This document describes how to use the ’static-static Elliptic Curve Diffie-Hellman key-agreement scheme (i.e., Elliptic Curve Diffie-Hellman where both participants use static Diffie-Hellman values) with the Cryptographic Message Syntax. In this form of key agreement, the Diffie-Hellman values of both the sender and receiver are long-term values contained in certificates. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at