< draft-mattsson-tls-ecdhe-psk-aead-02.txt   draft-mattsson-tls-ecdhe-psk-aead-03.txt >
Network Working Group J. Mattsson Network Working Group J. Mattsson
Internet-Draft D. Migault Internet-Draft D. Migault
Intended status: Standards Track Ericsson Intended status: Standards Track Ericsson
Expires: January 25, 2016 July 24, 2015 Expires: June 10, 2016 December 8, 2015
ECDHE_PSK with AES-GCM and AES-CCM Cipher Suites ECDHE_PSK with AES-GCM and AES-CCM Cipher Suites
for Transport Layer Security (TLS) for Transport Layer Security (TLS)
draft-mattsson-tls-ecdhe-psk-aead-02 draft-mattsson-tls-ecdhe-psk-aead-03
Abstract Abstract
This memo defines several new cipher suites for the Transport Layer This document defines several new cipher suites for the Transport
Security (TLS) protocol. The cipher suites are all based on the Layer Security (TLS) protocol. The cipher suites are all based on
Ephemeral Elliptic Curve Diffie-Hellman with Pre-Shared Key the Ephemeral Elliptic Curve Diffie-Hellman with Pre-Shared Key
(ECDHE_PSK) key exchange together with the Authenticated Encryption (ECDHE_PSK) key exchange together with the Authenticated Encryption
with Associated Data (AEAD) algorithms AES-GCM and AES-CCM. PSK with Associated Data (AEAD) algorithms AES-GCM and AES-CCM. PSK
provides light and efficient authentication, ECDHE provides perfect provides light and efficient authentication, ECDHE provides perfect
forward secrecy, and AES-GCM and AES-CCM provides encryption and forward secrecy, and AES-GCM and AES-CCM provides encryption and
integrity protection. integrity protection.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
skipping to change at page 1, line 38 skipping to change at page 1, line 38
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 http://datatracker.ietf.org/drafts/current/. Drafts is at http://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 January 25, 2016. This Internet-Draft will expire on June 10, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 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
(http://trustee.ietf.org/license-info) in effect on the date of (http://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
skipping to change at page 2, line 14 skipping to change at page 2, line 14
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. ECDHE_PSK with AES-GCM and AES-CCM Cipher Suites . . . . . . 3 2. ECDHE_PSK with AES-GCM and AES-CCM Cipher Suites . . . . . . 3
3. Applicable TLS Versions . . . . . . . . . . . . . . . . . . . 3 3. Applicable TLS Versions . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
This document defines new cipher suites that provide Pre-Shared Key This document defines new cipher suites that provide Pre-Shared Key
(PSK) authentication, Perfect Forward Secrecy (PFS), and (PSK) authentication, Perfect Forward Secrecy (PFS), and
Authenticated Encryption with Associated Data (AEAD). Authenticated Encryption with Associated Data (AEAD). The cipher
suites are defined for version 1.2 or later of the the Transport
Layer Security (TLS) [RFC5246] protocol, as well as version 1.2 or
later of the Datagram Transport Layer Security (DTLS) protocol
[RFC6347].
Pre-Shared Key (PSK) Authentication is widely used in many scenarios. Pre-Shared Key (PSK) Authentication is widely used in many scenarios.
One deployment is 3GPP networks where pre-shared keys are used to One deployment is 3GPP networks where pre-shared keys are used to
authenticate both subscriber and network. Another deployment is authenticate both subscriber and network. Another deployment is
Internet of Things where PSK authentication is often preferred for Internet of Things where PSK authentication is often preferred for
performance and energy efficiency reasons. In both scenarios the performance and energy efficiency reasons. In both scenarios the
endpoints are owned/controlled by a party that provisions the pre- endpoints are owned/controlled by a party that provisions the pre-
shared keys and makes sure that they provide a high level of entropy. shared keys and makes sure that they provide a high level of entropy.
