SCHENECTADY, N.Y.
May 20, 2004

Authentidate International AG, a subsidiary of Authentidate Holding Corp. (Nasdaq:ADAT), announced today that it has entered into a five-year agreement with John Deere Central Services, Mannheim, Germany, to provide an European-wide eBilling Signature Solution for processing and distributing electronic invoices, compliant with stringent European legal and tax regulations.

Using the Authentidate eBilling Signature Solution, Deere & Company (NYSE:DE), the world's leading manufacturer of agricultural and forestry equipment and a leading manufacturer of construction equipment and equipment used in lawn, grounds and turf care, will realize economic benefits from the conversion of paper-based invoicing to electronic invoice processing and distribution in Europe. Initial rollout this year is planned for Germany, followed by other European countries. Authentidate will generate revenues through recurring runtime license fees and transaction fees.

About Authentidate Holding Corp.

Authentidate Holding Corp. (AHC) is the holding company of five business units; DocStar, Authentidate International AG, Authentidate, Inc., DJS Marketing Group/Computer Professionals International and Trac Medical Solutions, Inc. DocStar sells proprietary document imaging software that includes the Authentidate technology. Authentidate and Authentidate AG provide the authentication of digital data through its proprietary and patent pending technology. Authentidate intends to establish itself as the authority on "content security" as it is a growing sector of the electronic network security infrastructure market. DJS delivers professional services centered around technology systems integration projects, staff augmentation, out-tasking, outsourcing services and resells computer related products. Trac Medical offers an electronic form processing solution and utilizes the Authentidate technology to prove the authenticity of the content represented in completed healthcare forms.

About Authentidate International AG

Authentidate International AG (www.Authentidate.de), Dusseldorf, Germany is the first accredited certification provider, certified by the German Regulatory Authority for Telecommunications and Posts (RegTP), providing legally-binding timestamps compliant with German electronic signature laws and European signature directives.

Authentidate International is also the first accredited vendor for providing business process solutions utilizing electronic signatures and timestamping technology. These solutions feature easy integration, high economic efficiency, platform independence and protection of investment.

The Authentidate solutions are used by well-known companies in different industries. The customers utilize the signature solutions to obtain legal security for eBilling, archiving, scanning and workflow processes.

Authentidate International is present in Europe, USA and also through partners in Asia. Authentidate Holding Corp, Inc. located in USA (New York) is listed on the Nasdaq National Market (ADAT) and in Germany (WKN 893715).

This press release contains forward-looking statements within the meaning of section 27A of the Securities Act of 1933 and section 21E of the Securities Act of 1934. When used in this release, the words "believe," "anticipate," "think," "intend," "plan," "will be," "expect," and similar expressions identify such forward-looking statements. Such statements regarding future events and/or the future financial performance of The Company are subject to certain risks and uncertainties, which could cause actual events or the actual future results of the Company to differ materially from any forward-looking statement. Such risks and uncertainties include, among other things, the availability of any needed financing, the Company's ability to implement its business plan for various applications of its technologies, the impact of competition, the management of growth, and the other risks and uncertainties that may be detailed from time to time in the Company's reports filed with the Securities and Exchange Commission. In light of the significant risks and uncertainties inherent in the forward-looking statements included herein, the inclusion of such statements should not be regarded as a representation by the Company or any other person that the objectives and plans of the Company will be achieved.

SOURCE: Authentidate Holding Corp.