1 CONSENT OF INDEPENDENT AUDITORS The Board of Directors S1 Corporation We consent to incorporation by reference in the current report on Form 8-K of S1 Corporation, of our report dated January 25, 1999, with respect to the consolidated balance sheets of Edify Corporation and subsidiary as of December 31, 1998, and 1997, and the related consolidated statements of operations, stockholders' equity, and cash flows for each of the years in the three-year period ended December 31, 1998, and the related schedule, which report appears in the December 31, 1998 annual report on Form 10-K of Edify Corporation. /s/ KPMG LLP Mountain View, California November 15, 1999