Perfect Forward Secrecy (PFS) is a strongly recommended feature in Perfect Forward Secrecy (PFS) is a strongly recommended feature in
security protocol design and can be accomplished by using an security protocol design and can be accomplished by using an
ephemeral Diffie-Hellman key exchange method. Ephemeral Elliptic ephemeral Diffie-Hellman key exchange method. Ephemeral Elliptic
Curve Diffie-Hellman (ECDHE) provides PFS with excellent performance Curve Diffie-Hellman (ECDHE) provides PFS with excellent performance
and small key sizes. ECDHE is mandatory to implement in both HTTP/2 and small key sizes. ECDHE is mandatory to implement in both HTTP/2
[RFC7540] and CoAP [RFC7252]. [RFC7540] and CoAP [RFC7252].
AEAD algorithms that combine encryption and integrity protection are AEAD algorithms that combine encryption and integrity protection are
strongly recommended [RFC7525] and non-AEAD algorithms will be strongly recommended [RFC7525] and non-AEAD algorithms are forbidden
forbidden to use in future versions of TLS. The AEAD algorithms 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- 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 GCM in TLS is defined in [RFC5288] and the use of AES-CCM is defined
in [RFC6655]. in [RFC6655].
[RFC4279] defines Pre-Shared Key (PSK) cipher suites for TLS but does [RFC4279] defines Pre-Shared Key (PSK) cipher suites for TLS but does
not consider Elliptic Curve Cryptography. [RFC4492] introduces not consider Elliptic Curve Cryptography. [RFC4492] introduces
Elliptic Curve Cryptography for TLS but does not consider PSK Elliptic Curve Cryptography for TLS but does not consider PSK
authentication. [RFC5487] describes the use of AES-GCM in authentication. [RFC5487] describes the use of AES-GCM in
combination with PSK authentication, but does not consider ECDHE. combination with PSK authentication, but does not consider ECDHE.
[RFC5489] describes the use of PSK in combination with ECDHE but does [RFC5489] describes the use of PSK in combination with ECDHE but does
skipping to change at page 3, line 32 skipping to change at page 3, line 37
TLS_ECDHE_PSK_WITH_AES_256_CCM_SHA384 = {TDB8,TDB9}; TLS_ECDHE_PSK_WITH_AES_256_CCM_SHA384 = {TDB8,TDB9};
For the AES-128 cipher suites, the TLS Pseudorandom Function (PRF) For the AES-128 cipher suites, the TLS Pseudorandom Function (PRF)
with SHA-256 as the hash function SHALL be used and Clients and with SHA-256 as the hash function SHALL be used and Clients and
Servers MUST NOT negotiate curves of less than 255 bits. Servers MUST NOT negotiate curves of less than 255 bits.
For the AES-256 cipher suites, the TLS PRF with SHA-384 as the hash For the AES-256 cipher suites, the TLS PRF with SHA-384 as the hash
function SHALL be used and Clients and Servers MUST NOT negotiate function SHALL be used and Clients and Servers MUST NOT negotiate
curves of less than 384 bits. curves of less than 384 bits.
When used in TLS 1.2, the keying material is derived as described in
[RFC5489] and [RFC5246] and nonces are constructed as described in
[RFC5288], and [RFC6655]. When used in TLS 1.3, the keying material
is derived as described in [I-D.ietf-tls-tls13], and the nonces are
constructed as described in [I-D.ietf-tls-tls13].
3. Applicable TLS Versions 3. Applicable TLS Versions
The cipher suites defined in this document make use of the The cipher suites defined in this document make use of the
authenticated encryption with additional data (AEAD) defined in TLS authenticated encryption with additional data (AEAD) defined in TLS
1.2 [RFC5246]. Earlier versions of TLS do not have support for AEAD 1.2 [RFC5246] and DTLS 1.2 [RFC6347]. Earlier versions of TLS do not
and consequently, these cipher suites MUST NOT be negotiated in TLS have support for AEAD and consequently, these cipher suites MUST NOT
versions prior to 1.2. Clients MUST NOT offer these cipher suites if be negotiated in TLS versions prior to 1.2. Clients MUST NOT offer
they do not offer TLS 1.2 or later. Servers, which select an earlier these cipher suites if they do not offer TLS 1.2 or later. Servers,
version of TLS MUST NOT select one of these cipher suites. A client which select an earlier version of TLS MUST NOT select one of these
MUST treat the selection of these cipher suites in combination with a cipher suites. A client MUST treat the selection of these cipher
version of TLS that does not support AEAD (i.e., TLS 1.1 or earlier) suites in combination with a version of TLS that does not support
as an error and generate a fatal 'illegal_parameter' TLS alert. AEAD (i.e., TLS 1.1 or earlier) as an error and generate a fatal
'illegal_parameter' TLS alert.
