International Business Machines Corporation
522 South Road
Poughkeepsie, N. Y. 12602

February 2, 1998

Burt Kaliski (Chair IEEE P1363)
RSA Laboratories
20 Crosby Drive
Bedford, MA 01730-1402

Burt:

With respect to draft proposed IEEE Standard described in IEEE P1363/Editorial Contribution to Standard Specification for Public Key Cryptography, IBM is willing to offer a license under the patents and patent applications listed in Attachment A hereto in accordance with the terms set forth below. It is the belief of IBM that these are the only IBM patents or patent applications that is relevant to cited draft proposed IEEE Standard.

In the event that the standard cannot be practiced without the use of one or more issued patents, including design patents for type fonts but excluding other design patents, which are now or hereafter owned or controlled by IBM, IBM agrees upon request to grant a non-exclusive license under such patent or patents on a n ondiscriminatory basis and on reasonable terms and conditions including its then current royalty rates and provided a similar grant under licensee's patents within the scope of the license granted to licensee is made available upon request to IBM.

Any requests for license information may be directed to:

IBM is pleased to make this offer in support of the standardization activities in IEEE P1363. If you have any questions, please let me know.

                                                       Sincerely,


                                                       S. M. Matyas

cc: G. Rosenthal



Attachment A: List of Patents and Patent Applications

U.S. Patent 5,177,791, "Secure Translation of Usage-Control Values for Cryptographic Keys" issued Jan. 5, 1993.

U.S. Patent 5,432,849, "Secure Cryptographic Operations Using Alternate Modes of Control Vector Enforcement," issued 1995.

U.S. Patent 5,103,478, "Secure Management of Keys Using Control Vectors with Multi-Path Checking," issued Apr. 7, 1992.

U.S. Patent 5,007,089, "Secure Key Management Using Programmable Control Vector Checking," issued April 9, 1991.

U.S. Patent 4,993,069, "Secure Key Management Using Control Vector Translation," issued Feb. 12, 1991.

U.S. Patent 4,924,515, "Secure Management of Keys Using Extended Control Vectors," issued May 8, 1990,

U.S. Patent 4,924,514, "Personal Identification Number Processing Using Control Vectors," issued May 8, 1990.

U.S. Patent 4,918,728, "Data Cryptography Operations Using Control Vectors," issued April 17, 1990.

U.S. Patent 4,941,176, "Secure Management of Keys Using Control Vectors," issued July 10, 1990.

U.S. Patent 4,850,017, "Controlled Use of Cryptographic Keys Via Generating Stations Established Controlled Values," issued July 18, 1989.

"Method and Apparatus for Encrypting Long Blocks Using a Short-Block Encryption Procedure," serial number 08/603,771, filed February 20, 1996.

"Method and Apparatus for Establishing an Authenticated Shared Secret Value Between a Pair of Users," serial number 08/736,774, filed October 25, 1996.