QUIC M. Thomson, Ed.
Internet-Draft Mozilla
Intended status: Standards Track S. Turner, Ed.
Expires: February 16, 2019 sn3rd
August 15, 2018
Using Transport Layer Security (TLS) to Secure QUIC
draft-ietf-quic-tls-14
Abstract
This document describes how Transport Layer Security (TLS) is used to
secure QUIC.
Note to Readers
Discussion of this draft takes place on the QUIC working group
mailing list (quic@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/search/?email_list=quic [1].
Working Group information can be found at https://github.com/quicwg
[2]; source code and issues list for this draft can be found at
https://github.com/quicwg/base-drafts/labels/-tls [3].
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-
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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 February 16, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Notational Conventions . . . . . . . . . . . . . . . . . . . 3
2.1. TLS Overview . . . . . . . . . . . . . . . . . . . . . . 4
3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 6
4. Carrying TLS Messages . . . . . . . . . . . . . . . . . . . . 7
4.1. Interface to TLS . . . . . . . . . . . . . . . . . . . . 9
4.1.1. Sending and Receiving Handshake Messages . . . . . . 9
4.1.2. Encryption Level Changes . . . . . . . . . . . . . . 11
4.1.3. TLS Interface Summary . . . . . . . . . . . . . . . . 11
4.2. TLS Version . . . . . . . . . . . . . . . . . . . . . . . 12
4.3. ClientHello Size . . . . . . . . . . . . . . . . . . . . 13
4.4. Peer Authentication . . . . . . . . . . . . . . . . . . . 13
4.5. Enabling 0-RTT . . . . . . . . . . . . . . . . . . . . . 14
4.6. Rejecting 0-RTT . . . . . . . . . . . . . . . . . . . . . 14
4.7. HelloRetryRequest . . . . . . . . . . . . . . . . . . . . 14
4.8. TLS Errors . . . . . . . . . . . . . . . . . . . . . . . 15
4.9. Discarding Unused Keys . . . . . . . . . . . . . . . . . 15
5. QUIC Packet Protection . . . . . . . . . . . . . . . . . . . 16
5.1. QUIC Packet Encryption Keys . . . . . . . . . . . . . . . 16
5.1.1. Initial Secrets . . . . . . . . . . . . . . . . . . . 17
5.2. QUIC AEAD Usage . . . . . . . . . . . . . . . . . . . . . 17
5.3. Packet Number Protection . . . . . . . . . . . . . . . . 18
5.3.1. AES-Based Packet Number Protection . . . . . . . . . 20
5.3.2. ChaCha20-Based Packet Number Protection . . . . . . . 20
5.4. Receiving Protected Packets . . . . . . . . . . . . . . . 20
5.5. Use of 0-RTT Keys . . . . . . . . . . . . . . . . . . . . 21
5.6. Receiving Out-of-Order Protected Frames . . . . . . . . . 21
6. Key Update . . . . . . . . . . . . . . . . . . . . . . . . . 22
7. Security of Initial Messages . . . . . . . . . . . . . . . . 23
8. QUIC-Specific Additions to the TLS Handshake . . . . . . . . 24
8.1. Protocol and Version Negotiation . . . . . . . . . . . . 24
8.2. QUIC Transport Parameters Extension . . . . . . . . . . . 24
9. Security Considerations . . . . . . . . . . . . . . . . . . . 25
9.1. Packet Reflection Attack Mitigation . . . . . . . . . . . 25
9.2. Peer Denial of Service . . . . . . . . . . . . . . . . . 25
9.3. Packet Number Protection Analysis . . . . . . . . . . . . 26
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10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
11.1. Normative References . . . . . . . . . . . . . . . . . . 27
11.2. Informative References . . . . . . . . . . . . . . . . . 28
11.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 29
A.1. Since draft-ietf-quic-tls-13 . . . . . . . . . . . . . . 29
A.2. Since draft-ietf-quic-tls-12 . . . . . . . . . . . . . . 29
A.3. Since draft-ietf-quic-tls-11 . . . . . . . . . . . . . . 30
A.4. Since draft-ietf-quic-tls-10 . . . . . . . . . . . . . . 30
A.5. Since draft-ietf-quic-tls-09 . . . . . . . . . . . . . . 30
A.6. Since draft-ietf-quic-tls-08 . . . . . . . . . . . . . . 30
A.7. Since draft-ietf-quic-tls-07 . . . . . . . . . . . . . . 30
A.8. Since draft-ietf-quic-tls-05 . . . . . . . . . . . . . . 30
A.9. Since draft-ietf-quic-tls-04 . . . . . . . . . . . . . . 30
A.10. Since draft-ietf-quic-tls-03 . . . . . . . . . . . . . . 30
A.11. Since draft-ietf-quic-tls-02 . . . . . . . . . . . . . . 30
A.12. Since draft-ietf-quic-tls-01 . . . . . . . . . . . . . . 30
A.13. Since draft-ietf-quic-tls-00 . . . . . . . . . . . . . . 31
A.14. Since draft-thomson-quic-tls-01 . . . . . . . . . . . . . 31
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 31
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction
This document describes how QUIC [QUIC-TRANSPORT] is secured using
Transport Layer Security (TLS) version 1.3 [TLS13]. TLS 1.3 provides
critical latency improvements for connection establishment over
previous versions. Absent packet loss, most new connections can be
established and secured within a single round trip; on subsequent
connections between the same client and server, the client can often
send application data immediately, that is, using a zero round trip
setup.
This document describes how the standardized TLS 1.3 acts as a
security component of QUIC.
2. Notational Conventions
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.
This document uses the terminology established in [QUIC-TRANSPORT].
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For brevity, the acronym TLS is used to refer to TLS 1.3.
2.1. TLS Overview
TLS provides two endpoints with a way to establish a means of
communication over an untrusted medium (that is, the Internet) that
ensures that messages they exchange cannot be observed, modified, or
forged.
Internally, TLS is a layered protocol, with the structure shown
below:
+--------------+--------------+--------------+
| Handshake | Alerts | Application |
| Layer | | Data |
| | | |
+--------------+--------------+--------------+
| |
| Record Layer |
| |
+--------------------------------------------+
Each upper layer (handshake, alerts, and application data) is carried
as a series of typed TLS records. Records are individually
cryptographically protected and then transmitted over a reliable
transport (typically TCP) which provides sequencing and guaranteed
delivery.