4. IANA Considerations 4. IANA Considerations
This document defines the following new cipher suites, whose values This document defines the following new cipher suites, whose values
have been assigned in the TLS Cipher Suite Registry defined by have been assigned in the TLS Cipher Suite Registry defined by
[RFC5246]. [RFC5246].
TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256 = {TDB0,TDB1}; TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256 = {TDB0,TDB1};
TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384 = {TDB2,TDB3}; TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384 = {TDB2,TDB3};
TLS_ECDHE_PSK_WITH_AES_128_CCM_8_SHA256 = {TDB4,TDB5}; TLS_ECDHE_PSK_WITH_AES_128_CCM_8_SHA256 = {TDB4,TDB5};
TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256 = {TDB6,TDB7}; TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256 = {TDB6,TDB7};
TLS_ECDHE_PSK_WITH_AES_256_CCM_SHA384 = {TDB8,TDB9}; TLS_ECDHE_PSK_WITH_AES_256_CCM_SHA384 = {TDB8,TDB9};
5. Security Considerations 5. Security Considerations
The security considerations in TLS 1.2 [RFC5246], ECDHE_PSK The security considerations in TLS 1.2 [RFC5246], DTLS 1.2 [RFC6347],
[RFC5489], AES_GCM [RFC5288], and AES_CCM [RFC6655] apply to this TLS 1.3 [I-D.ietf-tls-tls13], ECDHE_PSK [RFC5489], AES-GCM [RFC5288],
document as well. and AES-CCM [RFC6655] apply to this document as well.
All the cipher suites defined in this document provide All the cipher suites defined in this document provide
confidentiality, mutual authentication, and perfect forward secrecy. confidentiality, mutual authentication, and perfect forward secrecy.
The AES-128 cipher suites provide 128-bit security and the AES-256 The AES-128 cipher suites provide 128-bit security and the AES-256
cipher suites provide at least 192-bit security. However, cipher suites provide at least 192-bit security. However,
AES_128_CCM_8 only provides 64-bit security against message forgery AES_128_CCM_8 only provides 64-bit security against message forgery
and AES_256_GCM and AES_256_CCM only provide 128-bit security against and AES_256_GCM and AES_256_CCM only provide 128-bit security against
message forgery. message forgery.
Use of Pre-Shared Keys of limited entropy (for example, a PSK that is Use of Pre-Shared Keys of limited entropy (for example, a PSK that is
skipping to change at page 4, line 37 skipping to change at page 4, line 47
entropy than its length would imply) may allow an active attacker to entropy than its length would imply) may allow an active attacker to
perform a brute-force attack where the attacker attempts to connect perform a brute-force attack where the attacker attempts to connect
to the server and tries different keys. Passive eavesdropping alone to the server and tries different keys. Passive eavesdropping alone
is not sufficient. For these reasons the Pre-Shared Keys used for is not sufficient. For these reasons the Pre-Shared Keys used for
authentication MUST have a security level equal or higher than the 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 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. suites and at least 192-bit for the AES-256 cipher suites.
6. Acknowledgements 6. Acknowledgements
The authors would like to thank Ilari Liusvaara, Eric Rescorla, and The authors would like to thank Ilari Liusvaara, Eric Rescorla, Dan
Dan Harkins for their valuable comments and feedback. Harkins, and Russ Housley for their valuable comments and feedback.
7. References 7. References
7.1. Normative References 7.1. Normative References
[I-D.ietf-tls-tls13]
Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", draft-ietf-tls-tls13-10 (work in progress),
October 2015.
