draft-ietf-tls-certificate-compression-03.txt   draft-ietf-tls-certificate-compression-04.txt 
TLS A. Ghedini TLS A. Ghedini
Internet-Draft Cloudflare, Inc. Internet-Draft Cloudflare, Inc.
Intended status: Standards Track V. Vasiliev Intended status: Standards Track V. Vasiliev
Expires: October 25, 2018 Google Expires: April 6, 2019 Google
April 23, 2018 October 03, 2018
Transport Layer Security (TLS) Certificate Compression TLS Certificate Compression
draft-ietf-tls-certificate-compression-03 draft-ietf-tls-certificate-compression-04
Abstract Abstract
In Transport Layer Security (TLS) handshakes, certificate chains In TLS handshakes, certificate chains often take up the majority of
often take up the majority of the bytes transmitted. the bytes transmitted.
This document describes how certificate chains can be compressed to This document describes how certificate chains can be compressed to
reduce the amount of data transmitted and avoid some round trips. reduce the amount of data transmitted and avoid some round trips.
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
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 25, 2018. This Internet-Draft will expire on April 6, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 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 Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 26 skipping to change at page 2, line 26
7.1. Update of the TLS ExtensionType Registry . . . . . . . . 5 7.1. Update of the TLS ExtensionType Registry . . . . . . . . 5
7.2. Update of the TLS HandshakeType Registry . . . . . . . . 5 7.2. Update of the TLS HandshakeType Registry . . . . . . . . 5
7.3. Registry for Compression Algorithms . . . . . . . . . . . 5 7.3. Registry for Compression Algorithms . . . . . . . . . . . 5
8. Normative References . . . . . . . . . . . . . . . . . . . . 6 8. Normative References . . . . . . . . . . . . . . . . . . . . 6
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 7 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
In order to reduce latency and improve performance it can be useful In order to reduce latency and improve performance it can be useful
to reduce the amount of data exchanged during a Transport Layer to reduce the amount of data exchanged during a TLS handshake.
Security (TLS) handshake.
[RFC7924] describes a mechanism that allows a client and a server to [RFC7924] describes a mechanism that allows a client and a server to
avoid transmitting certificates already shared in an earlier avoid transmitting certificates already shared in an earlier
handshake, but it doesn't help when the client connects to a server handshake, but it doesn't help when the client connects to a server
for the first time and doesn't already have knowledge of the server's for the first time and doesn't already have knowledge of the server's
certificate chain. certificate chain.
This document describes a mechanism that would allow certificates to This document describes a mechanism that would allow certificates to
be compressed during full handshakes. be compressed during full handshakes.
skipping to change at page 3, line 6 skipping to change at page 2, line 51
"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.
3. Negotiating Certificate Compression 3. Negotiating Certificate Compression
This extension is only supported with TLS 1.3 and newer; if TLS 1.2 This extension is only supported with TLS 1.3 and newer; if TLS 1.2
or earlier is negotiated, the peers MUST ignore this extension. or earlier is negotiated, the peers MUST ignore this extension.
This document defines a new extension type This document defines a new extension type
(compress_certificate(TBD)), which can be used to signal the (compress_certificate(27)), which can be used to signal the supported
supported compression formats for the Certificate message to the compression formats for the Certificate message to the peer.
peer. Whenever it is sent by the client as a ClientHello message Whenever it is sent by the client as a ClientHello message extension
extension ([I-D.ietf-tls-tls13], Section 4.1.2), it indicates the ([RFC8446], Section 4.1.2), it indicates the support for compressed
support for compressed server certificates. Whenever it is sent by server certificates. Whenever it is sent by the server as a
the server as a CertificateRequest extension ([I-D.ietf-tls-tls13], CertificateRequest extension ([RFC8446], Section 4.3.2), it indicates
Section 4.3.2), it indicates the support for compressed client the support for compressed client certificates.
certificates.
By sending a compress_certificate extension, the sender indicates to By sending a compress_certificate extension, the sender indicates to
the peer the certificate compression algorithms it is willing to use the peer the certificate compression algorithms it is willing to use
for decompression. The "extension_data" field of this extension for decompression. The "extension_data" field of this extension
SHALL contain a CertificateCompressionAlgorithms value: SHALL contain a CertificateCompressionAlgorithms value:
enum { enum {
zlib(1), zlib(1),
brotli(2), brotli(2),
(65535) (65535)
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6. Middlebox Compatibility 6. Middlebox Compatibility
It's been observed that a significant number of middleboxes intercept It's been observed that a significant number of middleboxes intercept
and try to validate the Certificate message exchanged during a TLS and try to validate the Certificate message exchanged during a TLS
handshake. This means that middleboxes that don't understand the handshake. This means that middleboxes that don't understand the
CompressedCertificate message might misbehave and drop connections CompressedCertificate message might misbehave and drop connections
that adopt certificate compression. Because of that, the extension that adopt certificate compression. Because of that, the extension
is only supported in the versions of TLS where the certificate is only supported in the versions of TLS where the certificate
message is encrypted in a way that prevents middleboxes from message is encrypted in a way that prevents middleboxes from
intercepting it, that is, TLS version 1.3 [I-D.ietf-tls-tls13] and intercepting it, that is, TLS version 1.3 [RFC8446] and higher.
higher.
