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                                                                     EXHIBIT 4.1

                     ZIX CORPORATION 2001 STOCK OPTION PLAN
                   (AMENDED AND RESTATED AS OF AUGUST 1, 2002)



SECTION 1.        PURPOSE

         The purpose of the Zix Corporation 2001 Stock Option Plan (hereinafter
called the "2001 Plan") is to advance the interests of Zix Corporation
(hereinafter called the "Company") by strengthening the ability of the Company
to attract, on its behalf and on behalf of its Subsidiaries (as hereinafter
defined), and retain personnel of high caliber through encouraging a sense of
proprietorship by means of stock ownership.

SECTION 2.        DEFINITIONS

         "Board of Directors" shall mean the Board of Directors of the Company.

         "Code" shall mean the Internal Revenue Code of 1986, as amended from
time-to-time.

         "Committee" shall mean a committee of the Board of Directors comprised
of at least two directors or the entire Board of Directors, as the case may be.
Members of the Committee shall be selected by the Board of Directors. To the
extent necessary to comply with the requirements of Rule 16b-3, the Committee
shall consist of two or more Non-employee Directors. Also, if the requirements
of Section 162(m) of the Code are intended to be met, the Committee shall
consist of two or more "outside directors" within the meaning of Section 162(m)
of the Code.

         "Common Stock" shall mean the Common Stock of the Company, par value
$.01 per share.

         "Date of Grant" shall mean the date on which an Option is granted
pursuant to this 2001 Plan.

         "Designated Beneficiary" shall mean the beneficiary designated by the
Optionee, in a manner determined by the Committee, to receive amounts due the
Optionee in the event of the Optionee's death. In the absence of an effective
designation by the Optionee, Designated Beneficiary shall mean the Optionee's
estate.

         "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended.

         "Fair Market Value" shall mean the closing sale price (or average of
the quoted closing bid and asked prices if there is no closing sale price
reported) of the Common Stock on the date specified as reported by The Nasdaq
Stock Market, or by the principal national stock exchange on which the Common
Stock is then listed. If there is no reported price information for such date,
the Fair Market Value will be determined by the reported price information for
Common Stock on the day nearest preceding such date.

         "Incentive Stock Option" shall mean a stock option granted under
Section 6 that is intended to meet the requirements of Section 422 of the Code
(or any successor provision).

         "Non-employee Director" shall have the meaning given such term in Rule
16b-3.

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         "Nonqualified Stock Option" shall mean a stock option granted under
Section 6 that is not intended to be an Incentive Stock Option.

         "Option" shall mean an Incentive Stock Option or a Nonqualified Stock
Option.

         "Optionee" shall mean the person to whom an option is granted under the
2001 Plan or who has obtained the right to exercise an option in accordance with
the provisions of the 2001 Plan.

         "Rule 16b-3" shall mean Rule 16b-3 of the rules and regulations under
the Exchange Act as it may be amended from time-to-time and any successor
provision to Rule 16b-3 under the Exchange Act.

         "Subsidiary" shall mean any now existing or hereafter organized or
acquired corporation or other entity of which fifty percent (50%) or more of the
issued and outstanding voting stock or other economic interest is owned or
controlled directly or indirectly by the Company or through one or more
Subsidiaries of the Company.

SECTION 3.        ADMINISTRATION

         The 2001 Plan shall be administered by the Committee. The Committee
shall have sole and complete authority to adopt, alter and repeal such
administrative rules, guidelines and practices governing the operation of the
2001 Plan as it shall from time-to-time deem advisable, and to construe,
interpret and administer the terms and provisions of the 2001 Plan and the
agreements thereunder. The determinations and interpretations made by the
Committee are final and conclusive.

SECTION 4.        ELIGIBILITY

         All employees and non-employee consultants and advisors (other than
Non-employee Directors) who, in the opinion of the Committee, have the capacity
for contributing in a substantial measure to the successful performance of the
Company are eligible to receive Options under the 2001 Plan.

