< draft-ietf-quic-tls-16.txt   draft-ietf-quic-tls-17.txt >
QUIC M. Thomson, Ed. QUIC M. Thomson, Ed.
Internet-Draft Mozilla Internet-Draft Mozilla
Intended status: Standards Track S. Turner, Ed. Intended status: Standards Track S. Turner, Ed.
Expires: April 26, 2019 sn3rd Expires: June 21, 2019 sn3rd
October 23, 2018 December 18, 2018
Using Transport Layer Security (TLS) to Secure QUIC Using TLS to Secure QUIC
draft-ietf-quic-tls-16 draft-ietf-quic-tls-17
Abstract Abstract
This document describes how Transport Layer Security (TLS) is used to This document describes how Transport Layer Security (TLS) is used to
secure QUIC. secure QUIC.
Note to Readers Note to Readers
Discussion of this draft takes place on the QUIC working group Discussion of this draft takes place on the QUIC working group
mailing list (quic@ietf.org), which is archived at mailing list (quic@ietf.org), which is archived at
skipping to change at page 1, line 42 skipping to change at page 1, line 42
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 26, 2019. This Internet-Draft will expire on June 21, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Notational Conventions . . . . . . . . . . . . . . . . . . . 3 2. Notational Conventions . . . . . . . . . . . . . . . . . . . 4
2.1. TLS Overview . . . . . . . . . . . . . . . . . . . . . . 4 2.1. TLS Overview . . . . . . . . . . . . . . . . . . . . . . 4
3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 6 3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 6
4. Carrying TLS Messages . . . . . . . . . . . . . . . . . . . . 7 4. Carrying TLS Messages . . . . . . . . . . . . . . . . . . . . 7
4.1. Interface to TLS . . . . . . . . . . . . . . . . . . . . 9 4.1. Interface to TLS . . . . . . . . . . . . . . . . . . . . 9
4.1.1. Sending and Receiving Handshake Messages . . . . . . 9 4.1.1. Sending and Receiving Handshake Messages . . . . . . 9
4.1.2. Encryption Level Changes . . . . . . . . . . . . . . 11 4.1.2. Encryption Level Changes . . . . . . . . . . . . . . 11
4.1.3. TLS Interface Summary . . . . . . . . . . . . . . . . 11 4.1.3. TLS Interface Summary . . . . . . . . . . . . . . . . 12
4.2. TLS Version . . . . . . . . . . . . . . . . . . . . . . . 12 4.2. TLS Version . . . . . . . . . . . . . . . . . . . . . . . 13
4.3. ClientHello Size . . . . . . . . . . . . . . . . . . . . 13 4.3. ClientHello Size . . . . . . . . . . . . . . . . . . . . 14
4.4. Peer Authentication . . . . . . . . . . . . . . . . . . . 13 4.4. Peer Authentication . . . . . . . . . . . . . . . . . . . 14
4.5. Enabling 0-RTT . . . . . . . . . . . . . . . . . . . . . 14 4.5. Enabling 0-RTT . . . . . . . . . . . . . . . . . . . . . 15
4.6. Rejecting 0-RTT . . . . . . . . . . . . . . . . . . . . . 14 4.6. Rejecting 0-RTT . . . . . . . . . . . . . . . . . . . . . 15
4.7. HelloRetryRequest . . . . . . . . . . . . . . . . . . . . 14 4.7. HelloRetryRequest . . . . . . . . . . . . . . . . . . . . 15
4.8. TLS Errors . . . . . . . . . . . . . . . . . . . . . . . 15 4.8. TLS Errors . . . . . . . . . . . . . . . . . . . . . . . 16
4.9. Discarding Unused Keys . . . . . . . . . . . . . . . . . 15 4.9. Discarding Unused Keys . . . . . . . . . . . . . . . . . 16
5. Packet Protection . . . . . . . . . . . . . . . . . . . . . . 16 4.10. Discarding Initial Keys . . . . . . . . . . . . . . . . . 17
5.1. Packet Protection Keys . . . . . . . . . . . . . . . . . 16 5. Packet Protection . . . . . . . . . . . . . . . . . . . . . . 18
5.2. Initial Secrets . . . . . . . . . . . . . . . . . . . . . 17 5.1. Packet Protection Keys . . . . . . . . . . . . . . . . . 18
5.3. AEAD Usage . . . . . . . . . . . . . . . . . . . . . . . 18 5.2. Initial Secrets . . . . . . . . . . . . . . . . . . . . . 18
5.4. Packet Number Protection . . . . . . . . . . . . . . . . 19 5.3. AEAD Usage . . . . . . . . . . . . . . . . . . . . . . . 19
5.4.1. AES-Based Packet Number Protection . . . . . . . . . 20 5.4. Header Protection . . . . . . . . . . . . . . . . . . . . 20
5.4.2. ChaCha20-Based Packet Number Protection . . . . . . . 20 5.4.1. Header Protection Application . . . . . . . . . . . . 21
5.5. Receiving Protected Packets . . . . . . . . . . . . . . . 20 5.4.2. Header Protection Sample . . . . . . . . . . . . . . 22
5.6. Use of 0-RTT Keys . . . . . . . . . . . . . . . . . . . . 21 5.4.3. AES-Based Header Protection . . . . . . . . . . . . . 23
5.7. Receiving Out-of-Order Protected Frames . . . . . . . . . 21 5.4.4. ChaCha20-Based Header Protection . . . . . . . . . . 24
6. Key Update . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.5. Receiving Protected Packets . . . . . . . . . . . . . . . 24
7. Security of Initial Messages . . . . . . . . . . . . . . . . 23 5.6. Use of 0-RTT Keys . . . . . . . . . . . . . . . . . . . . 24
8. QUIC-Specific Additions to the TLS Handshake . . . . . . . . 24 5.7. Receiving Out-of-Order Protected Frames . . . . . . . . . 25
8.1. Protocol and Version Negotiation . . . . . . . . . . . . 24 6. Key Update . . . . . . . . . . . . . . . . . . . . . . . . . 25
8.2. QUIC Transport Parameters Extension . . . . . . . . . . . 25 7. Security of Initial Messages . . . . . . . . . . . . . . . . 27
8.3. Removing the EndOfEarlyData Message . . . . . . . . . . . 25 8. QUIC-Specific Additions to the TLS Handshake . . . . . . . . 28
9. Security Considerations . . . . . . . . . . . . . . . . . . . 26 8.1. Protocol and Version Negotiation . . . . . . . . . . . . 28
9.1. Packet Reflection Attack Mitigation . . . . . . . . . . . 26 8.2. QUIC Transport Parameters Extension . . . . . . . . . . . 28
9.2. Peer Denial of Service . . . . . . . . . . . . . . . . . 26 8.3. Removing the EndOfEarlyData Message . . . . . . . . . . . 29
9.3. Packet Number Protection Analysis . . . . . . . . . . . . 26
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27 9. Security Considerations . . . . . . . . . . . . . . . . . . . 29
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 28 9.1. Packet Reflection Attack Mitigation . . . . . . . . . . . 29
11.1. Normative References . . . . . . . . . . . . . . . . . . 28 9.2. Peer Denial of Service . . . . . . . . . . . . . . . . . 30
11.2. Informative References . . . . . . . . . . . . . . . . . 29 9.3. Header Protection Analysis . . . . . . . . . . . . . . . 30
11.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 29 9.4. Key Diversity . . . . . . . . . . . . . . . . . . . . . . 31
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 30 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
A.1. Since draft-ietf-quic-tls-13 . . . . . . . . . . . . . . 30 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 32
A.2. Since draft-ietf-quic-tls-12 . . . . . . . . . . . . . . 30 11.1. Normative References . . . . . . . . . . . . . . . . . . 32
A.3. Since draft-ietf-quic-tls-11 . . . . . . . . . . . . . . 30 11.2. Informative References . . . . . . . . . . . . . . . . . 33
A.4. Since draft-ietf-quic-tls-10 . . . . . . . . . . . . . . 30 11.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 34
A.5. Since draft-ietf-quic-tls-09 . . . . . . . . . . . . . . 30 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 34
A.6. Since draft-ietf-quic-tls-08 . . . . . . . . . . . . . . 30 A.1. Since draft-ietf-quic-tls-14 . . . . . . . . . . . . . . 34
A.7. Since draft-ietf-quic-tls-07 . . . . . . . . . . . . . . 31 A.2. Since draft-ietf-quic-tls-13 . . . . . . . . . . . . . . 34
A.8. Since draft-ietf-quic-tls-05 . . . . . . . . . . . . . . 31 A.3. Since draft-ietf-quic-tls-12 . . . . . . . . . . . . . . 34
A.9. Since draft-ietf-quic-tls-04 . . . . . . . . . . . . . . 31 A.4. Since draft-ietf-quic-tls-11 . . . . . . . . . . . . . . 35
A.10. Since draft-ietf-quic-tls-03 . . . . . . . . . . . . . . 31 A.5. Since draft-ietf-quic-tls-10 . . . . . . . . . . . . . . 35
A.11. Since draft-ietf-quic-tls-02 . . . . . . . . . . . . . . 31 A.6. Since draft-ietf-quic-tls-09 . . . . . . . . . . . . . . 35
A.12. Since draft-ietf-quic-tls-01 . . . . . . . . . . . . . . 31 A.7. Since draft-ietf-quic-tls-08 . . . . . . . . . . . . . . 35
A.13. Since draft-ietf-quic-tls-00 . . . . . . . . . . . . . . 32 A.8. Since draft-ietf-quic-tls-07 . . . . . . . . . . . . . . 35
A.14. Since draft-thomson-quic-tls-01 . . . . . . . . . . . . . 32 A.9. Since draft-ietf-quic-tls-05 . . . . . . . . . . . . . . 35
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 32 A.10. Since draft-ietf-quic-tls-04 . . . . . . . . . . . . . . 35
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 32 A.11. Since draft-ietf-quic-tls-03 . . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32 A.12. Since draft-ietf-quic-tls-02 . . . . . . . . . . . . . . 36
A.13. Since draft-ietf-quic-tls-01 . . . . . . . . . . . . . . 36
A.14. Since draft-ietf-quic-tls-00 . . . . . . . . . . . . . . 36
A.15. Since draft-thomson-quic-tls-01 . . . . . . . . . . . . . 37
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 37
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37
1. Introduction 1. Introduction
This document describes how QUIC [QUIC-TRANSPORT] is secured using This document describes how QUIC [QUIC-TRANSPORT] is secured using
Transport Layer Security (TLS) version 1.3 [TLS13]. TLS 1.3 provides TLS [TLS13].