The TLS authenticated key exchange occurs between two entities:
client and server. The client initiates the exchange and the server
responds. If the key exchange completes successfully, both client
and server will agree on a secret. TLS supports both pre-shared key
(PSK) and Diffie-Hellman (DH) key exchanges. PSK is the basis for
0-RTT; the latter provides perfect forward secrecy (PFS) when the DH
keys are destroyed.
After completing the TLS handshake, the client will have learned and
authenticated an identity for the server and the server is optionally
able to learn and authenticate an identity for the client. TLS
supports X.509 [RFC5280] certificate-based authentication for both
server and client.
The TLS key exchange is resistent to tampering by attackers and it
produces shared secrets that cannot be controlled by either
participating peer.
TLS 1.3 provides two basic handshake modes of interest to QUIC:
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o A full 1-RTT handshake in which the client is able to send
application data after one round trip and the server immediately
responds after receiving the first handshake message from the
client.
o A 0-RTT handshake in which the client uses information it has
previously learned about the server to send application data
immediately. This application data can be replayed by an attacker
so it MUST NOT carry a self-contained trigger for any non-
idempotent action.
A simplified TLS 1.3 handshake with 0-RTT application data is shown
in Figure 1, see [TLS13] for more options and details.
Client Server
ClientHello
(0-RTT Application Data) -------->
ServerHello
{EncryptedExtensions}
{Finished}
<-------- [Application Data]
(EndOfEarlyData)
{Finished} -------->
[Application Data] <-------> [Application Data]
() Indicates messages protected by early data (0-RTT) keys
{} Indicates messages protected using handshake keys
[] Indicates messages protected using application data
(1-RTT) keys
Figure 1: TLS Handshake with 0-RTT
Data is protected using a number of encryption levels:
o Plaintext
o Early Data (0-RTT) Keys
o Handshake Keys
o Application Data (1-RTT) Keys
Application data may appear only in the early data and application
data levels. Handshake and Alert messages may appear in any level.
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The 0-RTT handshake is only possible if the client and server have
previously communicated. In the 1-RTT handshake, the client is
unable to send protected application data until it has received all
of the handshake messages sent by the server.
3. Protocol Overview
QUIC [QUIC-TRANSPORT] assumes responsibility for the confidentiality
and integrity protection of packets. For this it uses keys derived
from a TLS 1.3 handshake [TLS13], but instead of carrying TLS records
over QUIC (as with TCP), TLS Handshake and Alert messages are carried
directly over the QUIC transport, which takes over the
responsibilities of the TLS record layer, as shown below.
+--------------+--------------+ +-------------+
| TLS | TLS | | QUIC |
| Handshake | Alerts | | Applications|
| | | | (h2q, etc.) |
+--------------+--------------+-+-------------+
| |
| QUIC Transport |
| (streams, reliability, congestion, etc.) |
| |
+---------------------------------------------+
| |
| QUIC Packet Protection |
| |
+---------------------------------------------+
QUIC also relies on TLS 1.3 for authentication and negotiation of
parameters that are critical to security and performance.
Rather than a strict layering, these two protocols are co-dependent:
QUIC uses the TLS handshake; TLS uses the reliability and ordered
delivery provided by QUIC streams.
At a high level, there are two main interactions between the TLS and
QUIC components:
o The TLS component sends and receives messages via the QUIC
component, with QUIC providing a reliable stream abstraction to
TLS.
o The TLS component provides a series of updates to the QUIC
component, including (a) new packet protection keys to install (b)
state changes such as handshake completion, the server
certificate, etc.
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Figure 2 shows these interactions in more detail, with the QUIC
packet protection being called out specially.
+------------+ +------------+
| |<- Handshake Messages ->| |
| |<---- 0-RTT Keys -------| |
| |<--- Handshake Keys-----| |
| QUIC |<---- 1-RTT Keys -------| TLS |
| |<--- Handshake Done ----| |
+------------+ +------------+
| ^
| Protect | Protected
v | Packet
+------------+
| QUIC |
| Packet |
| Protection |
+------------+
Figure 2: QUIC and TLS Interactions
Unlike TLS over TCP, QUIC applications which want to send data do not
send it through TLS "application_data" records. Rather, they send it
as QUIC STREAM frames which are then carried in QUIC packets.
4. Carrying TLS Messages
QUIC carries TLS handshake data in CRYPTO frames, each of which
consists of a contiguous block of handshake data identified by an
offset and length. Those frames are packaged into QUIC packets and
encrypted under the current TLS encryption level. As with TLS over
TCP, once TLS handshake data has been delivered to QUIC, it is QUIC's
responsibility to deliver it reliably. Each chunk of data that is
produced by TLS is associated with the set of keys that TLS is
currently using. If QUIC needs to retransmit that data, it MUST use
the same keys even if TLS has already updated to newer keys.
One important difference between TLS 1.3 records (used with TCP) and
QUIC CRYPTO frames is that in QUIC multiple frames may appear in the
same QUIC packet as long as they are associated with the same
encryption level. For instance, an implementation might bundle a
Handshake message and an ACK for some Handshake data into the same
packet.
Each encryption level has a specific list of frames which may appear
in it. The rules here generalize those of TLS, in that frames
associated with establishing the connection can usually appear at any
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encryption level, whereas those associated with transferring data can
only appear in the 0-RTT and 1-RTT encryption levels
o CRYPTO frames MAY appear in packets of any encryption level.
o CONNECTION_CLOSE MAY appear in packets of any encryption level
other than 0-RTT.
o PADDING and PING frames MAY appear in packets of any encryption
level.
o ACK frames MAY appear in packets of any encryption level other
than 0-RTT, but can only acknowledge packets which appeared in
that encryption level.
o STREAM frames MUST ONLY appear in the 0-RTT and 1-RTT levels.
o All other frame types MUST only appear at the 1-RTT levels.
Because packets could be reordered on the wire, QUIC uses the packet
type to indicate which level a given packet was encrypted under, as
shown in Table 1. When multiple packets of different encryption
levels need to be sent, endpoints SHOULD use coalesced packets to
send them in the same UDP datagram.
+-----------------+------------------+-----------+
| Packet Type | Encryption Level | PN Space |
+-----------------+------------------+-----------+
| Initial | Initial secrets | Initial |
| | | |
| 0-RTT Protected | 0-RTT | 0/1-RTT |
| | | |
| Handshake | Handshake | Handshake |
| | | |
| Retry | N/A | N/A |
| | | |
| Short Header | 1-RTT | 0/1-RTT |
+-----------------+------------------+-----------+
Table 1: Encryption Levels by Packet Type
Section 6.5 of [QUIC-TRANSPORT] shows how packets at the various
encryption levels fit into the handshake process.