SECTION 5.        MAXIMUM AMOUNT AVAILABLE FOR OPTIONS

         (a) The maximum number of shares of Common Stock in respect of which
Options may be made under the 2001 Plan shall be a total of 1,500,000 shares of
Common Stock. Of that amount, no participant may be granted Options for more
than 600,000 shares of Common Stock in the aggregate during the term of the 2001
Plan. Options that expire, lapse or are cancelled or forfeited nonetheless
continue to count against the 1,500,000 share limit. Shares of Common Stock may
be made available from the authorized but unissued shares of the Company or from
shares reacquired by the Company, including shares purchased in the open market.
In the event that an Option is terminated unexercised as to any shares of Common
Stock covered thereby, such shares shall thereafter be again available for award
pursuant to the 2001 Plan.

         (b) In the event that the Committee shall determine that any stock
dividend, recapitalization, reorganization, merger, consolidation, split-up,
spin-off, combination, exchange of shares, warrants or rights offering to
purchase Common Stock at a price substantially below fair market value, or other
similar corporate event affects the Common Stock such that an adjustment is
required in order to preserve the benefits or potential benefits intended to be
made available under the 2001 Plan, then the Committee shall adjust
appropriately any or all of (1) the number and kind of shares which thereafter
may be optioned under the 2001 Plan and (2) the grant, exercise or conversion
price and/or number of shares with respect to the

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Options and/or, if deemed appropriate, make provision for cash payment to an
Optionee; provided, however, that the number of shares subject to any Option
shall always be a whole number.


SECTION 6.        STOCK OPTIONS

         (a) Subject to the provisions of the 2001 Plan, the Committee shall
have sole and complete authority to determine the persons to whom Options shall
be granted, the number of shares to be covered by each Option, the option price
therefor and the conditions and limitations applicable to the exercise of the
Option.

         (b) The Committee shall have the authority to grant Incentive Stock
Options, or to grant Nonqualified Stock Options, or to grant both types of
options. In the case of Incentive Stock Options, the terms and conditions of
such grants shall be subject to and comply with the Code and relevant
regulations. Incentive Stock Options to purchase Common Stock may be granted to
such employees of the Company or its Subsidiaries (including any director who is
also an employee of the Company or one of its Subsidiaries) as shall be
determined by the Committee. Nonqualified Stock Options to purchase Common Stock
may be granted to such eligible participants as shall be determined by the
Committee. Neither the Company nor any of its Subsidiaries or any of their
respective directors, officers or employees, shall be liable to any Optionee or
other person if it is determined for any reason by the Internal Revenue Service
or any court having jurisdiction that any Incentive Stock Option granted
hereunder does not qualify for tax treatment as an Incentive Stock Option under
the then-applicable provisions of the Code.

         (c) The Committee shall, in its discretion, establish the exercise
price at the time each Option is granted, which in the case of Nonqualified
Stock Options, shall not be less than 100% of the Fair Market Value of the
Common Stock on the Date of Grant, or in the case of grants of Incentive Stock
Options, shall not be less than 100% of the Fair Market Value of the Common
Stock on the Date of Grant or such greater amount as may be prescribed by the
Code.

         (d) Exercise

                  (1) Each Option shall be exercisable at such times and subject
         to such terms and conditions as the Committee may, in its sole
         discretion, specify in the applicable grant or thereafter; provided,
         however, that in no event may any Option granted hereunder be
         exercisable after the expiration of ten years from the Date of Grant.
         The Committee may impose such conditions with respect to the exercise
         of Options, including without limitation, any relating to the
         application of federal or state securities laws, as it may deem
         necessary or advisable.

                  (2) No shares shall be delivered pursuant to any exercise of
         an Option until payment in full of the option price therefore is
         received by the Company. Such payment may be made in cash, or its
         equivalent, or, if and to the extent permitted by the Committee or
         under the terms of the applicable agreement, by exchanging shares of
         Common Stock owned by the Optionee (which are not the subject of any
         pledge or other security interest), or by a combination of the
         foregoing, provided that the combined value of all cash and cash
         equivalents and the Fair Market Value of any such Common Stock so
         tendered to the Company, valued as of the date of such tender, is at
         least equal to such option price.

                  If the shares to be purchased are covered by an effective
                  registration statement under the Securities Act of 1933, as
                  amended, any Option may be exercised by a broker-dealer acting
                  on behalf of an Optionee if (a) the broker-dealer has received
                  from the Optionee instructions signed
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                  by the Optionee requesting the Company to deliver the shares
                  of Common Stock subject to such Option to the broker-dealer on
                  behalf of the Optionee and specifying the account into which
                  such shares should be deposited, (b) adequate provision has
                  been made with respect to the payment of any withholding taxes
                  due upon such exercise, and (c) the broker-dealer and the
                  Optionee have otherwise complied with Section 220.3(e)(4) of
                  Regulation T, 12 CFR Part 220, or any successor provision.