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 TLS 1.3 provides critical latency improvements for connection
security component of QUIC. 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 TLS acts as a security component of QUIC.
2. Notational Conventions 2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
This document uses the terminology established in [QUIC-TRANSPORT]. This document uses the terminology established in [QUIC-TRANSPORT].
For brevity, the acronym TLS is used to refer to TLS 1.3. For brevity, the acronym TLS is used to refer to TLS 1.3, though a
newer version could be used (see Section 4.2).
2.1. TLS Overview 2.1. TLS Overview
TLS provides two endpoints with a way to establish a means of TLS provides two endpoints with a way to establish a means of
communication over an untrusted medium (that is, the Internet) that communication over an untrusted medium (that is, the Internet) that
ensures that messages they exchange cannot be observed, modified, or ensures that messages they exchange cannot be observed, modified, or
forged. forged.
Internally, TLS is a layered protocol, with the structure shown Internally, TLS is a layered protocol, with the structure shown
below: below:
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After completing the TLS handshake, the client will have learned and After completing the TLS handshake, the client will have learned and
authenticated an identity for the server and the server is optionally authenticated an identity for the server and the server is optionally
able to learn and authenticate an identity for the client. TLS able to learn and authenticate an identity for the client. TLS
supports X.509 [RFC5280] certificate-based authentication for both supports X.509 [RFC5280] certificate-based authentication for both
server and client. server and client.
The TLS key exchange is resistant to tampering by attackers and it The TLS key exchange is resistant to tampering by attackers and it
produces shared secrets that cannot be controlled by either produces shared secrets that cannot be controlled by either
participating peer. participating peer.
TLS 1.3 provides two basic handshake modes of interest to QUIC: TLS provides two basic handshake modes of interest to QUIC:
o A full 1-RTT handshake in which the client is able to send o A full 1-RTT handshake in which the client is able to send
application data after one round trip and the server immediately application data after one round trip and the server immediately
responds after receiving the first handshake message from the responds after receiving the first handshake message from the
client. client.
o A 0-RTT handshake in which the client uses information it has o A 0-RTT handshake in which the client uses information it has
previously learned about the server to send application data previously learned about the server to send application data
immediately. This application data can be replayed by an attacker immediately. This application data can be replayed by an attacker
so it MUST NOT carry a self-contained trigger for any non- so it MUST NOT carry a self-contained trigger for any non-
idempotent action. idempotent action.
A simplified TLS 1.3 handshake with 0-RTT application data is shown A simplified TLS handshake with 0-RTT application data is shown in
in Figure 1. Note that this omits the EndOfEarlyData message, which Figure 1. Note that this omits the EndOfEarlyData message, which is
is not used in QUIC (see Section 8.3). not used in QUIC (see Section 8.3).
Client Server Client Server
ClientHello ClientHello
(0-RTT Application Data) --------> (0-RTT Application Data) -------->
ServerHello ServerHello
{EncryptedExtensions} {EncryptedExtensions}
{Finished} {Finished}
<-------- [Application Data] <-------- [Application Data]
{Finished} --------> {Finished} -------->
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The 0-RTT handshake is only possible if the client and server have The 0-RTT handshake is only possible if the client and server have
previously communicated. In the 1-RTT handshake, the client is previously communicated. In the 1-RTT handshake, the client is
unable to send protected application data until it has received all unable to send protected application data until it has received all
of the handshake messages sent by the server. of the handshake messages sent by the server.
3. Protocol Overview 3. Protocol Overview
QUIC [QUIC-TRANSPORT] assumes responsibility for the confidentiality QUIC [QUIC-TRANSPORT] assumes responsibility for the confidentiality
and integrity protection of packets. For this it uses keys derived and integrity protection of packets. For this it uses keys derived
from a TLS 1.3 handshake [TLS13], but instead of carrying TLS records from a TLS handshake [TLS13], but instead of carrying TLS records
over QUIC (as with TCP), TLS Handshake and Alert messages are carried over QUIC (as with TCP), TLS Handshake and Alert messages are carried
directly over the QUIC transport, which takes over the directly over the QUIC transport, which takes over the
responsibilities of the TLS record layer, as shown below. responsibilities of the TLS record layer, as shown below.
+--------------+--------------+ +-------------+ +--------------+--------------+ +-------------+
| TLS | TLS | | QUIC | | TLS | TLS | | QUIC |
| Handshake | Alerts | | Applications| | Handshake | Alerts | | Applications|
| | | | (h2q, etc.) | | | | | (h2q, etc.) |
+--------------+--------------+-+-------------+ +--------------+--------------+-+-------------+
| | | |
| QUIC Transport | | QUIC Transport |
| (streams, reliability, congestion, etc.) | | (streams, reliability, congestion, etc.) |
| | | |
+---------------------------------------------+ +---------------------------------------------+
| | | |
| QUIC Packet Protection | | QUIC Packet Protection |
| | | |
+---------------------------------------------+ +---------------------------------------------+
QUIC also relies on TLS 1.3 for authentication and negotiation of QUIC also relies on TLS for authentication and negotiation of
parameters that are critical to security and performance. parameters that are critical to security and performance.
Rather than a strict layering, these two protocols are co-dependent: Rather than a strict layering, these two protocols are co-dependent:
QUIC uses the TLS handshake; TLS uses the reliability, ordered QUIC uses the TLS handshake; TLS uses the reliability, ordered
delivery, and record layer provided by QUIC. delivery, and record layer provided by QUIC.
At a high level, there are two main interactions between the TLS and At a high level, there are two main interactions between the TLS and
QUIC components: QUIC components:
o The TLS component sends and receives messages via the QUIC o The TLS component sends and receives messages via the QUIC
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QUIC carries TLS handshake data in CRYPTO frames, each of which QUIC carries TLS handshake data in CRYPTO frames, each of which
consists of a contiguous block of handshake data identified by an consists of a contiguous block of handshake data identified by an
offset and length. Those frames are packaged into QUIC packets and offset and length. Those frames are packaged into QUIC packets and
encrypted under the current TLS encryption level. As with TLS over 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 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 responsibility to deliver it reliably. Each chunk of data that is
produced by TLS is associated with the set of keys that TLS 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 currently using. If QUIC needs to retransmit that data, it MUST use
the same keys even if TLS has already updated to newer keys. the same keys even if TLS has already updated to newer keys.
One important difference between TLS 1.3 records (used with TCP) and One important difference between TLS records (used with TCP) and QUIC
QUIC CRYPTO frames is that in QUIC multiple frames may appear in the CRYPTO frames is that in QUIC multiple frames may appear in the same
same QUIC packet as long as they are associated with the same QUIC packet as long as they are associated with the same encryption
encryption level. For instance, an implementation might bundle a level. For instance, an implementation might bundle a Handshake
Handshake message and an ACK for some Handshake data into the same message and an ACK for some Handshake data into the same packet.
packet.
