IPWAVE M. Msahli, Ed.
Internet-Draft Telecom ParisTech
Intended status: Informational P. Kampanakis, Ed.
Expires: September 29, 2019 Cisco
March 28, 2019
TLS Authentication using IEEE 1609.2 certificates
draft-msahli-ipwave-extension-ieee1609-03.txt
Abstract
This document specifies the use of a new certificate type to
authenticate TLS entities. The first type enables the use of a
certificate specified by the IEEE and the European Telecommunications
Standards Institute (ETSI).
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Terminology . . . . . . . . . . . . . . . . . . 2
3. Extension Overview . . . . . . . . . . . . . . . . . . . . . 2
4. TLS Client and Server Handshake . . . . . . . . . . . . . . . 4
4.1. Client Hello . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Server Hello . . . . . . . . . . . . . . . . . . . . . . 5
5. Certificate Verification . . . . . . . . . . . . . . . . . . 6
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. TLS Server and TLS Client use the 1609Dot2 Certificate . 6
6.2. TLS Client uses the IEEE 1609.2 certificate and TLS
Server uses the X 509 certificate . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 9
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
11.1. Normative References . . . . . . . . . . . . . . . . . . 9
11.2. Informative References . . . . . . . . . . . . . . . . . 10
Appendix A. Co-Authors . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
The TLS protocol [RFC8446] [RFC5246] uses X509 and Raw Public Key in
order to authenticate servers and clients. This document describes
the use of the certificate specified by the IEEE in [IEEE1609.2] and
profiled by the European Telecommunications Standards Institute
(ETSI) in [TS103097]. These standards specify secure communications
in vehicular environments. The certificate types are optimized for
bandwidth and processing time to support delay-sensitive
applications, and also provide both authentication and authorization
information to enable fast access control decisions in ad hoc
networks such as are found in Intelligent Transportation System
(ITS). The extension is following the [RFC6066].
2. Requirements Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Extension Overview
This specification extends the Client Hello and Server Hello
messages, by using the "extension_data" field of the ClientCertType
Extension and the ServerCertType Extension structures defined in
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RFC7250. In order to negotiate the support of IEEE 1609.2 or ETSI TS
103097 certificate-based authentication, the clients and the servers
MAY include the extension of type "client_certificate_type" and
"server_certificate_type" in the extended Client Hello and
"EncryptedExtensions". The "extension_data" field of this extension
SHALL contain a list of supported certificate types proposed by the
client as provided in the figure below:
/* Managed by IANA */
enum {
X509(0),
RawPublicKey(2),
1609Dot2(3),
(255)
} CertificateType;
struct {
select (certificate_type) {
/* certificate type defined in this document.*/
case 1609Dot2:
opaque cert_data<1..2^24-1>;
/* RawPublicKey defined in RFC 7250*/
case RawPublicKey:
opaque ASN.1_subjectPublicKeyInfo<1..2^24-1>;
/* X.509 certificate defined in RFC 5246*/
case X.509:
opaque cert_data<1..2^24-1>;
};
Extension extensions<0..2^16-1>;
} CertificateEntry;
In case where the TLS server accepts the described extension, it
selects one of the certificate types in the extension described
above. Note that a server MAY authenticate the client using other
authentication methods. The end-entity certificate's public key has
to be compatible with one of the certificate types listed in the
extension described above.
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4. TLS Client and Server Handshake
The "client_certificate_type" and "server_certificate_type"
extensions MUST be sent in handshake phase as illustrated in Figure 1
below. The same extension shall be sent in Server Hello for TLS 1.2.
Client Server
Key ^ ClientHello
Exch | + server_certificate_type*
| + client_certificate_type*
| + key_share*
v + signature_algorithms* -------->
ServerHello ^ Key
+ key_share* v Exch
{EncryptedExtensions} ^ Server
{+ server_certificate_type*}| Params
{+ client_certificate_type*}|
{CertificateRequest*} v
{Certificate*} ^
{CertificateVerify*} | Auth
{Finished} v
<------- [Application Data*]
^ {Certificate*}
Auth | {CertificateVerify*}
v {Finished} -------->
[Application Data] <-------> [Application Data]
+ Indicates noteworthy extensions sent in the
previously noted message.
* Indicates optional or situation-dependent
messages/extensions that are not always sent.
