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draft-ietf-quic-version-negotiation.txt
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QUIC D. Schinazi
Internet-Draft Google LLC
Intended status: Standards Track E. Rescorla
Expires: 8 October 2022 Mozilla
6 April 2022
Compatible Version Negotiation for QUIC
draft-ietf-quic-version-negotiation-latest
Abstract
QUIC does not provide a complete version negotiation mechanism but
instead only provides a way for the server to indicate that the
version the client chose is unacceptable. This document describes a
version negotiation mechanism that allows a client and server to
select a mutually supported version. Optionally, if the client's
chosen version and the negotiated version share a compatible first
flight format, the negotiation can take place without incurring an
extra round trip.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://quicwg.github.io/version-negotiation/draft-ietf-quic-version-
negotiation.html. Status information for this document may be found
at https://datatracker.ietf.org/doc/draft-ietf-quic-version-
negotiation/.
Discussion of this document takes place on the QUIC Working Group
mailing list (mailto:quic@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/quic/.
Source for this draft and an issue tracker can be found at
https://github.com/quicwg/version-negotiation.
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 8 October 2022.
Copyright Notice
Copyright (c) 2022 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 Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction
1.1. Conventions and Definitions
2. Version Negotiation Mechanism
2.1. Incompatible Version Negotiation
2.2. Compatible Versions
2.3. Compatible Version Negotiation
2.4. Connections and Version Negotiation
2.5. Client Choice of Original Version
3. Version Information
4. Version Downgrade Prevention
5. Server Deployments of QUIC
6. Application Layer Protocol Considerations
7. Considerations for Future Versions
7.1. Interaction with Retry
7.2. Interaction with TLS resumption
7.3. Interaction with 0-RTT
8. Special Handling for QUIC Version 1
9. Security Considerations
10. IANA Considerations
10.1. QUIC Transport Parameter
10.2. QUIC Transport Error Code
11. Normative References
Acknowledgments
Authors' Addresses
1. Introduction
The version-invariant properties of QUIC [INV] define a Version
Negotiation packet but do not specify how an endpoint reacts when it
receives one. QUIC version 1 [QUIC] allows the server to use a
Version Negotiation packet to indicate that the version the client
chose is unacceptable, but doesn't allow the client to safely make
use of that information to create a new connection with a mutually
supported version.
With proper safety mechanisms in place, the Version Negotiation
packet can be part of a mechanism to allow two QUIC implementations
to negotiate between two totally disjoint versions of QUIC. This
document specifies version negotiation using Version Negotiation
packets, which adds an extra round trip to connection establishment
if needed.
It is beneficial to avoid additional round trips whenever possible,
especially given that most incremental versions are broadly similar
to the the previous version. This specification also defines a
simple version negotiation mechanism which leverages similarities
between versions and can negotiate between the set of "compatible"
versions without additional round trips.
1.1. Conventions and Definitions
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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
In this document, the Maximum Segment Lifetime (MSL) represents the
time a QUIC packet can exist in the network. Implementations can
make this configurable, and a RECOMMENDED value is one minute.
2. Version Negotiation Mechanism
This document specifies two means of performing version negotiation:
one "incompatible" which requires a round trip and is applicable to
all versions, and one "compatible" that allows saving the round trip
but only applies when the versions are compatible.
The client initiates a QUIC connection by choosing an initial version
and sending a first flight of QUIC packets with a long header to the
server [INV]. The client's first flight includes Version Information
(see Section 3) which will be used to optionally enable compatible
version negotation (see Section 2.3), and to prevent version
downgrade attacks (see Section 4). We'll refer to the version of the
very first packets the client sends as the "original version" and the
version of the first packets the client sends in a given QUIC
connection as the "client's chosen version".
Upon receiving this first flight, the server verifies whether it
knows how to parse first flights from the original version. If it
does not, then it starts incompatible version negotiation, see
Section 2.1, which causes the client to initiate a new connection
with a different version. For instance, if the client initiates a
connection with version A and the server starts incompatible version
negotiation and the client then initiates a new connection with
version B, we say that the first connection's client chosen version
is A, the second connection's client chosen version is B, and the
original version for the entire sequence is A.
If the server can parse the first flight, it can either establish the
connection using the client's chosen version, or it MAY select any
other compatible version, as described in Section 2.3.
Note that it is possible for a server to have the ability to parse
the first flight of a given version without fully supporting it, in
the sense that it implements enough of the version's specification to
parse first flight packets but not enough to fully establish a
connection using that version.