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4.1. Interface to TLS
As shown in Figure 2, the interface from QUIC to TLS consists of
three primary functions:
o Sending and receiving handshake messages
o Rekeying (both transmit and receive)
o Handshake state updates
Additional functions might be needed to configure TLS.
4.1.1. Sending and Receiving Handshake Messages
In order to drive the handshake, TLS depends on being able to send
and receive handshake messages. There are two basic functions on
this interface: one where QUIC requests handshake messages and one
where QUIC provides handshake packets.
Before starting the handshake QUIC provides TLS with the transport
parameters (see Section 8.2) that it wishes to carry.
A QUIC client starts TLS by requesting TLS handshake octets from TLS.
The client acquires handshake octets before sending its first packet.
A QUIC server starts the process by providing TLS with the client's
handshake octets.
At any given time, the TLS stack at an endpoint will have a current
sending encryption level and receiving encryption level. Each
encryption level is associated with a different flow of bytes, which
is reliably transmitted to the peer in CRYPTO frames. When TLS
provides handshake octets to be sent, they are appended to the
current flow and any packet that includes the CRYPTO frame is
protected using keys from the corresponding encryption level.
When an endpoint receives a QUIC packet containing a CRYPTO frame
from the network, it proceeds as follows:
o If the packet was in the TLS receiving encryption level, sequence
the data into the input flow as usual. As with STREAM frames, the
offset is used to find the proper location in the data sequence.
If the result of this process is that new data is available, then
it is delivered to TLS in order.
o If the packet is from a previously installed encryption level, it
MUST not contain data which extends past the end of previously
received data in that flow. Implementations MUST treat any
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violations of this requirement as a connection error of type
PROTOCOL_VIOLATION.
o If the packet is from a new encryption level, it is saved for
later processing by TLS. Once TLS moves to receiving from this
encryption level, saved data can be provided. When providing data
from any new encryption level to TLS, if there is data from a
previous encryption level that TLS has not consumed, this MUST be
treated as a connection error of type PROTOCOL_VIOLATION.
Each time that TLS is provided with new data, new handshake octets
are requested from TLS. TLS might not provide any octets if the
handshake messages it has received are incomplete or it has no data
to send.
Once the TLS handshake is complete, this is indicated to QUIC along
with any final handshake octets that TLS needs to send. TLS also
provides QUIC with the transport parameters that the peer advertised
during the handshake.
Once the handshake is complete, TLS becomes passive. TLS can still
receive data from its peer and respond in kind, but it will not need
to send more data unless specifically requested - either by an
application or QUIC. One reason to send data is that the server
might wish to provide additional or updated session tickets to a
client.
When the handshake is complete, QUIC only needs to provide TLS with
any data that arrives in CRYPTO streams. In the same way that is
done during the handshake, new data is requested from TLS after
providing received data.
Important: Until the handshake is reported as complete, the
connection and key exchange are not properly authenticated at the
server. Even though 1-RTT keys are available to a server after
receiving the first handshake messages from a client, the server
cannot consider the client to be authenticated until it receives
and validates the client's Finished message.
The requirement for the server to wait for the client Finished
message creates a dependency on that message being delivered. A
client can avoid the potential for head-of-line blocking that this
implies by sending a copy of the CRYPTO frame that carries the
Finished message in multiple packets. This enables immediate
server processing for those packets.
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4.1.2. Encryption Level Changes
As keys for new encryption levels become available, TLS provides QUIC
with those keys. Separately, as TLS starts using keys at a given
encryption level, TLS indicates to QUIC that it is now reading or
writing with keys at that encryption level. These events are not
asynchronous; they always occur immediately after TLS is provided
with new handshake octets, or after TLS produces handshake octets.
If 0-RTT is possible, it is ready after the client sends a TLS
ClientHello message or the server receives that message. After
providing a QUIC client with the first handshake octets, the TLS
stack might signal the change to 0-RTT keys. On the server, after
receiving handshake octets that contain a ClientHello message, a TLS
server might signal that 0-RTT keys are available.
Although TLS only uses one encryption level at a time, QUIC may use
more than one level. For instance, after sending its Finished
message (using a CRYPTO frame at the Handshake encryption level) an
endpoint can send STREAM data (in 1-RTT encryption). If the Finished
message is lost, the endpoint uses the Handshake encryption level to
retransmit the lost message. Reordering or loss of packets can mean
that QUIC will need to handle packets at multiple encryption levels.
During the handshake, this means potentially handling packets at
higher and lower encryption levels than the current encryption level
used by TLS.
In particular, server implementations need to be able to read packets
at the Handshake encryption level before the final TLS handshake
message at the 0-RTT encryption level (EndOfEarlyData) is available.
Though the content of CRYPTO frames at the Handshake encryption level
cannot be forwarded to TLS before EndOfEarlyData is processed, the
client could send ACK frames that the server needs to process in
order to detect lost Handshake packets.
4.1.3. TLS Interface Summary
Figure 3 summarizes the exchange between QUIC and TLS for both client
and server. Each arrow is tagged with the encryption level used for
that transmission.
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Client Server
Get Handshake
Initial ------------->
Rekey tx to 0-RTT Keys
0-RTT --------------->
Handshake Received
Get Handshake
<------------- Initial
Rekey rx to 0-RTT keys
Handshake Received
Rekey rx to Handshake keys
Get Handshake
<----------- Handshake
Rekey tx to 1-RTT keys
<--------------- 1-RTT
Handshake Received
Rekey rx to Handshake keys
Handshake Received
Get Handshake
Handshake Complete
Handshake ----------->
Rekey tx to 1-RTT keys
1-RTT --------------->
Handshake Received
Rekey rx to 1-RTT keys
Get Handshake
Handshake Complete
<--------------- 1-RTT
Handshake Received
Figure 3: Interaction Summary between QUIC and TLS
4.2. TLS Version
This document describes how TLS 1.3 [TLS13] is used with QUIC.
In practice, the TLS handshake will negotiate a version of TLS to
use. This could result in a newer version of TLS than 1.3 being
negotiated if both endpoints support that version. This is
acceptable provided that the features of TLS 1.3 that are used by
QUIC are supported by the newer version.
