draft-ietf-quic-tls-10.txt   draft-ietf-quic-tls-11.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: September 6, 2018 sn3rd Expires: October 19, 2018 sn3rd
March 05, 2018 April 17, 2018
Using Transport Layer Security (TLS) to Secure QUIC Using Transport Layer Security (TLS) to Secure QUIC
draft-ietf-quic-tls-10 draft-ietf-quic-tls-11
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
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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 September 6, 2018. This Internet-Draft will expire on October 19, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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4.1. Handshake and Setup Sequence . . . . . . . . . . . . . . 8 4.1. Handshake and Setup Sequence . . . . . . . . . . . . . . 8
4.2. Interface to TLS . . . . . . . . . . . . . . . . . . . . 9 4.2. Interface to TLS . . . . . . . . . . . . . . . . . . . . 9
4.2.1. Handshake Interface . . . . . . . . . . . . . . . . . 10 4.2.1. Handshake Interface . . . . . . . . . . . . . . . . . 10
4.2.2. Source Address Validation . . . . . . . . . . . . . . 11 4.2.2. Source Address Validation . . . . . . . . . . . . . . 11
4.2.3. Key Ready Events . . . . . . . . . . . . . . . . . . 12 4.2.3. Key Ready Events . . . . . . . . . . . . . . . . . . 12
4.2.4. Secret Export . . . . . . . . . . . . . . . . . . . . 12 4.2.4. Secret Export . . . . . . . . . . . . . . . . . . . . 12
4.2.5. TLS Interface Summary . . . . . . . . . . . . . . . . 12 4.2.5. TLS Interface Summary . . . . . . . . . . . . . . . . 12
4.3. TLS Version . . . . . . . . . . . . . . . . . . . . . . . 13 4.3. TLS Version . . . . . . . . . . . . . . . . . . . . . . . 13
4.4. ClientHello Size . . . . . . . . . . . . . . . . . . . . 13 4.4. ClientHello Size . . . . . . . . . . . . . . . . . . . . 13
4.5. Peer Authentication . . . . . . . . . . . . . . . . . . . 14 4.5. Peer Authentication . . . . . . . . . . . . . . . . . . . 14
4.6. TLS Errors . . . . . . . . . . . . . . . . . . . . . . . 14 4.6. Rejecting 0-RTT . . . . . . . . . . . . . . . . . . . . . 14
5. QUIC Packet Protection . . . . . . . . . . . . . . . . . . . 14 4.7. TLS Errors . . . . . . . . . . . . . . . . . . . . . . . 15
5. QUIC Packet Protection . . . . . . . . . . . . . . . . . . . 15
5.1. Installing New Keys . . . . . . . . . . . . . . . . . . . 15 5.1. Installing New Keys . . . . . . . . . . . . . . . . . . . 15
5.2. QUIC Key Expansion . . . . . . . . . . . . . . . . . . . 15 5.2. Enabling 0-RTT . . . . . . . . . . . . . . . . . . . . . 15
5.2.1. QHKDF-Expand . . . . . . . . . . . . . . . . . . . . 15 5.3. QUIC Key Expansion . . . . . . . . . . . . . . . . . . . 16
5.2.2. Handshake Secrets . . . . . . . . . . . . . . . . . . 16 5.3.1. QHKDF-Expand . . . . . . . . . . . . . . . . . . . . 16
5.2.3. 0-RTT Secret . . . . . . . . . . . . . . . . . . . . 17 5.3.2. Handshake Secrets . . . . . . . . . . . . . . . . . . 17
5.2.4. 1-RTT Secrets . . . . . . . . . . . . . . . . . . . . 17 5.3.3. 0-RTT Secret . . . . . . . . . . . . . . . . . . . . 17
5.2.5. Updating 1-RTT Secrets . . . . . . . . . . . . . . . 17 5.3.4. 1-RTT Secrets . . . . . . . . . . . . . . . . . . . . 18
5.2.6. Packet Protection Keys . . . . . . . . . . . . . . . 18 5.3.5. Updating 1-RTT Secrets . . . . . . . . . . . . . . . 18
5.3. QUIC AEAD Usage . . . . . . . . . . . . . . . . . . . . . 18 5.3.6. Packet Protection Keys . . . . . . . . . . . . . . . 18
5.4. Packet Numbers . . . . . . . . . . . . . . . . . . . . . 19 5.4. QUIC AEAD Usage . . . . . . . . . . . . . . . . . . . . . 19
5.5. Receiving Protected Packets . . . . . . . . . . . . . . . 20 5.5. Packet Numbers . . . . . . . . . . . . . . . . . . . . . 20
5.6. Packet Number Gaps . . . . . . . . . . . . . . . . . . . 20 5.6. Receiving Protected Packets . . . . . . . . . . . . . . . 21
6. Key Phases . . . . . . . . . . . . . . . . . . . . . . . . . 20 5.7. Packet Number Gaps . . . . . . . . . . . . . . . . . . . 21
6.1. Packet Protection for the TLS Handshake . . . . . . . . . 21 6. Key Phases . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.1.1. Initial Key Transitions . . . . . . . . . . . . . . . 21 6.1. Packet Protection for the TLS Handshake . . . . . . . . . 22
6.1.1. Initial Key Transitions . . . . . . . . . . . . . . . 22
6.1.2. Retransmission and Acknowledgment of Unprotected 6.1.2. Retransmission and Acknowledgment of Unprotected
Packets . . . . . . . . . . . . . . . . . . . . . . . 22 Packets . . . . . . . . . . . . . . . . . . . . . . . 23
6.2. Key Update . . . . . . . . . . . . . . . . . . . . . . . 23 6.2. Key Update . . . . . . . . . . . . . . . . . . . . . . . 24
7. Client Address Validation . . . . . . . . . . . . . . . . . . 25 7. Client Address Validation . . . . . . . . . . . . . . . . . . 25
7.1. HelloRetryRequest Address Validation . . . . . . . . . . 25 7.1. HelloRetryRequest Address Validation . . . . . . . . . . 26
7.1.1. Stateless Address Validation . . . . . . . . . . . . 26 7.1.1. Stateless Address Validation . . . . . . . . . . . . 26
7.1.2. Sending HelloRetryRequest . . . . . . . . . . . . . . 26 7.1.2. Sending HelloRetryRequest . . . . . . . . . . . . . . 27
7.2. NewSessionTicket Address Validation . . . . . . . . . . . 26 7.2. NewSessionTicket Address Validation . . . . . . . . . . . 27
7.3. Address Validation Token Integrity . . . . . . . . . . . 27 7.3. Address Validation Token Integrity . . . . . . . . . . . 28
8. Pre-handshake QUIC Messages . . . . . . . . . . . . . . . . . 27 8. Pre-handshake QUIC Messages . . . . . . . . . . . . . . . . . 28
8.1. Unprotected Packets Prior to Handshake Completion . . . . 28 8.1. Unprotected Packets Prior to Handshake Completion . . . . 29
8.1.1. STREAM Frames . . . . . . . . . . . . . . . . . . . . 28 8.1.1. STREAM Frames . . . . . . . . . . . . . . . . . . . . 29
8.1.2. ACK Frames . . . . . . . . . . . . . . . . . . . . . 29 8.1.2. ACK Frames . . . . . . . . . . . . . . . . . . . . . 29
8.1.3. Updates to Data and Stream Limits . . . . . . . . . . 29 8.1.3. Updates to Data and Stream Limits . . . . . . . . . . 30
8.1.4. Handshake Failures . . . . . . . . . . . . . . . . . 30 8.1.4. Handshake Failures . . . . . . . . . . . . . . . . . 31
8.1.5. Address Verification . . . . . . . . . . . . . . . . 30 8.1.5. Address Verification . . . . . . . . . . . . . . . . 31
8.1.6. Denial of Service with Unprotected Packets . . . . . 30 8.1.6. Denial of Service with Unprotected Packets . . . . . 31
8.2. Use of 0-RTT Keys . . . . . . . . . . . . . . . . . . . . 31 8.2. Use of 0-RTT Keys . . . . . . . . . . . . . . . . . . . . 32
8.3. Receiving Out-of-Order Protected Frames . . . . . . . . . 31 8.3. Receiving Out-of-Order Protected Frames . . . . . . . . . 32
9. QUIC-Specific Additions to the TLS Handshake . . . . . . . . 32 9. QUIC-Specific Additions to the TLS Handshake . . . . . . . . 33
9.1. Protocol and Version Negotiation . . . . . . . . . . . . 32 9.1. Protocol and Version Negotiation . . . . . . . . . . . . 33