7. IANA Considerations 7. IANA Considerations
7.1. Update of the TLS ExtensionType Registry 7.1. Update of the TLS ExtensionType Registry
Create an entry, compress_certificate(TBD), in the existing registry Create an entry, compress_certificate(27), in the existing registry
for ExtensionType (defined in [I-D.ietf-tls-tls13]), with "TLS 1.3" for ExtensionType (defined in [RFC8446]), with "TLS 1.3" column
column values being set to "CH, CR". values being set to "CH, CR", and "Recommended" column being set to
"Yes".
7.2. Update of the TLS HandshakeType Registry 7.2. Update of the TLS HandshakeType Registry
Create an entry, compressed_certificate(TBD), in the existing Create an entry, compressed_certificate(25), in the existing registry
registry for HandshakeType (defined in [RFC5246]). for HandshakeType (defined in [RFC8446]).
7.3. Registry for Compression Algorithms 7.3. Registry for Compression Algorithms
This document establishes a registry of compression algorithms This document establishes a registry of compression algorithms
supported for compressing the Certificate message, titled supported for compressing the Certificate message, titled
"Certificate Compression Algorithm IDs", under the existing "Certificate Compression Algorithm IDs", under the existing
"Transport Layer Security (TLS) Extensions" heading. "Transport Layer Security (TLS) Extensions" heading.
The entries in the registry are: The entries in the registry are:
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+------------------+-------------------------------+ +------------------+-------------------------------+
The values in this registry shall be allocated under "IETF Review" The values in this registry shall be allocated under "IETF Review"
policy for values strictly smaller than 256, under "Specification policy for values strictly smaller than 256, under "Specification
Required" policy for values 256-16383, and under "Experimental Use" Required" policy for values 256-16383, and under "Experimental Use"
otherwise (see [RFC8126] for the definition of relevant policies). otherwise (see [RFC8126] for the definition of relevant policies).
Experimental Use extensions can be used both on private networks and Experimental Use extensions can be used both on private networks and
over the open Internet. over the open Internet.
The procedures for requesting values in the Specification Required The procedures for requesting values in the Specification Required
space are specified in [I-D.ietf-tls-iana-registry-updates]. space are specified in [RFC8447].
8. Normative References 8. Normative References
[I-D.ietf-tls-iana-registry-updates]
Salowey, J. and S. Turner, "IANA Registry Updates for TLS
and DTLS", draft-ietf-tls-iana-registry-updates-04 (work
in progress), February 2018.
[I-D.ietf-tls-tls13]
Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", draft-ietf-tls-tls13-28 (work in progress),
March 2018.
[RFC1950] Deutsch, P. and J-L. Gailly, "ZLIB Compressed Data Format [RFC1950] Deutsch, P. and J-L. Gailly, "ZLIB Compressed Data Format
Specification version 3.3", RFC 1950, Specification version 3.3", RFC 1950,
DOI 10.17487/RFC1950, May 1996, DOI 10.17487/RFC1950, May 1996,
<https://www.rfc-editor.org/info/rfc1950>. <https://www.rfc-editor.org/info/rfc1950>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
[RFC7250] Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J., [RFC7250] Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J.,
Weiler, S., and T. Kivinen, "Using Raw Public Keys in Weiler, S., and T. Kivinen, "Using Raw Public Keys in
Transport Layer Security (TLS) and Datagram Transport Transport Layer Security (TLS) and Datagram Transport
Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250, Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250,
June 2014, <https://www.rfc-editor.org/info/rfc7250>. June 2014, <https://www.rfc-editor.org/info/rfc7250>.
[RFC7924] Santesson, S. and H. Tschofenig, "Transport Layer Security [RFC7924] Santesson, S. and H. Tschofenig, "Transport Layer Security
(TLS) Cached Information Extension", RFC 7924, (TLS) Cached Information Extension", RFC 7924,
DOI 10.17487/RFC7924, July 2016, DOI 10.17487/RFC7924, July 2016,
<https://www.rfc-editor.org/info/rfc7924>. <https://www.rfc-editor.org/info/rfc7924>.
skipping to change at page 7, line 18 skipping to change at page 6, line 48
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8447] Salowey, J. and S. Turner, "IANA Registry Updates for TLS
and DTLS", RFC 8447, DOI 10.17487/RFC8447, August 2018,
<https://www.rfc-editor.org/info/rfc8447>.
Appendix A. Acknowledgements Appendix A. Acknowledgements
Certificate compression was originally introduced in the QUIC Crypto Certificate compression was originally introduced in the QUIC Crypto
protocol, designed by Adam Langley and Wan-Teh Chang. protocol, designed by Adam Langley and Wan-Teh Chang.
This document has benefited from contributions and suggestions from This document has benefited from contributions and suggestions from
David Benjamin, Ryan Hamilton, Ilari Liusvaara, Piotr Sikora, Ian David Benjamin, Ryan Hamilton, Ilari Liusvaara, Piotr Sikora, Ian
Swett, Martin Thomson, Sean Turner and many others. Swett, Martin Thomson, Sean Turner and many others.
Authors' Addresses Authors' Addresses
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