Japan Research Institute, Limited Adopts Tumbleweed Communications' Integrated Messaging Exchange

Electronic "Registered Mail" Service Launched

REDWOOD CITY, CA - December 20, 2000 - Tumbleweed® Communications Corp. (Nasdaq:TMWD), a leading provider of secure Internet messaging services, announced today that the Japan Research Institute, Limited, one of Japan's prominent think tanks, has adopted Tumbleweed Integrated Messaging Exchange (IME) for an electronic "registered mail" service inaugurated this month by JRI's Financial Solutions Division.

Tumbleweed IME is a platform and set of applications for creating secure email channels between a business and its customers, partners and suppliers. IME4.06J is the localized Japanese version Tumbleweed IME.

JRI's Financial Solutions Division is implementing IME 4.06J to offer secure Internet communications services for clients of all sizes in all business sectors. JRI envisions delivering transaction breakdowns, contracts, payment slips, and other business correspondence that require a high degree of security.

Several factors led JRI to choose IME 4.06J, notably Tumbleweed's proven track record in Japan and the Tumbleweed platform's advantages as the infrastructure for JRI's expanding outsourcing ventures. JRI intends to develop Tumbleweed solutions for its consulting, systems integration, and application service provider businesses.

The implementation of IME4.06J is one more step in JRI's ongoing commitment to developing and deploying email solutions and other ASP applications to address the diverse needs of customers for timely and low cost, high security communications channels for businesses to communicate with other businesses, with consumers and with governments.

"The progress in digitalization and business globalization that has followed the relaxing of government regulations is expected to lead to the further expansion of the e-business market, and this in turn will increase the value of using the highly secure mailing service we provide," comments JRI Director Yasuyuki Yamaguchi.

"The Japan Research Institute will continue to provide its clients with outstanding services as a business that satisfies their multiple needs through organic integration of its think tank, consulting, and system integration functions. JRI will further strengthen its relationships with Tumbleweed Communications and related partners to develop new business models for the next century," he adds.

About JRI
Japan Research Institute, Limited, maintains corporate offices at 16 Ichibancho, Chiyoda-ku, Tokyo, Japan. Led by president Masahiko Koido, the company was founded on February 20, 1969, and has an annual turnover of ¥60 billion (FY99) on capitalization of ¥2 billion. The institute's 2,400 employees leverage its strengths as a think tank, consultancy, and systems integrator to address the full range of customers' IT needs - from business consulting to outsourcing services. JRI has a solid reputation for technological prowess, particularly in providing services to banking, credit, finance, and other businesses in the financials sector. More information about JRI can be obtained from its Web site at: http://www.jri.co.jp/english/index.html.

About Tumbleweed Communications Corp.
Tumbleweed is a leading provider of solutions for managing secure communication and collaboration to enable the business Internet. Tumbleweed's robust policy-based framework empowers organizations to safely share and protect critical information, increase customer loyalty and privacy and dramatically reduce costs. Tumbleweed is trusted by 1,000 blue-chip customers including American Express, Chevron, Datek Online, the European Union's Joint Research Council, First Union Wachovia, John Deere, Merrill Lynch, Nike, Northern Trust, NTT, Salomon Smith Barney, Travelers and US Food and Drug Administration. One hundred of the Fortune 500 are Tumbleweed customers. Tumbleweed Communications was founded in 1993 and is headquartered in Redwood City, Calif., with offices around the world.

Except for the historical information contained herein, the matters discussed in this press release may constitute forward-looking statements that involve risks and uncertainties that could cause actual results to differ materially from those projected, particularly with respect to the security features of Tumbleweed's products and the activities of any third party. In some cases, forward-looking statements can be identified by terminology such as "may," "will," "should," "potential," "continue," "expects," "anticipates," "intends," "plans," "believes," "estimates," and similar expressions. For further cautions about the risks of investing in Tumbleweed, we refer you to the documents Tumbleweed files from time to time with the Securities and Exchange Commission, particularly Tumbleweed's Form 10-K filed March 30, 2001 and Form 10-Q filed November 13, 2001. Tumbleweed assumes no obligation to update information contained in this press release.