9.2. QUIC Transport Parameters Extension . . . . . . . . . . . 32 9.2. QUIC Transport Parameters Extension . . . . . . . . . . . 33
9.3. Priming 0-RTT . . . . . . . . . . . . . . . . . . . . . . 33 10. Security Considerations . . . . . . . . . . . . . . . . . . . 34
10. Security Considerations . . . . . . . . . . . . . . . . . . . 33
10.1. Packet Reflection Attack Mitigation . . . . . . . . . . 34 10.1. Packet Reflection Attack Mitigation . . . . . . . . . . 34
10.2. Peer Denial of Service . . . . . . . . . . . . . . . . . 34 10.2. Peer Denial of Service . . . . . . . . . . . . . . . . . 34
11. Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . 34 11. Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . 35
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 36 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 36
13.1. Normative References . . . . . . . . . . . . . . . . . . 36 13.1. Normative References . . . . . . . . . . . . . . . . . . 36
13.2. Informative References . . . . . . . . . . . . . . . . . 37 13.2. Informative References . . . . . . . . . . . . . . . . . 37
13.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 37 13.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 37 Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 38
Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 38 Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 38
Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 38 Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 38
C.1. Since draft-ietf-quic-tls-09 . . . . . . . . . . . . . . 38 C.1. Since draft-ietf-quic-tls-10 . . . . . . . . . . . . . . 38
C.2. Since draft-ietf-quic-tls-08 . . . . . . . . . . . . . . 38 C.2. Since draft-ietf-quic-tls-09 . . . . . . . . . . . . . . 38
C.3. Since draft-ietf-quic-tls-07 . . . . . . . . . . . . . . 38 C.3. Since draft-ietf-quic-tls-08 . . . . . . . . . . . . . . 38
C.4. Since draft-ietf-quic-tls-05 . . . . . . . . . . . . . . 38 C.4. Since draft-ietf-quic-tls-07 . . . . . . . . . . . . . . 38
C.5. Since draft-ietf-quic-tls-04 . . . . . . . . . . . . . . 38 C.5. Since draft-ietf-quic-tls-05 . . . . . . . . . . . . . . 39
C.6. Since draft-ietf-quic-tls-03 . . . . . . . . . . . . . . 38 C.6. Since draft-ietf-quic-tls-04 . . . . . . . . . . . . . . 39
C.7. Since draft-ietf-quic-tls-02 . . . . . . . . . . . . . . 38 C.7. Since draft-ietf-quic-tls-03 . . . . . . . . . . . . . . 39
C.8. Since draft-ietf-quic-tls-01 . . . . . . . . . . . . . . 39 C.8. Since draft-ietf-quic-tls-02 . . . . . . . . . . . . . . 39
C.9. Since draft-ietf-quic-tls-00 . . . . . . . . . . . . . . 39 C.9. Since draft-ietf-quic-tls-01 . . . . . . . . . . . . . . 39
C.10. Since draft-thomson-quic-tls-01 . . . . . . . . . . . . . 39 C.10. Since draft-ietf-quic-tls-00 . . . . . . . . . . . . . . 39
C.11. Since draft-thomson-quic-tls-01 . . . . . . . . . . . . . 40
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40
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 Transport Layer Security (TLS) version 1.3 [TLS13]. TLS 1.3 provides
critical latency improvements for connection establishment over critical latency improvements for connection establishment over
previous versions. Absent packet loss, most new connections can be previous versions. Absent packet loss, most new connections can be
established and secured within a single round trip; on subsequent established and secured within a single round trip; on subsequent
connections between the same client and server, the client can often connections between the same client and server, the client can often
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QUIC permits a client to send frames on streams starting from the QUIC permits a client to send frames on streams starting from the
first packet. The initial packet from a client contains a stream first packet. The initial packet from a client contains a stream
frame for stream 0 that contains the first TLS handshake messages frame for stream 0 that contains the first TLS handshake messages
from the client. This allows the TLS handshake to start with the from the client. This allows the TLS handshake to start with the
first packet that a client sends. first packet that a client sends.
QUIC packets are protected using a scheme that is specific to QUIC, QUIC packets are protected using a scheme that is specific to QUIC,
see Section 5. Keys are exported from the TLS connection when they see Section 5. Keys are exported from the TLS connection when they
become available using a TLS exporter (see Section 7.5 of [TLS13] and become available using a TLS exporter (see Section 7.5 of [TLS13] and
Section 5.2). After keys are exported from TLS, QUIC manages its own Section 5.3). After keys are exported from TLS, QUIC manages its own
key schedule. key schedule.
4.1. Handshake and Setup Sequence 4.1. Handshake and Setup Sequence
The integration of QUIC with a TLS handshake is shown in more detail The integration of QUIC with a TLS handshake is shown in more detail
in Figure 3. QUIC "STREAM" frames on stream 0 carry the TLS in Figure 3. QUIC "STREAM" frames on stream 0 carry the TLS
handshake. QUIC performs loss recovery [QUIC-RECOVERY] for this handshake. QUIC performs loss recovery [QUIC-RECOVERY] for this
stream and ensures that TLS handshake messages are delivered in the stream and ensures that TLS handshake messages are delivered in the
correct order. correct order.
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A QUIC server starts the process by providing TLS with stream 0 A QUIC server starts the process by providing TLS with stream 0
octets. octets.
Each time that an endpoint receives data on stream 0, it delivers the Each time that an endpoint receives data on stream 0, it delivers the
octets to TLS if it is able. Each time that TLS is provided with new octets to TLS if it is able. Each time that TLS is provided with new
data, new handshake octets are requested from TLS. TLS might not data, new handshake octets are requested from TLS. TLS might not
provide any octets if the handshake messages it has received are provide any octets if the handshake messages it has received are
incomplete or it has no data to send. incomplete or it has no data to send.
At the server, when TLS provides handshake octets, it also needs to
indicate whether the octets contain a HelloRetryRequest. A
HelloRetryRequest MUST always be sent in a Retry packet, so the QUIC
server needs to know whether the octets are a HelloRetryRequest.
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 octets 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
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TLS produces handshake octets. TLS produces handshake octets.
When TLS completed its handshake, 1-RTT keys can be provided to QUIC. When TLS completed its handshake, 1-RTT keys can be provided to QUIC.
On both client and server, this occurs after sending the TLS Finished On both client and server, this occurs after sending the TLS Finished
message. message.
