Internet DRAFT - draft-ietf-tls-ecdhe-psk-aead
draft-ietf-tls-ecdhe-psk-aead
Network Working Group J. Mattsson
Internet-Draft D. Migault
Intended status: Standards Track Ericsson
Expires: November 25, 2017 May 24, 2017
ECDHE_PSK with AES-GCM and AES-CCM Cipher Suites for Transport Layer
Security (TLS) Protocol version 1.2
draft-ietf-tls-ecdhe-psk-aead-05
Abstract
This document defines several new cipher suites for the Transport
Layer Security (TLS) protocol version 1.2. The cipher suites are all
based on the Ephemeral Elliptic Curve Diffie-Hellman with Pre-Shared
Key (ECDHE_PSK) key exchange together with the Authenticated
Encryption with Associated Data (AEAD) algorithms AES-GCM and AES-
CCM. PSK provides light and efficient authentication, ECDHE provides
forward secrecy, and AES-GCM and AES-CCM provides encryption and
integrity protection.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on November 25, 2017.
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Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
3. ECDHE_PSK with AES-GCM and AES-CCM Cipher Suites . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Requirements notation
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].
2. Introduction
This document defines new cipher suites that provide Pre-Shared Key
(PSK) authentication, Perfect Forward Secrecy (PFS), and
Authenticated Encryption with Associated Data (AEAD). The cipher
suites are defined for version 1.2 of the Transport Layer Security
(TLS) [RFC5246] protocol and version 1.2 of the Datagram Transport
Layer Security (DTLS) protocol [RFC6347].
Pre-Shared Key (PSK) Authentication is widely used in many scenarios.
One deployment is 3GPP networks where pre-shared keys are used to
authenticate both subscriber and network. Another deployment is
Internet of Things where PSK authentication is often preferred for
performance and energy efficiency reasons. In both scenarios the
endpoints are owned/controlled by a party that provisions the pre-
shared keys and makes sure that they provide a high level of entropy.
Perfect Forward Secrecy (PFS) is a strongly recommended feature in
security protocol design and can be accomplished by using an
ephemeral Diffie-Hellman key exchange method. Ephemeral Elliptic
Curve Diffie-Hellman (ECDHE) provides PFS with excellent performance
and small key sizes. ECDHE is mandatory to implement in both HTTP/2
[RFC7540] and CoAP [RFC7252].
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AEAD algorithms that combine encryption and integrity protection are
strongly recommended for (D)TLS [RFC7525] and non-AEAD algorithms are
forbidden to use in TLS 1.3 [I-D.ietf-tls-tls13]. The AEAD
algorithms considered in this document are AES-GCM and AES-CCM. The
use of AES-GCM in TLS is defined in [RFC5288] and the use of AES-CCM
is defined in [RFC6655].
[RFC4279] defines Pre-Shared Key (PSK) cipher suites for TLS but does
not consider Elliptic Curve Cryptography. [RFC4492] introduces
Elliptic Curve Cryptography for TLS but does not consider PSK
authentication. [RFC5487] describes the use of AES-GCM in
combination with PSK authentication, but does not consider ECDHE.
[RFC5489] describes the use of PSK in combination with ECDHE but does
not consider AES-GCM or AES-CCM.
3. ECDHE_PSK with AES-GCM and AES-CCM Cipher Suites
The cipher suites defined in this document are based on the AES-GCM
and AES-CCM Authenticated Encryption with Associated Data (AEAD)
algorithms AEAD_AES_128_GCM, AEAD_AES_256_GCM, AEAD_AES_128_CCM_8
defined in [RFC6655] and AEAD_AES_128_CCM defined in [RFC5116].
Messages and premaster secret construction in this document are
defined in [RFC5489]. The ServerKeyExchange and ClientKeyExchange
messages are used and the premaster secret is computed as for the
ECDHE_PSK key exchange. The elliptic curve parameters used in in the
Diffie-Hellman parameters are negotiated using extensions defined in
[I-D.ietf-tls-rfc4492bis].
For TLS 1.2, the following cipher suites are defined:
TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256 = {0xTBD,0xTBD};
TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384 = {0xTBD,0xTBD};
TLS_ECDHE_PSK_WITH_AES_128_CCM_8_SHA256 = {0xTBD,0xTBD};
TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256 = {0xTBD,0xTBD};
The assigned code points can only be used for TLS 1.2.
The cipher suites defined in this document MUST NOT be negotiated for
any version of (D)TLS other than TLS 1.2. Servers MUST NOT select
one of these cipher suites when selecting TLS version other than TLS
1.2. A client MUST treat the selection of these cipher suites in
combination with a different version of TLS as an error and generate
a fatal 'illegal_parameter' TLS alert.
Cipher suites TLS_AES_128_GCM_SHA256, TLS_AES_256_GCM_SHA384,
TLS_AES_128_CCM_8_SHA256 and TLS_AES_128_CCM_SHA256 are used to
support equivalent functionality in TLS 1.3 [I-D.ietf-tls-tls13].
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4. IANA Considerations
This document defines the following new cipher suites, whose values
have been assigned in the TLS Cipher Suite Registry defined by
[RFC5246].
TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256 = {0xTBD; 0xTBD} {0xD0,0x01};
TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384 = {0xTBD; 0xTBD} {0xD0,0x02};
TLS_ECDHE_PSK_WITH_AES_128_CCM_8_SHA256 = {0xTBD; 0xTBD} {0xD0,0x03};
TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256 = {0xTBD; 0xTBD} {0xD0,0x05};
NOTE TO THE RFC EDITOR: PLEASE REMOVE THIS PARAGRAPH. The cipher
suite numbers listed in the last column are numbers used for cipher
suite interoperability testing and it's suggested that IANA use these
values for assignment.
5. Security Considerations
The security considerations in TLS 1.2 [RFC5246], DTLS 1.2 [RFC6347],
PSK Ciphersuites for TLS [RFC4279], ECDHE_PSK [RFC5489], AES-GCM
[RFC5288], and AES-CCM [RFC6655] apply to this document as well.
All the cipher suites defined in this document provide
confidentiality, mutual authentication, and forward secrecy. The
AES-128 cipher suites provide 128-bit security and the AES-256 cipher
suites provide at least 192-bit security. However, AES_128_CCM_8
only provides 64-bit security against message forgery.
The Pre-Shared Keys used for authentication MUST have a security
level equal or higher than the cipher suite used, i.e., at least
128-bit for the AES-128 cipher suites and at least 192-bit for the
AES-256 cipher suites.
GCM or CCM encryption - even of different clear text - re-using a
nonce with a same key undermines the security of GCM and CCM. As a
result, GCM and CCM MUST only be used with a system guaranteeing
nonce uniqueness [RFC5116].
6. Acknowledgements
The authors would like to thank Ilari Liusvaara, Eric Rescorla, Dan
Harkins, Russ Housley, Dan Harkins, Martin Thomson, Nikos
Mavrogiannopoulos, Peter Dettman, Xiaoyin Liu, Joseph Salowey, Sean
Turner Dave Garrett, Martin Rex and Kathleen Moriarty for their
valuable comments and feedback.
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7. References
7.1. Normative References
[I-D.ietf-tls-rfc4492bis]
Nir, Y., Josefsson, S., and M. Pegourie-Gonnard, "Elliptic
Curve Cryptography (ECC) Cipher Suites for Transport Layer
Security (TLS) Versions 1.2 and Earlier", draft-ietf-tls-
rfc4492bis-17 (work in progress), May 2017.
[I-D.ietf-tls-tls13]
Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", draft-ietf-tls-tls13-20 (work in progress),
April 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4279] Eronen, P., Ed. and H. Tschofenig, Ed., "Pre-Shared Key
Ciphersuites for Transport Layer Security (TLS)",
RFC 4279, DOI 10.17487/RFC4279, December 2005,
<http://www.rfc-editor.org/info/rfc4279>.
[RFC5116] McGrew, D., "An Interface and Algorithms for Authenticated
Encryption", RFC 5116, DOI 10.17487/RFC5116, January 2008,
<http://www.rfc-editor.org/info/rfc5116>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<http://www.rfc-editor.org/info/rfc5246>.
[RFC5288] Salowey, J., Choudhury, A., and D. McGrew, "AES Galois
Counter Mode (GCM) Cipher Suites for TLS", RFC 5288,
DOI 10.17487/RFC5288, August 2008,
<http://www.rfc-editor.org/info/rfc5288>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <http://www.rfc-editor.org/info/rfc6347>.
[RFC6655] McGrew, D. and D. Bailey, "AES-CCM Cipher Suites for
Transport Layer Security (TLS)", RFC 6655,
DOI 10.17487/RFC6655, July 2012,
<http://www.rfc-editor.org/info/rfc6655>.
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7.2. Informative References
[RFC4492] Blake-Wilson, S., Bolyard, N., Gupta, V., Hawk, C., and B.
Moeller, "Elliptic Curve Cryptography (ECC) Cipher Suites
for Transport Layer Security (TLS)", RFC 4492,
DOI 10.17487/RFC4492, May 2006,
<http://www.rfc-editor.org/info/rfc4492>.
[RFC5487] Badra, M., "Pre-Shared Key Cipher Suites for TLS with SHA-
256/384 and AES Galois Counter Mode", RFC 5487,
DOI 10.17487/RFC5487, March 2009,
<http://www.rfc-editor.org/info/rfc5487>.
[RFC5489] Badra, M. and I. Hajjeh, "ECDHE_PSK Cipher Suites for
Transport Layer Security (TLS)", RFC 5489,
DOI 10.17487/RFC5489, March 2009,
<http://www.rfc-editor.org/info/rfc5489>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014,
<http://www.rfc-editor.org/info/rfc7252>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <http://www.rfc-editor.org/info/rfc7525>.
[RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
DOI 10.17487/RFC7540, May 2015,
<http://www.rfc-editor.org/info/rfc7540>.
Authors' Addresses
John Mattsson
Ericsson AB
SE-164 80 Stockholm
Sweden
Phone: +46 76 115 35 01
Email: john.mattsson@ericsson.com
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Daniel Migault
Ericsson
8400 boulevard Decarie
Montreal, QC H4P 2N2
Canada
Phone: +1 514-452-2160
Email: daniel.migault@ericsson.com
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