Network Working Group J. Mattsson
Internet-Draft D. Migault
Intended status: Standards Track Ericsson
Expires: December 31, 2015 June 29, 2015
ECDHE_PSK with AES-GCM and AES-CCM Cipher Suites
for Transport Layer Security (TLS)
draft-mattsson-tls-ecdhe-psk-aead-00
Abstract
This memo defines several new cipher suites for the Transport Layer
Security (TLS) protocol. 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 perfect
forward secrecy, and AES-GCM and AES-CCM provides encryption and
integrity protection.
Status of This Memo
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This Internet-Draft will expire on December 31, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. ECDHE_PSK with AES-GCM and AES-CCM Cipher Suites . . . . . . 3
3. Applicable TLS Versions . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. 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).
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].
AEAD algorithms that combine encryption and integrity protection are
strongly recommended [RFC7525], and non-AEAD algorithms will likely
be forbidden to use in TLS1.3. The AEAD algorithms considered in
this document are AES-CCM and AES-GCM. The use of AES-CCM in TLS is
defined in [RFC6655] and the use of AES-GCM is defined [RFC5288].
[RFC4279] defines Pre-Shared Key (PSK) cipher suites for TLS but does
not consider Elliptic Curve Cryptography. [RFC5489] 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.
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[RFC5489] describes the use of PSK in combination with ECDHE but does
not consider AES-GCM or AES-CCM.
2. 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, and
AEAD_AES_256_CCM described in [RFC5116]. The following cipher suites
are defined:
TLS_PSK_ECDHE_WITH_AES_128_GCM = {TDB0,TDB1};
TLS_PSK_ECDHE_WITH_AES_256_GCM = {TDB2,TDB3};
TLS_PSK_ECDHE_WITH_AES_128_CCM_8 = {TDB4,TDB5};
TLS_PSK_ECDHE_WITH_AES_128_CCM = {TDB6,TDB7};
TLS_PSK_ECDHE_WITH_AES_256_CCM = {TDB8,TDB9};
These cipher suites make use of the default TLS 1.2 Pseudorandom
Function (PRF), which uses HMAC with the SHA-256 hash function.
Clients and Servers MUST NOT negotiate curves of less than 256 bits
and the Pre-Shared-Keys MUST NOT have an entropy of less than 128
bits.
3. Applicable TLS Versions
These cipher suites make use of the authenticated encryption with
additional data (AEAD) defined in TLS 1.2 [RFC5246]. Earlier
versions of TLS do not have support for AEAD and consequently, these
cipher suites MUST NOT be negotiated in TLS versions prior to 1.2.
Clients MUST NOT offer these cipher suites if they do not offer TLS
1.2 or later. Servers, which select an earlier version of TLS MUST
NOT select one of these cipher suites. A client MUST treat the
selection of these cipher suites in combination with a version of TLS
that does not support AEAD (i.e., TLS 1.1 or earlier) as an error and
generate a fatal 'illegal_parameter' TLS alert.
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_PSK_ECDHE_WITH_AES_128_GCM = {TDB0,TDB1};
TLS_PSK_ECDHE_WITH_AES_256_GCM = {TDB2,TDB3};
TLS_PSK_ECDHE_WITH_AES_128_CCM_8 = {TDB4,TDB5};
TLS_PSK_ECDHE_WITH_AES_128_CCM = {TDB6,TDB7};
TLS_PSK_ECDHE_WITH_AES_256_CCM = {TDB8,TDB9};
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5. Security Considerations
Most of the security considerations in [RFC5246], [RFC4279],
[RFC4492], [RFC5288], [RFC5489], and [RFC6655] apply to this document
as well. The cipher suites defined in this document provides perfect
forward secrecy.
6. Acknowledgements
7. References
[RFC4279] Eronen, P. and H. Tschofenig, "Pre-Shared Key Ciphersuites
for Transport Layer Security (TLS)", RFC 4279, December
2005.
[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, May 2006.
[RFC5116] McGrew, D., "An Interface and Algorithms for Authenticated
Encryption", RFC 5116, January 2008.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5288] Salowey, J., Choudhury, A., and D. McGrew, "AES Galois
Counter Mode (GCM) Cipher Suites for TLS", RFC 5288,
August 2008.
[RFC5487] Badra, M., "Pre-Shared Key Cipher Suites for TLS with SHA-
256/384 and AES Galois Counter Mode", RFC 5487, March
2009.
[RFC5489] Badra, M. and I. Hajjeh, "ECDHE_PSK Cipher Suites for
Transport Layer Security (TLS)", RFC 5489, March 2009.
[RFC6655] McGrew, D. and D. Bailey, "AES-CCM Cipher Suites for
Transport Layer Security (TLS)", RFC 6655, July 2012.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252, June 2014.
[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, May 2015.
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[RFC7540] Belshe, M., Peon, R., and M. Thomson, "Hypertext Transfer
Protocol Version 2 (HTTP/2)", RFC 7540, May 2015.
Authors' Addresses
John Mattsson
Ericsson AB
SE-164 80 Stockholm
Sweden
Email: john.mattsson@ericsson.com
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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