draft-ietf-kitten-tls-channel-bindings-for-tls13-00.txt   draft-ietf-kitten-tls-channel-bindings-for-tls13-01.txt 
Transport Layer Security S. Whited Transport Layer Security S. Whited
Internet-Draft 11 June 2020 Internet-Draft 18 November 2020
Updates: RFC5802, RFC8446 (if approved) Updates: 5802, 8446 (if approved)
Intended status: Standards Track Intended status: Standards Track
Expires: 13 December 2020 Expires: 22 May 2021
Channel Bindings for TLS 1.3 Channel Bindings for TLS 1.3
draft-ietf-kitten-tls-channel-bindings-for-tls13-00 draft-ietf-kitten-tls-channel-bindings-for-tls13-01
Abstract Abstract
This document defines a channel binding type, tls-exporter, that is This document defines a channel binding type, tls-exporter, that is
compatible with TLS 1.3 [RFC8446] in accordance with On Channel compatible with TLS 1.3 in accordance with RFC 5056, On Channel
Binding [RFC5056]. Binding.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
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This Internet-Draft will expire on 13 December 2020. This Internet-Draft will expire on 22 May 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions and Terminology . . . . . . . . . . . . . . . 2 1.1. Conventions and Terminology . . . . . . . . . . . . . . . 2
2. The 'tls-exporter' Channel Binding Type . . . . . . . . . . . 2 2. The 'tls-exporter' Channel Binding Type . . . . . . . . . . . 2
3. Security Considerations . . . . . . . . . . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
4.1. Registration of Channel Binding Type . . . . . . . . . . 3 4.1. Registration of Channel Binding Type . . . . . . . . . . 3
4.2. Registration of Channel Binding TLS Exporter Label . . . 4 4.2. Registration of Channel Binding TLS Exporter Label . . . 4
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.1. Normative References . . . . . . . . . . . . . . . . . . 4 5.1. Normative References . . . . . . . . . . . . . . . . . . 4
5.2. Informative References . . . . . . . . . . . . . . . . . 4 5.2. Informative References . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
After problems were found with the channel binding types defined in The channel binding types defined in [RFC5929] were found to be
[RFC5929] they were not defined for TLS 1.3 (see [RFC8446] section vulnerable to the "triple handshake vulnerability" [TRIPLE-HANDSHAKE]
7.5). To facilitate channel binding with TLS 1.3, a new channel without the extended master secret extension defined in [RFC7627].
binding type is needed. Because of this they were not defined for TLS 1.3 (see [RFC8446]
section C.5). To facilitate channel binding with TLS 1.3, a new
channel binding type is needed.
1.1. Conventions and Terminology 1.1. Conventions and Terminology
Throughout this document the acronym "EKM" is used to refer to Throughout this document the acronym "EKM" is used to refer to
Exported Keying Material as defined in [RFC5705]. Exported Keying Material as defined in [RFC5705].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
2. The 'tls-exporter' Channel Binding Type 2. The 'tls-exporter' Channel Binding Type
IANA will register the 'tls-exporter' channel binding type to match Channel binding mechanisms are not useful until TLS implementations
the description below. expose the required data. To facilitate this, "tls-exporter" uses
exported keying material (EKM) which is already widely exposed by TLS
Description: The EKM value obtained from the current TLS connection. implementations. The EKM is obtained using the keying material
exporters for TLS as defined in [RFC5705] and [RFC8446] section 7.5
The EKM is obtained using the keying material exporters for TLS as by supplying the following inputs:
defined in [RFC5705] by supplying the following inputs:
Label: The ASCII string "EXPORTER-Channel-Binding" with no Label: The ASCII string "EXPORTER-Channel-Binding" with no
terminating NUL. terminating NUL.
Context value: Empty context value. Context value: Empty context value.
Length: 32 bytes. Length: 32 bytes.
When TLS renegotiation is enabled channel binding using the "tls- When TLS renegotiation is enabled the "tls-exporter" channel binding
exporter" type is not define and MUST NOT be supported. type is not defined and implementations MUST NOT support it.
3. Security Considerations 3. Security Considerations
While it is possible to use this channel binding mechanism with TLS While it is possible to use this channel binding mechanism with TLS
versions below 1.3, extra precaution must be taken to ensure that the versions below 1.3, extra precaution must be taken to ensure that the
chosen cipher suites always result in unique master secrets. For chosen cipher suites always result in unique master secrets. For
more information see the Security Considerations section of more information see the Security Considerations section of
[RFC5705]. [RFC5705].
The Security Considerations sections of [RFC5056], [RFC5705], and The Security Considerations sections of [RFC5056], [RFC5705], and
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Subject: Registration of channel binding tls-exporter Subject: Registration of channel binding tls-exporter
Channel binding unique prefix: tls-exporter Channel binding unique prefix: tls-exporter
Channel binding type: unique Channel binding type: unique
Channel type: TLS [RFC8446] Channel type: TLS [RFC8446]
Published specification: draft-ietf-kitten-tls-channel-bindings-for- Published specification: draft-ietf-kitten-tls-channel-bindings-for-
tls13-00 tls13-01
Channel binding is secret: no Channel binding is secret: no
Description: <See specification> Description: The EKM value obtained from the current TLS connection.
Intended usage: COMMON Intended usage: COMMON
Person and email address to contact for further information: Sam Person and email address to contact for further information: Sam
Whited <sam@samwhited.com>. Whited <sam@samwhited.com>.
Owner/Change controller name and email address: IESG. Owner/Change controller name and email address: IESG.
Expert reviewer name and contact information: IETF KITTEN or TLS WG Expert reviewer name and contact information: IETF KITTEN or TLS WG
(kitten@ietf.org or tls@ietf.org, failing that, ietf@ietf.org). (kitten@ietf.org or tls@ietf.org, failing that, ietf@ietf.org).
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[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
5.2. Informative References 5.2. Informative References
[RFC5929] Altman, J., Williams, N., and L. Zhu, "Channel Bindings [RFC5929] Altman, J., Williams, N., and L. Zhu, "Channel Bindings
for TLS", RFC 5929, DOI 10.17487/RFC5929, July 2010, for TLS", RFC 5929, DOI 10.17487/RFC5929, July 2010,
<https://www.rfc-editor.org/info/rfc5929>. <https://www.rfc-editor.org/info/rfc5929>.
[RFC7627] Bhargavan, K., Ed., Delignat-Lavaud, A., Pironti, A.,
Langley, A., and M. Ray, "Transport Layer Security (TLS)
Session Hash and Extended Master Secret Extension",
RFC 7627, DOI 10.17487/RFC7627, September 2015,
<https://www.rfc-editor.org/info/rfc7627>.
[TRIPLE-HANDSHAKE]
Bhargavan, K., Delignat-Lavaud, A., Fournet, C., Pironti,
A., and P. Strub, "Password Storage", March 2014,
<https://www.mitls.org/pages/attacks/3SHAKE>.
Author's Address Author's Address
Sam Whited Sam Whited
Atlanta, GA Atlanta, GA
United States of America United States of America
Email: sam@samwhited.com Email: sam@samwhited.com
URI: https://blog.samwhited.com/ URI: https://blog.samwhited.com/
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