December 18, 2008

S1 Corporation (NASDAQ: SONE) , a leading global provider of customer interaction financial and payment solutions, today announced the appointment of Paul Parrish as its Chief Financial Officer. Mr. Parrish brings more than 26 years of experience in corporate finance, accounting, financial planning and analysis, and financial reporting to S1. Mr. Parrish will join S1 on January 12, 2009.

"We are extremely pleased to have Paul join the S1 management team," said Johann Dreyer, Chief Executive Officer of S1 Corporation. "His skills and experience as a financial executive, along with his understanding of the financial services software industry, will be invaluable in helping S1 achieve its business objectives."

Mr. Parrish joins S1 from Infor Global Solutions, a global enterprise software company, where he served as Senior Vice President, Controller and Principal Accounting Officer. Prior to this role, Mr. Parrish spent ten years at the John H. Harland Company where he served in various roles including most recently as Senior Vice President of Finance, Information Technology and Chief Financial Officer of their Printed Products Division, and the Vice President and Chief Financial Officer of their Software and Services Division.