICLE V.
                            EXPENSES OF REGISTRATION

         All reasonable expenses, other than underwriting discounts and
commissions, incurred in connection with registrations, filings or
qualifications pursuant to Sections 2 and 3, including, without limitation, all
registration, listing and qualification fees, printers and accounting fees, the
fees and disbursements of legal counsel for the Company, and the reasonable fees
and disbursements of one legal counsel for all holders of Registrable
Securities, selected by the Investors pursuant to Sections 2.2 and 3.8 hereof,
shall be borne by the Company.

                                       9
<PAGE>

                                   ARTICLE VI.
                                 INDEMNIFICATION

         In the event any Registrable Securities are included in a Registration
Statement under this Agreement:

         Section 6.1. To the extent permitted by law, the Company will
indemnify, hold harmless and defend (a) each Investor who holds such Registrable
Securities, (b) the directors, officers, partners, employees, agents and each
person who controls any Investor within the meaning of the 1933 Act or the
Securities Exchange Act of 1934, as amended (the "1934 ACT"), if any, (c) any
underwriter (as defined in the 1933 Act) for the Investors, and (d) the
directors, officers, partners, employees and each person who controls any such
underwriter within the meaning of the 1933 Act or the 1934 Act, if any (each, an
"INDEMNIFIED PERSON"), against any joint or several losses, claims, damages,
liabilities or expenses (collectively, together with actions, proceedings or
inquiries by any regulatory or self-regulatory organization, whether commenced
or threatened, in respect thereof, "CLAIMS") to which any of them may become
subject insofar as such Claims arise out of or are based upon: (i) any untrue
statement or alleged untrue statement of a material fact in a Registration
Statement or the omission or alleged omission to state therein a material fact
required to be stated or necessary to make the statements therein not
misleading; (ii) any untrue statement or alleged untrue statement of a material
fact contained in any preliminary prospectus if used prior to the effective date
of such Registration Statement, or contained in the final prospectus (as amended
or supplemented, if the Company files any amendment thereof or supplement
thereto with the SEC) or the omission or alleged omission to state therein any
material fact necessary to make the statements made therein, in light of the
circumstances under which the statements therein were made, not misleading; or
(iii) any violation or alleged violation by the Company of the 1933 Act, the
1934 Act, any other law, including, without limitation, any state securities
law, or any rule or regulation thereunder relating to the offer or sale of the
Registrable Securities (the matters in the foregoing clauses (i) through (iii)
being, collectively, "VIOLATIONS"). Subject to the restrictions set forth in
Section 6.3 with respect to the number of legal counsel, the Company shall
reimburse the Indemnified Person, promptly as such expenses are incurred and are
due and payable, for any reasonable legal fees or other reasonable expenses
incurred by them in connection with investigating or defending any such Claim.
Notwithstanding anything to the contrary contained herein, the indemnification
agreement contained in this Section 6.1: (A) shall not apply to a Claim arising
out of or based upon a Violation which occurs in reliance upon and in conformity
with information furnished in writing to the Company by any Indemnified Person
or underwriter for such Indemnified Person expressly for use in connection with
the preparation of such Registration Statement or any such amendment thereof or
supplement thereto; (B) shall not apply to amounts paid in settlement of any
Claim if such settlement is effected without the prior written consent of the
Company, which consent shall not be unreasonably withheld; and (C) with respect
to any preliminary prospectus, shall not inure to the benefit of any Indemnified
Person if the untrue statement or omission of material fact contained in the
preliminary prospectus was corrected on a timely basis in the prospectus, as
then amended or supplemented, such corrected prospectus was timely made
available by the Company pursuant to Section 3.3 hereof, and the Indemnified
Person was promptly advised in writing not to use the incorrect prospectus prior
to the

                                       10
<PAGE>

use giving rise to a Violation and such Indemnified Person, notwithstanding such
advice, used it. Such indemnity shall remain in full force and effect regardless
of any investigation made by or on behalf of the Indemnified Person and shall
survive the transfer of the Registrable Securities by the Investors pursuant to
Section 9.