Each encryption level has a specific list of frames which may appear Each encryption level has a specific list of frames which may appear
in it. The rules here generalize those of TLS, in that frames in it. The rules here generalize those of TLS, in that frames
associated with establishing the connection can usually appear at any associated with establishing the connection can usually appear at any
encryption level, whereas those associated with transferring data can encryption level, whereas those associated with transferring data can
only appear in the 0-RTT and 1-RTT encryption levels: only appear in the 0-RTT and 1-RTT encryption levels:
o CRYPTO frames MAY appear in packets of any encryption level except o CRYPTO frames MAY appear in packets of any encryption level except
0-RTT. 0-RTT.
o CONNECTION_CLOSE MAY appear in packets of any encryption level o CONNECTION_CLOSE MAY appear in packets of any encryption level
other than 0-RTT. other than 0-RTT.
o APPLICATION_CLOSE MAY appear in packets of any encryption level
other than Initial and 0-RTT.
o PADDING frames MAY appear in packets of any encryption level. o PADDING frames MAY appear in packets of any encryption level.
o ACK frames MAY appear in packets of any encryption level other o ACK frames MAY appear in packets of any encryption level other
than 0-RTT, but can only acknowledge packets which appeared in than 0-RTT, but can only acknowledge packets which appeared in
that packet number space. that packet number space.
o STREAM frames MUST ONLY appear in the 0-RTT and 1-RTT levels. 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. o All other frame types MUST only appear at the 1-RTT levels.
skipping to change at page 8, line 48 skipping to change at page 9, line 21
| | | | | | | |
| Handshake | Handshake | Handshake | | Handshake | Handshake | Handshake |
| | | | | | | |
| Retry | N/A | N/A | | Retry | N/A | N/A |
| | | | | | | |
| Short Header | 1-RTT | 0/1-RTT | | Short Header | 1-RTT | 0/1-RTT |
+-----------------+------------------+-----------+ +-----------------+------------------+-----------+
Table 1: Encryption Levels by Packet Type Table 1: Encryption Levels by Packet Type
Section 6.5 of [QUIC-TRANSPORT] shows how packets at the various Section 17 of [QUIC-TRANSPORT] shows how packets at the various
encryption levels fit into the handshake process. encryption levels fit into the handshake process.
4.1. Interface to TLS 4.1. Interface to TLS
As shown in Figure 2, the interface from QUIC to TLS consists of As shown in Figure 2, the interface from QUIC to TLS consists of
three primary functions: three primary functions:
o Sending and receiving handshake messages o Sending and receiving handshake messages
o Rekeying (both transmit and receive) o Rekeying (both transmit and receive)
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4.1.1. Sending and Receiving Handshake Messages 4.1.1. Sending and Receiving Handshake Messages
In order to drive the handshake, TLS depends on being able to send In order to drive the handshake, TLS depends on being able to send
and receive handshake messages. There are two basic functions on and receive handshake messages. There are two basic functions on
this interface: one where QUIC requests handshake messages and one this interface: one where QUIC requests handshake messages and one
where QUIC provides handshake packets. where QUIC provides handshake packets.
Before starting the handshake QUIC provides TLS with the transport Before starting the handshake QUIC provides TLS with the transport
parameters (see Section 8.2) that it wishes to carry. parameters (see Section 8.2) that it wishes to carry.
A QUIC client starts TLS by requesting TLS handshake octets from TLS. A QUIC client starts TLS by requesting TLS handshake bytes from TLS.
The client acquires handshake octets before sending its first packet. The client acquires handshake bytes before sending its first packet.
A QUIC server starts the process by providing TLS with the client's A QUIC server starts the process by providing TLS with the client's
handshake octets. handshake bytes.
At any given time, the TLS stack at an endpoint will have a current At any given time, the TLS stack at an endpoint will have a current
sending encryption level and receiving encryption level. Each sending encryption level and receiving encryption level. Each
encryption level is associated with a different flow of bytes, which encryption level is associated with a different flow of bytes, which
is reliably transmitted to the peer in CRYPTO frames. When TLS is reliably transmitted to the peer in CRYPTO frames. When TLS
provides handshake octets to be sent, they are appended to the provides handshake bytes to be sent, they are appended to the current
current flow and any packet that includes the CRYPTO frame is flow and any packet that includes the CRYPTO frame is protected using
protected using keys from the corresponding encryption level. keys from the corresponding encryption level.
QUIC takes the unprotected content of TLS handshake records as the QUIC takes the unprotected content of TLS handshake records as the
content of CRYPTO frames. TLS record protection is not used by QUIC. content of CRYPTO frames. TLS record protection is not used by QUIC.
QUIC assembles CRYPTO frames into QUIC packets, which are protected QUIC assembles CRYPTO frames into QUIC packets, which are protected
using QUIC packet protection. using QUIC packet protection.
When an endpoint receives a QUIC packet containing a CRYPTO frame When an endpoint receives a QUIC packet containing a CRYPTO frame
from the network, it proceeds as follows: from the network, it proceeds as follows:
o If the packet was in the TLS receiving encryption level, sequence o If the packet was in the TLS receiving encryption level, sequence
skipping to change at page 10, line 4 skipping to change at page 10, line 24
content of CRYPTO frames. TLS record protection is not used by QUIC. content of CRYPTO frames. TLS record protection is not used by QUIC.
QUIC assembles CRYPTO frames into QUIC packets, which are protected QUIC assembles CRYPTO frames into QUIC packets, which are protected
using QUIC packet protection. using QUIC packet protection.
When an endpoint receives a QUIC packet containing a CRYPTO frame When an endpoint receives a QUIC packet containing a CRYPTO frame
from the network, it proceeds as follows: from the network, it proceeds as follows:
o If the packet was in the TLS receiving encryption level, sequence 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 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. 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 If the result of this process is that new data is available, then
it is delivered to TLS in order. it is delivered to TLS in order.
o If the packet is from a previously installed encryption level, it o If the packet is from a previously installed encryption level, it
MUST not contain data which extends past the end of previously MUST not contain data which extends past the end of previously
received data in that flow. Implementations MUST treat any received data in that flow. Implementations MUST treat any
violations of this requirement as a connection error of type violations of this requirement as a connection error of type
PROTOCOL_VIOLATION. PROTOCOL_VIOLATION.
o If the packet is from a new encryption level, it is saved for 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 later processing by TLS. Once TLS moves to receiving from this
encryption level, saved data can be provided. When providing data encryption level, saved data can be provided. When providing data
from any new encryption level to TLS, if there is data from a from any new encryption level to TLS, if there is data from a
previous encryption level that TLS has not consumed, this MUST be previous encryption level that TLS has not consumed, this MUST be
treated as a connection error of type PROTOCOL_VIOLATION. treated as a connection error of type PROTOCOL_VIOLATION.
Each time that TLS is provided with new data, new handshake octets Each time that TLS is provided with new data, new handshake bytes are
are requested from TLS. TLS might not provide any octets if the requested from TLS. TLS might not provide any bytes if the handshake
handshake messages it has received are incomplete or it has no data messages it has received are incomplete or it has no data to send.
to send.
Once the TLS handshake is complete, this is indicated to QUIC along Once the TLS handshake is complete, this is indicated to QUIC along
with any final handshake octets that TLS needs to send. TLS also with any final handshake bytes that TLS needs to send. TLS also
provides QUIC with the transport parameters that the peer advertised provides QUIC with the transport parameters that the peer advertised
during the handshake. during the handshake.
Once the handshake is complete, TLS becomes passive. TLS can still 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 receive data from its peer and respond in kind, but it will not need
to send more data unless specifically requested - either by an to send more data unless specifically requested - either by an
application or QUIC. One reason to send data is that the server application or QUIC. One reason to send data is that the server
might wish to provide additional or updated session tickets to a might wish to provide additional or updated session tickets to a
client. client.
skipping to change at page 11, line 15 skipping to change at page 11, line 33
Finished message in multiple packets. This enables immediate Finished message in multiple packets. This enables immediate
server processing for those packets. server processing for those packets.
4.1.2. Encryption Level Changes 4.1.2. Encryption Level Changes
As keys for new encryption levels become available, TLS provides QUIC As keys for new encryption levels become available, TLS provides QUIC
with those keys. Separately, as TLS starts using keys at a given with those keys. Separately, as TLS starts using keys at a given
encryption level, TLS indicates to QUIC that it is now reading or encryption level, TLS indicates to QUIC that it is now reading or
writing with keys at that encryption level. These events are not writing with keys at that encryption level. These events are not
asynchronous; they always occur immediately after TLS is provided asynchronous; they always occur immediately after TLS is provided
with new handshake octets, or after TLS produces handshake octets. with new handshake bytes, or after TLS produces handshake bytes.
TLS provides QUIC with three items as a new encryption level becomes
available:
o A secret
o An Authenticated Encryption with Associated Data (AEAD) function
o A Key Derivation Function (KDF)
These values are based on the values that TLS negotiates and are used
by QUIC to generate packet and header protection keys (see Section 5
and Section 5.4).
If 0-RTT is possible, it is ready after the client sends a TLS If 0-RTT is possible, it is ready after the client sends a TLS
ClientHello message or the server receives that message. After ClientHello message or the server receives that message. After
providing a QUIC client with the first handshake octets, the TLS providing a QUIC client with the first handshake bytes, the TLS stack
stack might signal the change to 0-RTT keys. On the server, after might signal the change to 0-RTT keys. On the server, after
receiving handshake octets that contain a ClientHello message, a TLS receiving handshake bytes that contain a ClientHello message, a TLS
server might signal that 0-RTT keys are available. server might signal that 0-RTT keys are available.
Although TLS only uses one encryption level at a time, QUIC may use Although TLS only uses one encryption level at a time, QUIC may use
more than one level. For instance, after sending its Finished more than one level. For instance, after sending its Finished
message (using a CRYPTO frame at the Handshake encryption level) an message (using a CRYPTO frame at the Handshake encryption level) an
endpoint can send STREAM data (in 1-RTT encryption). If the Finished endpoint can send STREAM data (in 1-RTT encryption). If the Finished
message is lost, the endpoint uses the Handshake encryption level to message is lost, the endpoint uses the Handshake encryption level to
retransmit the lost message. Reordering or loss of packets can mean retransmit the lost message. Reordering or loss of packets can mean
that QUIC will need to handle packets at multiple encryption levels. that QUIC will need to handle packets at multiple encryption levels.