2.1. Incompatible Version Negotiation
The server starts incompatible version negotiation by sending a
Version Negotiation packet. This packet SHALL include each entry
from the server's set of Offered Versions (see Section 5) in a
Supported Version field. The server MAY add reserved versions (as
defined in Section 6.3 of [QUIC]) in Supported Version fields.
Clients will ignore a Version Negotiation packet if it contains the
original version attempted by the client. The client also ignores a
Version Negotiation packet that contains incorrect connection ID
fields; see Section 6 of [INV].
Upon receiving the Version Negotiation packet, the client will search
for a version it supports in the list provided by the server. If it
doesn't find one, it aborts the connection attempt. Otherwise, it
selects a mutually supported version and sends a new first flight
with that version - we refer to this version as the "negotiated
version".
The new first flight will allow the endpoints to establish a
connection using the negotiated version. The handshake of the
negotiated version will exchange version information (see Section 3)
required to ensure that version negotiation was genuine, i.e. that no
attacker injected packets in order to influence the version
negotiation process, see Section 4.
2.2. Compatible Versions
If A and B are two distinct versions of QUIC, A is said to be
"compatible" with B if it is possible to take a first flight of
packets from version A and convert it into a first flight of packets
from version B. As an example, if versions A and B are absolutely
equal in their wire image and behavior during the handshake but
differ after the handshake, then A is compatible with B and B is
compatible with A. Note that the conversion of the first flight can
be lossy: some data such as QUIC version 1 0-RTT packets could be
ignored during conversion and retransmitted later.
Version compatibility is not symmetric: it is possible for version A
to be compatible with version B and for B not to be compatible with
A. This could happen for example if version B is a strict superset
of version A: if version A includes the concept of streams and STREAM
frames, and version B includes the concepts of streams and tubes
along with STREAM and TUBE frames, then A would be compatible with B
but B would not be compatible with A.
Note that version compatibility does not mean that every single
possible instance of a first flight will succeed in conversion to the
other version. A first flight using version A is said to be
"compatible" with version B if two conditions are met: first that
version A is compatible with version B, and second that the
conversion of this first flight to version B is well-defined. For
example, if version B is equal to A in all aspects except it
introduced a new frame in its first flight that version A cannot
parse or even ignore, then B could still be compatible with A as
conversions would succeed for connections where that frame is not
used. In this example, first flights using version B that carry this
new frame would not be compatible with version A.
When a new version of QUIC is defined, it is assumed to not be
compatible with any other version unless otherwise specified.
Similarly, no other version is compatible with the new version unless
otherwise specified. Implementations MUST NOT assume compatibility
between versions unless explicitly specified.
Note that both endpoints might disagree on whether two versions are
compatible or not. For example, two versions could have been defined
concurrently and then specified as compatible in a third document
much later - in that scenario one endpoint might be aware of the
compatibility document while the other may not.
2.3. Compatible Version Negotiation
When the server can parse the client's first flight using the
client's chosen version, it can extract the client's Version
Information structure (see Section 3). This contains the list of
versions that the client knows its first flight is compatible with.
In order to perform compatible version negotiation, the server MUST
select one of these versions that (1) it supports and (2) it knows
the client's chosen version to be compatible with. Once the server
has selected a version, termed the "negotiated version", it then
attempts to convert the client's first flight into that version, and
replies to the client as if it had received the converted first
flight.
If those formats are identical, as in cases where the negotiated
version is the same as the client's chosen version, then this will be
the identity transform. If the first flight is correctly formatted,
then this conversion process cannot fail by definition of the first
flight being compatible; if the server is unable to convert the first
flight, it MUST abort the handshake.
Clients can determine the server's negotiated version by examining
the QUIC long header Version field. It is possible for the server to
initially send packets with the client's chosen version before
switching to the negotiated version (for example, this can happen
when the client's Version Information structure spans multiple
packets; in that case the server might acknowledge the first packet
in the client's chosen version and later switch to a different
negotiated version).
Note that, after the first flight is converted to the negotiated
version, the handshake completes in the negotiated version. The
entire handshake (including the converted first flight) needs to
conform to the rules of the negotiated version. For instance, if the
negotiated version requires that the 5-tuple remain stable for the
entire handshake (as QUIC version 1 does), then this applies to the
entire handshake, including the first flight.
Note also that the client can disable compatible version negotiation
by only including the Chosen Version in the Other Versions field of
the Version Information transport parameter.
If the server does not find a compatible version (including the
client's chosen version), it will perform incompatible version
negotiation instead, see Section 2.1.