{} Indicates messages protected using keys
derived from a [sender]_handshake_traffic_secret.
[] Indicates messages protected using keys
derived from [sender]_application_traffic_secret_N.
Figure 1: Message Flow with certificate type extension for Full TLS
1.3 Handshake
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4.1. Client Hello
In order to indicate the support of IEEE 1609.2 or ETSI TS 103097
certificates, client MUST include an extension of type
"client_certificate_type" and "server_certificate_type" in the
extended Client Hello message. The Hello extension is described in
Section 4.1.2 of TLS 1.3 [RFC8446].
The extension 'client_certificate_type' sent in the client hello MAY
carry a list of supported certificate types, sorted by client
preference. It is a list in the case where the client supports
multiple certificate types.
Client MAY respond along with supported certificates by sending a
"Certificate" message immediately followed by the "CetificateVerify"
message. These specifications are valid for TLS 1.2 and TLS 1.3.
All implementations SHOULD be prepared to handle extraneous
certificates and arbitrary orderings from any TLS version, with the
exception of the end-entity certificate which MUST be first.
4.2. Server Hello
When the server receives the Client Hello containing the
client_certificate_type extension and/or the server_certificate_type
extension, the following options are possible:
- The server supports the extension described in this document.
It selects a certificate type from the client_certificate_type
field in the extended Client Hello and must take into account the
client authentication list priority.
- The server does not support the proposed certificate type and
terminates the session with a fatal alert of type
"unsupported_certificate".
- The server does not support the extension defined in this
document. In this case, the server returns the server hello
without the extensions defined in this document.
- The server supports the extension defined in this document, but
it does not have any certificate type in common with the client.
Then, the server terminates the session with a fatal alert of type
"unsupported_certificate".
- The server supports the extensions defined in this document and
has at least one certificate type in common with the client. In
this case, the server MAY include the client_certificate_type
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extension in the Server Hello for TLS 1.2 or in Encrypted
Extension for TLS 1.3. Then, the server requests a certificate
from the client (via the certificate_request message)
It is worth to mention that the TLS client or server public keys are
obtained from a certificate chain from a web page.
5. Certificate Verification
Verification of an IEEE 1609.2/ ETSI TS 103097 certificates or
certificate chain is described in section 5.5.2 of [IEEE1609.2]. In
the case where the certificate_type is 1609Dot2, the
CertificateVerify message does not contain a raw signature but
instead contains a Canonical Octet Encoding Rules (COER)-encoded
Ieee1609Dot2Data of type signed as specified in [1609.2b], with the
pduFunctionalType field present and set to tlsHandshake. A full
specification of the contents of this Ieee1609Dot2Data, including
optional fields, is given in [1609.2b]. The message input to the
signature calculation is the usual message input for TLS 1.3, as
specified in [RFC8446] section 4.4.3, consisting of pad, context
string, separator and content, where content is Transcript-
Hash(Handshake Context, Certificate).
6. Examples
Some of exchanged messages examples are illustrated in Figures 2 and
3.
6.1. TLS Server and TLS Client use the 1609Dot2 Certificate
This section shows an example where the TLS client as well as the TLS
server use the IEEE 1609.2 certificate. In consequence, both the
server and the client populate the client_certificate_type and
server_certificate_type with extension IEEE 1609.2 certificates as
mentioned in figure 2.
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Client Server
ClientHello,
client_certificate_type*=1609Dot2,
server_certificate_type*=1609Dot2, --------> ServerHello,
{EncryptedExtensions}
{client_certificate_type*=1609Dot2}
{server_certificate_type*=1609Dot2}
{CertificateRequest*}
{Certificate*}
{CertificateVerify*}
{Finished}
{Certificate*} <------- [Application Data*]
{CertificateVerify*}
{Finished} -------->
[Application Data] <-------> [Application Data]
Figure 2: TLS Client and TLS Server use the IEEE 1609.2 certificate
6.2. TLS Client uses the IEEE 1609.2 certificate and TLS Server uses
the X 509 certificate
This example shows the TLS authentication, where the TLS Client
populates the server_certificate_type extension with the X509
certificate and Raw Public Key type as presented in figure 3. the
client indicates its ability to receive and to validate an X509
certificate from the server. The server chooses the X509
certificateto make its authentication with the Client.