During the handshake, this means potentially handling packets at During the handshake, this means potentially handling packets at
skipping to change at page 13, line 9 skipping to change at page 14, line 9
QUIC are supported by the newer version. QUIC are supported by the newer version.
A badly configured TLS implementation could negotiate TLS 1.2 or A badly configured TLS implementation could negotiate TLS 1.2 or
another older version of TLS. An endpoint MUST terminate the another older version of TLS. An endpoint MUST terminate the
connection if a version of TLS older than 1.3 is negotiated. connection if a version of TLS older than 1.3 is negotiated.
4.3. ClientHello Size 4.3. ClientHello Size
QUIC requires that the first Initial packet from a client contain an QUIC requires that the first Initial packet from a client contain an
entire cryptographic handshake message, which for TLS is the entire cryptographic handshake message, which for TLS is the
ClientHello. Though a packet larger than 1200 octets might be ClientHello. Though a packet larger than 1200 bytes might be
supported by the path, a client improves the likelihood that a packet supported by the path, a client improves the likelihood that a packet
is accepted if it ensures that the first ClientHello message is small is accepted if it ensures that the first ClientHello message is small
enough to stay within this limit. enough to stay within this limit.
QUIC packet and framing add at least 36 octets of overhead to the QUIC packet and framing add at least 36 bytes of overhead to the
ClientHello message. That overhead increases if the client chooses a ClientHello message. That overhead increases if the client chooses a
connection ID without zero length. Overheads also do not include the 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 token or a connection ID longer than 8 bytes, both of which might be
required if a server sends a Retry packet. required if a server sends a Retry packet.
A typical TLS ClientHello can easily fit into a 1200 octet packet. A typical TLS ClientHello can easily fit into a 1200 byte packet.
However, in addition to the overheads added by QUIC, there are However, in addition to the overheads added by QUIC, there are
several variables that could cause this limit to be exceeded. Large several variables that could cause this limit to be exceeded. Large
session tickets, multiple or large key shares, and long lists of session tickets, multiple or large key shares, and long lists of
supported ciphers, signature algorithms, versions, QUIC transport supported ciphers, signature algorithms, versions, QUIC transport
parameters, and other negotiable parameters and extensions could parameters, and other negotiable parameters and extensions could
cause this message to grow. cause this message to grow.
For servers, in addition to connection IDs and tokens, the size of For servers, in addition to connection IDs and tokens, the size of
TLS session tickets can have an effect on a client's ability to TLS session tickets can have an effect on a client's ability to
connect. Minimizing the size of these values increases the connect. Minimizing the size of these values increases the
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of 0-RTT. of 0-RTT.
4.7. HelloRetryRequest 4.7. HelloRetryRequest
In TLS over TCP, the HelloRetryRequest feature (see Section 4.1.4 of In TLS over TCP, the HelloRetryRequest feature (see Section 4.1.4 of
[TLS13]) can be used to correct a client's incorrect KeyShare [TLS13]) can be used to correct a client's incorrect KeyShare
extension as well as for a stateless round-trip check. From the extension as well as for a stateless round-trip check. From the
perspective of QUIC, this just looks like additional messages carried perspective of QUIC, this just looks like additional messages carried
in the Initial encryption level. Although it is in principle in the Initial encryption level. Although it is in principle
possible to use this feature for address verification in QUIC, QUIC possible to use this feature for address verification in QUIC, QUIC
implementations SHOULD instead use the Retry feature (see Section 4.4 implementations SHOULD instead use the Retry feature (see Section 8.1
of [QUIC-TRANSPORT]). HelloRetryRequest is still used to request key of [QUIC-TRANSPORT]). HelloRetryRequest is still used to request key
shares. shares.
4.8. TLS Errors 4.8. TLS Errors
If TLS experiences an error, it generates an appropriate alert as If TLS experiences an error, it generates an appropriate alert as
defined in Section 6 of [TLS13]. defined in Section 6 of [TLS13].
A TLS alert is turned into a QUIC connection error by converting the A TLS alert is turned into a QUIC connection error by converting the
one-octet alert description into a QUIC error code. The alert one-byte alert description into a QUIC error code. The alert
description is added to 0x100 to produce a QUIC error code from the 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 range reserved for CRYPTO_ERROR. The resulting value is sent in a
QUIC CONNECTION_CLOSE frame. QUIC CONNECTION_CLOSE frame.
The alert level of all TLS alerts is "fatal"; a TLS stack MUST NOT The alert level of all TLS alerts is "fatal"; a TLS stack MUST NOT
generate alerts at the "warning" level. generate alerts at the "warning" level.
4.9. Discarding Unused Keys 4.9. Discarding Unused Keys
After QUIC moves to a new encryption level, packet protection keys After QUIC moves to a new encryption level, packet protection keys
for previous encryption levels can be discarded. This occurs several for previous encryption levels can be discarded. This occurs several
times during the handshake, as well as when keys are updated (see times during the handshake, as well as when keys are updated (see
Section 6). Section 6). Initial packet protection keys are treated specially,
see Section 4.10.
Packet protection keys are not discarded immediately when new keys Packet protection keys are not discarded immediately when new keys
are available. If packets from a lower encryption level contain are available. If packets from a lower encryption level contain
CRYPTO frames, frames that retransmit that data MUST be sent at the CRYPTO frames, frames that retransmit that data MUST be sent at the
same encryption level. Similarly, an endpoint generates same encryption level. Similarly, an endpoint generates
acknowledgements for packets at the same encryption level as the acknowledgements for packets at the same encryption level as the
packet being acknowledged. Thus, it is possible that keys for a packet being acknowledged. Thus, it is possible that keys for a
lower encryption level are needed for a short time after keys for a lower encryption level are needed for a short time after keys for a
newer encryption level are available. newer encryption level are available.
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sent two updates prior will appear to use the same keys. After the sent two updates prior will appear to use the same keys. After the
handshake is complete, endpoints only need to maintain the two latest handshake is complete, endpoints only need to maintain the two latest
sets of packet protection keys and MAY discard older keys. Updating sets of packet protection keys and MAY discard older keys. Updating
keys multiple times rapidly can cause packets to be effectively lost keys multiple times rapidly can cause packets to be effectively lost
if packets are significantly delayed. Because key updates can only if packets are significantly delayed. Because key updates can only
be performed once per round trip time, only packets that are delayed 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; 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 such packets will be marked as lost before this, as they leave a gap
in the sequence of packet numbers. in the sequence of packet numbers.
4.10. Discarding Initial Keys
Packets protected with Initial secrets (Section 5.2) are not
authenticated, meaning that an attacker could spoof packets with the
intent to disrupt a connection. To limit these attacks, Initial
packet protection keys can be discarded more aggressively than other
keys.
The successful use of Handshake packets indicates that no more
Initial packets need to be exchanged, as these keys can only be
produced after receiving all CRYPTO frames from Initial packets.
Thus, a client MUST discard Initial keys when it first sends a
Handshake packet and a server MUST discard Initial keys when it first
successfully processes a Handshake packet. Endpoints MUST NOT send
Initial packets after this point.
This results in abandoning loss recovery state for the Initial
encryption level and ignoring any outstanding Initial packets.
5. Packet Protection 5. Packet Protection
As with TLS over TCP, QUIC protects packets with keys derived from As with TLS over TCP, QUIC protects packets with keys derived from
the TLS handshake, using the AEAD algorithm negotiated by TLS. the TLS handshake, using the AEAD algorithm negotiated by TLS.
5.1. Packet Protection Keys 5.1. Packet Protection Keys
QUIC derives packet protection keys in the same way that TLS derives QUIC derives packet protection keys in the same way that TLS derives
record protection keys. record protection keys.
Each encryption level has separate secret values for protection of Each encryption level has separate secret values for protection of
packets sent in each direction. These traffic secrets are derived by packets sent in each direction. These traffic secrets are derived by
TLS (see Section 7.1 of [TLS13]) and are used by QUIC for all TLS (see Section 7.1 of [TLS13]) and are used by QUIC for all
encryption levels except the Initial encryption level. The secrets encryption levels except the Initial encryption level. The secrets
for the Initial encryption level are computed based on the client's for the Initial encryption level are computed based on the client's
initial Destination Connection ID, as described in Section 5.2. initial Destination Connection ID, as described in Section 5.2.
The keys used for packet protection are computed from the TLS secrets The keys used for packet protection are computed from the TLS secrets
using the method described in Section 7.3 of [TLS13]), except that using the KDF provided by TLS. In TLS 1.3, the HKDF-Expand-Label
the label for HKDF-Expand-Label uses the prefix "quic " rather than function described in Section 7.1 of [TLS13]) is used, using the hash
"tls13 ". A different label provides key separation between TLS and function from the negotiated cipher suite. Other versions of TLS
QUIC. MUST provide a similar function in order to be used QUIC.