         Section 6.2. In connection with any Registration Statement in which an
Investor is participating, each such Investor agrees severally and not jointly
to indemnify, hold harmless and defend, to the same extent and in the same
manner set forth in Section 6.1, the Company, each of its directors, each of its
officers who signs the Registration Statement, each person, if any, who controls
the Company within the meaning of the 1933 Act or the 1934 Act, any underwriter
and any other shareholder selling securities pursuant to the Registration
Statement or any of its directors or officers or any person who controls such
shareholder or underwriter within the meaning of the 1933 Act or the 1934 Act
(collectively and together with an Indemnified Person, an "INDEMNIFIED PARTY"),
against any Claim to which any of them may become subject, under the 1933 Act,
the 1934 Act or otherwise, insofar as such Claim arises out of or is based upon
any Violation, in each case to the extent (and only to the extent) that such
Violation occurs in reliance upon and in conformity with written information
furnished to the Company by such Investor expressly for use in connection with
such Registration Statement; and subject to Section 6.3, such Investor will
reimburse any legal or other expenses (promptly as such expenses are incurred
and are due and payable) reasonably incurred by them in connection with
investigating or defending any such Claim; provided, however, that the indemnity
agreement contained in this Section 6.2 shall not apply to amounts paid in
settlement of any Claim if such settlement is effected without the prior written
consent of such Investor, which consent shall not be unreasonably withheld;
provided, further, however, that the Investor shall be liable under this
Agreement (including this Section 6.2 and Section 7) for only that amount as
does not exceed the net proceeds to such Investor as a result of the sale of
Registrable Securities pursuant to such Registration Statement. Such indemnity
shall remain in full force and effect regardless of any investigation made by or
on behalf of such Indemnified Party and shall survive the transfer of the
Registrable Securities by the Investors pursuant to Section 9. Notwithstanding
anything to the contrary contained herein, the indemnification agreement
contained in this Section 6.2 with respect to any preliminary prospectus shall
not inure to the benefit of any Indemnified Party if the untrue statement or
omission of material fact contained in the preliminary prospectus was corrected
on a timely basis in the prospectus, as then amended or supplemented, and the
Indemnified Party was promptly advised in writing not to use the incorrect
information prior to the use giving rise to a Violation and such Indemnified
Party, notwithstanding such advice, used it.

         Section 6.3. Promptly after receipt by an Indemnified Party under this
Section 6 of notice of the commencement of any action (including any
governmental action), such Indemnified Party shall, if a Claim in respect
thereof is to be made against any indemnifying party under this Section 6,
deliver to the indemnifying party a written notice of the commencement thereof,
and the indemnifying party shall have the right to participate in, and, to the
extent the indemnifying party so desires, jointly with any other indemnifying
party similarly noticed, to assume control of the defense thereof with counsel
selected by the indemnifying party and reasonably satisfactory to the
Indemnified Party, as the case may be; provided, however, that an Indemnified
Party shall have the

                                       11
<PAGE>

right to retain its own counsel with the fees and expenses to be paid by the
indemnifying party, if, in the reasonable opinion of counsel retained by the
indemnifying party, the representation by such counsel of the Indemnified Party
and the indemnifying party would be inappropriate due to actual or potential
differing interests between such Indemnified Party and any other party
represented by such counsel in such proceeding. The indemnifying party shall pay
for only one separate legal counsel for the Indemnified Parties, as applicable,
and such legal counsel shall be selected by Investors holding a
majority-in-interest of the Registrable Securities included in the Registration
Statement to which the Claim relates, if the Investors are entitled to
indemnification hereunder, or the Company, if the Company is entitled to
indemnification hereunder, as applicable. The failure to deliver written notice
to the indemnifying party within a reasonable time of the commencement of any
such action shall not relieve such indemnifying party of any liability to the
Indemnified Party under this Section 6, except to the extent that the
indemnifying party is actually prejudiced in its ability to defend such action.
The indemnification required by this Section 6 shall be made by periodic
payments of the amount thereof during the course of the investigation or
defense, as such expense, loss, damage or liability is incurred and is due and
payable.

