Exhibit 3.2

THIRD AMENDED AND RESTATED BYLAWS

ZIX CORPORATION

ARTICLE I

OFFICES

SECTION 1. REGISTERED OFFICE. The registered office shall be established and maintained at the office of Corporation Service Company d/b/a CSC-Lawyers Incorporating Service Company, in the City of Austin, in Travis County, in the State of Texas, and said corporation shall be the registered agent of this corporation (the “Corporation”) in charge thereof.

SECTION 2. OTHER OFFICES. The Corporation may have other offices, either within or without the State of Texas, at such place or places as the board of directors of the Corporation (the “Board of Directors”) may from time to time appoint or the business of the Corporation may require.

ARTICLE II

MEETING OF STOCKHOLDERS

SECTION 1. ANNUAL MEETINGS. Annual meetings of stockholders for the election of directors, and for such other business as may be stated in the notice of the meeting, shall be held at such place, either within or without the State of Texas, and at such time and date as the Board of Directors, by resolution, shall determine and as set forth in the notice of the meeting. At each annual meeting, the stockholders entitled to vote shall elect a Board of Directors and they may transact such other corporate business as shall be stated in the notice of the meeting.

SECTION 3. VOTING. Each stockholder entitled to vote in accordance with the terms of the Certificate of Formation and in accordance with the provisions of these Bylaws shall be entitled to one vote, in person or by proxy, for each share of stock entitled to vote held by such stockholder, but no proxy shall be voted after three years from its date unless such proxy provides for a longer period. Upon the demand of any stockholder, the vote for directors and the vote upon any question before the meeting shall be by ballot. All elections for directors shall be decided by plurality vote; all questions shall be decided by majority vote except as otherwise provided by the Certificate of Formation or the laws of the State of Texas.

A complete list of the stockholders entitled to vote at the ensuing election, arranged in alphabetical order, with the address of each and the number of shares held by each, shall be open to the examination of any stockholder for any purpose germane to the meeting during ordinary business hours, for a period of at least ten days beginning on the tenth day prior to the meeting, either at a place within the city where the meeting is to be held, which place shall be specified in the notice of the meeting or, if not so specified, at the place where the meeting is to be held. This list shall also be produced and kept at the meeting and place of the meeting during the whole time thereof and may be inspected by any stockholder who is present.

SECTION 4. QUORUM. Except as otherwise required by law, by the Certificate of Formation or by these Bylaws, the presence, in person or by proxy, of stockholders holding a majority of the stock of the Corporation entitled to vote shall constitute a quorum at all meetings of the stockholders. In case a quorum shall not be present at any meeting, a majority in interest of the stockholders entitled to vote thereat, present in person or by

proxy, shall have the power to adjourn the meeting from time to time, without notice other than announcement at the meeting, until the requisite amount of stock entitled to vote shall be present. At any such adjourned meeting at which the requisite amount of stock entitled to vote shall be represented, any business may be transacted which might have been transacted at the meeting as originally noticed; provided, however, that only those stockholders entitled to vote at the meeting as originally noticed shall be entitled to vote at any adjournment or adjournments thereof.

SECTION 5. SPECIAL MEETINGS. Special meetings of the stockholders for any purpose or purposes may be called by the President or Secretary of the Corporation or by resolution of the Board of Directors.

SECTION 6. NOTICE OF MEETINGS. Written notice, stating the place, date and time of the meeting, and the general nature of the business to be considered, shall be given to each stockholder entitled to vote thereat at his, her or its address as it appears in the records of the Corporation not less than ten nor more than sixty days before the date of the meeting. No business other than that stated in the notice shall be transacted at any meeting without the unanimous consent of all the stockholders entitled to vote thereat.

SECTION 7. ACTION WITHOUT MEETING. Unless otherwise provided by the Certificate of Formation, any action required to be taken at any annual or special meeting of stockholders, or any action which may be taken at any annual or special meeting, may be taken without a meeting, without prior notice and without a vote, if a consent in writing setting forth the action so taken shall be signed by the holders of outstanding stock having not less than the minimum number of votes that would be necessary to authorize or take such action at a meeting at which all shares entitled to vote thereon were present and voted. Prompt notice of the taking of the corporate action without a meeting by less than unanimous written consent shall be given to those stockholders who have not consented in writing.