This ordering means that there could be frames that carry TLS This ordering means that there could be frames that carry TLS
handshake messages ready to send at the same time that application handshake messages ready to send at the same time that application
data is available. An implementation MUST ensure that TLS handshake data is available. An implementation MUST ensure that TLS handshake
messages are always sent in packets protected with handshake keys messages are always sent in packets protected with handshake keys
(see Section 5.2.2). Separate packets are required for data that (see Section 5.3.2). Separate packets are required for data that
needs protection from 1-RTT keys. needs protection from 1-RTT keys.
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 octets, the TLS
stack might signal that 0-RTT keys are ready. On the server, after stack might signal that 0-RTT keys are ready. On the server, after
receiving handshake octets that contain a ClientHello message, a TLS receiving handshake octets 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.
1-RTT keys are used for packets in both directions. 0-RTT keys are 1-RTT keys are used for packets in both directions. 0-RTT keys are
only used to protect packets sent by the client. only used to protect packets sent by the client.
4.2.4. Secret Export 4.2.4. Secret Export
Details how secrets are exported from TLS are included in Details how secrets are exported from TLS are included in
Section 5.2. Section 5.3.
4.2.5. TLS Interface Summary 4.2.5. TLS Interface Summary
Figure 4 summarizes the exchange between QUIC and TLS for both client Figure 4 summarizes the exchange between QUIC and TLS for both client
and server. and server.
Client Server Client Server
Get Handshake Get Handshake
0-RTT Key Ready 0-RTT Key Ready
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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.
4.4. ClientHello Size 4.4. ClientHello Size
QUIC requires that the initial handshake packet from a client fit QUIC requires that the initial handshake packet from a client fit
within the payload of a single packet. The size limits on QUIC within the payload of a single packet. The size limits on QUIC
packets mean that a record containing a ClientHello needs to fit packets mean that a record containing a ClientHello needs to fit
within 1171 octets. within 1129 octets, though endpoints can reduce the size of their
connection ID to increase by up to 22 octets.
A TLS ClientHello can fit within this limit with ample space A TLS ClientHello can fit within this limit with ample space
remaining. However, there are several variables that could cause remaining. However, there are several variables that could cause
this limit to be exceeded. Implementations are reminded that large this limit to be exceeded. Implementations are reminded that large
session tickets or HelloRetryRequest cookies, multiple or large key session tickets or HelloRetryRequest cookies, multiple or large key
shares, and long lists of supported ciphers, signature algorithms, shares, and long lists of supported ciphers, signature algorithms,
versions, QUIC transport parameters, and other negotiable parameters versions, QUIC transport parameters, and other negotiable parameters
and extensions could cause this message to grow. and extensions could cause this message to grow.
For servers, the size of the session tickets and HelloRetryRequest For servers, the size of the session tickets and HelloRetryRequest
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trusted entity (see for example [RFC2818]). trusted entity (see for example [RFC2818]).
A server MAY request that the client authenticate during the A server MAY request that the client authenticate during the
handshake. A server MAY refuse a connection if the client is unable handshake. A server MAY refuse a connection if the client is unable
to authenticate when requested. The requirements for client to authenticate when requested. The requirements for client
authentication vary based on application protocol and deployment. authentication vary based on application protocol and deployment.
A server MUST NOT use post-handshake client authentication (see A server MUST NOT use post-handshake client authentication (see
Section 4.6.2 of [TLS13]). Section 4.6.2 of [TLS13]).
4.6. TLS Errors 4.6. Rejecting 0-RTT
A server rejects 0-RTT by rejecting 0-RTT at the TLS layer. This
results in early exporter keys being unavailable, thereby preventing
the use of 0-RTT for QUIC.
A client that attempts 0-RTT MUST also consider 0-RTT to be rejected
if it receives a Retry or Version Negotiation packet.
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.
4.7. TLS Errors
Errors in the TLS connection SHOULD be signaled using TLS alerts on Errors in the TLS connection SHOULD be signaled using TLS alerts on
stream 0. A failure in the handshake MUST be treated as a QUIC stream 0. A failure in the handshake MUST be treated as a QUIC
connection error of type TLS_HANDSHAKE_FAILED. Once the handshake is connection error of type TLS_HANDSHAKE_FAILED. Once the handshake is
complete, an error in the TLS connection that causes a TLS alert to complete, an error in the TLS connection that causes a TLS alert to
be sent or received MUST be treated as a QUIC connection error of be sent or received MUST be treated as a QUIC connection error of
type TLS_FATAL_ALERT_GENERATED or TLS_FATAL_ALERT_RECEIVED type TLS_FATAL_ALERT_GENERATED or TLS_FATAL_ALERT_RECEIVED
respectively. respectively.
5. QUIC Packet Protection 5. QUIC Packet Protection
QUIC packet protection provides authenticated encryption of packets. QUIC packet protection provides authenticated encryption of packets.
This provides confidentiality and integrity protection for the This provides confidentiality and integrity protection for the
content of packets (see Section 5.3). Packet protection uses keys content of packets (see Section 5.4). Packet protection uses keys
that are exported from the TLS connection (see Section 5.2). that are exported from the TLS connection (see Section 5.3).
Different keys are used for QUIC packet protection and TLS record Different keys are used for QUIC packet protection and TLS record
protection. TLS handshake messages are protected solely with TLS protection. TLS handshake messages are protected solely with TLS
record protection, but post-handshake messages are redundantly record protection, but post-handshake messages are redundantly
proteted with both both the QUIC packet protection and the TLS record protected with both the QUIC packet protection and the TLS record
protection. These messages are limited in number, and so the protection. These messages are limited in number, and so the
additional overhead is small. additional overhead is small.
5.1. Installing New Keys 5.1. Installing New Keys
As TLS reports the availability of keying material, the packet As TLS reports the availability of keying material, the packet
protection keys and initialization vectors (IVs) are updated (see protection keys and initialization vectors (IVs) are updated (see
Section 5.2). The selection of AEAD function is also updated to Section 5.3). The selection of AEAD function is also updated to
match the AEAD negotiated by TLS. match the AEAD negotiated by TLS.
For packets other than any handshake packets (see Section 6.1), once For packets other than any handshake packets (see Section 6.1), once
a change of keys has been made, packets with higher packet numbers a change of keys has been made, packets with higher packet numbers
MUST be sent with the new keying material. The KEY_PHASE bit on MUST be sent with the new keying material. The KEY_PHASE bit on
these packets is inverted each time new keys are installed to signal these packets is inverted each time new keys are installed to signal
the use of the new keys to the recipient (see Section 6 for details). the use of the new keys to the recipient (see Section 6 for details).
An endpoint retransmits stream data in a new packet. New packets An endpoint retransmits stream data in a new packet. New packets
have new packet numbers and use the latest packet protection keys. have new packet numbers and use the latest packet protection keys.
This simplifies key management when there are key updates (see This simplifies key management when there are key updates (see
Section 6.2). Section 6.2).
5.2. QUIC Key Expansion 5.2. 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.
5.3. QUIC Key Expansion
QUIC uses a system of packet protection secrets, keys and IVs that QUIC uses a system of packet protection secrets, keys and IVs that
are modelled on the system used in TLS [TLS13]. The secrets that are modelled on the system used in TLS [TLS13]. The secrets that
QUIC uses as the basis of its key schedule are obtained using TLS QUIC uses as the basis of its key schedule are obtained using TLS
exporters (see Section 7.5 of [TLS13]). exporters (see Section 7.5 of [TLS13]).
