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                                                                     EXHIBIT 4.1

                                 ZIX CORPORATION
                        1999 DIRECTORS' STOCK OPTION PLAN
                   (AMENDED AND RESTATED AS OF AUGUST 1, 2002)


Section 1. PURPOSE

         The purpose of the Zix Corporation 1999 Directors' Stock Option Plan
(hereinafter called the "1999 Plan") is to advance the interests of Zix
Corporation, a Texas corporation (hereinafter called the "Company"), by
strengthening the ability of the Company to attract, on its behalf, and retain
External Directors (as defined below) of high caliber through encouraging a
sense of proprietorship by means of stock ownership.

Section 2. DEFINITIONS

         "Adoption Date" shall mean January 28, 1999.

         "Board" 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 the entire Board of Directors, or if the
administration of the 1999 Plan has been delegated to a committee of the Board,
a committee selected by the Board and comprised of at least two 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.

         "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 under
the 1999 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.

         "Eligible Director" shall mean an External Director who has served on
the Board at least 12 consecutive months as of the Date of Grant.

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

         "External Director" shall mean a member of the Board who is not an
employee of the Company or a subsidiary.

         "Fair Market Value" shall mean the closing sales price (or average of
the quoted closing bid and asked prices if there is no closing sales 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.



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         "Grant Shares" shall mean, with respect to each Eligible Director for a
particular year, a number of shares calculated according to the following
formula: 1% of the number of the Company's outstanding Common Stock shares as of
the December 31 immediately preceding the Date of Grant divided by the number of
then-Eligible Directors. In no event may the number of Grant Shares in any given
year to any given Eligible Director exceed one-half of 1% of the Company's
outstanding Common Stock shares.

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

         "Option" shall mean a nonqualified option to purchase shares of the
Company's Common Stock.

         "Optionee" shall mean the person to whom an Option is granted under the
1999 Plan or who has obtained the right to exercise an Option in accordance with
the provisions of the 1999 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.

Section 3. ADMINISTRATION

         The 1999 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
1999 Plan as it shall from time-to-time deem advisable, and to construe,
interpret and administer the terms and provisions of the 1999 Plan and the
agreements thereunder. The determinations and interpretations made by the
Committee are final and conclusive and binding on all persons.

Section 4. ELIGIBILITY

         All External Directors shall be eligible to receive awards of Options
under the 1999 Plan.

Section 5. MAXIMUM AMOUNT AVAILABLE FOR AWARDS

         Subject to the provisions of Section 9, the maximum number of shares of
Common Stock in respect of which Options may be granted under the 1999 Plan
shall be 975,000 shares of Common Stock. Shares of Common Stock may be made
available from 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 1999 Plan.

Section 6. STOCK OPTIONS

         (a) During the term of the 1999 Plan, on the day that an External
Director is first appointed or elected to the Board, such director shall be
granted nonqualified Options to purchase 25,000 shares of the Company's Common
Stock. Also, during the term of the 1999 Plan, on the first business day of
January of each year after the Adoption Date, each Eligible Director shall be
granted Options to purchase the Grant Shares. Each Eligible Director serving on
the Board on the Adoption Date shall be granted Options to purchase the Grant
Shares, effective as of the Adoption Date. Directors that receive the Grant
Shares are not eligible to receive a directors' retainer cash payment, although
they are eligible to be reimbursed for expenses related to Board activities.

         (b) All Options granted under the 1999 Plan prior to shareholder
approval of the 1999 Plan shall be subject to the approval of the 1999 Plan by
the shareholders of the Company.



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         (c) The exercise price of the 25,000 share option grants shall be 100%
of the Fair Market Value of the Common Stock on the Date of Grant. The exercise
price for the Grant Shares shall be 120% of the Fair Market Value of the Common
Stock on the Date of Grant. The exercise price of any outstanding Options may
not be re-priced without the approval of the Company's shareholders (obtained in
accordance with applicable law), given in each specific instance.