ARTICLE III

DIRECTORS

SECTION 1. NUMBER AND TERM. The number of directors shall be not less than one nor more than five. The first Board of Directors shall consist of two directors. Thereafter, within the limits specified above, the number of directors shall be determined by the Board of Directors. The directors shall be elected at the annual meeting of the stockholders and each director shall be elected to serve until his or her successor shall be elected and takes office. Directors need not be stockholders.

SECTION 2. RESIGNATIONS. Any director or member of a committee of the Board of Directors may resign at any time. Such resignation shall be made in writing and shall take effect at the time specified therein, or if no time is specified, at the time of its receipt by the President or Secretary of the Corporation. The acceptance of a resignation shall not be necessary to make it effective.

SECTION 3. VACANCIES. If the office of any director or member of a committee of the Board of Directors becomes vacant, the remaining directors in office, though less than a quorum, by a majority vote, may appoint any qualified person to fill such vacancy and such person shall hold office for the unexpired term and until his or her successor shall be duly chosen.

SECTION 4. REMOVAL. Except as hereinafter provided, any director or directors may be removed either for or without cause at any time by the affirmative vote of the holders of a majority of all the shares of stock outstanding and entitled to vote at a special meeting of the stockholders called for the purpose and the vacancies thus created may be filled at the meeting held for the purpose of removal by the affirmative vote of a majority in interest of the stockholders entitled to vote.

SECTION 5. INCREASE OF NUMBER. The number of directors may be increased by amendment of these Bylaws by the affirmative vote of a majority of the directors, though less than a quorum, or by the affirmative vote of a majority interest of the stockholders at the annual meeting or at a special meeting called for that purpose, and by like vote the additional directors may be chosen at such meeting to hold office until the next annual election and until their successors are elected and qualify.

SECTION 6. POWERS. The Board of Directors shall exercise all of the powers of the Corporation, except such as are by law, by the Certificate of Formation or by these Bylaws conferred upon or reserved to the stockholders.

SECTION 7. COMMITTEES. The Board of Directors may, by resolution or resolutions passed by a majority of the whole board, designate one or more committees consisting of one or more directors of the Corporation. The Board of Directors may designate one or more directors as alternate members of any committee who may replace any absent or disqualified member at any meeting of the committee. In the absence or disqualification of any member of such committee or committees, the member or members thereof present at any meeting and not disqualified from voting, whether or not he, she or they constitute a quorum, may unanimously appoint another member of the Board of Directors to act at the meeting in the place of any such absent or disqualified member.

Any such committee, to the extent provided in the resolution of the Board of Directors creating such committee or in these Bylaws, shall have and may exercise all the powers and authority of the Board of Directors in the management of the business and affairs of the Corporation and may authorize the seal of the Corporation to be affixed to all papers which may require it; provided, however, that no such committee shall have the power or authority in reference to amending the Certificate of Formation, adopting an agreement of merger or consolidation, recommending to the stockholders the sale, lease or exchange of all or substantially all of the Corporation’s property and assets, recommending to the stockholders a dissolution of the Corporation or a revocation of a dissolution or amending these Bylaws of the Corporation; and, unless the resolution, these Bylaws or the Certificate of Formation expressly so provide, no such committee shall have the power or authority to declare a dividend or to authorize the issuance of stock.

SECTION 8. MEETINGS. The newly elected directors may hold their first meeting for the purposes of organization and the transaction of business, if a quorum be present, immediately after the annual meeting of the stockholders or, alternatively, the time and place of such meeting may be fixed by consent in writing of all the directors.

Regular meetings of the directors may be held without notice at such places and times as shall be determined from time to time by resolution of the directors.

Special meetings of the Board of Directors may be called by the President or by the Secretary of the Corporation on the written request of any two directors on at least two days’ prior written notice to each director and shall be held at such place or places as may be determined by the director or as may be stated in the notice of the meeting.

Unless otherwise restricted by the Certificate of Formation or by these Bylaws, members of the Board of Directors, or any committee designated by the Board of Directors, may participate in a meeting of the Board of Directors, or any such committee, by means of telephone conference or similar communications equipment by means of which all persons participating in the meeting can hear each other and such participation in a meeting shall constitute presence in person at the meeting.

SECTION 9. QUORUM. A majority of the directors shall constitute a quorum for the transaction of business. If at any meeting of the Board of Directors there shall be less than a quorum present, a majority of those present may adjourn the meeting from time to time until a quorum is obtained and no further notice thereof need be given other than by announcement at the meeting which shall be so adjourned.