5.2.1. QHKDF-Expand 5.3.1. QHKDF-Expand
QUIC uses the Hash-based Key Derivation Function (HKDF) [HKDF] with QUIC uses the Hash-based Key Derivation Function (HKDF) [HKDF] with
the same hash function negotiated by TLS for key derivation. For the same hash function negotiated by TLS for key derivation. For
example, if TLS is using the TLS_AES_128_GCM_SHA256, the SHA-256 hash example, if TLS is using the TLS_AES_128_GCM_SHA256, the SHA-256 hash
function is used. function is used.
Most key derivations in this document use the QHKDF-Expand function, Most key derivations in this document use the QHKDF-Expand function,
which uses the HKDF expand function and is modelled on the HKDF- which uses the HKDF expand function and is modelled on the HKDF-
Expand-Label function from TLS 1.3 (see Section 7.1 of [TLS13]). Expand-Label function from TLS 1.3 (see Section 7.1 of [TLS13]).
QHKDF-Expand differs from HKDF-Expand-Label in that it uses a QHKDF-Expand differs from HKDF-Expand-Label in that it uses a
different base label and omits the Context argument. different base label and omits the Context argument.
QHKDF-Expand(Secret, Label, Length) = QHKDF-Expand(Secret, Label, Length) =
HKDF-Expand(Secret, QhkdfExpandInfo, Length) HKDF-Expand(Secret, QhkdfExpandInfo, Length)
The HKDF-Expand function used by QHKDF-Expand uses the PRF hash The HKDF-Expand function used by QHKDF-Expand uses the PRF hash
function negotiated by TLS, except for handshake secrets and keys function negotiated by TLS, except for handshake secrets and keys
derived from them (see Section 5.2.2). derived from them (see Section 5.3.2).
Where the "info" parameter of HKDF-Expand is an encoded Where the "info" parameter of HKDF-Expand is an encoded
"QhkdfExpandInfo" structure: "QhkdfExpandInfo" structure:
struct { struct {
uint16 length = Length; uint16 length = Length;
opaque label<6..255> = "QUIC " + Label; opaque label<6..255> = "QUIC " + Label;
} QhkdfExpandInfo; } QhkdfExpandInfo;
For example, assuming a hash function with a 32 octet output, For example, assuming a hash function with a 32 octet output,
derivation for a client packet protection key would use HKDF-Expand derivation for a client packet protection key would use HKDF-Expand
with an "info" parameter of 0x00200851554943206b6579. with an "info" parameter of 0x00200851554943206b6579.
5.2.2. Handshake Secrets 5.3.2. Handshake Secrets
Packets that carry the TLS handshake (Initial, Retry, and Handshake) Packets that carry the TLS handshake (Initial, Retry, and Handshake)
are protected with a secret derived from the connection ID used in are protected with a secret derived from the Destination Connection
the client's Initial packet. Specifically: ID field from the client's Initial packet. Specifically:
handshake_salt = 0x9c108f98520a5c5c32968e950e8a2c5fe06d6c38 handshake_salt = 0x9c108f98520a5c5c32968e950e8a2c5fe06d6c38
handshake_secret = handshake_secret =
HKDF-Extract(handshake_salt, client_connection_id) HKDF-Extract(handshake_salt, client_dst_connection_id)
client_handshake_secret = client_handshake_secret =
QHKDF-Expand(handshake_secret, "client hs", Hash.length) QHKDF-Expand(handshake_secret, "client hs", Hash.length)
server_handshake_secret = server_handshake_secret =
QHKDF-Expand(handshake_secret, "server hs", Hash.length) QHKDF-Expand(handshake_secret, "server hs", Hash.length)
The hash function for HKDF when deriving handshake secrets and keys The hash function for HKDF when deriving handshake secrets and keys
is SHA-256 [FIPS180]. The connection ID used with QHKDF-Expand is is SHA-256 [FIPS180]. The connection ID used with QHKDF-Expand is
the connection ID chosen by the client. the connection ID chosen by the client.
The handshake salt is a 20 octet sequence shown in the figure in The handshake salt is a 20 octet sequence shown in the figure in
hexadecimal notation. Future versions of QUIC SHOULD generate a new hexadecimal notation. Future versions of QUIC SHOULD generate a new
salt value, thus ensuring that the keys are different for each 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.
5.2.3. 0-RTT Secret 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
handshake 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.
5.3.3. 0-RTT Secret
0-RTT keys are those keys that are used in resumed connections prior 0-RTT keys are those keys that are used in resumed connections prior
to the completion of the TLS handshake. Data sent using 0-RTT keys to the completion of the TLS handshake. Data sent using 0-RTT keys
might be replayed and so has some restrictions on its use, see might be replayed and so has some restrictions on its use, see
Section 8.2. 0-RTT keys are used after sending or receiving a Section 8.2. 0-RTT keys are used after sending or receiving a
ClientHello. ClientHello.
The secret is exported from TLS using the exporter label "EXPORTER- The secret is exported from TLS using the exporter label "EXPORTER-
QUIC 0rtt" and an empty context. The size of the secret MUST be the QUIC 0rtt" and an empty context. The size of the secret MUST be the
size of the hash output for the PRF hash function negotiated by TLS. size of the hash output for the PRF hash function negotiated by TLS.
This uses the TLS early_exporter_secret. The QUIC 0-RTT secret is This uses the TLS early_exporter_secret. The QUIC 0-RTT secret is
only used for protection of packets sent by the client. only used for protection of packets sent by the client.
client_0rtt_secret = client_0rtt_secret =
TLS-Early-Exporter("EXPORTER-QUIC 0rtt", "", Hash.length) TLS-Early-Exporter("EXPORTER-QUIC 0rtt", "", Hash.length)
5.2.4. 1-RTT Secrets 5.3.4. 1-RTT Secrets
1-RTT keys are used by both client and server after the TLS handshake 1-RTT keys are used by both client and server after the TLS handshake
completes. There are two secrets used at any time: one is used to completes. There are two secrets used at any time: one is used to
derive packet protection keys for packets sent by the client, the derive packet protection keys for packets sent by the client, the
other for packet protection keys on packets sent by the server. other for packet protection keys on packets sent by the server.
The initial client packet protection secret is exported from TLS The initial client packet protection secret is exported from TLS
using the exporter label "EXPORTER-QUIC client 1rtt"; the initial using the exporter label "EXPORTER-QUIC client 1rtt"; the initial
server packet protection secret uses the exporter label "EXPORTER- server packet protection secret uses the exporter label "EXPORTER-
QUIC server 1rtt". Both exporters use an empty context. The size of QUIC server 1rtt". Both exporters use an empty context. The size of
the secret MUST be the size of the hash output for the PRF hash the secret MUST be the size of the hash output for the PRF hash
function negotiated by TLS. function negotiated by TLS.
client_pp_secret_0 = client_pp_secret<0> =
TLS-Exporter("EXPORTER-QUIC client 1rtt", "", Hash.length) TLS-Exporter("EXPORTER-QUIC client 1rtt", "", Hash.length)
server_pp_secret_0 = server_pp_secret<0> =
TLS-Exporter("EXPORTER-QUIC server 1rtt", "", Hash.length) TLS-Exporter("EXPORTER-QUIC server 1rtt", "", Hash.length)
These secrets are used to derive the initial client and server packet These secrets are used to derive the initial client and server packet
protection keys. protection keys.
