Zix (ZIXI) 8-K Departure of Directors or Principal Officers

Exhibit 17.1

Ben G. Streetman

3915 Glengarry
Austin, TX 78731
(512) 453 9612 at UT Austin
(512) 471 1166

February 14, 2007

Richard D. Spurr
Zix Corp.
2711 N. Haskell Ave.
Suite 2200
Dallas, TX 75204-2911

Dear Rick,

I hereby resign from the Board of Directors of Zix Corp. effective April 4, 2007.

I appreciate the opportunity to serve on the Board and wish you well in your leadership of the company.

Warmest regards,

/s/ Ben Streetman

Ben Streetman

cc: Ron Woessner