Transport Layer Security (TLS) Cached Information Extension
RFC 7924
Document | Type | RFC - Proposed Standard (July 2016; No errata) | |
---|---|---|---|
Authors | Stefan Santesson , Hannes Tschofenig | ||
Last updated | 2018-12-20 | ||
Replaces | draft-santesson-tls-certcache | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Joseph Salowey | ||
Shepherd write-up | Show (last changed 2015-11-02) | ||
IESG | IESG state | RFC 7924 (Proposed Standard) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Stephen Farrell | ||
Send notices to | (None) | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) S. Santesson Request for Comments: 7924 3xA Security AB Category: Standards Track H. Tschofenig ISSN: 2070-1721 ARM Ltd. July 2016 Transport Layer Security (TLS) Cached Information Extension Abstract Transport Layer Security (TLS) handshakes often include fairly static information, such as the server certificate and a list of trusted certification authorities (CAs). This information can be of considerable size, particularly if the server certificate is bundled with a complete certificate chain (i.e., the certificates of intermediate CAs up to the root CA). This document defines an extension that allows a TLS client to inform a server of cached information, thereby enabling the server to omit already available information. Status of This Memo This is an Internet Standards Track document. 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). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7924. Santesson & Tschofenig Standards Track [Page 1] RFC 7924 TLS Cached Information Extension July 2016 Copyright Notice Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Cached Information Extension . . . . . . . . . . . . . . . . 3 4. Exchange Specification . . . . . . . . . . . . . . . . . . . 5 4.1. Server Certificate Message . . . . . . . . . . . . . . . 6 4.2. CertificateRequest Message . . . . . . . . . . . . . . . 7 5. Fingerprint Calculation . . . . . . . . . . . . . . . . . . . 7 6. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 8.1. New Entry to the TLS ExtensionType Registry . . . . . . . 10 8.2. New Registry for CachedInformationType . . . . . . . . . 11 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 9.1. Normative References . . . . . . . . . . . . . . . . . . 11 9.2. Informative References . . . . . . . . . . . . . . . . . 12 Appendix A. Example . . . . . . . . . . . . . . . . . . . . . . 13 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 Santesson & Tschofenig Standards Track [Page 2] RFC 7924 TLS Cached Information Extension July 2016 1. Introduction Reducing the amount of information exchanged during a Transport Layer Security handshake to a minimum helps to improve performance in environments where devices are connected to a network with a low bandwidth and lossy radio technology. With the Internet of Things, such environments exist, for example, when devices use IEEE 802.15.4, Bluetooth Low Energy, or low power wide area networks. For more information about the challenges with smart object deployments, please see [RFC6574]. This specification defines a TLS extension that allows a client and a server to exclude transmission information cached in an earlier TLS handshake. A typical example exchange may therefore look as follows. First, the client and the server execute the full TLS handshake. The client then caches the certificate provided by the server. When the TLS client connects to the TLS server some time in the future, without using session resumption, it then attaches the "cached_info" extension defined in this document to the ClientHello message toShow full document text