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                                                                   EXHIBIT 3.1.4

                           AUTHENTIDATE HOLDING CORP.

                           CERTIFICATE OF AMENDMENT TO

                  CERTIFICATE OF DESIGNATIONS, PREFERENCES AND
                     RIGHTS AND NUMBER OF SHARES OF SERIES C
                           CONVERTIBLE PREFERRED STOCK

      The undersigned President and Secretary, respectively, of AUTHENTIDATE
HOLDING CORP., a Delaware corporation (the "Corporation"), hereby certify that
pursuant to authority granted to and vested in the Board of Directors of the
corporation by the provisions of the Certificate of Incorporation and in
accordance with the provisions of Section 151, 228 and 242 of the General
Corporation Law of the State of Delaware, as follows:

      FIRST: That the Board of Directors of said corporation by the unanimous
written consent of its members, filed with the minutes of the Board on May 16,
2001 duly adopted a resolution authorizing and directing the following
amendments to the Certificate of Designations, Rights and Preferences and Number
of Series C Convertible Preferred Stock (the "Certificate of Designation") of
said corporation:

            RESOLVED, that the Certificate of Designation of Authentidate
      Holding Corp be amended by (1) increasing the number of shares designated
      as SERIES C CONVERTIBLE PREFERRED STOCK, from 4,000 shares to 9,000
      shares; (2) changing the definition of "Conversion Price" set forth in
      Article 1; and (3) changing Article 6(a) thereof so that, as amended the
      definition of "Conversion Price" set forth in Article 1 and Article 6(a)
      shall be and read as follows:

            1.    CERTAIN DEFINITIONS

            Conversion Price: The term "Conversion Price" shall mean the price
            at which shares of Common Stock shall be delivered upon the
            conversion of the Series C Shares, which price shall be initially
            $4.845, subject to the adjustments set out in Section 6 of this
            Certificate of Designation.

            6.    CONVERSION RIGHTS

            The Series C Preferred Stock shall be convertible into Common Stock
            as follows:

                  (a) Voluntary Conversion. Subject to and upon compliance with
            the provisions of this Section 6, unless previously redeemed by the
            Corporation, the Holders have the right, at such Holder's option, at
            any time, and from time to time, commencing on the earlier of (a)
            one year from the Issue Date or (b) the effective
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            date of a registration statement filed with the Securities and
            Exchange Commission covering the issuance and resale of the
            Conversion Shares, to convert such Holder's shares of Series C
            Preferred Stock into fully paid and nonassessable shares of Common
            Stock. The number of shares of Common Stock issuable upon conversion
            of each share of this Series C Preferred Stock shall be equal to the
            Issue Price divided by the Conversion Price in effect at the time of
            conversion, determined as hereinafter provided. The price at which
            shares of Common Stock shall be delivered upon conversion shall be
            initially $4.845 (subject to the adjustments set out in this Section
            6). The right to convert shares called for redemption pursuant to
            Section 5 shall terminate on the earlier of five years from the
            Issue Date or the close of business on the date fixed for such
            redemption unless the Corporation shall default in making payment of
            the amount payable upon such redemption.

      SECOND: That in lieu of a meeting and vote of the holders of the
outstanding shares of Series C Convertible Preferred Stock, the holders of such
shares of preferred stock have given their written consent to said amendment in
accordance with the provisions of Section 228 of the General Corporation Law of
the State of Delaware.

      THIRD: That the aforesaid amendment was duly adopted in accordance with
the applicable provisions of Sections 242 and 228 of the General Corporation Law
of the State of Delaware.

      IN WITNESS WHEREOF, this Certificate of Amendment has been made under the
seal of the Corporation and the hands of the undersigned on May 21, 2001.


                                           /s/ John T. Botti
                                          ---------------------------------
                                          Name: John T. Botti
                                          Title:   President
Attest:

/s/ Ira C. Whitman
----------------------------------
Name: Ira C. Whitman
Title: Secretary


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