Received August 3, 2001 From: "Linn, John" RSA Security Inc. has submitted a patent application concerning client puzzles, a technique initially described in Juels and Brainard, "Client Puzzles: A Cryptographic Countermeasure against Connection Depletion Attacks", ISOC NDSS, 1999. Discussions within the IPsec WG have cited this technique and have considered incorporation of methods with similar properties, and the client puzzles concept has recently been referenced in draft-ietf-ipsec-properties-00.txt. If use of client puzzles is incorporated into a future IPsec specification, and if the currently active application leads to an issued patent, RSA Security Inc. is willing to grant licenses to such patent under reasonable and non-discriminatory terms for purposes of implementing that IPsec specification. Correspondence concerning licensing for this technology should be addressed to: RSA Security Inc., 36 Crosby Drive, Bedford, MA 01730, USA, Attn: General Counsel.