SECTION 10. COMPENSATION. Directors shall not receive any stated salary for their services as directors or as members of committees; provided, however, that, by resolution of the Board of Directors, a fixed fee and expenses of attendance may be allowed for attendance at each meeting. Nothing herein contained shall be construed to preclude any director from serving the Corporation in any other capacity, as an officer, agent or otherwise, and receiving compensation therefor.

SECTION 11. ACTION WITHOUT MEETING. Any action required or permitted to be taken at any meeting of the Board of Directors, or of any committee thereof, may be taken without a meeting if prior to such action a written consent thereto is signed by all members of the Board of Directors or of such committee, as the case may be, and such written consent is filed with the minutes of proceedings of the Board of Directors or such committee.

ARTICLE IV

OFFICERS

SECTION 1. OFFICERS. The officers of the Corporation shall be a President, a Treasurer and a Secretary, all of whom shall be elected by the Board of Directors from time to time and who shall hold office until their successors are elected and qualified. In addition, the Board of Directors may elect a Chairman, one or more Vice Presidents and one or more Assistant Secretaries and Assistant Treasurers as they may deem proper. None of the officers of the Corporation need be directors. The officers shall be elected at the first meeting of the Board of Directors after each annual meeting. More than two offices may be held by the same person.

SECTION 2. RESIGNATIONS. Any officer may resign at any time. Such resignation shall be made in writing and shall take effect at the time specified therein, or if no time is specified, at the time of its receipt by the President, Secretary or Chairman of the Board of Directors of the Corporation. The acceptance of a resignation shall not be necessary to make it effective.

SECTION 3. REMOVAL. Except as hereinafter provided, any officer or officers may be removed either for or without cause at any time by the Board of Directors.

SECTION 4. OTHER OFFICERS AND AGENTS. The Board of Directors may appoint such other officers and agents as it may deem advisable, who shall hold their offices for such terms and shall exercise such powers and perform such duties as shall be determined from time to time by the Board of Directors.

SECTION 5. CHAIRMAN. The Chairman of the Board of Directors, if one is elected, shall preside at all meetings of the Board of Directors and he or she shall have and perform such other duties as from time to time may be assigned to him or her by the Board of Directors.

SECTION 6. PRESIDENT. The President shall be the chief executive officer of the Corporation and shall have the general powers and duties of supervision and management usually vested in the office of President of a corporation. He or she shall preside at all meetings of the stockholders if present thereat and, in the absence or nonelection of the Chairman of the Board of Directors, at all meetings of the Board of Directors, and shall have general supervision, direction and control of the business of the Corporation. Except as the Board of Directors shall authorize the execution thereof in some other manner, he or she shall execute bonds, mortgages and other contracts on behalf of the Corporation and shall cause the seal to be affixed to any instrument requiring it and when so affixed the seal shall be attested by the signature of the Secretary or the Treasurer or an Assistant Secretary or an Assistant Treasurer.

SECTION 7. VICE PRESIDENT. Each Vice President shall have such powers and shall perform such duties as shall be assigned to him or her by the directors.

SECTION 8. TREASURER. The Treasurer shall have the custody of the corporate funds and securities and shall keep full and accurate account of receipts and disbursements in books belonging to the Corporation. He or she shall deposit all moneys and other valuables in the name and to the credit of the Corporation in such depositaries as may be designated by the Board of Directors.

The Treasurer shall disburse the funds of the Corporation as may be ordered by the Board of Directors or the President, taking proper vouchers for such disbursements. He or she shall render to the President and the Board of Directors at the regular meetings of the Board of Directors, or whenever they may request it, an account of all of his or her transactions as Treasurer and of the financial condition of the Corporation. If required by the Board of Directors, he or she shall give the Corporation a bond for the faithful discharge of his or her duties in such amount and with such surety as the Board of Directors shall prescribe.

SECTION 9. SECRETARY. The Secretary shall give, or cause to be given, notice of all meetings of stockholders and directors and all other notices required by law or by these Bylaws. In case of his or her absence or refusal or neglect so to do, any such notice may be given by any person thereunto directed by the President. He or she shall record all the proceedings of the meetings of the Corporation and of the directors in a book to be kept for that purpose and shall perform such other duties as may be assigned to him or her by the directors or the President. He or she shall have the custody of the seal of the Corporation and shall affix the same to all instruments requiring it, when authorized by the directors or the President, and attest the same.

