<?xml version="1.0" encoding="UTF-8"?>
  <?xml-stylesheet type="text/xsl" href="rfc2629.xslt" ?>
  <!-- generated by https://github.com/cabo/kramdown-rfc2629 version  -->

<!DOCTYPE rfc SYSTEM "rfc2629.dtd" [
]>

<?rfc toc="yes"?>
<?rfc sortrefs="yes"?>
<?rfc symrefs="yes"?>
<?rfc docmapping="yes"?>

<rfc docName="draft-ietf-tls-certificate-compression-09" category="std">

  <front>
    <title abbrev="TLS Certificate Compression">TLS Certificate Compression</title>

    <author initials="A." surname="Ghedini" fullname="Alessandro Ghedini">
      <organization>Cloudflare, Inc.</organization>
      <address>
        <email>alessandro@cloudflare.com</email>
      </address>
    </author>
    <author initials="V." surname="Vasiliev" fullname="Victor Vasiliev">
      <organization>Google</organization>
      <address>
        <email>vasilvv@google.com</email>
      </address>
    </author>

    <date year="2019" month="December" day="23"/>

    <area>Security</area>
    <workgroup>TLS</workgroup>
    

    <abstract>


<t>In TLS handshakes, certificate chains often take up
the majority of the bytes transmitted.</t>

<t>This document describes how certificate chains can be compressed to reduce the
amount of data transmitted and avoid some round trips.</t>



    </abstract>


  </front>

  <middle>


<section anchor="introduction" title="Introduction">

<t>In order to reduce latency and improve performance it can be useful to reduce
the amount of data exchanged during a TLS handshake.</t>

<t><xref target="RFC7924"></xref> describes a mechanism that allows a client and a server to avoid
transmitting certificates already shared in an earlier 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 certificate chain.</t>

<t>This document describes a mechanism that would allow certificates to be
compressed during all handshakes.</t>

</section>
<section anchor="notational-conventions" title="Notational Conventions">

<t>The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”,
“SHOULD NOT”, “RECOMMENDED”, “NOT RECOMMENDED”, “MAY”, and “OPTIONAL” in this
document are to be interpreted as described in BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/>
when, and only when, they appear in all capitals, as shown here.</t>

</section>
<section anchor="negotiating-certificate-compression" title="Negotiating Certificate Compression">

<t>This extension is only supported with TLS 1.3 <xref target="RFC8446"></xref> and newer; if TLS 1.2
<xref target="RFC5246"></xref> or earlier is negotiated, the peers MUST ignore this extension.</t>

<t>This document defines a new extension type (compress_certificate(27)), which
can be used to signal the supported compression formats for the Certificate
message to the peer.  Whenever it is sent by the client as a ClientHello message
extension (<xref target="RFC8446"></xref>, Section 4.1.2), it indicates the support for
compressed server certificates.  Whenever it is sent by the server as a
CertificateRequest extension (<xref target="RFC8446"></xref>, Section 4.3.2), it indicates
the support for compressed client certificates.</t>

<t>By sending a compress_certificate extension, the sender indicates to the peer
the certificate compression algorithms it is willing to use for decompression.
The “extension_data” field of this extension SHALL contain a
CertificateCompressionAlgorithms value:</t>

<figure><artwork><![CDATA[
    enum {
        zlib(1),
        brotli(2),
        zstd(3),
        (65535)
    } CertificateCompressionAlgorithm;

    struct {
        CertificateCompressionAlgorithm algorithms<2..2^8-2>;
    } CertificateCompressionAlgorithms;
]]></artwork></figure>

<t>The compress_certificate extension is a unidirectional indication; no
corresponding response extension is needed.</t>

</section>
<section anchor="compressed-certificate-message" title="Compressed Certificate Message">

<t>If the peer has indicated that it supports compression, server and client MAY
compress their corresponding Certificate messages (Section 4.4.2 of <xref target="RFC8446"/>)
and send them in the form of the CompressedCertificate message (replacing the
Certificate message).</t>