For example, where TLS might use a label of The current encryption level secret and the label "quic key" are
0x002009746c733133206b657900 to derive a key, QUIC uses input to the KDF to produce the AEAD key; the label "quic iv" is used
0x00200871756963206b657900. to derive the IV, see Section 5.3. The header protection key uses
the "quic hp" label, see Section 5.4). Using these labels provides
key separation between QUIC and TLS, see Section 9.4.
The HKDF-Expand-Label function with a "quic " label is also used to The KDF used for initial secrets is always the HKDF-Expand-Label
derive the initial secrets (see Section 5.2) and to derive a packet function from TLS 1.3 (see Section 5.2).
number protection key (the "pn" label, see Section 5.4).
5.2. Initial Secrets 5.2. Initial Secrets
Initial packets are protected with a secret derived from the Initial packets are protected with a secret derived from the
Destination Connection ID field from the client's first Initial Destination Connection ID field from the client's first Initial
packet of the connection. Specifically: packet of the connection. Specifically:
initial_salt = 0x9c108f98520a5c5c32968e950e8a2c5fe06d6c38 initial_salt = 0xef4fb0abb47470c41befcf8031334fae485e09a0
initial_secret = HKDF-Extract(initial_salt, initial_secret = HKDF-Extract(initial_salt,
client_dst_connection_id) client_dst_connection_id)
client_initial_secret = HKDF-Expand-Label(initial_secret, client_initial_secret = HKDF-Expand-Label(initial_secret,
"client in", "", "client in", "",
Hash.length) Hash.length)
server_initial_secret = HKDF-Expand-Label(initial_secret, server_initial_secret = HKDF-Expand-Label(initial_secret,
"server in", "", "server in", "",
Hash.length) Hash.length)
The hash function for HKDF when deriving initial secrets and keys is The hash function for HKDF when deriving initial secrets and keys is
SHA-256 [SHA]. SHA-256 [SHA].
The connection ID used with HKDF-Expand-Label is the Destination The connection ID used with HKDF-Expand-Label is the Destination
Connection ID in the Initial packet sent by the client. This will be Connection ID in the Initial packet sent by the client. This will be
a randomly-selected value unless the client creates the Initial a randomly-selected value unless the client creates the Initial
packet after receiving a Retry packet, where the Destination packet after receiving a Retry packet, where the Destination
Connection ID is selected by the server. Connection ID is selected by the server.
The value of initial_salt is a 20 octet sequence shown in the figure The value of initial_salt is a 20 byte sequence shown in the figure
in hexadecimal notation. Future versions of QUIC SHOULD generate a in hexadecimal notation. Future versions of QUIC SHOULD generate a
new salt value, thus ensuring that the keys are different for each 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. This prevents a middlebox that only recognizes one
version of QUIC from seeing or modifying the contents of handshake version of QUIC from seeing or modifying the contents of handshake
packets from future versions. packets from future versions.
The HKDF-Expand-Label function defined in TLS 1.3 MUST be used for
Initial packets even where the TLS versions offered do not include
TLS 1.3.
Note: The Destination Connection ID is of arbitrary length, and it Note: The Destination Connection ID is of arbitrary length, and it
could be zero length if the server sends a Retry packet with a could be zero length if the server sends a Retry packet with a
zero-length Source Connection ID field. In this case, the Initial zero-length Source Connection ID field. In this case, the Initial
keys provide no assurance to the client that the server received keys provide no assurance to the client that the server received
its packet; the client has to rely on the exchange that included its packet; the client has to rely on the exchange that included
the Retry packet for that property. the Retry packet for that property.
5.3. AEAD Usage 5.3. AEAD Usage
The Authentication Encryption with Associated Data (AEAD) [AEAD] The Authentication Encryption with Associated Data (AEAD) [AEAD]
function used for QUIC packet protection is the AEAD that is function used for QUIC packet protection is the AEAD that is
negotiated for use with the TLS connection. For example, if TLS 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 using the TLS_AES_128_GCM_SHA256, the AEAD_AES_128_GCM function is
used. used.
QUIC packets are protected prior to applying packet number protection Packets are protected prior to applying header protection
(Section 5.4). The unprotected packet number is part of the (Section 5.4). The unprotected packet header is part of the
associated data (A). When removing packet protection, an endpoint associated data (A). When removing packet protection, an endpoint
first removes the protection from the packet number. first removes the header protection.
All QUIC packets other than Version Negotiation and Retry packets are All QUIC packets other than Version Negotiation and Retry packets are
protected with an AEAD algorithm [AEAD]. Prior to establishing a protected with an AEAD algorithm [AEAD]. Prior to establishing a
shared secret, packets are protected with AEAD_AES_128_GCM and a key shared secret, packets are protected with AEAD_AES_128_GCM and a key
derived from the destination connection ID in the client's first derived from the destination connection ID in the client's first
Initial packet (see Section 5.2). This provides protection against Initial packet (see Section 5.2). This provides protection against
off-path attackers and robustness against QUIC version unaware off-path attackers and robustness against QUIC version unaware
middleboxes, but not against on-path attackers. middleboxes, but not against on-path attackers.
All ciphersuites currently defined for TLS 1.3 - and therefore QUIC - QUIC can use any of the ciphersuites defined in [TLS13] with the
have a 16-byte authentication tag and produce an output 16 bytes exception of TLS_AES_128_CCM_8_SHA256. The AEAD for that
larger than their input. ciphersuite, AEAD_AES_128_CCM_8 [CCM], does not produce a large
enough authentication tag for use with the header protection designs
provided (see Section 5.4). All other ciphersuites defined in
[TLS13] 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 The key and IV for the packet are computed as described in
Section 5.1. The nonce, N, is formed by combining the packet Section 5.1. The nonce, N, is formed by combining the packet
protection IV with the packet number. The 64 bits of the protection IV with the packet number. The 64 bits of the
reconstructed QUIC packet number in network byte order are left- 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 with zeros to the size of the IV. The exclusive OR of the
padded packet number and the IV forms the AEAD nonce. padded packet number and the IV forms the AEAD nonce.
The associated data, A, for the AEAD is the contents of the QUIC 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, starting from the flags byte in either the short or long
header, up to and including the unprotected packet number. header, up to and including the unprotected packet number.
The input plaintext, P, for the AEAD is the content of the QUIC frame The input plaintext, P, for the AEAD is the payload of the QUIC
following the header, as described in [QUIC-TRANSPORT]. packet, as described in [QUIC-TRANSPORT].
The output ciphertext, C, of the AEAD is transmitted in place of P. 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 Some AEAD functions have limits for how many packets can be encrypted
under the same key and IV (see for example [AEBounds]). This might under the same key and IV (see for example [AEBounds]). This might
be lower than the packet number limit. An endpoint MUST initiate a 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 key update (Section 6) prior to exceeding any limit set for the AEAD
that is in use. that is in use.
5.4. Packet Number Protection 5.4. Header Protection
QUIC packet numbers are protected using a key that is derived from Parts of QUIC packet headers, in particular the Packet Number field,
the current set of secrets. The key derived using the "pn" label is are protected using a key that is derived separate to the packet
used to protect the packet number from casual observation. The protection key and IV. The key derived using the "quic hp" label is
packet number protection algorithm depends on the negotiated AEAD. used to provide confidentiality protection for those fields that are
not exposed to on-path elements.
Packet number protection is applied after packet protection is This protection applies to the least-significant bits of the first
applied (see Section 5.3). The ciphertext of the packet is sampled byte, plus the Packet Number field. The four least-significant bits
and used as input to an encryption algorithm. of the first byte are protected for packets with long headers; the
five least significant bits of the first byte are protected for
packets with short headers. For both header forms, this covers the
reserved bits and the Packet Number Length field; the Key Phase bit
is also protected for packets with a short header.
In sampling the packet ciphertext, the packet number length is The same header protection key is used for the duration of the
assumed to be 4 octets (its maximum possible encoded length), unless connection, with the value not changing after a key update (see
there is insufficient space in the packet for sampling. The sampled Section 6). This allows header protection to be used to protect the
ciphertext starts after allowing for a 4 octet packet number unless key phase.
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 This process does not apply to Retry or Version Negotiation packets,
can be determined by: which do not contain a protected payload or any of the fields that
are protected by this process.
5.4.1. Header Protection Application
Header protection is applied after packet protection is applied (see
Section 5.3). The ciphertext of the packet is sampled and used as
input to an encryption algorithm. The algorithm used depends on the
negotiated AEAD.
The output of this algorithm is a 5 byte mask which is applied to the
protected header fields using exclusive OR. The least significant
bits of the first byte of the packet are masked by the least
significant bits of the first mask byte, and the packet number is
masked with the remaining bytes. Any unused bytes of mask that might
result from a shorter packet number encoding are unused.
Figure 4 shows a sample algorithm for applying header protection.
Removing header protection only differs in the order in which the
packet number length (pn_length) is determined.
mask = header_protection(hp_key, sample)
pn_length = (packet[0] & 0x03) + 1
if (packet[0] & 0x80) == 0x80:
# Long header: 4 bits masked
packet[0] ^= mask[0] & 0x0f
else:
# Short header: 5 bits masked
packet[0] ^= mask[0] & 0x1f
# pn_offset is the start of the Packet Number field.
packet[pn_offset:pn_offset+pn_length] ^= mask[1:1+pn_length]
Figure 4: Header Protection Pseudocode
Figure 5 shows the protected fields of long and short headers marked
with an E. Figure 5 also shows the sampled fields.