Note that it is possible to have incompatible version negotation
followed by compatible version negotiation. For instance, if version
A is compatible with B and C is compatible with D, the following
scenario could occur:
Client Server
Chosen = A, Other Versions = (A, B) ----------------->
<------------------------ Version Negotiation = (D, C)
Chosen = C, Other Versions = (C, D) ----------------->
<----------------- Chosen = D, Other Versions = (D, C)
Figure 1: Combined Negotiation Example
In this example, the client selected C from the server's Version
Negotiation packet, but the server preferred D and then selected it
from the client's offer.
2.4. Connections and Version Negotiation
QUIC connections are shared state between a client and a server
[INV]. The compatible version negotiation mechanism defined in this
document (see Section 2.3) is performed as part of a single QUIC
connection; that is, the packets with the client's chosen version are
part of the same connection as the packets with the negotiated
version.
In comparison, the incompatible version negotiation mechanism, which
leverages QUIC Version Negotiation packets (see Section 2.1)
conceptually operates across two QUIC connections: the connection
attempt prior to receiving the Version Negotiation packet is distinct
from the connection with the incompatible version that follows.
Note that this separation across two connections is conceptual: it
applies to normative requirements on QUIC connections, but does not
require implementations to internally use two distinct connection
objects.
2.5. Client Choice of Original Version
When the client picks its original version, it will try to avoid
incompatible version negotiation to save a round trip. Therefore,
the client SHOULD pick an original version to maximize the combined
probability that both:
* The server knows how to parse first flights from the original
version.
* The original version is compatible with the client's preferred
version.
Without additional information, this could mean selecting the oldest
version that the client supports.
3. Version Information
During the handshake, endpoints will exchange Version Information,
which consists of a chosen version and a list of other versions. Any
version of QUIC that supports this mechanism MUST provide a mechanism
to exchange Version Information in both directions during the
handshake, such that this data is authenticated.
In QUIC version 1, the Version Information is transmitted using a new
transport parameter, version_information. The contents of Version
Information are shown below (using the notation from the "Notational
Conventions" section of [QUIC]):
Version Information {
Chosen Version (32),
Other Versions (32) ...,
}
Figure 2: Version Information Format
The content of each field is described below:
Chosen Version: The version that the sender has chosen to use for
this connection. In most cases, this field will be equal to the
value of the Version field in the long header that carries this
data.
The contents of the Other Versions field depends on whether it is
sent by the client or by the server.
Client-Sent Other Versions: When sent by a client, the Other
Versions field lists all the versions that this first flight is
compatible with, ordered by descending preference. Note that the
version in the Chosen Version field MUST be included in this list
to allow the client to communicate the chosen version's
preference. Note that this preference is only advisory, servers
MAY choose to use their own preference instead.
Server-Sent Other Versions: When sent by a server, the Other
Versions field lists all the Fully-Deployed Versions of this
server deployment, see Section 5. Note that the version in the
Chosen Version field is not necessarily included in this list,
because the server operator could be in the process of removing
support for this version. For the same reason, the Other Versions
field MAY be empty.
Clients and servers MAY both include versions following the pattern
0x?a?a?a?a in their Other Versions list. Those versions are reserved
to exercise version negotiation (see the Versions section of [QUIC]),
and will never be selected when choosing a version to use.
4. Version Downgrade Prevention
Clients MUST ignore any received Version Negotiation packets that
contain the version that they initially attempted. A client that
makes a connection attempt based on information received from a
Version Negotiation packet MUST ignore any Version Negotiation
packets it receives in response to that connection attempt.
Both endpoints MUST parse their peer's Version Information during the
handshake. If parsing the Version Information failed (for example,
if it is too short or if its length is not divisible by four), then
the endpoint MUST close the connection; if the connection was using
QUIC version 1, that connection closure MUST use a transport error of
type TRANSPORT_PARAMETER_ERROR. If an endpoint receives a Chosen
Version equal to zero, or any Other Version equal to zero, it MUST
treat it as a parsing failure.
Every QUIC version that supports version negotiation MUST define a
method for closing the connection with a version negotiation error.
For QUIC version 1, version negotiation errors are signaled using a
transport error of type VERSION_NEGOTIATION_ERROR; see Section 10.2.
If the Version Information was missing, the endpoints MAY complete
the handshake. However, if a client has reacted to a Version
Negotiation packet and the Version Information was missing, the
client MUST close the connection with a version negotiation error.
If the client received and acted on a Version Negotiation packet, the
client MUST validate the server's Other Versions field. The Other
Versions field is validated by confirming that the client would have
attempted the same version with knowledge of the versions the server
supports. That is, the client would have selected the same version
if it received a Version Negotiation packet that listed the versions
in the server's Other Versions field, plus the negotiated version.
