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                                                                     EXHIBIT 5.1

                               December 16, 1999

E-SYNC NETWORKS, INC.
35 Nutmeg Drive
Trumbull, Connecticut 06611

RE: REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

     We have acted as counsel to E-Sync Networks, Inc., a Delaware corporation,
successor by merger to Wiltek, Inc. (the "Company"), in connection with the
preparation and filing with the Securities and Exchange Commission of a
registration statement on Form S-8 (the "Registration Statement") of the
Company, covering (i) 393,000 shares of the Common Stock, $.01 par value, of the
Company, to be issued pursuant to the Company's 1994 Employees' Stock Option
Plan, as amended (the "1994 Plan"), and (ii) 750,000 shares of Common Stock to
be issued pursuant to the Company's 1999 Long-Term Incentive Plan (collectively
referred to with the 1994 Plan as the "Plans").

     In rendering the opinion set forth herein, we have examined executed
copies, telecopies or photocopies of: (i) the Registration Statement and the
Plans; (ii) the certificate of incorporation of the Company, as amended, the
By-laws of the Company, as amended, and excerpts from the minute books of the
Company; and (iii) such other records, documents, certificates and other
instruments which in our judgment are necessary or appropriate as a basis for
the opinion expressed below. In our examination of such documents we have
assumed the genuineness of all signatures, the legal capacity of natural
persons, the authenticity of all documents submitted to us as originals, the
conformity to original documents of all documents submitted to us as certified
or photostatic copies, and the authenticity of the originals of such copies. As
to any facts material to this opinion which we did not independently establish
or verify, we have relied upon statements and representations of officers and
other representatives of the Company.

     Based upon the foregoing, and in reliance thereon, and subject to the
qualifications, assumptions and exceptions heretofore and hereinafter set forth,
we are of the opinion that, upon the issuance of the shares of Common Stock in
accordance with the Plans (and in accordance with the terms of any awards and
agreements which are issued or entered into pursuant to the terms and conditions
of the Plans) and as contemplated by the Registration Statement, such shares
will be validly issued, fully paid and non-assessable.

     We do not express, or purport to express, any opinion with respect to the
laws of any jurisdiction other than the General Corporation Law of the State of
Delaware and the federal securities laws of the United States of America.

     We hereby consent to the filing of this letter as an exhibit to the
Registration Statement and further consent to the use of our name wherever
appearing in the Registration Statement. In giving this consent, we do not
thereby admit that we are in the category of persons whose consent is required
under Section 7 of the Securities Act of 1933, as amended, or the rules and
regulations promulgated thereunder by the Securities and Exchange Commission.
This opinion is given as of the date hereof and we assume no obligation to
update or supplement this opinion to reflect any facts or circumstances which
may hereafter occur or come to our attention or any changes in law which may
hereafter occur.

                                          Very truly yours,

                                             /s/ FINN DIXON & HERLING LLP
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