5.2.5. Updating 1-RTT Secrets 5.3.5. Updating 1-RTT Secrets
After a key update (see Section 6.2), the 1-RTT secrets are updated After a key update (see Section 6.2), the 1-RTT secrets are updated
using QHKDF-Expand. Updated secrets are derived from the existing using QHKDF-Expand. Updated secrets are derived from the existing
packet protection secret. A Label parameter of "client 1rtt" is used packet protection secret. A Label parameter of "client 1rtt" is used
for the client secret and "server 1rtt" for the server. The Length for the client secret and "server 1rtt" for the server. The Length
is the same as the native output of the PRF hash function. is the same as the native output of the PRF hash function.
client_pp_secret_<N+1> = client_pp_secret<N+1> =
QHKDF-Update(client_pp_secret_<N>, "client 1rtt", Hash.length) QHKDF-Expand(client_pp_secret<N>, "client 1rtt", Hash.length)
server_pp_secret_<N+1> = server_pp_secret<N+1> =
QHKDF-Update(server_pp_secret_<N>, "server 1rtt", Hash.length) QHKDF-Expand(server_pp_secret<N>, "server 1rtt", Hash.length)
This allows for a succession of new secrets to be created as needed. This allows for a succession of new secrets to be created as needed.
5.2.6. Packet Protection Keys 5.3.6. Packet Protection Keys
The complete key expansion uses a similar process for key expansion The complete key expansion uses a similar process for key expansion
to that defined in Section 7.3 of [TLS13], using QHKDF-Expand in to that defined in Section 7.3 of [TLS13], using QHKDF-Expand in
place of HKDF-Expand-Label. QUIC uses the AEAD function negotiated place of HKDF-Expand-Label. QUIC uses the AEAD function negotiated
by TLS. by TLS.
The packet protection key and IV used to protect the 0-RTT packets The packet protection key and IV used to protect the 0-RTT packets
sent by a client are derived from the QUIC 0-RTT secret. The packet sent by a client are derived from the QUIC 0-RTT secret. The packet
protection keys and IVs for 1-RTT packets sent by the client and protection keys and IVs for 1-RTT packets sent by the client and
server are derived from the current generation of client and server server are derived from the current generation of client and server
1-RTT secrets (client_pp_secret_<i> and server_pp_secret_<i>) 1-RTT secrets (client_pp_secret<i> and server_pp_secret<i>)
respectively. respectively.
The length of the QHKDF-Expand output is determined by the The length of the QHKDF-Expand output is determined by the
requirements of the AEAD function selected by TLS. The key length is requirements of the AEAD function selected by TLS. The key length is
the AEAD key size. As defined in Section 5.3 of [TLS13], the IV the AEAD key size. As defined in Section 5.3 of [TLS13], the IV
length is the larger of 8 or N_MIN (see Section 4 of [AEAD]; all length is the larger of 8 or N_MIN (see Section 4 of [AEAD]; all
ciphersuites defined in [TLS13] have N_MIN set to 12). ciphersuites defined in [TLS13] have N_MIN set to 12).
For any secret S, the AEAD key uses a label of "key", and the IV uses For any secret S, the AEAD key uses a label of "key", and the IV uses
a label of "iv": a label of "iv":
key = QHKDF-Expand(S, "key", key_length) key = QHKDF-Expand(S, "key", key_length)
iv = QHKDF-Expand(S, "iv", iv_length) iv = QHKDF-Expand(S, "iv", iv_length)
Separate keys are derived for packet protection by clients and
servers. Each endpoint uses the packet protection key of its peer to
remove packet protection. For example, client packet protection keys
and IVs - which are also used by the server to remove the protection
added by a client - for AEAD_AES_128_GCM are derived from 1-RTT
secrets as follows:
client_pp_key<i> = QHKDF-Expand(client_pp_secret<i>, "key", 16)
client_pp_iv<i> = QHKDF-Expand(client_pp_secret<i>, "iv", 12)
The QUIC record protection initially starts with keying material The QUIC record protection initially starts with keying material
derived from handshake keys. For a client, when the TLS state derived from handshake keys. For a client, when the TLS state
machine reports that the ClientHello has been sent, 0-RTT keys can be machine reports that the ClientHello has been sent, 0-RTT keys can be
generated and installed for writing, if 0-RTT is available. Finally, generated and installed for writing, if 0-RTT is available. Finally,
the TLS state machine reports completion of the handshake and 1-RTT the TLS state machine reports completion of the handshake and 1-RTT
keys can be generated and installed for writing. keys can be generated and installed for writing.
5.3. QUIC AEAD Usage 5.4. QUIC 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 AEAD that is negotiated function used for QUIC packet protection is AEAD that is negotiated
for use with the TLS connection. For example, if TLS is using the 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. TLS_AES_128_GCM_SHA256, the AEAD_AES_128_GCM function is used.
All QUIC packets other than Version Negotiation and Stateless Reset All QUIC packets other than Version Negotiation and Stateless Reset
packets are protected with an AEAD algorithm [AEAD]. Prior to packets are protected with an AEAD algorithm [AEAD]. Prior to
establishing a shared secret, packets are protected with establishing a shared secret, packets are protected with
AEAD_AES_128_GCM and a key derived from the client's connection ID AEAD_AES_128_GCM and a key derived from the client's connection ID
(see Section 5.2.2). This provides protection against off-path (see Section 5.3.2). This provides protection against off-path
attackers and robustness against QUIC version unaware middleboxes, attackers and robustness against QUIC version unaware middleboxes,
but not against on-path attackers. but not against on-path attackers.
All ciphersuites currently defined for TLS 1.3 - and therefore QUIC - All ciphersuites currently defined for TLS 1.3 - and therefore QUIC -
have a 16-byte authentication tag and produce an output 16 bytes have a 16-byte authentication tag and produce an output 16 bytes
larger than their input. larger than their input.
Once TLS has provided a key, the contents of regular QUIC packets Once TLS has provided a key, the contents of regular QUIC packets
immediately after any TLS messages have been sent are protected by immediately after any TLS messages have been sent are protected by
the AEAD selected by TLS. the AEAD selected by TLS.
The key, K, is either the client packet protection key The key, K, is either the client packet protection key
(client_pp_key_<i>) or the server packet protection key (client_pp_key<i>) or the server packet protection key
(server_pp_key_<i>), derived as defined in Section 5.2. (server_pp_key<i>), derived as defined in Section 5.3.
The nonce, N, is formed by combining the packet protection IV (either The nonce, N, is formed by combining the packet protection IV (either
client_pp_iv_<i> or server_pp_iv_<i>) with the packet number. The 64 client_pp_iv<i> or server_pp_iv<i>) with the packet number. The 64
bits of the reconstructed QUIC packet number in network byte order is bits of the reconstructed QUIC packet number in network byte order is
left-padded with zeros to the size of the IV. The exclusive OR of 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 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 octet in either the short or long
header. header.
The input plaintext, P, for the AEAD is the content of the QUIC frame The input plaintext, P, for the AEAD is the content of the QUIC frame
following the header, as described in [QUIC-TRANSPORT]. following the header, 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.
5.4. Packet Numbers 5.5. Packet Numbers
QUIC has a single, contiguous packet number space. In comparison, QUIC has a single, contiguous packet number space. In comparison,
TLS restarts its sequence number each time that record protection TLS restarts its sequence number each time that record protection
keys are changed. The sequence number restart in TLS ensures that a keys are changed. The sequence number restart in TLS ensures that a
compromise of the current traffic keys does not allow an attacker to compromise of the current traffic keys does not allow an attacker to
truncate the data that is sent after a key update by sending truncate the data that is sent after a key update by sending
additional packets under the old key (causing new packets to be additional packets under the old key (causing new packets to be
discarded). discarded).