A badly configured TLS implementation could negotiate TLS 1.2 or
another older version of TLS. An endpoint MUST terminate the
connection if a version of TLS older than 1.3 is negotiated.
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4.3. ClientHello Size
QUIC requires that the first Initial packet from a client contain an
entire crytographic handshake message, which for TLS is the
ClientHello. Though a packet larger than 1200 octets might be
supported by the path, a client improves the likelihood that a packet
is accepted if it ensures that the first ClientHello message is small
enough to stay within this limit.
QUIC packet and framing add at least 36 octets of overhead to the
ClientHello message. That overhead increases if the client chooses a
connection ID without zero length. Overheads also do not include the
token or a connection ID longer than 8 octets, both of which might be
required if a server sends a Retry packet.
A typical TLS ClientHello can easily fit into a 1200 octet packet.
However, in addition to the overheads added by QUIC, there are
several variables that could cause this limit to be exceeded. Large
session tickets, multiple or large key shares, and long lists of
supported ciphers, signature algorithms, versions, QUIC transport
parameters, and other negotiable parameters and extensions could
cause this message to grow.
For servers, in addition to connection ID and tokens, the size of TLS
session tickets can have an effect on a client's ability to connect.
Minimizing the size of these values increases the probability that
they can be successfully used by a client.
A client is not required to fit the ClientHello that it sends in
response to a HelloRetryRequest message into a single UDP datagram.
The TLS implementation does not need to ensure that the ClientHello
is sufficiently large. QUIC PADDING frames are added to increase the
size of the packet as necessary.
4.4. Peer Authentication
The requirements for authentication depend on the application
protocol that is in use. TLS provides server authentication and
permits the server to request client authentication.
A client MUST authenticate the identity of the server. This
typically involves verification that the identity of the server is
included in a certificate and that the certificate is issued by a
trusted entity (see for example [RFC2818]).
A server MAY request that the client authenticate during the
handshake. A server MAY refuse a connection if the client is unable
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to authenticate when requested. The requirements for client
authentication vary based on application protocol and deployment.
A server MUST NOT use post-handshake client authentication (see
Section 4.6.2 of [TLS13]).
4.5. Enabling 0-RTT
In order to be usable for 0-RTT, TLS MUST provide a NewSessionTicket
message that contains the "max_early_data" extension with the value
0xffffffff; the amount of data which the client can send in 0-RTT is
controlled by the "initial_max_data" transport parameter supplied by
the server. A client MUST treat receipt of a NewSessionTicket that
contains a "max_early_data" extension with any other value as a
connection error of type PROTOCOL_VIOLATION.
Early data within the TLS connection MUST NOT be used. As it is for
other TLS application data, a server MUST treat receiving early data
on the TLS connection as a connection error of type
PROTOCOL_VIOLATION.
4.6. Rejecting 0-RTT
A server rejects 0-RTT by rejecting 0-RTT at the TLS layer. This
also prevents QUIC from sending 0-RTT data. A server will always
reject 0-RTT if it sends a TLS HelloRetryRequest.
When 0-RTT is rejected, all connection characteristics that the
client assumed might be incorrect. This includes the choice of
application protocol, transport parameters, and any application
configuration. The client therefore MUST reset the state of all
streams, including application state bound to those streams.
A client MAY attempt to send 0-RTT again if it receives a Retry or
Version Negotiation packet. These packets do not signify rejection
of 0-RTT.
4.7. HelloRetryRequest
In TLS over TCP, the HelloRetryRequest feature (see Section 4.1.4 of
[TLS13]) can be used to correct a client's incorrect KeyShare
extension as well as for a stateless round-trip check. From the
perspective of QUIC, this just looks like additional messages carried
in the Initial encryption level. Although it is in principle
possible to use this feature for address verification in QUIC, QUIC
implementations SHOULD instead use the Retry feature (see Section 4.4
of [QUIC-TRANSPORT]). HelloRetryRequest is still used to request key
shares.
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4.8. TLS Errors
If TLS experiences an error, it generates an appropriate alert as
defined in Section 6 of [TLS13].
A TLS alert is turned into a QUIC connection error by converting the
one-octet alert description into a QUIC error code. The alert
description is added to 0x100 to produce a QUIC error code from the
range reserved for CRYPTO_ERROR. The resulting value is sent in a
QUIC CONNECTION_CLOSE frame.
The alert level of all TLS alerts is "fatal"; a TLS stack MUST NOT
generate alerts at the "warning" level.
4.9. Discarding Unused Keys
After QUIC moves to a new encryption level, packet protection keys
for previous encryption levels can be discarded. This occurs several
times during the handshake, as well as when keys are updated (see
Section 6).
Packet protection keys are not discarded immediately when new keys
are availble. If packets from a lower encryption level contain
CRYPTO frames, frames that retransmit that data MUST be sent at the
same encryption level. Similarly, an endpoint generates
acknowledgements for packets at the same encryption level as the
packet being acknowledged. Thus, it is possible that keys for a
lower encryption level are needed for a short time after keys for a
newer encryption level are available.
An endpoint cannot discard keys for a given encryption level unless
it has both received and acknowledged all CRYPTO frames for that
encryption level and when all CRYPTO frames for that encryption level
have been acknowledged by its peer. However, this does not guarantee
that no further packets will need to be received or sent at that
encryption level because a peer might not have received all the
acknowledgements necessary to reach the same state.
After all CRYPTO frames for a given encryption level have been sent
and all expected CRYPTO frames received, and all the corresponding
acknowledgments have been received or sent, an endpoint starts a
timer. To limit the effect of packet loss around a change in keys,
endpoints MUST retain packet protection keys for that encryption
level for at least three times the current Retramsmission Timeout
(RTO) interval as defined in [QUIC-RECOVERY]. Retaining keys for
this interval allows packets containing CRYPTO or ACK frames at that
encryption level to be sent if packets are determined to be lost or
new packets require acknowledgment.
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Though an endpoint might retain older keys, new data MUST be sent at
the highest currently-available encryption level. Only ACK frames
and retransmissions of data in CRYPTO frames are sent at a previous
encryption level. These packets MAY also include PADDING frames.
Once this timer expires, an endpoint MUST NOT either accept or
generate new packets using those packet protection keys. An endpoint
can discard packet protection keys for that encryption level.