[RFC4279] Eronen, P., Ed. and H. Tschofenig, Ed., "Pre-Shared Key [RFC4279] Eronen, P., Ed. and H. Tschofenig, Ed., "Pre-Shared Key
Ciphersuites for Transport Layer Security (TLS)", Ciphersuites for Transport Layer Security (TLS)",
RFC 4279, DOI 10.17487/RFC4279, December 2005, RFC 4279, DOI 10.17487/RFC4279, December 2005,
<http://www.rfc-editor.org/info/rfc4279>. <http://www.rfc-editor.org/info/rfc4279>.
[RFC4492] Blake-Wilson, S., Bolyard, N., Gupta, V., Hawk, C., and B. [RFC4492] Blake-Wilson, S., Bolyard, N., Gupta, V., Hawk, C., and B.
Moeller, "Elliptic Curve Cryptography (ECC) Cipher Suites Moeller, "Elliptic Curve Cryptography (ECC) Cipher Suites
for Transport Layer Security (TLS)", RFC 4492, for Transport Layer Security (TLS)", RFC 4492,
DOI 10.17487/RFC4492, May 2006, DOI 10.17487/RFC4492, May 2006,
<http://www.rfc-editor.org/info/rfc4492>. <http://www.rfc-editor.org/info/rfc4492>.
skipping to change at page 5, line 30 skipping to change at page 5, line 44
[RFC5288] Salowey, J., Choudhury, A., and D. McGrew, "AES Galois [RFC5288] Salowey, J., Choudhury, A., and D. McGrew, "AES Galois
Counter Mode (GCM) Cipher Suites for TLS", RFC 5288, Counter Mode (GCM) Cipher Suites for TLS", RFC 5288,
DOI 10.17487/RFC5288, August 2008, DOI 10.17487/RFC5288, August 2008,
<http://www.rfc-editor.org/info/rfc5288>. <http://www.rfc-editor.org/info/rfc5288>.
[RFC5489] Badra, M. and I. Hajjeh, "ECDHE_PSK Cipher Suites for [RFC5489] Badra, M. and I. Hajjeh, "ECDHE_PSK Cipher Suites for
Transport Layer Security (TLS)", RFC 5489, Transport Layer Security (TLS)", RFC 5489,
DOI 10.17487/RFC5489, March 2009, DOI 10.17487/RFC5489, March 2009,
<http://www.rfc-editor.org/info/rfc5489>. <http://www.rfc-editor.org/info/rfc5489>.
[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 [RFC6655] McGrew, D. and D. Bailey, "AES-CCM Cipher Suites for
Transport Layer Security (TLS)", RFC 6655, Transport Layer Security (TLS)", RFC 6655,
DOI 10.17487/RFC6655, July 2012, DOI 10.17487/RFC6655, July 2012,
<http://www.rfc-editor.org/info/rfc6655>. <http://www.rfc-editor.org/info/rfc6655>.
7.2. Informative References 7.2. Informative References
[RFC5487] Badra, M., "Pre-Shared Key Cipher Suites for TLS with SHA- [RFC5487] Badra, M., "Pre-Shared Key Cipher Suites for TLS with SHA-
256/384 and AES Galois Counter Mode", RFC 5487, 256/384 and AES Galois Counter Mode", RFC 5487,
DOI 10.17487/RFC5487, March 2009, DOI 10.17487/RFC5487, March 2009,
skipping to change at page 6, line 17 skipping to change at page 6, line 35
DOI 10.17487/RFC7540, May 2015, DOI 10.17487/RFC7540, May 2015,
<http://www.rfc-editor.org/info/rfc7540>. <http://www.rfc-editor.org/info/rfc7540>.
Authors' Addresses Authors' Addresses
John Mattsson John Mattsson
Ericsson AB Ericsson AB
SE-164 80 Stockholm SE-164 80 Stockholm
Sweden Sweden
Phone: +46 76 115 35 01
Email: john.mattsson@ericsson.com Email: john.mattsson@ericsson.com
Daniel Migault Daniel Migault
Ericsson Ericsson
8400 boulevard Decarie 8400 boulevard Decarie
Montreal, QC H4P 2N2 Montreal, QC H4P 2N2
Canada Canada
Phone: +1 514-452-2160 Phone: +1 514-452-2160
Email: daniel.migault@ericsson.com Email: daniel.migault@ericsson.com
 End of changes. 15 change blocks. 
26 lines changed or deleted 47 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/