SUBSIDIARY GUARANTY AGREEMENT SUPPLEMENT

        SUBSIDIARY GUARANTY AGREEMENT SUPPLEMENT, dated as of April 19, 2004
(the “Supplement”), made by User Technology Associates, Inc., a Virginia
corporation (the “New Guarantor”), in favor of Bank of America, N.A., as
Administrative Agent (in such capacity, the “Administrative Agent”) under the
Credit Agreement (as defined in the Guaranty Agreement referred to below) for
the ratable benefit of itself and the Lenders (as defined in the Guaranty
Agreement referred to below).

        Section 1.    Reference is hereby made to the Subsidiary Guaranty
Agreement dated as of November 26, 2002 (as amended, restated supplemented or
otherwise modified as of the date hereof, the “Guaranty Agreement”), made by
certain subsidiaries of DigitalNet Holdings, Inc. (“Holdings”) and DigitalNet,
Inc. (the “Borrower”) party thereto on the Closing Date or otherwise joined as a
party thereto (such subsidiaries collectively, the “Guarantors”, and each, a
“Guarantor”), in favor of the Administrative Agent for the benefit of itself and
the Lenders. This Supplement supplements the Guaranty Agreement, forms a part
thereof and is subject to the terms thereof. Capitalized terms used and not
defined herein shall have the meanings given thereto or referenced in the
Guaranty Agreement.

        Section 2.    The New Guarantor hereby agrees to unconditionally
guarantee to the Administrative Agent, for the ratable benefit of itself and the
Lenders, and their respective successors, endorsees, transferees and assigns,
the prompt payment (whether at stated maturity, by acceleration or otherwise) of
all Obligations of the Borrower to the same extent and upon the same terms and
conditions as are contained in the Guaranty Agreement.

        Section 3.    The New Guarantor hereby agrees that by executing this
Supplement it is a party to the Guaranty Agreement as if a signatory thereto on
the Closing Date of the Credit Agreement, and the New Guarantor shall comply
with all of the terms, covenants, conditions and agreements and hereby makes
each representation and warranty, in each case set forth therein. The New
Guarantor agrees that the “Subsidiary Guaranty Agreement”, “Guaranty Agreement”
or “Guaranty” as used therein or in any other Loan Documents shall mean the
Guaranty Agreement as supplemented hereby.

        Section 4.    The New Guarantor hereby acknowledges it has received a
copy of the Guaranty Agreement and that it has read and understands the terms
thereof.

[Signature Page Follows]

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        IN WITNESS WHEREOF, the undersigned hereby causes this Supplement to be
executed and delivered as of the date first above written.

USER TECHNOLOGY ASSOCIATES, INC.

  By:  /s/ Ken S. Bajaj Name:  Ken S. Bajaj Title:  Chief Executive Officer and
President