QUIC does not assume a reliable transport and is required to handle QUIC does not assume a reliable transport and is required to handle
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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 6.2) prior to exceeding any limit set for the key update (Section 6.2) prior to exceeding any limit set for the
AEAD that is in use. AEAD that is in use.
TLS maintains a separate sequence number that is used for record TLS maintains a separate sequence number that is used for record
protection on the connection that is hosted on stream 0. This protection on the connection that is hosted on stream 0. This
sequence number is not visible to QUIC. sequence number is not visible to QUIC.
5.5. Receiving Protected Packets 5.6. 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 with higher packet numbers if number, it MUST discard all packets with higher packet numbers if
they cannot be successfully unprotected with either the same key, or they cannot be successfully unprotected with either the same key, or
- if there is a key update - the next packet protection key (see - if there is a key update - the next packet protection key (see
Section 6.2). Similarly, a packet that appears to trigger a key Section 6.2). Similarly, a packet that appears to trigger a key
update, but cannot be unprotected successfully MUST be discarded. update, but cannot be unprotected successfully MUST be discarded.
Failure to unprotect a packet does not necessarily indicate the Failure to unprotect a packet does not necessarily indicate the
existence of a protocol error in a peer or an attack. The truncated 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 packet number encoding used in QUIC can cause packet numbers to be
decoded incorrectly if they are delayed significantly. decoded incorrectly if they are delayed significantly.
5.6. Packet Number Gaps 5.7. Packet Number Gaps
Section 7.7.1.1 of [QUIC-TRANSPORT] also requires a secret to compute Section 6.8.5.1 of [QUIC-TRANSPORT] also requires a secret to compute
packet number gaps on connection ID transitions. That secret is packet number gaps on connection ID transitions. That secret is
computed as: computed as:
packet_number_secret = packet_number_secret =
TLS-Exporter("EXPORTER-QUIC packet number", "", Hash.length) TLS-Exporter("EXPORTER-QUIC packet number", "", Hash.length)
6. Key Phases 6. Key Phases
As TLS reports the availability of 0-RTT and 1-RTT keys, new keying As TLS reports the availability of 0-RTT and 1-RTT keys, new keying
material can be exported from TLS and used for QUIC packet material can be exported from TLS and used for QUIC packet
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header. header.
Transitions between keys during the handshake are complicated by the Transitions between keys during the handshake are complicated by the
need to ensure that TLS handshake messages are sent with the correct need to ensure that TLS handshake messages are sent with the correct
packet protection. packet protection.
6.1. Packet Protection for the TLS Handshake 6.1. Packet Protection for the TLS Handshake
The initial exchange of packets that carry the TLS handshake are The initial exchange of packets that carry the TLS handshake are
AEAD-protected using the handshake secrets generated as described in AEAD-protected using the handshake secrets generated as described in
Section 5.2.2. All TLS handshake messages up to the TLS Finished Section 5.3.2. All TLS handshake messages up to the TLS Finished
message sent by either endpoint use packets protected with handshake message sent by either endpoint use packets protected with handshake
keys. keys.
Any TLS handshake messages that are sent after completing the TLS Any TLS handshake messages that are sent after completing the TLS
handshake do not need special packet protection rules. Packets handshake do not need special packet protection rules. Packets
containing these messages use the packet protection keys that are containing these messages use the packet protection keys that are
current at the time of sending (or retransmission). current at the time of sending (or retransmission).
Like the client, a server MUST send retransmissions of its Like the client, a server MUST send retransmissions of its
unprotected handshake messages or acknowledgments for unprotected unprotected handshake messages or acknowledgments for unprotected
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The server transitions to using 1-RTT keys after sending its first The server transitions to using 1-RTT keys after sending its first
flight of TLS handshake messages, ending in the Finished. From this flight of TLS handshake messages, ending in the Finished. From this
point, the server protects all packets with 1-RTT keys. Future point, the server protects all packets with 1-RTT keys. Future
packets are therefore protected with 1-RTT keys. Initially, these packets are therefore protected with 1-RTT keys. Initially, these
are marked with a KEY_PHASE of 0. are marked with a KEY_PHASE of 0.
6.1.2. Retransmission and Acknowledgment of Unprotected Packets 6.1.2. Retransmission and Acknowledgment of Unprotected Packets
TLS handshake messages from both client and server are critical to TLS handshake messages from both client and server are critical to
the key exchange. The contents of these messages determines the keys the key exchange. The contents of these messages determine the keys
used to protect later messages. If these handshake messages are used to protect later messages. If these handshake messages are
included in packets that are protected with these keys, they will be included in packets that are protected with these keys, they will be
indecipherable to the recipient. indecipherable to the recipient.
Even though newer keys could be available when retransmitting, Even though newer keys could be available when retransmitting,
retransmissions of these handshake messages MUST be sent in packets retransmissions of these handshake messages MUST be sent in packets
protected with handshake keys. An endpoint MUST generate ACK frames protected with handshake keys. An endpoint MUST generate ACK frames
for these messages and send them in packets protected with handshake for these messages and send them in packets protected with handshake
keys. keys.
A HelloRetryRequest handshake message might be used to reject an A HelloRetryRequest handshake message might be used to reject an
initial ClientHello. A HelloRetryRequest handshake message is sent initial ClientHello. A HelloRetryRequest handshake message is sent
in a Retry packet; any second ClientHello that is sent in response in a Retry packet; any second ClientHello that is sent in response
uses a Initial packet type. These packets are only protected with a uses a Initial packet type. These packets are only protected with a
predictable key (see Section 5.2.2). This is natural, because no predictable key (see Section 5.3.2). This is natural, because no
shared secret will be available when these messages need to be sent. shared secret will be available when these messages need to be sent.
Upon receipt of a HelloRetryRequest, a client SHOULD cease any Upon receipt of a HelloRetryRequest, a client SHOULD cease any
transmission of 0-RTT data; 0-RTT data will only be discarded by any transmission of 0-RTT data; 0-RTT data will only be discarded by any
server that sends a HelloRetryRequest. server that sends a HelloRetryRequest.
The packet type ensures that protected packets are clearly The packet type ensures that protected packets are clearly
distinguished from unprotected packets. Loss or reordering might distinguished from unprotected packets. Loss or reordering might
cause unprotected packets to arrive once 1-RTT keys are in use, cause unprotected packets to arrive once 1-RTT keys are in use,
unprotected packets are easily distinguished from 1-RTT packets using unprotected packets are easily distinguished from 1-RTT packets using
the packet type. the packet type.
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the KEY_PHASE bit indicates that a new key is in use. the KEY_PHASE bit indicates that a new key is in use.
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. Note that successfully decrypted a packet with a matching KEY_PHASE. Note that
when 0-RTT is attempted the value of the KEY_PHASE bit will be when 0-RTT is attempted the value of the KEY_PHASE bit will be
different on packets sent by either peer. different on packets sent by either peer.
A receiving endpoint detects an update when the KEY_PHASE bit doesn't A receiving endpoint detects an update when the KEY_PHASE bit doesn't
match what it is expecting. It creates a new secret (see match what it is expecting. It creates a new secret (see
Section 5.2) and the corresponding read key and IV. If the packet Section 5.3) and the corresponding read key and IV. If the packet
can be decrypted and authenticated using these values, then the keys can be decrypted and authenticated using these values, then the keys
it uses for packet protection are also updated. The next packet sent it uses for packet protection are also updated. The next packet sent
by the endpoint will then use the new keys. by the endpoint will then use the new keys.
