[Letterhead of The Ashton Technology Group, Inc.]






                                  May 15, 1996




Computer Science Innovations, Inc.
1235 Evans Road
Melbourne, FL  32904-2314

Attention:        Mr. George Milligan
                  President

Subject:  Extension of Letter Contract No. ASH-LC12111

Gentlemen:

1.  Order:  An order is hereby  placed with you to continue to furnish to Ashton
Technology  Group,  Inc. the software required for the encryption server for the
Ashton Technology  Encryption Device (ATED). The detailed  requirements for this
work are as set forth in  Exhibit A  (Letter  Contract  of  December  11,  1995)
attached  hereto and  hereby  made a part  hereof.  This  order  shall  become a
contract on the terms and conditions set forth in the December 11, 1995 contract
upon your  unconditional  acceptance hereof, and shall be deemed effective as of
MAY 15. 1996.

2.       Negotiation of Definitive Contract:

         a. By your acceptance of this order, you agree to enter into good faith
negotiations immediately with Ashton Technology Group, Inc. with the expectation
of the execution of a definitive contract which will include mutually acceptable
detailed  prices,  delivery  schedules and other terms of this Letter  Contract,
provided,  however,  that the total price for the definitive  contract shall not
exceed U.S. $506,266.00.
         b. It is expected that such definitive contract will be issued prior to
DECEMBER  31,  1996.  If we fail to agree upon the  definitive  contract by said
date, this Letter Contract shall terminate automatically and you will be paid on
the  same  terms  as if this  Letter  Contract  had been  terminated  by  Ashton
Technology Group, Inc. for its convenience.

     3.  Acceptance:  If the foregoing is  satisfactory  to you, please indicate
your  acceptance  hereof by signing and returning the enclosed extra copy.  Such
acceptance  will  constitute  this as a contract on the terms and conditions set
forth herein.

                                      Very truly yours,




Ashton Technology Group, Inc.        Accepted this 15 day of May, 1996
                                     Computer Science Innovations, Inc.




By:    /s/ John A. Blohm             By:     /s/ George Milligan
       (Signature)                           (Signature)




for Raymond T. Tate                  George H. Milligan
President                            President


<PAGE>



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                [Letterhead of The Ashton Technology Group, Inc.]
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December 16, 1996


Computer Science Innovations, Inc.
1235 Evans Road
Melbourne, FL  32904-2314

Attention:        Mr. George Milligan
                  President

Subject:  Contract No. ASH-LC112111 dated December 11, 1995

Gentlemen:

Reference  subject  contract,  the  provisions  of  limitation of funds shown in
Paragraph 3(b) is hereby  amended to decrease the spending  ceiling to $404,603.
In addition,  the provisions of paragraph 4 are hereby modified to indicate that
a definitized  contract  (valued at $404,603) is hereby  completed (see enclosed
spreadsheet) and that the contract end date has been determined to be 31 January
1997.

If the foregoing is satisfactory to you, please indicate your acceptance  hereof
by signing and  returning  the enclosed  extra copy.  Upon your  acceptance  and
signature,  this letter will constitute an amendment to the referenced  contract
and will supersede all previous amendments to the referenced contract.
Telefacsimile signatures shall be effective as originals.

Very truly yours,



Ashton Technology Group, Inc.       Accepted this 20 day of December, 1996
                                    Computer Science Innovations, Inc.



By:    /s/ F. Rittereiser           By:     /s/ George Milligan
       (Signature)                          (Signature)



Mr. Fred Rittereiser                Mr. George Milligan
President                           President



Universal Trading Technologies, Inc.



By:    /s/ Fred Weingard 12-16-96
       (Signature)



Mr. Fred S. Weingard
Executive Vice President


<PAGE>



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                [Letterhead of The Ashton Technology Group, Inc.]
--------------------------------------------------------------------------------


February 5, 1997

Computer Science Innovations, Inc.
1235 Evans Road
Melbourne, FL  32904-2314

Attention:        Mr. George Milligan
                  President

Subject: Contract No. ASH-LC12111

Reference:        (1) Contract No. ASH-LC12111 dated December 11, 1995
                  (2) Contract Definition dated December 16, 1996

Gentlemen:

Reference (2) modifies and defines  reference (1). The purpose of this letter is
to provide a cost & time  extension to  definitized  contract  ASH-LC10261.  The
basis of  estimate  (BOE) and terms &  conditions  (T&Cs) are  attached  to this
letter.  Paragraph 3(b) is hereby amended to decrease the spending  ceiling from
$404,603 to $393,911.  In  addition,  the  provisions  of Paragraph 4 are hereby
modified  to  indicate a new  definitized  contract  (valued at  $393,911)  that
incorporates  the  attached BOE and T&Cs and has a contract end date shall be 28
March 1997.

If the foregoing is satisfactory to you, please indicate your acceptance  hereof
by signing and  returning  the enclosed  extra copy.  Upon your  acceptance  and
signature,   this  letter  will  constitute  an  incremental  amendment  to  the
referenced contract. Telefacsimile signatures shall be effective as originals.

Very truly yours,


Ashton Technology Group, Inc.        Accepted this 18 day of Feb 1996
                                     Computer Science Innovations, Inc.



By:    /s/ Fred Rittereiser          By:     /s/ George Milligan
       (Signature)                           (Signature)



Mr. Fred Rittereiser                 Mr. George Milligan
President                            President



Universal Trading Technologies, Inc.



By:    /s/ Fred Weingard 2-18-97
       (Signature)



Mr. Fred S. Weingard
Executive Vice President