                                  ARTICLE VII.
                                  CONTRIBUTION

         To the extent any indemnification by an indemnifying party is
prohibited or limited by law, the indemnifying party agrees to make the maximum
contribution with respect to any amounts for which it would otherwise be liable
under Section 6 to the fullest extent permitted by law; provided, however, that
(a) no contribution shall be made under circumstances where the indemnifying
party would not have been liable for indemnification under the fault standards
set forth in Section 6, (b) no seller of Registrable Securities guilty of
fraudulent misrepresentation (within the meaning of Section 11(f) of the 1933
Act) shall be entitled to contribution from any seller of Registrable Securities
who was not guilty of such fraudulent misrepresentation, and (c) contribution
(together with any indemnification or other obligations under this Agreement) by
any seller of Registrable Securities shall be limited in amount to the net
amount of proceeds received by such seller from the sale of such Registrable
Securities.

                                  ARTICLE VIII.
                           REPORTS UNDER THE 1934 ACT

         With a view to making available to the Investors the benefits of Rule
144 promulgated under the 1933 Act or any other similar rule or regulation of
the SEC that may at any time permit the investors to sell securities of the
Company to the public without registration ("RULE 144"), the Company agrees to:

                  (a) make and keep public information available, as those terms
         are understood and defined in Rule 144;

                                       12
<PAGE>

                  (b) file with the SEC in a timely manner all reports and other
         documents required of the Company under the 1933 Act and the 1934 Act
         so long as the Company remains subject to such requirements and the
         filing of such reports and other documents is required for the
         applicable provisions of Rule 144; and

                  (c) furnish to each Investor so long as such Investor owns
         Registrable Securities, promptly upon request, such information as may
         be reasonably requested to permit such Investor to sell such securities
         pursuant to Rule 144 without registration.

                                   ARTICLE IX.
                        ASSIGNMENT OF REGISTRATION RIGHTS

         The rights under this Agreement shall be automatically assignable by
the Investors to any transferee of all or any portion of Registrable Securities
if: (a) the Investor agrees in writing with the transferee or assignee to assign
such rights, and a copy of such agreement is furnished to the Company within a
reasonable time after such assignment, (b) the Company is, within a reasonable
time after such transfer or assignment, furnished with written notice of (i) the
name and address of such transferee or assignee, and (ii) the securities with
respect to which such registration rights are being transferred or assigned, (c)
following such transfer or assignment, the further disposition of such
securities by the transferee or assignee is restricted under the 1933 Act and
applicable state securities laws, (d) at or before the time the Company receives
the written notice contemplated by clause (b) of this sentence, the transferee
or assignee agrees in writing with the Company to be bound by all of the
provisions contained herein, and (e) such transferee shall be an "ACCREDITED
INVESTOR" as that term defined in Rule 501 of Regulation D promulgated under the
1933 Act.

                                   ARTICLE X.
                        AMENDMENT OF REGISTRATION RIGHTS

         Provisions of this Agreement may be amended and the observance thereof
may be waived (either generally or in a particular instance and either
retroactively or prospectively), only with written consent of the Company, and
Investors who hold a majority interest of the Registrable Securities. Any
amendment or waiver effected in accordance with this Section 10 shall be binding
upon each Investor and the Company.

                                   ARTICLE XI.
                                  MISCELLANEOUS

         Section 11.1. A person or entity is deemed to be a holder of
Registrable Securities whenever such person or entity owns of record such
Registrable Securities. If the Company receives conflicting instructions,
notices or elections from two or more persons or entities with respect to the

                                       13
<PAGE>

same Registrable Securities, the Company shall act upon the basis of
instructions, notice or election received from the registered owner of such
Registrable Securities.

