Transport Layer Security (TLS) Resumption across Server Names
draft-ietf-tls-cross-sni-resumption-00
TLS Working Group V. Vasiliev
Internet-Draft Google
Intended status: Standards Track 15 December 2020
Expires: 18 June 2021
Transport Layer Security (TLS) Resumption across Server Names
draft-ietf-tls-cross-sni-resumption-00
Abstract
This document specifies a way for the parties in the Transport Layer
Security (TLS) protocol to indicate that an individual session ticket
can be used to perform resumption even if the Server Name of the new
connection does not match the Server Name of the original.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the TLS Working Group
mailing list (tls@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/tls/
(https://mailarchive.ietf.org/arch/browse/tls/).
Source for this draft and an issue tracker can be found at
https://github.com/vasilvv/tls-cross-sni-resumption
(https://github.com/vasilvv/tls-cross-sni-resumption).
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 18 June 2021.
Vasiliev Expires 18 June 2021 [Page 1]
Internet-Draft TLS Cross-SNI Resumption December 2020
Copyright Notice
Copyright (c) 2020 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 (https://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 . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. The Extension . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
6.1. Normative References . . . . . . . . . . . . . . . . . . 4
6.2. Informative References . . . . . . . . . . . . . . . . . 5
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
Transport Layer Security protocol [RFC8446] allows the clients to use
an abbreviated handshake in cases where the client has previously
established a secure session with the same server. This mechanism is
known as "session resumption", and its positive impact on performance
makes it desirable to be able to use it as frequently as possible.
Vasiliev Expires 18 June 2021 [Page 2]
Internet-Draft TLS Cross-SNI Resumption December 2020
Modern application-level protocols, HTTP in particular, often require
accessing multiple servers within a single workflow. Since the
identity of the server is established through its certificate, in the
ideal case, the resumption would be possible to all of the domains
for which the certificate is valid (see [PERF] for a survey of
potential practical impact of such approach). TLS, starting with
version 1.3, defines the SNI value to be a property of an individual
connection that is not retained across sessions ([RFC8446],
Section 4.2.11). However, in the absence of additional signals, it
discourages using a session ticket when the SNI value does not match
([RFC8446], Section 4.6.1), as there is normally no reason to assume
that all servers sharing the same certificate would also share the
same session keys. The extension defined in this document allows the
server to provide such a signal in-band.
2. Conventions and Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
Show full document text