Aether Systems to License Diversinet's Passport Digital Signature Technology to Take the Security of Wireless Applications to a New Level.

Business Editors, High-Tech Writers

OWINGS MILLS, MD--(BUSINESS WIRE)--Dec. 21, 1999

Agreement will provide financial services, healthcare and other

industries with the latest, most secure wireless data applications

available

Aether Systems, Inc. (Nasdaq: AETH), the leading wireless applications services provider, today signed a letter of intent with Diversinet Corp. (Nasdaq Small Cap; DVNT; CDN; DVNT), a leader in security software for wireless e-commerce products, to license Diversinet's Passport(TM) software for a wide range of wireless e-commerce applications. In addition, the two companies will explore innovative security solutions and marketing ventures.

The agreement will allow Aether to employ "digital signatures" in its current and planned wireless data services offerings, including mobile stock trading, banking and healthcare applications. Digital signature technology ensures that an electronic message or transaction is being sent and received only by the intended parties, and that the data was not changed along the way. By integrating Diversinet's ability to capture digital signatures with Aether's wireless data enterprise solutions, Aether will enable corporations to take full advantage of wireless e-commerce solutions, completing secure wireless data transactions that were never before possible without paper signatures.

"Aether is pleased to team with Diversinet to take the security of wireless applications to a new level by integrating the latest, most innovative digital signature technology within its wireless data software," says Aether President and Chief Executive Officer David Oros. "By incorporating Diversinet's certificate and authorization technology into our leading Aether Intelligent Messaging (AIM) software, Aether once again takes the leading role in providing enterprises with the most secure, reliable means of wirelessly accessing their mission-critical data today."

AIM is Aether's leading wireless communications software and development platform that makes it easy for corporate enterprises and content providers to develop applications that deliver their data across multiple wireless devices and networks.

Specifically, the letter of intent calls for Aether to license Diversinet's updated Passport Certificate Server (Version 3.0) and its new Authorization Server (Version 2.0). The Passport Certificate Server, which supports digital signature use, issues certificates that are compliant with multiple wireless device technologies, including the Wireless Application Protocol standard for Web-enabled smart phones, 3Com's Palm Computing platform, the Inter@ctive Pager 950/850 and Blackberry devices from Research in Motion and Windows CE and Java-based devices.

Diversinet's unique Passport Authorization software is highly flexible in that it allows users to access information based on time, date, type of data, etc. This flexibility was a key attraction for Aether, whose AIM platform allows the company to deliver a customized wireless data solution to each corporate customer.

Using Diversinet's digital signature technology, Aether will be able to act as a Certificate Authority (CA) that validates e-commerce transactions for its corporate customers. This option would significantly expand Aether's capabilities as a trusted third-party host of sensitive data across wireless networks.

"Aether's expertise in developing wireless applications, especially in the key vertical market sector of financial services, offers Diversinet a great new distribution channel for our digital certificates and authorization permits," says Nagy Moustafa, president and CEO of Diversinet. "The combination of Aether's expertise in wireless applications development and network operations and Diversinet's expertise in wireless security will create significant growth opportunities for both companies."

As part of the letter of intent, Diversinet and Aether are planning a series of joint marketing efforts focusing on wireless financial applications.

About Diversinet Corp.

Diversinet Corp., headquartered in Toronto, Canada, is a leading developer of security products based on public key infrastructure (PKI) technology for wireless and wireline e-commerce applications, such as banking, stock trading, financial analysis and healthcare databases. Diversinet's innovative Passport client/server software, including authentication, digital certificates, digital signatures and digital permits, is especially designed for resource-constrained products, such as pagers, wireless phones and smart cards. Diversinet is a member of the WAP Forum and the Wireless Data Forum. Website: http://www.dvnet.com.

About Aether Systems, Inc.

Aether Systems, Inc., is a one-stop provider of wireless software and services connecting people to the information they need, wherever and whenever they need it. Aether allows individuals to receive real-time data on handheld wireless devices, using virtually any kind of wireless data network. Aether's ability to deliver real-time, secure and reliable wireless solutions comes through proven expertise in wireless system engineering, software tools and services, wireless network operations, product fulfillment and customer support. Current users of Aether's full-service solutions include Charles Schwab & Co., Morgan Stanley Dean Witter Online, OmniSky Inc., Reuters and Riverbed Technologies. For more information, visit Aether's website at http://www.aethersystems.com.

This press release includes forward-looking statements based on our current expectations and projections about future events. These forward-looking statements are subject to a number of risks, uncertainties and assumptions about Aether that could cause actual results to differ materially from those in such forward-looking statements. Potential risks and uncertainties include, but are not limited to, the negotiation and execution of definitive agreements relating to the licenses and joint marketing ventures described in the press release, the continued development and customer acceptance of the technology to be licensed by Aether and the ability to offer it on a cost-effective basis, and Aether's and Diversinet' ability to adapt to rapid technological change. These risks and other risk factors are described in Aether's Form S1\A prospectus under the caption, "Risk Factors" filed pursuant to Rule 424(b) with the Securities and Exchange Commission. Aether undertakes no obligation to update the forward looking statements contained in this press release.