Comparex and Authentidate Establish a Strategic Alliance
New, central convenience signatures with a health professional card and an electronic health card

DÜSSELDORF, GERMANY
January 13, 2009

Authentidate, a signature specialist operating on an international basis, and Comparex, a company of TDMi AG, are establishing a strategic alliance and will combine the secure Comparex chip-card safe IQ-Medi-LOG with the leading Authentidate signature application components. The new joint solution will make a central generation of qualified signatures possible with the health professional card (HPC) and the electronic health card (eHC). This type of signature is also designated as a convenience signature in accordance with the technical guideline (BSI TR-03114) of the German Federal Office of Information Technology Security (BSI).

The solution appreciably simplifies the practical use of the health professional card because of the elimination of a card reader and signature software at every single workstation and thereby reduces the operating costs of the HPC in a substantial way. The procurement, administration and licensing costs that are saved in this way can be used in other areas in a much more efficient way for the patient.

The Comparex chip-card safe IQ-Medi-LOG can be set up in the central office of a hospital, for example. The physicians and other employees put their health professional card in the chip-card safe when they enter the building and activate the card once via entry of the PIN number. Depending on the configuration, qualified signatures (convenience signatures) can subsequently be created from every workstation. The secure, central Authentidate signature component provides for this. A display of the data before it is signed via the central Authentidate signature component and the central Comparex chip-card safe is ensured via the Authentidate Trusted Viewer at every workstation. Qualified time stamps from accredited services and others can also be requested as an option through the signature service layer.

The product arising from the joint project will make the daily routine in the clinic easier, especially for physicians, because electronically signed data can be generated almost anywhere without high additional expenses. Multi-stage or spatially separate approval processes can also be implemented in a simple way and without major changes in the work flow.

About TDMi
The TDMi Group, with 36 branch offices across the nation, 1,300 employees and an overall sales volume of approx. 500 million euros, is one of the largest independent IT systems houses in Germany. The IT service providers and systems houses arxes NCC AG, becom Informationssysteme GmbH, COMPAREX Deutschland GmbH and inforsacom Informationssysteme GmbH joined together under the umbrella of TDMi in December of 2007. Around 1,200 companies are among the customers of TDMi.

About Authentidate International AG & Authentidate Deutschland GmbH
Authentidate (Düsseldorf) is the inventor of the centralized, qualified mass signature and one of the leading providers within the international signature market. The signature and IT-security specialist has been a pioneer for years and is influencing the signature market with its innovations.

More than 50% of the German health insurance companies and international companies and organizations, such as DPD, EnBw, HAYS, Klinikum Braunschweig, SOLVAY Chemicals und TÜV Rheinland have been using Authentidate signature products successfully for many years.

Authentidate technologies meet the strict requirements of the German Signature Law and the European Signature Directive. Authentidate International AG is accredited certification service provider by the Federal Network Agency and runs a Trust Center in compliance with the German Signature Law.

Authentidate is headquartered in the USA and is today the sole supplier of the United States Postal Service® Electronic Postmark® (USPS® EPM®), a unique service for secure electronic communication in the USA. Authentidate Holding Corp. is listed on the (Nasdaq: ADAT) and at German stock markets (Security Identification Code 893715).

About Authentidate Holding Corp.
Authentidate Holding Corp. (Authentidate®) is a worldwide provider of secure Health Information Exchange and workflow management services.  The company's software and web-based services enable healthcare organizations and other enterprises to increase revenues, improve productivity and reduce costs by eliminating paper and manual work steps from clinical, administrative and other processes and enhancing compliance with regulatory requirements. The web-based services are delivered as Software as a Service (Saas) to customers. These solutions incorporate rules-based electronic forms, intelligent routing, transaction management, electronic signatures, identity credentialing, content authentication and automated audit trails. Both web and fax based communications are integrated into automated and trusted workflow solutions. The company has offices in the United States and Germany. In the United States we offer our patent pending content authentication technology in the form of the United States Postal Service® Electronic Postmark® (EPM).

For more information, visit the company's website at www.authentidate.com

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, related decisions by the USPS, 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.

Authentidate is a registered trademark of Authentidate Holding Corp. Inscrybe is a trademark of Authentidate Holding Corp. All other trade names are the property of their respective owners.