<t>The CompressedCertificate message is formed as follows:</t>

<figure><artwork><![CDATA[
    struct {
         CertificateCompressionAlgorithm algorithm;
         uint24 uncompressed_length;
         opaque compressed_certificate_message<1..2^24-1>;
    } CompressedCertificate;
]]></artwork></figure>

<t><list style="hanging">
  <t hangText='algorithm'>
  The algorithm used to compress the certificate.  The algorithm MUST be one of
the algorithms listed in the peer’s compress_certificate extension.</t>
  <t hangText='uncompressed_length'>
  The length of the Certificate message once it is uncompressed.  If after
decompression the specified length does not match the actual length, the
party receiving the invalid message MUST abort the connection with the
“bad_certificate” alert.  The presence of this field allows the receiver to
pre-allocate the buffer for the uncompressed Certificate message and to
enforce limits on the message size before performing decompression.</t>
  <t hangText='compressed_certificate_message'>
  The result of applying the indicated compression algorithm to the encoded
Certificate message that would have been sent if certificate compression was not
in use. The compression algorithm defines how the
bytes in the compressed_certificate_message field are converted into the
Certificate message.</t>
</list></t>

<t>If the specified compression algorithm is zlib, then the Certificate message
MUST be compressed with the ZLIB compression algorithm, as defined in <xref target="RFC1950"></xref>.
If the specified compression algorithm is brotli, the Certificate message MUST
be compressed with the Brotli compression algorithm as defined in <xref target="RFC7932"></xref>.  If
the specified compression algorithm is zstd, the Certificate message MUST be
compressed with the Zstandard compression algorithm as defined in <xref target="I-D.kucherawy-rfc8478bis"></xref>.</t>

<t>It is possible to define a certificate compression algorithm that uses a
pre-shared dictionary to achieve higher compression ratio.  This document does
not define any such algorithms, but additional codepoints may be allocated for
such use per the policy in <xref target="registry"/>.</t>

<t>If the received CompressedCertificate message cannot be decompressed, the
connection MUST be terminated with the “bad_certificate” alert.</t>

<t>If the format of the Certificate message is altered using the
server_certificate_type or client_certificate_type extensions <xref target="RFC7250"></xref>, the
resulting altered message is compressed instead.</t>

</section>
<section anchor="security-considerations" title="Security Considerations">

<t>After decompression, the Certificate message MUST be processed as if it were
encoded without being compressed.  This way, the parsing and the verification
have the same security properties as they would have in TLS normally.</t>

<t>In order for certificate compression to function correctly, the underlying
compression algorithm MUST output the same data
that was provided as input by the peer.</t>

<t>Since certificate chains are typically presented on a per-server name or
per-user basis, a malicious application does not have control over any individual fragments
in the Certificate message, meaning that they cannot leak information about the
certificate by modifying the plaintext.</t>

<t>Implementations SHOULD bound the memory usage when decompressing the
CompressedCertificate message.</t>

<t>Implementations MUST limit the size of the resulting decompressed chain to
the specified uncompressed length, and they MUST abort the connection if the
size of the output of the decompression function exceeds that limit.  TLS framing
imposes 16777216 byte limit on the certificate message size, and the implementations
MAY impose a limit that is lower than that; in both cases, they MUST apply the same
limit as if no compression were used.</t>

<t>While the Certificate message in TLS 1.3 is encrypted, third parties can draw
inferences from the message length observed on the wire.  TLS 1.3 provides a padding
mechanism (discussed in Sections 5.4 and E.3 of <xref target="RFC8446"></xref>) to counteract such
analysis.  Certificate compression alters the length of the Certificate message,
and the change in length is dependent on the actual contents of the certificate.
Any padding scheme covering the Certificate message has to address compression
within its design, or disable it altogether.</t>

</section>
<section anchor="middlebox-compatibility" title="Middlebox Compatibility">

<t>It’s been observed that a significant number of middleboxes intercept and try
to validate the Certificate message exchanged during a TLS handshake. This
means that middleboxes that don’t understand the CompressedCertificate message
might misbehave and drop connections that adopt certificate compression.
Because of that, the extension is only supported in the versions of TLS where
the certificate message is encrypted in a way that prevents middleboxes from
intercepting it, that is, TLS version 1.3 <xref target="RFC8446"></xref> and higher.</t>