SECTION 10. ASSISTANT TREASURERS AND ASSISTANT SECRETARIES. Assistant Treasurers and Assistant Secretaries, if any, shall be elected and shall have such powers and shall perform such duties as shall be assigned to them, respectively, by the directors.

ARTICLE V

MISCELLANEOUS

SECTION 1. UNCERTIFICATED SHARES. Shares of the Corporation’s stock shall be issued in uncertificated form.

SECTION 2. TRANSFER OF SHARES. The shares of the Corporation’s stock shall be transferable only upon its books by the holders thereof in person or by their duly authorized attorneys or legal representatives. A record shall be made of each transfer and, whenever a transfer shall be made for collateral security and not absolutely, it shall be so expressed in the entry of the transfer.

SECTION 3. STOCKHOLDERS RECORD DATE. In order that the Corporation may determine the stockholders entitled to notice of or to vote at any meeting of stockholders or any adjournment thereof, or to express consent to corporate action in writing without a meeting, or entitled to receive payment of any dividend or other distribution or allotment of any rights, or entitled to exercise any rights in respect of any change, conversion or exchange of stock or for the purpose of any other lawful action, the Board of Directors may fix, in advance, a record date, which shall not be more than sixty nor less than ten days before the date of such meeting or more than sixty days prior to any other action. A determination of stockholders of record entitled to notice of or to vote at a meeting of stockholders shall apply to any adjournment of the meeting; provided, however, that the Board of Directors may fix a new record date for the adjourned meeting.

SECTION 4. DIVIDENDS. Subject to the provisions of the Certificate of Formation, the Board of Directors may, out of funds legally available therefor declare dividends upon the capital stock of the Corporation as and when they deem expedient. Before declaring any dividend, there may be set apart out of any funds of the Corporation available for dividends such sum or sums as the directors from time to time in their discretion deem proper for working capital or as a reserve fund to meet contingencies or for equalizing dividends or for such other purposes as the directors shall deem conducive to the interests of the Corporation.

SECTION 5. SEAL. The corporate seal shall be circular in form and shall contain the name of the Corporation, the year of its creation and the words “CORPORATE SEAL TEXAS”. Said seal may be used by causing it or a facsimile thereof to be impressed or affixed or reproduced or otherwise.

SECTION 6. FISCAL YEAR. The fiscal year of the Corporation shall be determined by resolution of the Board of Directors.

SECTION 7. CHECKS. All checks, drafts or other orders for the payment of money, notes or other evidences of indebtedness issued in the name of the Corporation shall be signed by such officer or officers or agent or agents of the Corporation and in such manner as shall be determined from time to time by resolutions of the Board of Directors.

SECTION 8. NOTICE AND WAIVER OF NOTICE. Whenever any notice is required by these Bylaws to be given, personal notice is not meant unless expressly so stated and any notice so required shall be deemed to be sufficient if given by depositing the same in the United States mail, postage prepaid, addressed to the person entitled thereto at his or her address as it appears on the records of the Corporation and such notice shall be deemed to have been given on the day of such mailing. Stockholders not entitled to vote shall not be entitled to receive notice of any meetings except as otherwise provided by statute.

Whenever any notice whatsoever is required to be given under the provisions of any law or under the provisions of the Certificate of Formation or these Bylaws, a waiver thereof in writing signed by the person or persons entitled to said notice, whether before or after the time stated therein, shall be deemed equivalent thereto.

ARTICLE VI

AMENDMENTS

These Bylaws may be altered or repealed and Bylaws may be made (i) at any annual meeting of the stockholders (or at any special meeting thereof if notice of the proposed alteration or repeal or Bylaw or Bylaws to be made is contained in the notice of such special meeting) by the affirmative vote of a majority of the stock issued and outstanding and entitled to vote thereat or (ii) by the affirmative vote of a majority of the Board of Directors, at any regular meeting of the Board of Directors (or at any special meeting of the Board of Directors if notice of the proposed alteration or repeal or Bylaw or Bylaws to be made is contained in the notice of such special meeting) or (iii) by action of the stockholders or the Board of Directions without a meeting as permitted by the laws of the State of Texas, the Certificate of Formation and these Bylaws.

ZIX CORP 8-K