Long Header:
+-+-+-+-+-+-+-+-+
|1|1|T T|E E E E|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version -> Length Fields ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Short Header:
+-+-+-+-+-+-+-+-+
|0|1|S|E E E E E|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Connection ID (0/32..144) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Common Fields:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|E E E E E E E E E Packet Number (8/16/24/32) E E E E E E E E...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| [Protected Payload (8/16/24)] ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sampled part of Protected Payload (128) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protected Payload Remainder (*) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Header Protection and Ciphertext Sample
Before a TLS ciphersuite can be used with QUIC, a header protection
algorithm MUST be specified 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]. Prior
to TLS selecting a ciphersuite, AES header protection is used
(Section 5.4.3), matching the AEAD_AES_128_GCM packet protection.
5.4.2. Header Protection Sample
The header protection algorithm uses both the header protection key
and a sample of the ciphertext from the packet Payload field.
The same number of bytes are always sampled, but an allowance needs
to be made for the endpoint removing protection, which will not know
the length of the Packet Number field. In sampling the packet
ciphertext, the Packet Number field is assumed to be 4 bytes long
(its maximum possible encoded length).
An endpoint MUST discard packets that are not long enough to contain
a complete sample.
To ensure that sufficient data is available for sampling, packets are
padded so that the combined lengths of the encoded packet number and
protected payload is at least 4 bytes longer than the sample required
for header protection. For the AEAD functions defined in [TLS13],
which have 16-byte expansions and 16-byte header protection samples,
this results in needing at least 3 bytes of frames in the unprotected
payload if the packet number is encoded on a single byte, or 2 bytes
of frames for a 2-byte packet number encoding.
The sampled ciphertext for a packet with a short header can be
determined by the following pseudocode:
sample_offset = 1 + len(connection_id) + 4 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] sample = packet[sample_offset..sample_offset+sample_length]
For example, for a packet with a short header, an 8 byte connection
ID, and protected with AEAD_AES_128_GCM, the sample takes bytes 13 to
28 inclusive (using zero-based indexing).
A packet with a long header is sampled in the same way, noting that 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 multiple QUIC packets might be included in the same UDP datagram and
that each one is handled separately. that each one is handled separately.
sample_offset = 6 + len(destination_connection_id) + sample_offset = 6 + len(destination_connection_id) +
len(source_connection_id) + len(source_connection_id) +
len(payload_length) + 4 len(payload_length) + 4
if packet_type == Initial: if packet_type == Initial:
sample_offset += len(token_length) + sample_offset += len(token_length) +
len(token) len(token)
To ensure that this process does not sample the packet number, packet sample = packet[sample_offset..sample_offset+sample_length]
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]).
5.4.1. AES-Based Packet Number Protection 5.4.3. AES-Based Header Protection
This section defines the packet protection algorithm for This section defines the packet protection algorithm for
AEAD_AES_128_GCM, AEAD_AES_128_CCM, AEAD_AES_256_GCM, and 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 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 AES [AES] in electronic code-book (ECB) mode. AEAD_AES_256_GCM, and
AEAD_AES_256_CCM use 256-bit AES in CTR mode. AEAD_AES_256_CCM use 256-bit AES in ECB mode.
This algorithm samples 16 octets from the packet ciphertext. This This algorithm samples 16 bytes from the packet ciphertext. This
value is used as the counter input to AES-CTR. value is used as the counter input to AES-ECB. In pseudocode:
encrypted_pn = AES-CTR(pn_key, sample, packet_number) mask = AES-ECB(pn_key, sample)
5.4.2. ChaCha20-Based Packet Number Protection 5.4.4. ChaCha20-Based Header Protection
When AEAD_CHACHA20_POLY1305 is in use, packet number protection uses When AEAD_CHACHA20_POLY1305 is in use, header protection uses the raw
the raw ChaCha20 function as defined in Section 2.4 of [CHACHA]. ChaCha20 function as defined in Section 2.4 of [CHACHA]. This uses a
This uses a 256-bit key and 16 octets sampled from the packet 256-bit key and 16 bytes sampled from the packet protection output.
protection output.
The first 4 octets of the sampled ciphertext are interpreted as a The first 4 bytes of the sampled ciphertext are interpreted as a
32-bit number in little-endian order and are used as the block count. 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 The remaining 12 bytes are interpreted as three concatenated 32-bit
numbers in little-endian order and used as the nonce. numbers in little-endian order and used as the nonce.
The encoded packet number is then encrypted with ChaCha20 directly. The encryption mask is produced by invoking ChaCha20 to protect 5
In pseudocode: zero bytes. In pseudocode:
counter = DecodeLE(sample[0..3]) counter = DecodeLE(sample[0..3])
nonce = DecodeLE(sample[4..7], sample[8..11], sample[12..15]) nonce = DecodeLE(sample[4..7], sample[8..11], sample[12..15])
encrypted_pn = ChaCha20(pn_key, counter, nonce, packet_number) mask = ChaCha20(pn_key, counter, nonce, {0,0,0,0,0})
5.5. Receiving Protected Packets 5.5. Receiving Protected Packets
Once an endpoint successfully receives a packet with a given packet Once an endpoint successfully receives a packet with a given packet
number, it MUST discard all packets in the same packet number space number, it MUST discard all packets in the same packet number space
with higher packet numbers if they cannot be successfully unprotected with higher packet numbers if they cannot be successfully unprotected
with either the same key, or - if there is a key update - the next with either the same key, or - if there is a key update - the next
packet protection key (see Section 6). Similarly, a packet that packet protection key (see Section 6). Similarly, a packet that
appears to trigger a key update, but cannot be unprotected appears to trigger a key update, but cannot be unprotected
successfully MUST be discarded. successfully MUST be discarded.
skipping to change at page 22, line 38 skipping to change at page 26, line 20
equivalent to a fatal TLS alert of unexpected_message (see equivalent to a fatal TLS alert of unexpected_message (see
Section 4.8). Section 4.8).
An endpoint MUST NOT initiate more than one key update at a time. A 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 new key cannot be used until the endpoint has received and
successfully decrypted a packet with a matching KEY_PHASE. successfully decrypted a packet with a matching KEY_PHASE.
A receiving endpoint detects an update when the KEY_PHASE bit does A receiving endpoint detects an update when the KEY_PHASE bit does
not match what it is expecting. It creates a new secret (see not match what it is expecting. It creates a new secret (see
Section 7.2 of [TLS13]) and the corresponding read key and IV using Section 7.2 of [TLS13]) and the corresponding read key and IV using
the same variation on HKDF as defined in Section 5.1; that is, the the KDF function provided by TLS. The header protection key is not
prefix "quic " is used in place of "tls13 ". updated.
If the packet can be decrypted and authenticated using the updated If the packet can be decrypted and authenticated using the updated
key and IV, then the keys the endpoint uses for packet protection are key and IV, then the keys the endpoint uses for packet protection are
also updated. The next packet sent by the endpoint will then use the also updated. The next packet sent by the endpoint will then use the
new keys. new keys.
An endpoint does not always need to send packets when it detects that An endpoint does not always need to send packets when it detects that
its peer has updated keys. The next packet that it sends will simply 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 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 sent any packets with updated keys, it indicates that its peer
has updated keys twice without awaiting a reciprocal update. An has updated keys twice without awaiting a reciprocal update. An
endpoint MUST treat consecutive key updates as a fatal error and endpoint MUST treat consecutive key updates as a fatal error and
abort the connection. abort the connection.
An endpoint SHOULD retain old keys for a short period to allow it to An endpoint SHOULD retain old keys for a period of no more than three
decrypt packets with smaller packet numbers than the packet that times the Probe Timeout (PTO, see [QUIC-RECOVERY]). After this
triggered the key update. This allows an endpoint to consume packets period, old keys and their corresponding secrets SHOULD be discarded.
that are reordered around the transition between keys. Packets with Retaining keys allow endpoints to process packets that were sent with
higher packet numbers always use the updated keys and MUST NOT be old keys and delayed in the network. Packets with higher packet
decrypted with old keys. 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
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 This ensures that once the handshake is complete, packets with the
same KEY_PHASE will have the same packet protection keys, unless same KEY_PHASE will have the same packet protection keys, unless
there are multiple key updates in a short time frame succession and there are multiple key updates in a short time frame succession and
significant packet reordering. significant packet reordering.
Initiating Peer Responding Peer Initiating Peer Responding Peer
@M QUIC Frames @M QUIC Frames
New Keys -> @N New Keys -> @N
@N QUIC Frames @N QUIC Frames
--------> -------->
QUIC Frames @M QUIC Frames @M
New Keys -> @N New Keys -> @N
QUIC Frames @N QUIC Frames @N
<-------- <--------
Figure 4: Key Update Figure 6: Key Update
A packet that triggers a key update could arrive after successfully A packet that triggers a key update could arrive after successfully
processing a packet with a higher packet number. This is only 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 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 is incorrectly reverting to use of old keys. Because the latter
cannot be differentiated from an attack, an endpoint MUST immediately cannot be differentiated from an attack, an endpoint MUST immediately
terminate the connection if it detects this condition. terminate the connection if it detects this condition.