</section>
<section anchor="iana-considerations" title="IANA Considerations">

<section anchor="update-of-the-tls-extensiontype-registry" title="Update of the TLS ExtensionType Registry">

<t>Create an entry, compress_certificate(27), in the existing registry for
ExtensionType (defined in <xref target="RFC8446"></xref>), with “TLS 1.3” column values
being set to “CH, CR”, and “Recommended” column being set to “Yes”.</t>

</section>
<section anchor="update-of-the-tls-handshaketype-registry" title="Update of the TLS HandshakeType Registry">

<t>Create an entry, compressed_certificate(25), in the existing registry for
HandshakeType (defined in <xref target="RFC8446"></xref>).</t>

</section>
<section anchor="registry" title="Registry for Compression Algorithms">

<t>This document establishes a registry of compression algorithms supported for
compressing the Certificate message, titled “Certificate Compression Algorithm
IDs”, under the existing “Transport Layer Security (TLS) Extensions” heading.</t>

<t>The entries in the registry are:</t>

<texttable>
      <ttcol align='left'>Algorithm Number</ttcol>
      <ttcol align='left'>Description</ttcol>
      <ttcol align='left'>Reference</ttcol>
      <c>0</c>
      <c>Reserved</c>
      <c>&#160;</c>
      <c>1</c>
      <c>zlib</c>
      <c>[this document]</c>
      <c>2</c>
      <c>brotli</c>
      <c>[this document]</c>
      <c>3</c>
      <c>zstd</c>
      <c>[this document]</c>
      <c>16384 to 65535</c>
      <c>Reserved for Experimental Use</c>
      <c>&#160;</c>
</texttable>

<t>The values in this registry shall be allocated under “IETF Review” policy for
values strictly smaller than 256, under “Specification Required” policy for
values 256-16383, and under “Experimental Use” otherwise (see <xref target="RFC8126"></xref> for the
definition of relevant policies).  Experimental Use extensions can be used both
on private networks and over the open Internet.</t>

<t>The procedures for requesting values in the Specification Required space are
specified in Section 17 of <xref target="RFC8447"></xref>.</t>

</section>
</section>


  </middle>

  <back>

    <references title='Normative References'>





<reference  anchor="RFC1950" target='https://www.rfc-editor.org/info/rfc1950'>
<front>
<title>ZLIB Compressed Data Format Specification version 3.3</title>
<author initials='P.' surname='Deutsch' fullname='P. Deutsch'><organization /></author>
<author initials='J-L.' surname='Gailly' fullname='J-L. Gailly'><organization /></author>
<date year='1996' month='May' />
<abstract><t>This specification defines a lossless compressed data format.  This memo provides information for the Internet community.  This memo does not specify an Internet standard of any kind.</t></abstract>
</front>
<seriesInfo name='RFC' value='1950'/>
<seriesInfo name='DOI' value='10.17487/RFC1950'/>
</reference>



<reference  anchor="RFC2119" target='https://www.rfc-editor.org/info/rfc2119'>
<front>
<title>Key words for use in RFCs to Indicate Requirement Levels</title>
<author initials='S.' surname='Bradner' fullname='S. Bradner'><organization /></author>
<date year='1997' month='March' />
<abstract><t>In many standards track documents several words are used to signify the requirements in the specification.  These words are often capitalized. This document defines these words as they should be interpreted in IETF documents.  This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t></abstract>
</front>
<seriesInfo name='BCP' value='14'/>
<seriesInfo name='RFC' value='2119'/>
<seriesInfo name='DOI' value='10.17487/RFC2119'/>
</reference>