If the client would have selected a different version, the client
MUST close the connection with a version negotiation error. In
particular, if the client reacted to a Version Negotiation packet and
the server's Other Versions field is empty, the client MUST close the
connection with a version negotiation error. These connection
closures prevent an attacker from being able to use forged Version
Negotiation packets to force a version downgrade.
This validation of Other Versions is not sufficient to prevent
downgrade. Downgrade prevention also depends on the client ignoring
Version Negotiation packets that contain the original version; see
Section 2.1.
After the process of version negotiation in this document completes,
the version in use for the connection is the version that the server
sent in the Chosen Version field of its Version Information. That
remains true even if other versions were used in the Version field of
long headers at any point in the lifetime of the connection. In
particular, since during compatible version negotiation the client is
made aware of the negotiated version by the QUIC long header version
(see Section 2.3), clients MUST validate that the server's Chosen
Version is equal to the negotiated version; if they do not match, the
client MUST close the connection with a version negotiation error.
This prevents an attacker's ability to influence version negotiation
by forging the Version long header field.
5. Server Deployments of QUIC
While this document mainly discusses a single QUIC server, it is
common for deployments of QUIC servers to include a fleet of multiple
server instances. We therefore define the following terms:
Acceptable Versions: This is the set of versions supported by a
given server instance. More specifically, these are the versions
that a given server instance will use if a client sends a first
flight using them.
Offered Versions: This is the set of versions that a given server
instance will send in a Version Negotiation packet if it receives
a first flight from an unknown version. This set will most often
be equal to the Acceptaple Versions set, except during short
transitions while versions are added or removed (see below).
Fully-Deployed Versions: This is the set of QUIC versions that is
supported and negotiated by every single QUIC server instance in
this deployment. If a deployment only contains a single server
instance, then this set is equal to the Offered Versions set,
except during short transitions while versions are added or
removed (see below).
If a deployment contains multiple server instances, software updates
may not happen at exactly the same time on all server instances.
Because of this, a client might receive a Version Negotiation packet
from a server instance that has already been updated and the client's
resulting connection attempt might reach a different server instance
which hasn't been updated yet.
However, even when there is only a single server instance, it is
still possible to receive a stale Version Negotiation packet if the
server performs its software update while the Version Negotiation
packet is in flight.
This could cause the version downgrade prevention mechanism described
in Section 4 to falsely detect a downgrade attack. To avoid that,
server operators SHOULD perform a three-step process when they wish
to add or remove support for a version:
When adding support for a new version:
* The first step is to progressively add support for the new version
to all server instances. This step updates the Acceptable
Versions but not the Offered Versions nor the Fully-Deployed
Versions. Once all server instances have been updated, operators
wait for at least one MSL to allow any in-flight Version
Negotiation packets to arrive.
* Then, the second step is to progressively add the new version to
Offered Versions on all server instances. Once complete,
operators wait for at least another MSL.
* Finally, the third step is to progressively add the new version to
Fully-Deployed Versions on all server instances.
When removing support for a version:
* The first step is to progressively remove the version from Fully-
Deployed Versions on all server instances. Once it has been
removed on all server instances, operators wait for at least one
MSL to allow any in-flight Version Negotiation packets to arrive.
* Then, the second step is to progressively remove the version from
Offered Versions on all server instances. Once complete,
operators wait for at least another MSL.
* Finally, the third step is to progressively remove support for the
version from all server instances. That step updates the
Acceptable Versions.
Note that this opens connections to version downgrades (but only for
partially-deployed versions) during the update window, since those
could be due to clients communicating with both updated and non-
updated server instances.
6. Application Layer Protocol Considerations
When a client creates a QUIC connection, its goal is to use an
application layer protocol. Therefore, when considering which
versions are compatible, clients will only consider versions that
support one of the intended application layer protocols. If the
client's first flight advertises multiple Application Layer Protocol
Negotiation (ALPN) [ALPN] tokens and multiple compatible versions, it
is possible for some application layer protocols to not be able to
run over some of the offered compatible versions. It is the server's
responsibility to only select an ALPN token that can run over the
compatible QUIC version that it selects.
A given ALPN token MUST NOT be used with a new QUIC version different
from the version for which the ALPN token was originally defined,
unless all the following requirements are met:
* The new QUIC version supports the transport features required by
the application protocol.
* The new QUIC version supports ALPN.
* The version of QUIC for which the ALPN token was originally
defined is compatible with the new QUIC version.
When incompatible version negotiation is in use, the second
connection which is created in response to the received version
negotiation packet MUST restart its application layer protocol
negotiation process without taking into account the original version.
7. Considerations for Future Versions
In order to facilitate the deployment of future versions of QUIC,
designers of future versions SHOULD attempt to design their new
version such that commonly deployed versions are compatible with it.