An endpoint doesn't need to send packets immediately when it detects 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 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 simply use the new keys. If an endpoint detects a second update
before it has sent any packets with updated keys it indicates that before it has sent any packets with updated keys it indicates that
its peer has updated keys twice without awaiting a reciprocal update. its peer has updated keys twice without awaiting a reciprocal update.
An endpoint MUST treat consecutive key updates as a fatal error and An 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 short period to allow it to
decrypt packets with smaller packet numbers than the packet that decrypt packets with smaller packet numbers than the packet that
triggered the key update. This allows an endpoint to consume packets triggered the key update. This allows an endpoint to consume packets
that are reordered around the transition between keys. Packets with that are reordered around the transition between keys. Packets with
higher packet numbers always use the updated keys and MUST NOT be higher packet numbers always use the updated keys and MUST NOT be
decrypted with old keys. decrypted with old keys.
Keys and their corresponding secrets SHOULD be discarded when an Keys and their corresponding secrets SHOULD be discarded when an
endpoint has received all packets with sequence numbers lower than endpoint has received all packets with packet numbers lower than the
the lowest sequence number used for the new key. An endpoint might lowest packet number used for the new key. An endpoint might discard
discard keys if it determines that the length of the delay to keys if it determines that the length of the delay to affected
affected packets is excessive. 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
skipping to change at page 24, line 34 skipping to change at page 25, line 28
QUIC Frames @M QUIC Frames @M
New Keys -> @N New Keys -> @N
QUIC Frames @N QUIC Frames @N
<-------- <--------
Figure 5: Key Update Figure 5: Key Update
As shown in Figure 3 and Figure 5, there is never a situation where As shown in Figure 3 and Figure 5, there is never a situation where
there are more than two different sets of keying material that might there are more than two different sets of keying material that might
be received by a peer. Once both sending and receiving keys have be received by a peer. Once both sending and receiving keys have
been updated, been updated, the peers immediately begin to use them.
A server cannot initiate a key update until it has received the A server cannot initiate a key update until it has received the
client's Finished message. Otherwise, packets protected by the client's Finished message. Otherwise, packets protected by the
updated keys could be confused for retransmissions of handshake updated keys could be confused for retransmissions of handshake
messages. A client cannot initiate a key update until all of its messages. A client cannot initiate a key update until all of its
handshake messages have been acknowledged by the server. handshake messages have been acknowledged by the server.
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
skipping to change at page 30, line 29 skipping to change at page 31, line 23
In order to perform source-address verification before the handshake In order to perform source-address verification before the handshake
is complete, "PATH_CHALLENGE" and "PATH_RESPONSE" frames MAY be is complete, "PATH_CHALLENGE" and "PATH_RESPONSE" frames MAY be
exchanged unprotected. exchanged unprotected.
8.1.6. Denial of Service with Unprotected Packets 8.1.6. Denial of Service with Unprotected Packets
Accepting unprotected - specifically unauthenticated - packets Accepting unprotected - specifically unauthenticated - packets
presents a denial of service risk to endpoints. An attacker that is presents a denial of service risk to endpoints. An attacker that is
able to inject unprotected packets can cause a recipient to drop even able to inject unprotected packets can cause a recipient to drop even
protected packets with a matching sequence number. The spurious protected packets with a matching packet number. The spurious packet
packet shadows the genuine packet, causing the genuine packet to be shadows the genuine packet, causing the genuine packet to be ignored
ignored as redundant. as redundant.
Once the TLS handshake is complete, both peers MUST ignore Once the TLS handshake is complete, both peers MUST ignore
unprotected packets. From that point onward, unprotected messages unprotected packets. From that point onward, unprotected messages
can be safely dropped. can be safely dropped.
Since only TLS handshake packets and acknowledgments are sent in the Since only TLS handshake packets and acknowledgments are sent in the
clear, an attacker is able to force implementations to rely on clear, an attacker is able to force implementations to rely on
retransmission for packets that are lost or shadowed. Thus, an retransmission for packets that are lost or shadowed. Thus, an
attacker that intends to deny service to an endpoint has to drop or attacker that intends to deny service to an endpoint has to drop or
shadow protected packets in order to ensure that their victim shadow protected packets in order to ensure that their victim
skipping to change at page 31, line 4 skipping to change at page 31, line 47
packets means that an attacker does not need to be on path. packets means that an attacker does not need to be on path.
In addition to causing valid packets to be dropped, an attacker can In addition to causing valid packets to be dropped, an attacker can
generate packets with an intent of causing the recipient to expend generate packets with an intent of causing the recipient to expend
processing resources. See Section 10.2 for a discussion of these processing resources. See Section 10.2 for a discussion of these
risks. risks.
To avoid receiving TLS packets that contain no useful data, a TLS To avoid receiving TLS packets that contain no useful data, a TLS
implementation MUST reject empty TLS handshake records and any record implementation MUST reject empty TLS handshake records and any record
that is not permitted by the TLS state machine. Any TLS application that is not permitted by the TLS state machine. Any TLS application
data or alerts that is received prior to the end of the handshake data or alerts that are received prior to the end of the handshake
MUST be treated as a fatal error. MUST be treated as a connection error of type PROTOCOL_VIOLATION.
8.2. Use of 0-RTT Keys 8.2. Use of 0-RTT Keys
If 0-RTT keys are available, the lack of replay protection means that If 0-RTT keys are available (see Section 5.2), the lack of replay
restrictions on their use are necessary to avoid replay attacks on protection means that restrictions on their use are necessary to
the protocol. avoid replay attacks on the protocol.
A client MUST only use 0-RTT keys to protect data that is idempotent. 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 A client MAY wish to apply additional restrictions on what data it
sends prior to the completion of the TLS handshake. A client sends prior to the completion of the TLS handshake. A client
otherwise treats 0-RTT keys as equivalent to 1-RTT keys. otherwise treats 0-RTT keys as equivalent to 1-RTT keys.
A client that receives an indication that its 0-RTT data has been 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 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 server's handshake messages. A client SHOULD stop sending 0-RTT data
if it receives an indication that 0-RTT data has been rejected. if it receives an indication that 0-RTT data has been rejected.
A server MUST NOT use 0-RTT keys to protect packets. A server MUST NOT use 0-RTT keys to protect packets.
If a server rejects 0-RTT, then the TLS stream will not include any
TLS records protected with 0-RTT keys.
8.3. Receiving Out-of-Order Protected Frames 8.3. Receiving Out-of-Order Protected Frames
Due to reordering and loss, protected packets might be received by an Due to reordering and loss, protected packets might be received by an
endpoint before the final TLS handshake messages are received. A endpoint before the final TLS handshake messages are received. A
client will be unable to decrypt 1-RTT packets from the server, 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 whereas a server will be able to decrypt 1-RTT packets from the
client. client.
Packets protected with 1-RTT keys MAY be stored and later decrypted Packets protected with 1-RTT keys MAY be stored and later decrypted
and used once the handshake is complete. A server MUST NOT use 1-RTT and used once the handshake is complete. A server MUST NOT use 1-RTT
skipping to change at page 33, line 10 skipping to change at page 34, line 10
The "extension_data" field of the quic_transport_parameters extension The "extension_data" field of the quic_transport_parameters extension
contains a value that is defined by the version of QUIC that is in contains a value that is defined by the version of QUIC that is in
use. The quic_transport_parameters extension carries a use. The quic_transport_parameters extension carries a
TransportParameters when the version of QUIC defined in TransportParameters when the version of QUIC defined in
[QUIC-TRANSPORT] is used. [QUIC-TRANSPORT] is used.
