Exhibit 32.2 CERTIFICATION OF CHIEF FINANCIAL OFFICER PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 In connection with the Quarterly Report of Transaction Systems Architects, Inc. (the "Company") on Form 10-Q for the fiscal quarter ended December 31, 2004 as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, David R. Bankhead, Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge: 1) The Report fully complies with the requirements of Sections 13(a) or 15(d) of the Securities Exchange Act of 1934; and 2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. Date: February 8, 2005 By: /s/ DAVID R. BANKHEAD ------------------------------------- David R. Bankhead Senior Vice President, Chief Financial Officer and Treasurer