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Client Server
ClientHello,
client_certificate_type*=(1609Dot2),
server_certificate_type*=(1609.9Dot,
X509,RawPublicKey), -----------> ServerHello,
{EncryptedExtensions}
{client_certificate_type*=1609Dot2}
{server_certificate_type*=X509}
{Certificate*}
{CertificateVerify*}
{Finished}
<--------- [Application Data*]
{Finished} --------->
[Application Data] <--------> [Application Data]
Figure 3: TLS Client uses the IEEE 1609.2 certificate and TLS Server
uses the X 509 certificate
7. Security Considerations
This section provides an overview of the basic security
considerations which need to be taken into account before
implementing the necessary security mechanisms. The security
considerations described throughout [RFC8446] and [RFC5246] apply
here as well.
For security considerations in a vehicular environment, the minimal
use of any TLS extensions is recommended such as :
The "client_certificate_type" [IANA value 19] extension who's
purpose was previously described in [RFC7250].
The "server_certificate_type" [IANA value 20] extension who's
purpose was previously described in [RFC7250].
The "SessionTicket" [IANA value 35] extension for session
resumption.
In addition, servers SHOULD not support renegotiation [RFC5746]
which presented Man-In-The-Middle (MITM) type attacks over the
past years for TLS 1.2.
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8. Privacy Considerations
For privacy considerations in a vehicular environment the use of EEE
1609.2/ETSI TS 103097 certificate is recommended for many reasons:
In order to address the risk of a personal data leakage, messages
exchanged for V2V communications are signed using IEEE 1609.2/ETSI
TS 103097 pseudonym certificates
The purpose of these certificates is to provide privacy relying on
geographical and/or temporal validity criteria, and minimizing the
exchange of private data
9. IANA Considerations
Existing IANA references have not been updated yet to point to this
document.
10. Acknowledgements
The authors wish to thank Eric Rescola and Ilari Liusvaara for their
feedback and suggestions on improving this document. Thanks are due
to Sean Turner for his valuable and detailed comments. Special
thanks to Maik Seewald for their guidance and support in the early
stages of the draft.
11. References
11.1. Normative References
[IEEE1609.2]
"IEEE Standard for Wireless Access in Vehicular
Environments - Security Services for Applications and
Management Messages", 2016.
[IEEE1609.2b]
"Draft Standard for Wireless Access in Vehicular
Environments Security Services for Applications and for
Management Messages", 2018.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[RFC4492] Blake-Wilson, S., Bolyard, N., Gupta, V., Hawk, C., and B.
Moeller, "Elliptic Curve Cryptography (ECC) Cipher Suites
for Transport Layer Security (TLS)", May 2006.
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[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", August 2008.
[RFC5746] Rescorla, E., Ray, M., Dispensa, S., and N. Oskov,
"Transport Layer Security (TLS) Renegotiation Indication
Extension"", February 2010.
[RFC6066] Eastlake, D., "Transport Layer Security (TLS) Extensions:
Extension Definitions", January 2011.
[RFC7250] Wouters, P., Tschofenig, H., Weiler, S., and T. Kivinen,
"Using Raw Public Keys in Transport Layer Security (TLS)
and Datagram Transport Layer Security (DTLS)", June 2014.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", August 2018.
[TS103097]
"ETSI TS 103 097 v1.3.1 (2017-10): Intelligent Transport
Systems (ITS); Security; Security header and certificate
formats", October 2017.
11.2. Informative References
[draft-serhrouchni-tls-certieee1609-00]
KAISER, A., LABIOD, H., LONC, B., MSAHLI, M., and A.
SERHROUCHNI, "Transport Layer Security (TLS)
Authentication using ITS ETSI and IEEE certificates",
august 2017.
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Appendix A. Co-Authors
o Houda Labiod
Telecom ParisTech
houda.labiod@telecom-paristech.fr
o Nancy Cam-Winget
CISCO, USA
ncamwing@cisco.com
o Ahmed Serhrouchni
Telecom ParisTech
ahmed.serhrouchni@telecom-paristech.fr
o William Whyte
Onboard Security
wwhyte@onboardsecurity.com
Authors' Addresses
Mounira Msahli (editor)
Telecom ParisTech
France
EMail: mounira.msahli@telecom-paristech.fr
Panos Kampanakis (editor)
Cisco
USA
EMail: pkampana@cisco.com
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