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                                                                    EXHIBIT 10.3

                                 S1 CORPORATION

                                    AMENDMENT
                                       TO
                     SECURITY FIRST TECHNOLOGIES CORPORATION
                   AMENDED AND RESTATED 1995 STOCK OPTION PLAN

       The Security First Technologies Corporation Amended and Restated 1995
Stock Option Plan, as amended (the "Plan") is hereby amended as set forth below:

       1.     The Name of the Plan is changed to the S1 Corporation Amended and
Restated 1995 Stock Option Plan and references in the Plan to Security First
Technologies Corporation shall be deemed to refer to S1 Corporation.

       2.     The third sentence of Section 10(c) of the Plan is amended to read
in its entirety as follows:

              Payment of the Option Price for the shares of Stock purchased
              pursuant to the exercise of an Option shall be made (i) in cash or
              in cash equivalents; (ii) through the tender to the Company of
              shares of Stock that have been held by the Optionee for at least
              six months, which shares shall be valued, for purposes of
              determining the extent to which the Option Price has been paid
              thereby, at their fair market value (determined in the manner
              described in Section 9 above) on the date of exercise; (iii) by
              delivering a written direction to the Company that the Option be
              exercised pursuant to a "cashless" exercise/sale procedure
              (pursuant to which funds to pay for exercise of the option are
              delivered to the Company by a broker upon receipt of stock
              certificates from the Company) or a cashless exercise/loan
              procedure (pursuant to which the optionees would obtain a margin
              loan from a broker to fund the exercise) through a licensed broker
              acceptable to the Company whereby the stock certificate or
              certificates for the shares of Stock for which the Option is
              exercised will be delivered to such broker as the agent for the
              individual exercising the Option and the broker will deliver to
              the Company cash (or cash equivalents acceptable to the Company)
              equal to the Option Price for the shares of Stock purchased
              pursuant to the exercise of the Option plus the amount (if any) of
              federal and other taxes that the Company, may, in its judgment, be
              required to withhold with respect to the exercise of the Option;
              or (iv) by a combination of the methods described in (i), (ii),
              and (iii); provided, however, that the Board may in its discretion
              impose and set forth in the Option Agreement such limitations or
              prohibitions on the use of shares of Stock to exercise Options as
              it deems appropriate.


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       3.     The Plan shall otherwise be unchanged by this Amendment.

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       The foregoing Amendment to the Plan was duly adopted and approved by the
Board of Directors of the Corporation by resolution at a meeting held on
December 16, 1999.

                                            /s/ Nancy Kenley
                                            ----------------------------------
                                            Secretary

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