         (d) Each Option hereunder shall be evidenced in writing, delivered to
the Optionee, and shall be exercisable at such times and subject to such terms
and conditions as specified in the applicable grant and agreement, subject to
the following principles:

         (1)      the 25,000 share option grants shall vest six months from the
                  Date of Grant;

         (2)      the Grant Shares shall vest annually and pro-rata on each of
                  the first three anniversaries of the Date of Grant; provided,
                  that, the vesting will accelerate if (a) a Change in Control
                  (as defined in the applicable agreement) of the Company occurs
                  or (b) the director is removed by vote of the shareholders
                  other than for Cause (as defined in the applicable agreement);
                  and

         (3)      the Options may not be exercised after the tenth anniversary
                  of the Date of Grant.

         The Committee may impose such conditions with respect to the exercise
of Options (that are consistent with the foregoing principles), including
without limitation, any relating to the application of federal or state
securities laws, as it may deem necessary or advisable.

         (e) No shares shall be delivered pursuant to any exercise of an Option
until cash payment in full of the option price therefor is received by the
Company. If the shares to be purchased are covered by an effective registration
statement under the Securities Act of 1933, 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 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. The
Company shall have the right to deduct from all amounts paid to an Optionee in
cash (whether under the 1999 Plan or otherwise) any taxes the Company withholds
in respect of Options under the 1999 Plan.

         (f) The Company shall not be required to issue any fractional shares
upon the exercise of any Options granted under the 1999 Plan. No Optionee or
such 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, and no right or interest of any Optionee shall be subject to any lien,
obligation or liability of the Optionee.



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Section 7. 1999 PLAN AMENDMENTS

         The Board may amend, abandon, suspend or terminate the 1999 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 shareholder
approval if such amendment is material or if shareholder approval is necessary
to comply with any tax or regulatory requirement.

Section 8. RESTRICTIONS ON ISSUANCE OF OPTIONS AND OPTION SHARES

         The Company shall not be obligated to issue any shares upon the
exercise of any Option granted under the 1999 Plan unless: (1) the shares
pertaining to such Option have been registered under applicable securities laws
or are exempt from such registration; (2) if required, the prior approval of
such sale or issuance has been obtained from any state regulatory body having
jurisdiction; and (3) 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 1999 Plan. If the shares to be issued upon the exercise
of any Option granted under the 1999 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.

         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 1999 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.

         The Committee may impose such other restrictions on the ownership and
transfer of shares issued pursuant to the 1999 Plan as it deems desirable; any
such restrictions shall be set forth in the agreement applicable thereto.

Section 9. ADJUSTMENT TO SHARES

         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 1999 Plan, then the Committee shall adjust
appropriately any or all of (a) the number and kind of shares that thereafter
may be optioned under the 1999 Plan, (b) the number and kind of shares subject
of Options and (c) the exercise price with respect to any of the foregoing
and/or, if deemed appropriate, make provision for cash payment to an Optionee or
a person who has an outstanding Option; provided, however, that the number of
shares subject to any Option shall always be a whole number.

Section 10. EFFECTIVE DATE; TERM; EFFECT ON 1996 PLAN

         The 1999 Plan was originally effective as of the Adoption Date. No
Options may be granted under the 1999 Plan after January 27, 2009; however, all
previously granted Options that have not expired under



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their original terms or will not then expire at the time the 1999 Plan expires
will remain outstanding. The 1999 Plan supersedes the Company's 1996 Directors'
Stock Option Plan.

Section 11. GENERAL PROVISIONS

         (a) Neither the 1999 Plan nor any Option granted hereunder is intended
to confer upon any Optionee any rights with respect to continuance of the
utilization of his or her services by the Company, nor to interfere in any way
with his or her right or that of the Company to terminate his or her services at
any time (subject to the terms of any applicable contract, law, regulation, and
the articles and bylaws of the Company).

         (b) No Optionee or Designated Beneficiary shall have any rights as a
shareholder with respect to any shares of Common Stock to be distributed under
the 1999 Plan until he or she has become the holder thereof.

         (c) The validity, construction, interpretation, administration and
effect of the 1999 Plan and of its rules and regulations, and rights relating to
the 1999 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.

         AMENDED AND RESTATED as of August 1, 2002.


                                            ZIX CORPORATION


                                            By: /s/ Ronald A. Woessner
                                                --------------------------------

                                            Title: S.V.P.
                                                  ------------------------------