Key updates (see Section 6) can be used to update 1-RTT keys before
keys from other encryption levels are discarded. In that case,
packets protected with the newest packet protection keys and packets
sent two updates prior will appear to use the same keys. After the
handshake is complete, endpoints only need to maintain the two latest
sets of packet protection keys and MAY discard older keys. Updating
keys multiple times rapidly can cause packets to be effectively lost
if packets are significantly delayed. Because key updates can only
be performed once per round trip time, only packets that are delayed
by more than a round trip will be lost as a result of changing keys;
such packets will be marked as lost before this, as they leave a gap
in the sequence of packet numbers.
5. QUIC Packet Protection
As with TLS over TCP, QUIC encrypts packets with keys derived from
the TLS handshake, using the AEAD algorithm negotiated by TLS.
5.1. QUIC Packet Encryption Keys
QUIC derives packet encryption keys in the same way as TLS 1.3: Each
encryption level/direction pair has a secret value, which is then
used to derive the traffic keys using as described in Section 7.3 of
[TLS13]
The keys for the Initial encryption level are computed based on the
client's initial Destination Connection ID, as described in
Section 5.1.1.
The keys for other encryption levels are computed in the same fashion
as the corresponding TLS keys (see Section 7 of [TLS13]), except that
the label for HKDF-Expand-Label uses the prefix "quic " rather than
"tls13 ". A different label provides key separation between TLS and
QUIC.
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5.1.1. Initial Secrets
Initial packets are protected with a secret derived from the
Destination Connection ID field from the client's first Initial
packet of the connection. Specifically:
initial_salt = 0x9c108f98520a5c5c32968e950e8a2c5fe06d6c38
initial_secret = HKDF-Extract(initial_salt,
client_dst_connection_id)
client_initial_secret = HKDF-Expand-Label(initial_secret,
"client in", "",
Hash.length)
server_initial_secret = HKDF-Expand-Label(initial_secret,
"server in", "",
Hash.length)
Note that if the server sends a Retry, the client's Initial will
correspond to a new connection and thus use the server provided
Destination Connection ID.
The hash function for HKDF when deriving initial secrets and keys is
SHA-256 [SHA]. The connection ID used with HKDF-Expand-Label is the
initial Destination Connection ID.
The value of initial_salt is a 20 octet sequence shown in the figure
in hexadecimal notation. Future versions of QUIC SHOULD generate a
new salt value, thus ensuring that the keys are different for each
version of QUIC. This prevents a middlebox that only recognizes one
version of QUIC from seeing or modifying the contents of handshake
packets from future versions.
Note: The Destination Connection ID is of arbitrary length, and it
could be zero length if the server sends a Retry packet with a
zero-length Source Connection ID field. In this case, the Initial
keys provide no assurance to the client that the server received
its packet; the client has to rely on the exchange that included
the Retry packet for that property.
5.2. QUIC AEAD Usage
The Authentication Encryption with Associated Data (AEAD) [AEAD]
function used for QUIC packet protection is the AEAD that is
negotiated for use with the TLS connection. For example, if TLS is
using the TLS_AES_128_GCM_SHA256, the AEAD_AES_128_GCM function is
used.
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QUIC packets are protected prior to applying packet number encryption
(Section 5.3). The unprotected packet number is part of the
associated data (A). When removing packet protection, an endpoint
first removes the protection from the packet number.
All QUIC packets other than Version Negotiation and Retry packets are
protected with an AEAD algorithm [AEAD]. Prior to establishing a
shared secret, packets are protected with AEAD_AES_128_GCM and a key
derived from the destination connection ID in the client's first
Initial packet (see Section 5.1.1). This provides protection against
off-path attackers and robustness against QUIC version unaware
middleboxes, but not against on-path attackers.
All ciphersuites currently defined for TLS 1.3 - and therefore QUIC -
have a 16-byte authentication tag and produce an output 16 bytes
larger than their input.
The key and IV for the packet are computed as described in
Section 5.1. The nonce, N, is formed by combining the packet
protection IV with the packet number. The 64 bits of the
reconstructed QUIC packet number in network byte order are left-
padded with zeros to the size of the IV. The exclusive OR of the
padded packet number and the IV forms the AEAD nonce.
The associated data, A, for the AEAD is the contents of the QUIC
header, starting from the flags octet in either the short or long
header, up to and including the unprotected packet number.
The input plaintext, P, for the AEAD is the content of the QUIC frame
following the header, as described in [QUIC-TRANSPORT].
The output ciphertext, C, of the AEAD is transmitted in place of P.
Some AEAD functions have limits for how many packets can be encrypted
under the same key and IV (see for example [AEBounds]). This might
be lower than the packet number limit. An endpoint MUST initiate a
key update (Section 6) prior to exceeding any limit set for the AEAD
that is in use.
5.3. Packet Number Protection
QUIC packet numbers are protected using a key that is derived from
the current set of secrets. The key derived using the "pn" label is
used to protect the packet number from casual observation. The
packet number protection algorithm depends on the negotiated AEAD.
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Packet number protection is applied after packet protection is
applied (see Section 5.2). The ciphertext of the packet is sampled
and used as input to an encryption algorithm.
In sampling the packet ciphertext, the packet number length is
assumed to be 4 octets (its maximum possible encoded length), unless
there is insufficient space in the packet for sampling. The sampled
ciphertext starts after allowing for a 4 octet packet number unless
this would cause the sample to extend past the end of the packet. If
the sample would extend past the end of the packet, the end of the
packet is sampled.
For example, the sampled ciphertext for a packet with a short header
can be determined by:
sample_offset = 1 + len(connection_id) + 4
if sample_offset + sample_length > packet_length then
sample_offset = packet_length - sample_length
sample = packet[sample_offset..sample_offset+sample_length]
A packet with a long header is sampled in the same way, noting that
multiple QUIC packets might be included in the same UDP datagram and
that each one is handled separately.
sample_offset = 6 + len(destination_connection_id) +
len(source_connection_id) +
len(payload_length) + 4
if packet_type == Initial:
sample_offset += len(token_length) +
len(token)
To ensure that this process does not sample the packet number, packet
number protection algorithms MUST NOT sample more ciphertext than the
minimum expansion of the corresponding AEAD.
Packet number protection is applied to the packet number encoded as
described in Section 4.11 of [QUIC-TRANSPORT]. Since the length of
the packet number is stored in the first octet of the encoded packet
number, it may be necessary to progressively decrypt the packet
number.
Before a TLS ciphersuite can be used with QUIC, a packet protection
algorithm MUST be specifed for the AEAD used with that ciphersuite.