<reference  anchor="RFC7250" target='https://www.rfc-editor.org/info/rfc7250'>
<front>
<title>Using Raw Public Keys in Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)</title>
<author initials='P.' surname='Wouters' fullname='P. Wouters' role='editor'><organization /></author>
<author initials='H.' surname='Tschofenig' fullname='H. Tschofenig' role='editor'><organization /></author>
<author initials='J.' surname='Gilmore' fullname='J. Gilmore'><organization /></author>
<author initials='S.' surname='Weiler' fullname='S. Weiler'><organization /></author>
<author initials='T.' surname='Kivinen' fullname='T. Kivinen'><organization /></author>
<date year='2014' month='June' />
<abstract><t>This document specifies a new certificate type and two TLS extensions for exchanging raw public keys in Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS).  The new certificate type allows raw public keys to be used for authentication.</t></abstract>
</front>
<seriesInfo name='RFC' value='7250'/>
<seriesInfo name='DOI' value='10.17487/RFC7250'/>
</reference>



<reference  anchor="RFC7932" target='https://www.rfc-editor.org/info/rfc7932'>
<front>
<title>Brotli Compressed Data Format</title>
<author initials='J.' surname='Alakuijala' fullname='J. Alakuijala'><organization /></author>
<author initials='Z.' surname='Szabadka' fullname='Z. Szabadka'><organization /></author>
<date year='2016' month='July' />
<abstract><t>This specification defines a lossless compressed data format that compresses data using a combination of the LZ77 algorithm and Huffman coding, with efficiency comparable to the best currently available general-purpose compression methods.</t></abstract>
</front>
<seriesInfo name='RFC' value='7932'/>
<seriesInfo name='DOI' value='10.17487/RFC7932'/>
</reference>



<reference  anchor="RFC7924" target='https://www.rfc-editor.org/info/rfc7924'>
<front>
<title>Transport Layer Security (TLS) Cached Information Extension</title>
<author initials='S.' surname='Santesson' fullname='S. Santesson'><organization /></author>
<author initials='H.' surname='Tschofenig' fullname='H. Tschofenig'><organization /></author>
<date year='2016' month='July' />
<abstract><t>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).</t><t>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.</t></abstract>
</front>
<seriesInfo name='RFC' value='7924'/>
<seriesInfo name='DOI' value='10.17487/RFC7924'/>
</reference>



<reference  anchor="RFC8126" target='https://www.rfc-editor.org/info/rfc8126'>
<front>
<title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
<author initials='M.' surname='Cotton' fullname='M. Cotton'><organization /></author>
<author initials='B.' surname='Leiba' fullname='B. Leiba'><organization /></author>
<author initials='T.' surname='Narten' fullname='T. Narten'><organization /></author>
<date year='2017' month='June' />
<abstract><t>Many protocols make use of points of extensibility that use constants to identify various protocol parameters.  To ensure that the values in these fields do not have conflicting uses and to promote interoperability, their allocations are often coordinated by a central record keeper.  For IETF protocols, that role is filled by the Internet Assigned Numbers Authority (IANA).</t><t>To make assignments in a given registry prudently, guidance describing the conditions under which new values should be assigned, as well as when and how modifications to existing values can be made, is needed.  This document defines a framework for the documentation of these guidelines by specification authors, in order to assure that the provided guidance for the IANA Considerations is clear and addresses the various issues that are likely in the operation of a registry.</t><t>This is the third edition of this document; it obsoletes RFC 5226.</t></abstract>
</front>
<seriesInfo name='BCP' value='26'/>
<seriesInfo name='RFC' value='8126'/>
<seriesInfo name='DOI' value='10.17487/RFC8126'/>
</reference>



<reference  anchor="RFC8174" target='https://www.rfc-editor.org/info/rfc8174'>
<front>
<title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title>
<author initials='B.' surname='Leiba' fullname='B. Leiba'><organization /></author>
<date year='2017' month='May' />
<abstract><t>RFC 2119 specifies common key words that may be used in protocol  specifications.  This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the  defined special meanings.</t></abstract>
</front>
<seriesInfo name='BCP' value='14'/>
<seriesInfo name='RFC' value='8174'/>
<seriesInfo name='DOI' value='10.17487/RFC8174'/>
</reference>