         Section 11.2. Any notices required or permitted to be given under the
terms hereof shall be sent by certified or registered mail (return receipt
requested) or delivered personally or by courier (including a recognized
overnight delivery service) or by facsimile and shall be effective five (5)
calendar days after being placed in the mail, if mailed by regular United States
mail, or upon receipt, if delivered personally or by courier (including a
recognized overnight delivery service) or by facsimile, in each case addressed
to a party. The addresses and facsimile numbers for such communications shall
be:

                           If to the Company:

                           Zix Corporation
                           2711 North Haskell Avenue
                           Suite 2300 LB36
                           Dallas, Texas 75204
                           Attention: General Counsel
                           Facsimile:  (214) 515-7385

                           With copy to:

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

If to an Investor: to the address and facsimile number set forth immediately
below such Investor's name on Schedule A or Schedule B, as applicable, to the
Securities Purchase Agreement.

         Section 11.3. Failure of any party to exercise any right or remedy
under this Agreement or otherwise, or delay by a party in exercising such right
or remedy, shall not operate as a waiver thereof.

         Section 11.4. 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 11.5. This Agreement and the Securities Purchase Agreement
(including all schedules and exhibits thereto) constitute the entire agreement
among the parties hereto with respect

                                       14
<PAGE>

to the subject matter hereof and thereof. There are no restrictions, promises,
warranties or undertakings, other than those set forth or referred to herein and
therein. This Agreement and the Securities Purchase Agreement supersede all
prior agreements and understandings among the parties hereto with respect to the
subject matter hereof and thereof.

         Section 11.6. Subject to the requirements of Section 9 hereof, this
Agreement shall inure to the benefit of and be binding upon the successors and
assigns of each of the parties hereto.

         Section 11.7. The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

         Section 11.8. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original but all of which shall
constitute one and the same agreement. This Agreement, once executed by a party,
may be delivered to the other party hereto by facsimile transmission of a copy
of this Agreement bearing the signature of the party so delivering this
Agreement.

         Section 11.9. Each party shall do and perform, or cause to be done and
performed, all such further acts and things, and shall execute and deliver all
such other agreements, certificates, instruments and documents, as the other
party may reasonably request in order to carry out the intent and accomplish the
purposes of this Agreement and the consummation of the transactions contemplated
hereby.

         Section 11.10. Except as otherwise provided herein, all consents and
other determinations to be made by the Investors pursuant to this Agreement
shall be made by Investors holding a majority of the Registrable Securities,
determined as if the all of the Preferred Shares then outstanding have been
converted into Registrable Securities.

         Section 11.11. The language used in this Agreement will be deemed to be
the language chosen by the parties to express their mutual intent, and no rules
of strict construction will be applied against any party.

         Section 11.12. In the event that any provision of this Agreement is
invalid or unenforceable under any applicable statute or rule of law, then such
provision shall be deemed inoperative to the extent that it may conflict
therewith and shall be deemed modified to conform with such statute or rule of
law. Any provision hereof which may prove invalid or unenforceable under any law
shall not affect the validity or enforceability of any other provision hereof.

         Section 11.13. The initial number of Registrable Securities included in
any Registration Statement and each increase to the number of Registrable
Securities included therein shall be allocated pro rata among the Investors
based on the number of Registrable Securities held by each Investor at the time
of such establishment or increase, as the case may be. In the event an Investor
shall sell or otherwise transfer any of such holder's Registrable Securities,
each transferee shall be allocated a pro rata portion of the number of
Registrable Securities included in a Registration

                                       15
<PAGE>

Statement for such transferor. For the avoidance of doubt, the number of
Registrable Securities held by an Investor shall be determined as if all
Preferred Shares and Warrants then outstanding and held by an Investor were
converted into or exercised for Registrable Securities.

                [REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK]

                                       16
<PAGE>

         IN WITNESS WHEREOF, the Company and the undersigned Investors have
caused this Agreement to be duly executed as of the date first above written.

<Table>
<S>                                                        <C>
COMPANY
Zix Corporation, a Texas corporation

/s/ Ronald A. Woessner
----------------------------------------------
By:        Ronald A. Woessner
Title:     S.V.P.

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>

                                       17

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"}]]