                  (3) The Company, in its sole discretion, may lend money to an
         Optionee, guarantee a loan to an Optionee or otherwise assist an
         Optionee to obtain the cash necessary to exercise all or any portion of
         an Option granted under the 2001 Plan.

                  (4) The Company shall not be required to issue any fractional
         shares upon the exercise of any Options granted under this 2001 Plan.
         No Optionee nor an Optionee's legal representatives, legatees or
         distributees, as the case may be, will be, or will be deemed to be, a
         holder of any shares subject to an Option unless and until said Option
         has been exercised and the purchase price of the shares in respect of
         which the Option has been exercised has been paid. Unless otherwise
         provided in the agreement applicable thereto, an Option shall not be
         exercisable except by the Optionee or by a person who has obtained the
         Optionee's rights under the Option by will or under the laws of descent
         and distribution or pursuant to a "qualified domestic relations order"
         as defined in the Code.

         (e) No Incentive Stock Options shall be exercisable (a) more than five
years (or such other period of time as from time-to-time provided in the
then-applicable provisions of the Code governing Incentive Stock Options) after
the Date of Grant with respect to an Optionee who owns ten percent or more of
the outstanding Common Stock (within the meaning of the Code), and (b) more than
ten years after the Date of Grant with respect to all other Optionees. No
Nonqualified Stock Options shall be exercisable more than ten years after the
Date of Grant.

         (f) In no event shall any Option granted to any employee who is
classified as "non-exempt" under the Fair Labor Standards Act of 1938 be
exercisable less than six months after the Date of Grant, except in the case of
death, disability, retirement, a change in control or other circumstances
permitted by regulations under the Worker Economic Opportunity Act ("WEOA").
Grants to such non-exempt employees shall not be based on pre-established
performance criteria, except as specifically permitted under the WEOA.
Non-exempt employees shall be notified of the terms of their Options in
accordance with the WEOA, and exercise of such Options must be voluntary.

SECTION 7.        GENERAL PROVISIONS

         (a) The Company and its Subsidiaries shall have the right to deduct
from all amounts paid to an Optionee in cash (whether under the 2001 Plan or
otherwise) any taxes required by law to be withheld in respect of Option
exercises under the 2001 Plan. However, if permitted by the Committee or under
the terms of the applicable agreement, the Optionee may pay all or any portion
of the taxes required to be withheld by the Company or its Subsidiaries or paid
by the Optionee with respect to such Common Stock by electing to have the
Company or its Subsidiaries withhold shares of Common Stock, or by delivering
previously owned shares of Common Stock, having a Fair Market Value equal to the
amount required to be withheld or paid. The Optionee must make the foregoing
election on or before the date that the amount of tax to be withheld is
determined. Any such election is irrevocable and subject to disapproval by the
Committee. If the Optionee is subject to the provisions of Section 16(b) of the
Exchange Act, then any such election shall be subject to the restrictions
imposed by Rule 16b-3.

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         (b) Each Option hereunder shall be evidenced in writing, delivered to
the Optionee, and shall specify the terms and conditions thereof and any rules
applicable thereto, including, but not limited to, the effect on such Option of
the death, retirement, disability or other termination of employment of the
Optionee and the effect thereon, if any, of a change in control of the Company.

         (c) Unless otherwise provided in the agreement applicable thereto, no
Option shall be assignable or transferable except by will or under the laws of
descent and distribution or pursuant to a "qualified domestic relations order"
as defined in the Code, and no right or interest of any Optionee shall be
subject to any lien, obligation or liability of the Optionee.

         (d) No person shall have any claim or right to be granted an Option.
Further, the Company and its Subsidiaries expressly reserve the right at any
time to terminate the employment of an Optionee free from any liability, or any
claim under the 2001 Plan, except as provided in any agreement entered into with
respect to an Option. Neither the 2001 Plan nor any Option granted hereunder is
intended to confer upon any Optionee any rights with respect to continuance of
employment or other utilization of his or her services by the Company or by a
Subsidiary, nor to interfere in any way with his or her right or that of his or
her employer to terminate his or her employment or other services at any time
(subject to the terms of any applicable contract). The conditions to apply to
the exercise of an Option in the event an Optionee ceases to be employed by the
Company or a Subsidiary for any reason shall be determined by the Committee or
specified in the written agreement evidencing the Option.