<reference  anchor="RFC8446" target='https://www.rfc-editor.org/info/rfc8446'>
<front>
<title>The Transport Layer Security (TLS) Protocol Version 1.3</title>
<author initials='E.' surname='Rescorla' fullname='E. Rescorla'><organization /></author>
<date year='2018' month='August' />
<abstract><t>This document specifies version 1.3 of the Transport Layer Security (TLS) protocol.  TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery.</t><t>This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961.  This document also specifies new requirements for TLS 1.2 implementations.</t></abstract>
</front>
<seriesInfo name='RFC' value='8446'/>
<seriesInfo name='DOI' value='10.17487/RFC8446'/>
</reference>



<reference  anchor="RFC8447" target='https://www.rfc-editor.org/info/rfc8447'>
<front>
<title>IANA Registry Updates for TLS and DTLS</title>
<author initials='J.' surname='Salowey' fullname='J. Salowey'><organization /></author>
<author initials='S.' surname='Turner' fullname='S. Turner'><organization /></author>
<date year='2018' month='August' />
<abstract><t>This document describes a number of changes to TLS and DTLS IANA registries that range from adding notes to the registry all the way to changing the registration policy.  These changes were mostly motivated by WG review of the TLS- and DTLS-related registries undertaken as part of the TLS 1.3 development process.</t><t>This document updates the following RFCs: 3749, 5077, 4680, 5246, 5705, 5878, 6520, and 7301.</t></abstract>
</front>
<seriesInfo name='RFC' value='8447'/>
<seriesInfo name='DOI' value='10.17487/RFC8447'/>
</reference>



<reference anchor="I-D.kucherawy-rfc8478bis">
<front>
<title>Zstandard Compression and the application/zstd Media Type</title>

<author initials='Y' surname='Collet' fullname='Yann Collet'>
    <organization />
</author>

<author initials='M' surname='Kucherawy' fullname='Murray Kucherawy'>
    <organization />
</author>

<date month='December' day='20' year='2019' />

<abstract><t>Zstandard, or "zstd" (pronounced "zee standard"), is a data compression mechanism.  This document describes the mechanism and registers a media type and content encoding to be used when transporting zstd-compressed content via Multipurpose Internet Mail Extensions (MIME).  Despite use of the word "standard" as part of its name, readers are advised that this document is not an Internet Standards Track specification; it is being published for informational purposes only.  This document replaces and obsoletes RFC 8478.</t></abstract>

</front>

<seriesInfo name='Internet-Draft' value='draft-kucherawy-rfc8478bis-03' />
<format type='TXT'
        target='http://www.ietf.org/internet-drafts/draft-kucherawy-rfc8478bis-03.txt' />
</reference>




    </references>

    <references title='Informative References'>





<reference  anchor="RFC5246" target='https://www.rfc-editor.org/info/rfc5246'>
<front>
<title>The Transport Layer Security (TLS) Protocol Version 1.2</title>
<author initials='T.' surname='Dierks' fullname='T. Dierks'><organization /></author>
<author initials='E.' surname='Rescorla' fullname='E. Rescorla'><organization /></author>
<date year='2008' month='August' />
<abstract><t>This document specifies Version 1.2 of the Transport Layer Security (TLS) protocol.  The TLS protocol provides communications security over the Internet.  The protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery.  [STANDARDS-TRACK]</t></abstract>
</front>
<seriesInfo name='RFC' value='5246'/>
<seriesInfo name='DOI' value='10.17487/RFC5246'/>
</reference>




    </references>


<section anchor="acknowledgements" title="Acknowledgements">

<t>Certificate compression was originally introduced in the QUIC Crypto protocol,
designed by Adam Langley and Wan-Teh Chang.</t>

<t>This document has benefited from contributions and suggestions from David
Benjamin, Ryan Hamilton, Christian Huitema, Benjamin Kaduk, Ilari Liusvaara,
Piotr Sikora, Ian Swett, Martin Thomson, Sean Turner and many others.</t>

</section>


  </back>

<!-- ##markdown-source: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-->

</rfc>