This document defines algorithms for AEAD_AES_128_GCM,
AEAD_AES_128_CCM, AEAD_AES_256_GCM, AEAD_AES_256_CCM (all AES AEADs
are defined in [AEAD]), and AEAD_CHACHA20_POLY1305 ([CHACHA]).
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5.3.1. AES-Based Packet Number Protection
This section defines the packet protection algorithm for
AEAD_AES_128_GCM, AEAD_AES_128_CCM, AEAD_AES_256_GCM, and
AEAD_AES_256_CCM. AEAD_AES_128_GCM and AEAD_AES_128_CCM use 128-bit
AES [AES] in counter (CTR) mode. AEAD_AES_256_GCM, and
AEAD_AES_256_CCM use 256-bit AES in CTR mode.
This algorithm samples 16 octets from the packet ciphertext. This
value is used as the counter input to AES-CTR.
encrypted_pn = AES-CTR(pn_key, sample, packet_number)
5.3.2. ChaCha20-Based Packet Number Protection
When AEAD_CHACHA20_POLY1305 is in use, packet number protection uses
the raw ChaCha20 function as defined in Section 2.4 of [CHACHA].
This uses a 256-bit key and 16 octets sampled from the packet
protection output.
The first 4 octets of the sampled ciphertext are interpreted as a
32-bit number in little-endian order and are used as the block count.
The remaining 12 octets are interpreted as three concatenated 32-bit
numbers in little-endian order and used as the nonce.
The encoded packet number is then encrypted with ChaCha20 directly.
In pseudocode:
counter = DecodeLE(sample[0..3])
nonce = DecodeLE(sample[4..7], sample[8..11], sample[12..15])
encrypted_pn = ChaCha20(pn_key, counter, nonce, packet_number)
5.4. Receiving Protected Packets
Once an endpoint successfully receives a packet with a given packet
number, it MUST discard all packets in the same packet number space
with higher packet numbers if they cannot be successfully unprotected
with either the same key, or - if there is a key update - the next
packet protection key (see Section 6). Similarly, a packet that
appears to trigger a key update, but cannot be unprotected
successfully MUST be discarded.
Failure to unprotect a packet does not necessarily indicate the
existence of a protocol error in a peer or an attack. The truncated
packet number encoding used in QUIC can cause packet numbers to be
decoded incorrectly if they are delayed significantly.
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5.5. Use of 0-RTT Keys
If 0-RTT keys are available (see Section 4.5), the lack of replay
protection means that restrictions on their use are necessary to
avoid replay attacks on the protocol.
A client MUST only use 0-RTT keys to protect data that is idempotent.
A client MAY wish to apply additional restrictions on what data it
sends prior to the completion of the TLS handshake. A client
otherwise treats 0-RTT keys as equivalent to 1-RTT keys, except that
it MUST NOT send ACKs with 0-RTT keys.
A client that receives an indication that its 0-RTT data has been
accepted by a server can send 0-RTT data until it receives all of the
server's handshake messages. A client SHOULD stop sending 0-RTT data
if it receives an indication that 0-RTT data has been rejected.
A server MUST NOT use 0-RTT keys to protect packets; it uses 1-RTT
keys to protect acknowledgements of 0-RTT packets. Clients MUST NOT
attempt to decrypt 0-RTT packets it receives and instead MUST discard
them.
Note: 0-RTT data can be acknowledged by the server as it receives
it, but any packets containing acknowledgments of 0-RTT data
cannot have packet protection removed by the client until the TLS
handshake is complete. The 1-RTT keys necessary to remove packet
protection cannot be derived until the client receives all server
handshake messages.
5.6. Receiving Out-of-Order Protected Frames
Due to reordering and loss, protected packets might be received by an
endpoint before the final TLS handshake messages are received. A
client will be unable to decrypt 1-RTT packets from the server,
whereas a server will be able to decrypt 1-RTT packets from the
client.
However, a server MUST NOT process data from incoming 1-RTT protected
packets before verifying either the client Finished message or - in
the case that the server has chosen to use a pre-shared key - the
pre-shared key binder (see Section 4.2.11 of [TLS13]). Verifying
these values provides the server with an assurance that the
ClientHello has not been modified. Packets protected with 1-RTT keys
MAY be stored and later decrypted and used once the handshake is
complete.
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A server could receive packets protected with 0-RTT keys prior to
receiving a TLS ClientHello. The server MAY retain these packets for
later decryption in anticipation of receiving a ClientHello.
6. Key Update
Once the 1-RTT keys are established and the short header is in use,
it is possible to update the keys. The KEY_PHASE bit in the short
header is used to indicate whether key updates have occurred. The
KEY_PHASE bit is initially set to 0 and then inverted with each key
update Section 6.
The KEY_PHASE bit allows a recipient to detect a change in keying
material without necessarily needing to receive the first packet that
triggered the change. An endpoint that notices a changed KEY_PHASE
bit can update keys and decrypt the packet that contains the changed
bit, see Section 6.
An endpoint MUST NOT initiate more than one key update at a time. A
new key cannot be used until the endpoint has received and
successfully decrypted a packet with a matching KEY_PHASE.
A receiving endpoint detects an update when the KEY_PHASE bit doesn't
match what it is expecting. It creates a new secret (see Section 7.2
of [TLS13]) and the corresponding read key and IV. If the packet can
be decrypted and authenticated using these values, then the keys it
uses for packet protection are also updated. The next packet sent by
the endpoint will then use the new keys.
An endpoint doesn't need to send packets immediately when it detects
that its peer has updated keys. The next packet that it sends will
simply use the new keys. If an endpoint detects a second update
before it has sent any packets with updated keys it indicates that
its peer has updated keys twice without awaiting a reciprocal update.
An endpoint MUST treat consecutive key updates as a fatal error and
abort the connection.
An endpoint SHOULD retain old keys for a short period to allow it to
decrypt packets with smaller packet numbers than the packet that
triggered the key update. This allows an endpoint to consume packets
that are reordered around the transition between keys. Packets with
higher packet numbers always use the updated keys and MUST NOT be
decrypted with old keys.
Keys and their corresponding secrets SHOULD be discarded when an
endpoint has received all packets with packet numbers lower than the
lowest packet number used for the new key. An endpoint might discard
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keys if it determines that the length of the delay to affected
packets is excessive.