The quic_transport_parameters extension is carried in the ClientHello The quic_transport_parameters extension is carried in the ClientHello
and the EncryptedExtensions messages during the handshake. and the EncryptedExtensions messages during the handshake.
9.3. Priming 0-RTT
QUIC uses TLS without modification. Therefore, it is possible to use
a pre-shared key that was established in a TLS handshake over TCP to
enable 0-RTT in QUIC. Similarly, QUIC can provide a pre-shared key
that can be used to enable 0-RTT in TCP.
All the restrictions on the use of 0-RTT apply, with the exception of
the ALPN label, which MUST only change to a label that is explicitly
designated as being compatible. The client indicates which ALPN
label it has chosen by placing that ALPN label first in the ALPN
extension. In order to be usable for 0-RTT, the NewSessionTicket
MUST contain 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.
The certificate that the server uses MUST be considered valid for
both connections, which will use different protocol stacks and could
use different port numbers. For instance, HTTP/1.1 and HTTP/2
operate over TLS and TCP, whereas QUIC operates over UDP.
Source address validation is not completely portable between
different protocol stacks. Even if the source IP address remains
constant, the port number is likely to be different. Packet
reflection attacks are still possible in this situation, though the
set of hosts that can initiate these attacks is greatly reduced. A
server might choose to avoid source address validation for such a
connection, or allow an increase to the amount of data that it sends
toward the client without source validation.
10. Security Considerations 10. Security Considerations
There are likely to be some real clangers here eventually, but the There are likely to be some real clangers here eventually, but the
current set of issues is well captured in the relevant sections of current set of issues is well captured in the relevant sections of
the main text. the main text.
Never assume that because it isn't in the security considerations Never assume that because it isn't in the security considerations
section it doesn't affect security. Most of this document does. section it doesn't affect security. Most of this document does.
10.1. Packet Reflection Attack Mitigation 10.1. Packet Reflection Attack Mitigation
skipping to change at page 34, line 39 skipping to change at page 35, line 5
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.
TLS records SHOULD always contain at least one octet of a handshake TLS records SHOULD always contain at least one octet of a handshake
messages or alert. Records containing only padding are permitted messages or alert. Records containing only padding are permitted
during the handshake, but an excessive number might be used to during the handshake, but an excessive number might be used to
generate unnecessary work. Once the TLS handshake is complete, generate unnecessary work. Once the TLS handshake is complete,
endpoints SHOULD NOT send TLS application data records unless it is endpoints MUST NOT send TLS application data records. Receiving TLS
to hide the length of QUIC records. QUIC packet protection does not application data MUST be treated as a connection error of type
include any allowance for padding; padded TLS application data PROTOCOL_VIOLATION.
records can be used to mask the length of QUIC frames.
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.
11. Error Codes 11. Error Codes
This section defines error codes from the error code space used in This section defines error codes from the error code space used in
[QUIC-TRANSPORT]. [QUIC-TRANSPORT].
skipping to change at page 35, line 32 skipping to change at page 35, line 45
register the three error codes found in Section 11, these are register the three error codes found in Section 11, these are
summarized in Table 1. summarized in Table 1.
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 9.2. the quic_transport_parameters extension found in Section 9.2.
Assigning 26 to the extension would be greatly appreciated. The Assigning 26 to the extension would be greatly appreciated. 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.
o TLS Exporter Label Registry [TLS-REGISTRIES] - IANA is requested o TLS Exporter Label Registry [TLS-REGISTRIES] - IANA is requested
to register "EXPORTER-QUIC 0rtt" from Section 5.2.3; "EXPORTER- to register "EXPORTER-QUIC 0rtt" from Section 5.3.3; "EXPORTER-
QUIC client 1rtt" and "EXPORTER-QUIC server 1-RTT" from QUIC client 1rtt" and "EXPORTER-QUIC server 1-RTT" from
Section 5.2.4. The DTLS column is to be marked No. The Section 5.3.4. The DTLS column is to be marked No. The
Recommended column is to be marked Yes. Recommended column is to be marked Yes.
+-------+---------------------------+---------------+---------------+ +-------+---------------------------+---------------+---------------+
| Value | Error | Description | Specification | | Value | Error | Description | Specification |
+-------+---------------------------+---------------+---------------+ +-------+---------------------------+---------------+---------------+
| 0x201 | TLS_HANDSHAKE_FAILED | TLS handshake | Section 11 | | 0x201 | TLS_HANDSHAKE_FAILED | TLS handshake | Section 11 |
| | | failure | | | | | failure | |
| | | | | | | | | |
| 0x202 | TLS_FATAL_ALERT_GENERATED | Sent TLS | Section 11 | | 0x202 | TLS_FATAL_ALERT_GENERATED | Sent TLS | Section 11 |
| | | alert | | | | | alert | |
skipping to change at page 36, line 26 skipping to change at page 36, line 41
fips-180-4.pdf>. fips-180-4.pdf>.
[HKDF] Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-Expand [HKDF] Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-Expand
Key Derivation Function (HKDF)", RFC 5869, Key Derivation Function (HKDF)", RFC 5869,
DOI 10.17487/RFC5869, May 2010, DOI 10.17487/RFC5869, May 2010,
<https://www.rfc-editor.org/info/rfc5869>. <https://www.rfc-editor.org/info/rfc5869>.
[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-10 (work in progress), March 2018. transport-11 (work in progress), April 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>.
skipping to change at page 37, line 14 skipping to change at page 37, line 27
13.2. Informative References 13.2. 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>.
[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-10 (work in progress), March QUIC", draft-ietf-quic-http-11 (work in progress), April
2018. 2018.
[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-10 (work and Congestion Control", draft-ietf-quic-recovery-11 (work
in progress), March 2018. in progress), April 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 38, line 18 skipping to change at page 38, line 30
Christian Huitema, Jana Iyengar, Adam Langley, Roberto Peon, Eric Christian Huitema, Jana Iyengar, Adam Langley, Roberto Peon, Eric
Rescorla, Ian Swett, and many others. Rescorla, Ian Swett, and many others.
Appendix C. Change Log Appendix C. 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.
C.1. Since draft-ietf-quic-tls-09 C.1. Since draft-ietf-quic-tls-10
o No significant changes.
C.2. 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)
C.2. Since draft-ietf-quic-tls-08 C.3. 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)
C.3. Since draft-ietf-quic-tls-07 C.4. 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)
C.4. Since draft-ietf-quic-tls-05 C.5. Since draft-ietf-quic-tls-05
No significant changes. No significant changes.
C.5. Since draft-ietf-quic-tls-04 C.6. 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)
C.6. Since draft-ietf-quic-tls-03 C.7. Since draft-ietf-quic-tls-03
No significant changes. No significant changes.
C.7. Since draft-ietf-quic-tls-02 C.8. Since draft-ietf-quic-tls-02
o Updates to match changes in transport draft o Updates to match changes in transport draft
C.8. Since draft-ietf-quic-tls-01 C.9. 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 39, line 30 skipping to change at page 39, line 46
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)
C.9. Since draft-ietf-quic-tls-00 C.10. 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
C.10. Since draft-thomson-quic-tls-01 C.11. 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
Authors' Addresses Authors' Addresses
Martin Thomson (editor) Martin Thomson (editor)
 End of changes. 72 change blocks. 
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