AMENDED AND RESTATED SEVERANCE AGREEMENT

Exhibit 10.30

AMENDED AND RESTATED SEVERANCE AGREEMENT

          THIS AMENDED AND RESTATED SEVERANCE AGREEMENT (this “Agreement”), entered into as of December 18, 2008, is made and entered into between Zix Corporation, a Texas corporation (the “Company”), and David J. Robertson (“Employee”), and restates, amends, and supersedes that certain severance agreement between the parties dated February 1, 2003.

     WHEREAS, Employee is currently employed by the Company;

     WHEREAS, Employee is willing to continue working for the Company or an Affiliate, as applicable, on an “at will” basis, if applicable;

     NOW, THEREFORE, in consideration of the foregoing and of the respective covenants and agreements of the parties herein contained, the parties agree as follows:

1. Definitions .

     1.1 Acquiring Person . An “Acquiring Person” shall mean any person (including any “person” as such term is used in Sections 13(d)(3) or 14(d)(2) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) that, together with all Affiliates and Associates of such person, is the beneficial owner of 35% or more of the outstanding Common Stock of the Company. The term “Acquiring Person” shall not include the Company, any subsidiary of the Company, any employee benefit plan of the Company, (or trust with respect thereto) or subsidiary of the Company, or any person holding Common Stock of the Company for or pursuant to the terms of any such plan. For purposes of this Agreement, a person who becomes an Acquiring Person by acquiring beneficial ownership of 35% of more of the Common Stock at any time after the date of this Agreement shall continue to be an Acquiring Person whether or not such person continues to be the beneficial owner of 35% or more of the outstanding Common Stock.

     1.2 Affiliate and Associate . “Affiliate” and “Associate” shall have the respective meanings ascribed to such terms in Rule 12b-2 of the General Rules and Regulations under the Exchange Act in effect on the date of this Agreement.

     1.3 Cause . For “Cause” shall mean any of the following shall have occurred:

     (a) The conviction of Employee of any felony;

     (b) The intentional and. continued failure by Employee to substantially perform Employee’s employment duties, such intentional action involving willful and deliberate malfeasance or gross negligence in the performance of Employee’s duties (other than any such failure resulting from Employee’s incapacity due to physical or mental illness), after written demand for substantial performance, such demand not to be unreasonable, is delivered by the Company or an Affiliate, as applicable, that specifically identifies the manner in which the Company or the Affiliate, as applicable, believes Employee has not substantially performed Employee’s duties and which continues

beyond a period of 10 business days immediately after notice thereof by the Company to Employee;

     (c) The intentional wrongdoing by Employee that is materially injurious to the Company or employing Affiliate, as applicable; or

     (d) Acts by Employee of moral turpitude that are injurious to the Company.

     For purposes of this definition, no act, or failure to act, on the part of Employee shall be deemed to be “intentional” unless done, or omitted to be done, by Employee not in good faith and without reasonable belief that Employee’s action or omission was in the best interests of the Company or the employing Affiliate, or both, as applicable.

     1.4 Change in Control . A “Change in Control” of the Company shall have occurred if at any time during the term of this Agreement any of the following events shall occur:

     (a) The Company is merged, consolidated or reorganized into or with another corporation or other legal person, other than an Affiliate, and as a result of such merger, consolidation or reorganization less than 50.1’% of the combined voting power to elect directors of the then-outstanding securities of the remaining corporation or legal person or its ultimate parent immediately after such transaction is owned, directly or indirectly, in the aggregate by persons who were shareholders, directly or indirectly, of the Company immediately prior to such merger, consolidation, or reorganization;

     (b) The Company sells all or substantially all of its assets to any other corporation or other legal person, other than an Affiliate, and as a result of such sale, less than 50.1% of the combined voting power to elect directors of the then-outstanding securities of such corporation or legal person or its ultimate parent immediately after such transaction is owned, directly or indirectly, in the aggregate by persons who were shareholders, directly or indirectly, of the Company immediately prior to such sale;

     (c) Any Acquiring Person has become the beneficial owner (as the term “beneficial owner” is defined under Rule 13d-3 or any successor rule or regulation promulgated under the Exchange Act) of securities which when added to any securities already owned by such person would represent in the aggregate 35% or more of the then-outstanding securities of the Company which are entitled to vote to elect directors;

     (d) If, at any time, the Continuing Directors then serving on the Board of Directors of the Company (“Board”) cease for any reason to constitute at least a majority thereof;

     (e) Any occurrence that would be required to be reported in response to Item 6(e) of Schedule 14A of Regulation 14A or any successor rule or regulation promulgated under the Exchange Act; or

     (f) Such other events that cause a change in control of the Company, as determined by the Board in its sole discretion.

     1.5 Change in Control Payments . “Change in Control Payments” shall mean six months of base salary utilizing the higher of (i) Employee’s annual base salary in effect on the date of the Change in Control or (ii) Employee’s highest annual base salary during the term of Employee’s employment with the Company.

     1.6 Continuing Director . A “Continuing Director” shall mean a director of the Company who (i) is not an Acquiring Person, an Affiliate or Associate, a representative of an Acquiring Person or nominated for election by an Acquiring Person, and (ii) was either a member of ‘the Board on the date of this Agreement or subsequently became a director of the Company and whose initial election or initial nomination for election by the Company’s shareholders was approved by a majority of the Continuing Directors then on the Board.

     1.7 Good Reason . “Good Reason” shall mean the occurrence of the following event:

     (a) a cumulative reduction of more than 10% based on Employee’s highest annual base salary during the term of Employee’s employment with the Company.

EXAMPLE : Assume Employee’s base salary is $100,000. The Company or Affiliate, as applicable, is permitted to reduce Employee’s base salary by up to 10% ($10,000) wit