This ensures that once the handshake is complete, packets with the
same KEY_PHASE will have the same packet protection keys, unless
there are multiple key updates in a short time frame succession and
significant packet reordering.
Initiating Peer Responding Peer
@M QUIC Frames
New Keys -> @N
@N QUIC Frames
-------->
QUIC Frames @M
New Keys -> @N
QUIC Frames @N
<--------
Figure 4: Key Update
A packet that triggers a key update could arrive after successfully
processing a packet with a higher packet number. This is only
possible if there is a key compromise and an attack, or if the peer
is incorrectly reverting to use of old keys. Because the latter
cannot be differentiated from an attack, an endpoint MUST immediately
terminate the connection if it detects this condition.
7. Security of Initial Messages
Initial packets are not protected with a secret key, so they are
subject to potential tampering by an attacker. QUIC provides
protection against attackers that cannot read packets, but does not
attempt to provide additional protection against attacks where the
attacker can observe and inject packets. Some forms of tampering -
such as modifying the TLS messages themselves - are detectable, but
some - such as modifying ACKs - are not.
For example, an attacker could inject a packet containing an ACK
frame that makes it appear that a packet had not been received or to
create a false impression of the state of the connection (e.g., by
modifying the ACK Delay). Note that such a packet could cause a
legitimate packet to be dropped as a duplicate. Implementations
SHOULD use caution in relying on any data which is contained in
Initial packets that is not otherwise authenticated.
It is also possible for the attacker to tamper with data that is
carried in Handshake packets, but because that tampering requires
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modifying TLS handshake messages, that tampering will cause the TLS
handshake to fail.
8. QUIC-Specific Additions to the TLS Handshake
QUIC uses the TLS handshake for more than just negotiation of
cryptographic parameters. The TLS handshake validates protocol
version selection, provides preliminary values for QUIC transport
parameters, and allows a server to perform return routeability checks
on clients.
8.1. Protocol and Version Negotiation
The QUIC version negotiation mechanism is used to negotiate the
version of QUIC that is used prior to the completion of the
handshake. However, this packet is not authenticated, enabling an
active attacker to force a version downgrade.
To ensure that a QUIC version downgrade is not forced by an attacker,
version information is copied into the TLS handshake, which provides
integrity protection for the QUIC negotiation. This does not prevent
version downgrade prior to the completion of the handshake, though it
means that a downgrade causes a handshake failure.
TLS uses Application Layer Protocol Negotiation (ALPN) [RFC7301] to
select an application protocol. The application-layer protocol MAY
restrict the QUIC versions that it can operate over. Servers MUST
select an application protocol compatible with the QUIC version that
the client has selected.
If the server cannot select a compatible combination of application
protocol and QUIC version, it MUST abort the connection. A client
MUST abort a connection if the server picks an incompatible
combination of QUIC version and ALPN identifier.
8.2. QUIC Transport Parameters Extension
QUIC transport parameters are carried in a TLS extension. Different
versions of QUIC might define a different format for this struct.
Including transport parameters in the TLS handshake provides
integrity protection for these values.
enum {
quic_transport_parameters(0xffa5), (65535)
} ExtensionType;
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The "extension_data" field of the quic_transport_parameters extension
contains a value that is defined by the version of QUIC that is in
use. The quic_transport_parameters extension carries a
TransportParameters when the version of QUIC defined in
[QUIC-TRANSPORT] is used.
The quic_transport_parameters extension is carried in the ClientHello
and the EncryptedExtensions messages during the handshake.
While the transport parameters are technically available prior to the
completion of the handshake, they cannot be fully trusted until the
handshake completes, and reliance on them should be minimized.
However, any tampering with the parameters will cause the handshake
to fail.
9. Security Considerations
There are likely to be some real clangers here eventually, but the
current set of issues is well captured in the relevant sections of
the main text.
Never assume that because it isn't in the security considerations
section it doesn't affect security. Most of this document does.
9.1. Packet Reflection Attack Mitigation
A small ClientHello that results in a large block of handshake
messages from a server can be used in packet reflection attacks to
amplify the traffic generated by an attacker.
QUIC includes three defenses against this attack. First, the packet
containing a ClientHello MUST be padded to a minimum size. Second,
if responding to an unverified source address, the server is
forbidden to send more than three UDP datagrams in its first flight
(see Section 4.7 of [QUIC-TRANSPORT]). Finally, because
acknowledgements of Handshake packets are authenticated, a blind
attacker cannot forge them. Put together, these defenses limit the
level of amplification.
9.2. Peer Denial of Service
QUIC, TLS and HTTP/2 all contain a messages that have legitimate uses
in some contexts, but that can be abused to cause a peer to expend
processing resources without having any observable impact on the
state of the connection. If processing is disproportionately large
in comparison to the observable effects on bandwidth or state, then
this could allow a malicious peer to exhaust processing capacity
without consequence.
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QUIC prohibits the sending of empty "STREAM" frames unless they are
marked with the FIN bit. This prevents "STREAM" frames from being
sent that only waste effort.
While there are legitimate uses for some redundant packets,
implementations SHOULD track redundant packets and treat excessive
volumes of any non-productive packets as indicative of an attack.
9.3. Packet Number Protection Analysis
Packet number protection relies on the packet protection AEAD being a
pseudorandom function (PRF), which is not a property that AEAD
algorithms guarantee. Therefore, no strong assurances about the
general security of this mechanism can be shown in the general case.
The AEAD algorithms described in this document are assumed to be
PRFs.
The packet number protection algorithms defined in this document take
the form:
encrypted_pn = packet_number XOR PRF(pn_key, sample)
This construction is secure against chosen plaintext attacks (IND-
CPA) [IMC].
Use of the same key and ciphertext sample more than once risks
compromising packet number protection. Protecting two different
packet numbers with the same key and ciphertext sample reveals the
exclusive OR of those packet numbers. Assuming that the AEAD acts as
a PRF, if L bits are sampled, the odds of two ciphertext samples
being identical approach 2^(-L/2), that is, the birthday bound. For
the algorithms described in this document, that probability is one in
2^64.
Note: In some cases, inputs shorter than the full size required by
the packet protection algorithm might be used.
To prevent an attacker from modifying packet numbers, values of
packet numbers are transitively authenticated using packet
protection; packet numbers are part of the authenticated additional
data. A falsified or modified packet number can only be detected
once the packet protection is removed.