In deciding when to update keys, endpoints MUST NOT exceed the limits
for use of specific keys, as described in Section 5.5 of [TLS13].
7. Security of Initial Messages 7. Security of Initial Messages
Initial packets are not protected with a secret key, so they are Initial packets are not protected with a secret key, so they are
subject to potential tampering by an attacker. QUIC provides subject to potential tampering by an attacker. QUIC provides
protection against attackers that cannot read packets, but does not protection against attackers that cannot read packets, but does not
attempt to provide additional protection against attacks where the attempt to provide additional protection against attacks where the
attacker can observe and inject packets. Some forms of tampering - attacker can observe and inject packets. Some forms of tampering -
such as modifying the TLS messages themselves - are detectable, but such as modifying the TLS messages themselves - are detectable, but
some - such as modifying ACKs - are not. some - such as modifying ACKs - are not.
skipping to change at page 26, line 24 skipping to change at page 30, line 5
9.1. Packet Reflection Attack Mitigation 9.1. Packet Reflection Attack Mitigation
A small ClientHello that results in a large block of handshake A small ClientHello that results in a large block of handshake
messages from a server can be used in packet reflection attacks to messages from a server can be used in packet reflection attacks to
amplify the traffic generated by an attacker. amplify the traffic generated by an attacker.
QUIC includes three defenses against this attack. First, the packet QUIC includes three defenses against this attack. First, the packet
containing a ClientHello MUST be padded to a minimum size. Second, containing a ClientHello MUST be padded to a minimum size. Second,
if responding to an unverified source address, the server is if responding to an unverified source address, the server is
forbidden to send more than three UDP datagrams in its first flight forbidden to send more than three UDP datagrams in its first flight
(see Section 4.7 of [QUIC-TRANSPORT]). Finally, because (see Section 8.1 of [QUIC-TRANSPORT]). Finally, because
acknowledgements of Handshake packets are authenticated, a blind acknowledgements of Handshake packets are authenticated, a blind
attacker cannot forge them. Put together, these defenses limit the attacker cannot forge them. Put together, these defenses limit the
level of amplification. level of amplification.
9.2. Peer Denial of Service 9.2. Peer Denial of Service
QUIC, TLS, and HTTP/2 all contain messages that have legitimate uses QUIC, TLS, and HTTP/2 all contain messages that have legitimate uses
in some contexts, but that can be abused to cause a peer to expend in some contexts, but that can be abused to cause a peer to expend
processing resources without having any observable impact on the processing resources without having any observable impact on the
state of the connection. If processing is disproportionately large state of the connection. If processing is disproportionately large
skipping to change at page 26, line 47 skipping to change at page 30, line 28
without consequence. without consequence.
QUIC prohibits the sending of empty "STREAM" frames unless they are QUIC prohibits the sending of empty "STREAM" frames unless they are
marked with the FIN bit. This prevents "STREAM" frames from being marked with the FIN bit. This prevents "STREAM" frames from being
sent that only waste effort. sent that only waste effort.
While there are legitimate uses for some redundant packets, While there are legitimate uses for some redundant packets,
implementations SHOULD track redundant packets and treat excessive implementations SHOULD track redundant packets and treat excessive
volumes of any non-productive packets as indicative of an attack. volumes of any non-productive packets as indicative of an attack.
9.3. Packet Number Protection Analysis 9.3. Header Protection Analysis
Packet number protection relies on the packet protection AEAD being a Header protection relies on the packet protection AEAD being a
pseudorandom function (PRF), which is not a property that AEAD pseudorandom function (PRF), which is not a property that AEAD
algorithms guarantee. Therefore, no strong assurances about the algorithms guarantee. Therefore, no strong assurances about the
general security of this mechanism can be shown in the general case. general security of this mechanism can be shown in the general case.
The AEAD algorithms described in this document are assumed to be The AEAD algorithms described in this document are assumed to be
PRFs. PRFs.
The packet number protection algorithms defined in this document take The header protection algorithms defined in this document take the
the form: form:
encrypted_pn = packet_number XOR PRF(pn_key, sample) protected_field = field XOR PRF(pn_key, sample)
This construction is secure against chosen plaintext attacks (IND- This construction is secure against chosen plaintext attacks (IND-
CPA) [IMC]. CPA) [IMC].
Use of the same key and ciphertext sample more than once risks Use of the same key and ciphertext sample more than once risks
compromising packet number protection. Protecting two different compromising header protection. Protecting two different headers
packet numbers with the same key and ciphertext sample reveals the with the same key and ciphertext sample reveals the exclusive OR of
exclusive OR of those packet numbers. Assuming that the AEAD acts as the protected fields. Assuming that the AEAD acts as a PRF, if L
a PRF, if L bits are sampled, the odds of two ciphertext samples bits are sampled, the odds of two ciphertext samples being identical
being identical approach 2^(-L/2), that is, the birthday bound. For approach 2^(-L/2), that is, the birthday bound. For the algorithms
the algorithms described in this document, that probability is one in described in this document, that probability is one in 2^64.
2^64.
Note: In some cases, inputs shorter than the full size required by Note: In some cases, inputs shorter than the full size required by
the packet protection algorithm might be used. the packet protection algorithm might be used.
To prevent an attacker from modifying packet numbers, values of To prevent an attacker from modifying packet headers, the header is
packet numbers are transitively authenticated using packet transitively authenticated using packet protection; the entire packet
protection; packet numbers are part of the authenticated additional header is part of the authenticated additional data. Protected
data. A falsified or modified packet number can only be detected fields that are falsified or modified can only be detected once the
once the packet protection is removed. packet protection is removed.
An attacker can guess values for packet numbers and have an endpoint An attacker could guess values for packet numbers and have an
confirm guesses through timing side channels. If the recipient of a endpoint confirm guesses through timing side channels. Similarly,
packet discards packets with duplicate packet numbers without guesses for the packet number length can be trialed and exposed. If
attempting to remove packet protection they could reveal through the recipient of a packet discards packets with duplicate packet
timing side-channels that the packet number matches a received numbers without attempting to remove packet protection they could
packet. For authentication to be free from side-channels, the entire reveal through timing side-channels that the packet number matches a
process of packet number protection removal, packet number recovery, received packet. For authentication to be free from side-channels,
and packet protection removal MUST be applied together without timing the entire process of header protection removal, packet number
and other side-channels. 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 For the sending of packets, construction and protection of packet
payloads and packet numbers MUST be free from side-channels that payloads and packet numbers MUST be free from side-channels that
would reveal the packet number or its encoded size. would reveal the packet number or its encoded size.
9.4. Key Diversity
In using TLS, the central key schedule of TLS is used. As a result
of the TLS handshake messages being integrated into the calculation
of secrets, the inclusion of the QUIC transport parameters extension
ensures that handshake and 1-RTT keys are not the same as those that
might be produced by a server running TLS over TCP. However, 0-RTT
keys only include the ClientHello message and might therefore use the
same secrets. To avoid the possibility of cross-protocol key
synchronization, additional measures are provided to improve key
separation.
The QUIC packet protection keys and IVs are derived using a different
label than the equivalent keys in TLS.
To preserve this separation, a new version of QUIC SHOULD define new
labels for key derivation for packet protection key and IV, plus the
packet number protection keys.
The initial secrets also use a key that is specific to the negotiated
QUIC version. New QUIC versions SHOULD define a new salt value used
in calculating initial secrets.
10. IANA Considerations 10. IANA Considerations
This document does not create any new IANA registries, but it This document does not create any new IANA registries, but it
registers the values in the following registries: registers the values in the following registries:
o TLS ExtensionsType Registry [TLS-REGISTRIES] - IANA is to register o TLS ExtensionsType Registry [TLS-REGISTRIES] - IANA is to register
the quic_transport_parameters extension found in Section 8.2. The 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 Recommended column is to be marked Yes. The TLS 1.3 Column is to
include CH and EE. include CH and EE.
skipping to change at page 28, line 28 skipping to change at page 32, line 33
[AES] "Advanced encryption standard (AES)", National Institute [AES] "Advanced encryption standard (AES)", National Institute
of Standards and Technology report, of Standards and Technology report,
DOI 10.6028/nist.fips.197, November 2001. DOI 10.6028/nist.fips.197, November 2001.
[CHACHA] Nir, Y. and A. Langley, "ChaCha20 and Poly1305 for IETF [CHACHA] Nir, Y. and A. Langley, "ChaCha20 and Poly1305 for IETF
Protocols", RFC 8439, DOI 10.17487/RFC8439, June 2018, Protocols", RFC 8439, DOI 10.17487/RFC8439, June 2018,
<https://www.rfc-editor.org/info/rfc8439>. <https://www.rfc-editor.org/info/rfc8439>.
[QUIC-RECOVERY] [QUIC-RECOVERY]
Iyengar, J., Ed. and I. Swett, Ed., "QUIC Loss Detection Iyengar, J., Ed. and I. Swett, Ed., "QUIC Loss Detection
and Congestion Control", draft-ietf-quic-recovery-16 (work and Congestion Control", draft-ietf-quic-recovery-17 (work
in progress), October 2018. in progress), December 2018.