         (e) Subject to the provisions of the applicable Option, no Optionee or
Designated Beneficiary shall have any rights as a stockholder with respect to
any shares of Common Stock to be distributed under the 2001 Plan until he or she
has become the holder thereof.

         (f) The validity, construction, interpretation, administration and
effect of the 2001 Plan and of its rules and regulations, and rights relating to
the 2001 Plan, shall be determined solely in accordance with the laws of the
State of Texas (without giving effect to its conflicts of laws rules) and, to
the extent applicable, federal law.

         (g) The 2001 Plan was originally effective on May 15, 2001. No Options
may be granted under the 2001 Plan after May 14, 2011; however, all previous
Options issued that have not expired under their original terms or will not then
expire at the time the 2001 Plan expires will remain outstanding.

         (h) Restrictions on Issuance of Shares

                  (1) The Company shall not be obligated to sell or issue any
         Shares upon the exercise of any Option granted under the 2001 Plan
         unless: (i) the shares pertaining to such Option have been registered
         under applicable federal and state securities laws or are exempt from
         such registration; (ii) the prior approval of such sale or issuance has
         been obtained from any state regulatory body having jurisdiction; and
         (iii) in the event the Common Stock has been listed on any exchange,
         the shares pertaining to such Option have been duly listed on such
         exchange in accordance with the procedure specified therefor. The
         Company shall be under no obligation to effect or obtain any listing,
         registration, qualification, consent or approval with respect to shares
         pertaining to any Option granted under the 2001 Plan. If the shares to
         be issued upon the exercise of any Option granted under the 2001 Plan
         are intended to be issued by the Company in reliance upon the
         exemptions from the registration requirements of applicable federal and
         state securities laws, the recipient of the Option, if so requested by
         the Company, shall furnish to the Company such evidence and
         representations, including an opinion of counsel, satisfactory to it,
         as the Company may reasonably request.

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                  (2) The Company shall not be liable for damages due to a delay
         in the delivery or issuance of any stock certificates for any reason
         whatsoever, including, but not limited to, a delay caused by listing,
         registration or qualification of the shares of Common Stock pertaining
         to any Option granted under the 2001 Plan upon any securities exchange
         or under any federal or state law or the effecting or obtaining of any
         consent or approval of any governmental body.

         (i) The Board of Directors or Committee may impose such other
restrictions on the ownership and transfer of shares issued pursuant to the 2001
Plan as it deems desirable; any such restrictions shall be set forth in the
applicable agreement.

         (j) The Board of Directors may amend, abandon, suspend or terminate the
2001 Plan or any portion thereof at any time in such respects as it may deem
advisable in its sole discretion, provided that no amendment shall be made
without stockholder approval (including an increase in the maximum number of
shares of Common Stock in respect of which Options may be made under the 2001
Plan) if such stockholder approval is necessary to comply with any tax or
regulatory requirement or exchange listing rules, including for these purposes
any approval requirement that is a prerequisite for exemptive relief under
Section 16(b) of the Exchange Act.

         (k) To preserve an Optionee's rights under an Option in the event of a
change in control of the Company or an Optionee's separation from employment,
the Committee in its discretion may, at the time an Option is made or any time
thereafter, take one or more of the following actions: (i) provide for the
acceleration of any time period relating to the exercise of the Option, (ii)
provide for the purchase of the Option, upon the Optionee's request, for an
amount of cash or other property that could have been received upon the exercise
or realization of the Option had the Option been currently exercisable or
payable, (iii) adjust the terms of the Option in a manner determined by the
Committee to reflect the change in control or to prevent the imposition of an
excise tax under section 280G(b) of the Code, (iv) cause the Option to be
assumed, or new rights substituted therefor, by another entity, or (v) make such
other provision as the Committee may consider equitable and in the best
interests of the Company.

         AMENDED AND RESTATED as of August 1, 2002.

                                         ZIX CORPORATION

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