An attacker can guess values for packet numbers and have an endpoint
confirm guesses through timing side channels. If the recipient of a
packet discards packets with duplicate packet numbers without
attempting to remove packet protection they could reveal through
timing side-channels that the packet number matches a received
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packet. For authentication to be free from side-channels, the entire
process of packet number protection removal, packet number recovery,
and packet protection removal MUST be applied together without timing
and other side-channels.
For the sending of packets, construction and protection of packet
payloads and packet numbers MUST be free from side-channels that
would reveal the packet number or its encoded size.
10. IANA Considerations
This document does not create any new IANA registries, but it
registers the values in the following registries:
o TLS ExtensionsType Registry [TLS-REGISTRIES] - IANA is to register
the quic_transport_parameters extension found in Section 8.2. The
Recommended column is to be marked Yes. The TLS 1.3 Column is to
include CH and EE.
11. References
11.1. Normative References
[AEAD] McGrew, D., "An Interface and Algorithms for Authenticated
Encryption", RFC 5116, DOI 10.17487/RFC5116, January 2008,
<https://www.rfc-editor.org/info/rfc5116>.
[AES] "Advanced encryption standard (AES)", National Institute
of Standards and Technology report,
DOI 10.6028/nist.fips.197, November 2001.
[CHACHA] Nir, Y. and A. Langley, "ChaCha20 and Poly1305 for IETF
Protocols", RFC 8439, DOI 10.17487/RFC8439, June 2018,
<https://www.rfc-editor.org/info/rfc8439>.
[QUIC-RECOVERY]
Iyengar, J., Ed. and I. Swett, Ed., "QUIC Loss Detection
and Congestion Control", draft-ietf-quic-recovery-14 (work
in progress), August 2018.
[QUIC-TRANSPORT]
Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", draft-ietf-quic-
transport-14 (work in progress), August 2018.
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[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/info/rfc2119>.
[RFC7301] 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/info/rfc7301>.
[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/info/rfc8174>.
[SHA] Dang, Q., "Secure Hash Standard", National Institute of
Standards and Technology report,
DOI 10.6028/nist.fips.180-4, July 2015.
[TLS-REGISTRIES]
Salowey, J. and S. Turner, "IANA Registry Updates for
Transport Layer Security (TLS) and Datagram Transport
Layer Security (DTLS)", draft-ietf-tls-iana-registry-
updates-05 (work in progress), May 2018.
[TLS13] 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>.
11.2. Informative References
[AEBounds]
Luykx, A. and K. Paterson, "Limits on Authenticated
Encryption Use in TLS", March 2016,
<http://www.isg.rhul.ac.uk/~kp/TLS-AEbounds.pdf>.
[IMC] Katz, J. and Y. Lindell, "Introduction to Modern
Cryptography, Second Edition", ISBN 978-1466570269,
November 2014.
[QUIC-HTTP]
Bishop, M., Ed., "Hypertext Transfer Protocol (HTTP) over
QUIC", draft-ietf-quic-http-14 (work in progress), August
2018.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000,
<https://www.rfc-editor.org/info/rfc2818>.
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[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>.
11.3. URIs
[1] https://mailarchive.ietf.org/arch/search/?email_list=quic
[2] https://github.com/quicwg
[3] https://github.com/quicwg/base-drafts/labels/-tls
Appendix A. Change Log
*RFC Editor's Note:* Please remove this section prior to
publication of a final version of this document.
Issue and pull request numbers are listed with a leading octothorp.
A.1. Since draft-ietf-quic-tls-13
o Updated to TLS 1.3 final (#1660)
A.2. Since draft-ietf-quic-tls-12
o Changes to integration of the TLS handshake (#829, #1018, #1094,
#1165, #1190, #1233, #1242, #1252, #1450)
* The cryptographic handshake uses CRYPTO frames, not stream 0
* QUIC packet protection is used in place of TLS record
protection
* Separate QUIC packet number spaces are used for the handshake
* Changed Retry to be independent of the cryptographic handshake
* Limit the use of HelloRetryRequest to address TLS needs (like
key shares)
o Changed codepoint of TLS extension (#1395, #1402)
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A.3. Since draft-ietf-quic-tls-11
o Encrypted packet numbers.
A.4. Since draft-ietf-quic-tls-10
o No significant changes.
A.5. Since draft-ietf-quic-tls-09
o Cleaned up key schedule and updated the salt used for handshake
packet protection (#1077)
A.6. Since draft-ietf-quic-tls-08
o Specify value for max_early_data_size to enable 0-RTT (#942)
o Update key derivation function (#1003, #1004)
A.7. Since draft-ietf-quic-tls-07
o Handshake errors can be reported with CONNECTION_CLOSE (#608,
#891)
A.8. Since draft-ietf-quic-tls-05
No significant changes.
A.9. Since draft-ietf-quic-tls-04
o Update labels used in HKDF-Expand-Label to match TLS 1.3 (#642)
A.10. Since draft-ietf-quic-tls-03
No significant changes.
A.11. Since draft-ietf-quic-tls-02
o Updates to match changes in transport draft
A.12. Since draft-ietf-quic-tls-01
o Use TLS alerts to signal TLS errors (#272, #374)
o Require ClientHello to fit in a single packet (#338)
o The second client handshake flight is now sent in the clear (#262,
#337)
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o The QUIC header is included as AEAD Associated Data (#226, #243,
#302)
o Add interface necessary for client address validation (#275)
o Define peer authentication (#140)
o Require at least TLS 1.3 (#138)
o Define transport parameters as a TLS extension (#122)
o Define handling for protected packets before the handshake
completes (#39)
o Decouple QUIC version and ALPN (#12)
A.13. Since draft-ietf-quic-tls-00
o Changed bit used to signal key phase
o Updated key phase markings during the handshake
o Added TLS interface requirements section
o Moved to use of TLS exporters for key derivation
o Moved TLS error code definitions into this document
A.14. Since draft-thomson-quic-tls-01
o Adopted as base for draft-ietf-quic-tls
o Updated authors/editors list
o Added status note
Acknowledgments
This document has benefited from input from Dragana Damjanovic,
Christian Huitema, Jana Iyengar, Adam Langley, Roberto Peon, Eric
Rescorla, Ian Swett, and many others.
Contributors
Ryan Hamilton was originally an author of this specification.
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Authors' Addresses
Martin Thomson (editor)
Mozilla
Email: martin.thomson@gmail.com
Sean Turner (editor)
sn3rd
Email: sean@sn3rd.com
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