[QUIC-TRANSPORT] [QUIC-TRANSPORT]
Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", draft-ietf-quic- Multiplexed and Secure Transport", draft-ietf-quic-
transport-16 (work in progress), October 2018. transport-17 (work in progress), December 2018.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan, [RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol "Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301, Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <https://www.rfc-editor.org/info/rfc7301>. July 2014, <https://www.rfc-editor.org/info/rfc7301>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[SHA] Dang, Q., "Secure Hash Standard", National Institute of [SHA] Dang, Q., "Secure Hash Standard", National Institute of
Standards and Technology report, Standards and Technology report,
DOI 10.6028/nist.fips.180-4, July 2015. DOI 10.6028/nist.fips.180-4, July 2015.
[TLS-REGISTRIES] [TLS-REGISTRIES]
Salowey, J. and S. Turner, "IANA Registry Updates for Salowey, J. and S. Turner, "IANA Registry Updates for TLS
Transport Layer Security (TLS) and Datagram Transport and DTLS", RFC 8447, DOI 10.17487/RFC8447, August 2018,
Layer Security (DTLS)", draft-ietf-tls-iana-registry- <https://www.rfc-editor.org/info/rfc8447>.
updates-05 (work in progress), May 2018.
[TLS13] Rescorla, E., "The Transport Layer Security (TLS) Protocol [TLS13] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
11.2. Informative References 11.2. Informative References
[AEBounds] [AEBounds]
Luykx, A. and K. Paterson, "Limits on Authenticated Luykx, A. and K. Paterson, "Limits on Authenticated
Encryption Use in TLS", March 2016, Encryption Use in TLS", March 2016,
<http://www.isg.rhul.ac.uk/~kp/TLS-AEbounds.pdf>. <http://www.isg.rhul.ac.uk/~kp/TLS-AEbounds.pdf>.
[CCM] McGrew, D. and D. Bailey, "AES-CCM Cipher Suites for
Transport Layer Security (TLS)", RFC 6655,
DOI 10.17487/RFC6655, July 2012,
<https://www.rfc-editor.org/info/rfc6655>.
[IMC] Katz, J. and Y. Lindell, "Introduction to Modern [IMC] Katz, J. and Y. Lindell, "Introduction to Modern
Cryptography, Second Edition", ISBN 978-1466570269, Cryptography, Second Edition", ISBN 978-1466570269,
November 2014. November 2014.
[QUIC-HTTP] [QUIC-HTTP]
Bishop, M., Ed., "Hypertext Transfer Protocol (HTTP) over Bishop, M., Ed., "Hypertext Transfer Protocol (HTTP) over
QUIC", draft-ietf-quic-http-16 (work in progress), October QUIC", draft-ietf-quic-http-17 (work in progress),
2018. December 2018.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000, DOI 10.17487/RFC2818, May 2000,
<https://www.rfc-editor.org/info/rfc2818>. <https://www.rfc-editor.org/info/rfc2818>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>. <https://www.rfc-editor.org/info/rfc5280>.
skipping to change at page 30, line 12 skipping to change at page 34, line 20
[3] https://github.com/quicwg/base-drafts/labels/-tls [3] https://github.com/quicwg/base-drafts/labels/-tls
Appendix A. Change Log Appendix A. Change Log
*RFC Editor's Note:* Please remove this section prior to *RFC Editor's Note:* Please remove this section prior to
publication of a final version of this document. publication of a final version of this document.
Issue and pull request numbers are listed with a leading octothorp. Issue and pull request numbers are listed with a leading octothorp.
A.1. Since draft-ietf-quic-tls-13 A.1. Since draft-ietf-quic-tls-14
o Update the salt used for Initial secrets (#1970)
o Clarify that TLS_AES_128_CCM_8_SHA256 isn't supported (#2019)
o Change header protection
* Sample from a fixed offset (#1575, #2030)
* Cover part of the first byte, including the key phase (#1322,
#2006)
o TLS provides an AEAD and KDF function (#2046)
* Clarify that the TLS KDF is used with TLS (#1997)
* Change the labels for calculation of QUIC keys (#1845, #1971,
#1991)
o Initial keys are discarded once Handshake are avaialble (#1951,
#2045)
A.2. Since draft-ietf-quic-tls-13
o Updated to TLS 1.3 final (#1660) o Updated to TLS 1.3 final (#1660)
A.2. Since draft-ietf-quic-tls-12 A.3. Since draft-ietf-quic-tls-12
o Changes to integration of the TLS handshake (#829, #1018, #1094, o Changes to integration of the TLS handshake (#829, #1018, #1094,
#1165, #1190, #1233, #1242, #1252, #1450) #1165, #1190, #1233, #1242, #1252, #1450)
* The cryptographic handshake uses CRYPTO frames, not stream 0 * The cryptographic handshake uses CRYPTO frames, not stream 0
* QUIC packet protection is used in place of TLS record * QUIC packet protection is used in place of TLS record
protection protection
* Separate QUIC packet number spaces are used for the handshake * Separate QUIC packet number spaces are used for the handshake
* Changed Retry to be independent of the cryptographic handshake * Changed Retry to be independent of the cryptographic handshake
* Limit the use of HelloRetryRequest to address TLS needs (like * Limit the use of HelloRetryRequest to address TLS needs (like
key shares) key shares)
o Changed codepoint of TLS extension (#1395, #1402) o Changed codepoint of TLS extension (#1395, #1402)
A.3. Since draft-ietf-quic-tls-11 A.4. Since draft-ietf-quic-tls-11
o Encrypted packet numbers. o Encrypted packet numbers.
A.4. Since draft-ietf-quic-tls-10 A.5. Since draft-ietf-quic-tls-10
o No significant changes. o No significant changes.
A.5. Since draft-ietf-quic-tls-09 A.6. Since draft-ietf-quic-tls-09
o Cleaned up key schedule and updated the salt used for handshake o Cleaned up key schedule and updated the salt used for handshake
packet protection (#1077) packet protection (#1077)
A.6. Since draft-ietf-quic-tls-08 A.7. Since draft-ietf-quic-tls-08
o Specify value for max_early_data_size to enable 0-RTT (#942) o Specify value for max_early_data_size to enable 0-RTT (#942)
o Update key derivation function (#1003, #1004) o Update key derivation function (#1003, #1004)
A.7. Since draft-ietf-quic-tls-07 A.8. Since draft-ietf-quic-tls-07
o Handshake errors can be reported with CONNECTION_CLOSE (#608, o Handshake errors can be reported with CONNECTION_CLOSE (#608,
#891) #891)
A.8. Since draft-ietf-quic-tls-05 A.9. Since draft-ietf-quic-tls-05
No significant changes. No significant changes.
A.9. Since draft-ietf-quic-tls-04 A.10. Since draft-ietf-quic-tls-04
o Update labels used in HKDF-Expand-Label to match TLS 1.3 (#642) o Update labels used in HKDF-Expand-Label to match TLS 1.3 (#642)
A.10. Since draft-ietf-quic-tls-03 A.11. Since draft-ietf-quic-tls-03
No significant changes. No significant changes.
A.11. Since draft-ietf-quic-tls-02 A.12. Since draft-ietf-quic-tls-02
o Updates to match changes in transport draft o Updates to match changes in transport draft
A.12. Since draft-ietf-quic-tls-01 A.13. Since draft-ietf-quic-tls-01
o Use TLS alerts to signal TLS errors (#272, #374) o Use TLS alerts to signal TLS errors (#272, #374)
o Require ClientHello to fit in a single packet (#338) o Require ClientHello to fit in a single packet (#338)
o The second client handshake flight is now sent in the clear (#262, o The second client handshake flight is now sent in the clear (#262,
#337) #337)
o The QUIC header is included as AEAD Associated Data (#226, #243, o The QUIC header is included as AEAD Associated Data (#226, #243,
#302) #302)
skipping to change at page 32, line 5 skipping to change at page 36, line 38
o Require at least TLS 1.3 (#138) o Require at least TLS 1.3 (#138)
o Define transport parameters as a TLS extension (#122) o Define transport parameters as a TLS extension (#122)
o Define handling for protected packets before the handshake o Define handling for protected packets before the handshake
completes (#39) completes (#39)
o Decouple QUIC version and ALPN (#12) o Decouple QUIC version and ALPN (#12)
A.13. Since draft-ietf-quic-tls-00 A.14. Since draft-ietf-quic-tls-00
o Changed bit used to signal key phase o Changed bit used to signal key phase
o Updated key phase markings during the handshake o Updated key phase markings during the handshake
o Added TLS interface requirements section o Added TLS interface requirements section
o Moved to use of TLS exporters for key derivation o Moved to use of TLS exporters for key derivation
o Moved TLS error code definitions into this document o Moved TLS error code definitions into this document
A.14. Since draft-thomson-quic-tls-01 A.15. Since draft-thomson-quic-tls-01
o Adopted as base for draft-ietf-quic-tls o Adopted as base for draft-ietf-quic-tls
o Updated authors/editors list o Updated authors/editors list
o Added status note o Added status note
Acknowledgments Acknowledgments
This document has benefited from input from Dragana Damjanovic, This document has benefited from input from Dragana Damjanovic,
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