<PAGE>
 
                               POWER OF ATTORNEY
                                        


     KNOW ALL MEN BY THESE PRESENTS, that the undersigned constitutes and
appoints L. Barry Thomson, Gregory A. Lewis and John J. Neubert and each of
them, his true and lawful attorneys-in-fact and agents, with full power of
substitution, for him and in his name, place and stead, in any and all
capacities, to sign the Annual Report on Form 10-K of IVI Checkmate Corp. for
the fiscal year ended December 31, 1998, and any and all amendments thereto, and
to file the same, with all exhibits thereto and other documents in connection
therewith, with the Securities and Exchange Commission and the National
Association of Securities Dealers, Inc., granting unto said attorneys-in-fact
and agents, and each of them, full power and authority to do and perform each
and every act and thing requisite or necessary to be done, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any of them, or their
or his substitute or substitutes, may lawfully do or cause to be done by virtue
hereof.

     This 16th day of March, 1999.


                         /s/ George Whitton
                         ----------------------------------
                         George Whitton
<PAGE>
 
                               POWER OF ATTORNEY
                                        


     KNOW ALL MEN BY THESE PRESENTS, that the undersigned constitutes and
appoints L. Barry Thomson, Gregory A. Lewis and John J. Neubert and each of
them, his true and lawful attorneys-in-fact and agents, with full power of
substitution, for him and in his name, place and stead, in any and all
capacities, to sign the Annual Report on Form 10-K of IVI Checkmate Corp. for
the fiscal year ended December 31, 1998, and any and all amendments thereto, and
to file the same, with all exhibits thereto and other documents in connection
therewith, with the Securities and Exchange Commission and the National
Association of Securities Dealers, Inc., granting unto said attorneys-in-fact
and agents, and each of them, full power and authority to do and perform each
and every act and thing requisite or necessary to be done, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any of them, or their
or his substitute or substitutes, may lawfully do or cause to be done by virtue
hereof.

     This 16th day of March, 1999.


                         /s/ Gerard Compain
                         ----------------------------------
                         Gerard Compain
<PAGE>
 
                               POWER OF ATTORNEY
                                        


     KNOW ALL MEN BY THESE PRESENTS, that the undersigned constitutes and
appoints L. Barry Thomson, Gregory A. Lewis and John J. Neubert and each of
them, his true and lawful attorneys-in-fact and agents, with full power of
substitution, for him and in his name, place and stead, in any and all
capacities, to sign the Annual Report on Form 10-K of IVI Checkmate Corp. for
the fiscal year ended December 31, 1998, and any and all amendments thereto, and
to file the same, with all exhibits thereto and other documents in connection
therewith, with the Securities and Exchange Commission and the National
Association of Securities Dealers, Inc., granting unto said attorneys-in-fact
and agents, and each of them, full power and authority to do and perform each
and every act and thing requisite or necessary to be done, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any of them, or their
or his substitute or substitutes, may lawfully do or cause to be done by virtue
hereof.

     This 16th day of March, 1999.


                         /s/ Paul W. Noblett
                         ----------------------------------
                         Paul W. Noblett

<PAGE>
                               POWER OF ATTORNEY
                                        


     KNOW ALL MEN BY THESE PRESENTS, that the undersigned constitutes and
appoints L. Barry Thomson, Gregory A. Lewis and John J. Neubert and each of
them, his true and lawful attorneys-in-fact and agents, with full power of
substitution, for him and in his name, place and stead, in any and all
capacities, to sign the Annual Report on Form 10-K of IVI Checkmate Corp. for
the fiscal year ended December 31, 1998, and any and all amendments thereto, and
to file the same, with all exhibits thereto and other documents in connection
therewith, with the Securities and Exchange Commission and the National
Association of Securities Dealers, Inc., granting unto said attorneys-in-fact
and agents, and each of them, full power and authority to do and perform each
and every act and thing requisite or necessary to be done, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any of them, or their
or his substitute or substitutes, may lawfully do or cause to be done by virtue
hereof.

     This   day of March, 1999.


                         /s/ Gareth Owen
                         ----------------------------------
                         Gareth Owen
     
<PAGE>
 
 
                               POWER OF ATTORNEY
                                        


     KNOW ALL MEN BY THESE PRESENTS, that the undersigned constitutes and
appoints L. Barry Thomson, Gregory A. Lewis and John J. Neubert and each of
them, his true and lawful attorneys-in-fact and agents, with full power of
substitution, for him and in his name, place and stead, in any and all
capacities, to sign the Annual Report on Form 10-K of IVI Checkmate Corp. for
the fiscal year ended December 31, 1998, and any and all amendments thereto, and
to file the same, with all exhibits thereto and other documents in connection
therewith, with the Securities and Exchange Commission and the National
Association of Securities Dealers, Inc., granting unto said attorneys-in-fact
and agents, and each of them, full power and authority to do and perform each
and every act and thing requisite or necessary to be done, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any of them, or their
or his substitute or substitutes, may lawfully do or cause to be done by virtue
hereof.

     This 15th day of March, 1999.


                         /s/ Peter E. Roode
                         ----------------------------------
                         Peter E. Roode