QUIC version 1 defines multiple features which are not documented in
the QUIC invariants. Since at the time of writing QUIC version 1 is
widely deployed, this section discusses considerations for future
versions to help with compatibility with QUIC version 1.
7.1. Interaction with Retry
QUIC version 1 features Retry packets, which the server can send to
validate the client's IP address before parsing the client's first
flight. A server that sends a Retry packet can do so before parsing
the client's first flight. A server that sends a Retry packet
therefore might not have processed the client's Version Information
before doing so.
If a future document wishes to define compatibility between two
versions that support retry, that document MUST specify how version
negotiation (both compatible and incompatible) interacts with retry
during a handshake that requires both. For example, that could be
accomplished by having the server send a Retry packet in the original
version first thereby validating the client's IP address before
attempting compatible version negotiation. If both versions support
authenticating Retry packets, the compatibility defition needs to
define how to authenticate the Retry in the negotiated version
handshake even though the Retry itself was sent using the client's
chosen version.
7.2. Interaction with TLS resumption
QUIC version 1 uses TLS 1.3, which supports session resumption by
sending session tickets in one connection that can be used in a later
connection; see Section 2.2 of [TLS]. New versions that also use TLS
1.3 SHOULD mandate that their session tickets are tightly scoped to
one version of QUIC; i.e., require that clients not use them across
multiple version and that servers validate this client requirement.
7.3. Interaction with 0-RTT
QUIC version 1 allows sending data from the client to the server
during the handshake, by using 0-RTT packets. If a future document
wishes to define compatibility between two versions that support
0-RTT, that document MUST address the scenario where there are 0-RTT
packets in the client's first flight. For example, this could be
accomplished by defining which transformations are applied to 0-RTT
packets. That document could specify that compatible version
negotiation causes 0-RTT data to be rejected by the server.
8. Special Handling for QUIC Version 1
Because QUIC version 1 was the only IETF Standards Track version of
QUIC published before this document, it is handled specially as
follows: if a client is starting a QUIC version 1 connection in
response to a received Version Negotiation packet, and the
version_information transport parameter is missing from the server's
transport parameters, then the client SHALL proceed as if the
server's transport parameters contained a version_information
transport parameter with a Chosen Version set to 0x00000001 and an
Other Version list containing exactly one version set to 0x00000001.
This allows version negotiation to work with servers that only
support QUIC version 1. Note that implementations which wish to use
version negotiation to negotiate versions other than QUIC version 1
will need to implement the version negotiation mechanism defined in
this document.
9. Security Considerations
The security of this version negotiation mechanism relies on the
authenticity of the Version Information exchanged during the
handshake. In QUIC version 1, transport parameters are authenticated
ensuring the security of this mechanism. Negotiation between
compatible versions will have the security of the weakest common
version.
The requirement that versions not be assumed compatible mitigates the
possibility of cross-protocol attacks, but more analysis is still
needed here.
10. IANA Considerations
10.1. QUIC Transport Parameter
This document registers a new value in the "QUIC Transport
Parameters" registry maintained at <https://www.iana.org/assignments/
quic>.
Value: 0xFF73DB
Parameter Name: version_information
Status: provisional
Specification: This document
When this document is approved, it will request permanent allocation
of a codepoint in the 0-63 range to replace the provisional codepoint
described above.
10.2. QUIC Transport Error Code
This document registers a new value in the "QUIC Transport Error
Codes" registry maintained at <https://www.iana.org/assignments/
quic>.
Value: 0x53F8
Code: VERSION_NEGOTIATION_ERROR
Description: Error negotiating version
Status: provisional
Specification: This document
When this document is approved, it will request permanent allocation
of a codepoint in the 0-63 range to replace the provisional codepoint
described above.
11. Normative References
[ALPN] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <https://www.rfc-editor.org/rfc/rfc7301>.
[INV] Thomson, M., "Version-Independent Properties of QUIC",
RFC 8999, DOI 10.17487/RFC8999, May 2021,
<https://www.rfc-editor.org/rfc/rfc8999>.
[QUIC] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/rfc/rfc9000>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[TLS] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/rfc/rfc8446>.
Acknowledgments
The authors would like to thank Nick Banks, Mike Bishop, Ryan
Hamilton, Roberto Peon, Anthony Rossi, and Martin Thomson for their
input and contributions.
Authors' Addresses
David Schinazi
Google LLC
1600 Amphitheatre Parkway
Mountain View, CA 94043
United States of America
Email: dschinazi.ietf@gmail.com
Eric Rescorla
Mozilla
Email: ekr@rtfm.com