draft-ietf-emu-rfc5448bis-01.txt   draft-ietf-emu-rfc5448bis-02.txt 
Network Working Group J. Arkko Network Working Group J. Arkko
Internet-Draft V. Lehtovirta Internet-Draft V. Lehtovirta
Obsoletes: 5448 (if approved) V. Torvinen Obsoletes: 5448 (if approved) V. Torvinen
Updates: 4187 (if approved) Ericsson Updates: 4187 (if approved) Ericsson
Intended status: Informational P. Eronen Intended status: Informational P. Eronen
Expires: January 3, 2019 Nokia Expires: March 21, 2019 Nokia
July 2, 2018 September 17, 2018
Improved Extensible Authentication Protocol Method for 3rd Generation Improved Extensible Authentication Protocol Method for 3rd Generation
Authentication and Key Agreement (EAP-AKA') Authentication and Key Agreement (EAP-AKA')
draft-ietf-emu-rfc5448bis-01 draft-ietf-emu-rfc5448bis-02
Abstract Abstract
This specification defines a new EAP method, EAP-AKA', a small This specification defines a new EAP method, EAP-AKA', a small
revision of the EAP-AKA method. The change is a new key derivation revision of the EAP-AKA method. The change is a new key derivation
function that binds the keys derived within the method to the name of function that binds the keys derived within the method to the name of
the access network. The new key derivation mechanism has been the access network. The new key derivation mechanism has been
defined in the 3rd Generation Partnership Project (3GPP). This defined in the 3rd Generation Partnership Project (3GPP). This
specification allows its use in EAP in an interoperable manner. In specification allows its use in EAP in an interoperable manner. In
addition, EAP-AKA' employs SHA-256 instead of SHA-1. addition, EAP-AKA' employs SHA-256 instead of SHA-1.
This specification also updates RFC 4187 EAP-AKA to prevent bidding This specification also updates RFC 4187 EAP-AKA to prevent bidding
down attacks from EAP-AKA'. down attacks from EAP-AKA'.
This version of the EAP-AKA' specification updates a reference to This version of the EAP-AKA' specification provides updates to
constructing one field in the protocol, so that EAP-AKA' becomes specify the protocol behaviour for 5G deployments as well.
compatible with 5G deployments as well.
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.
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 3, 2019. This Internet-Draft will expire on March 21, 2019.
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
(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
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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 . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 5 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 5
3. EAP-AKA' . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. EAP-AKA' . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. AT_KDF_INPUT . . . . . . . . . . . . . . . . . . . . . . 7 3.1. AT_KDF_INPUT . . . . . . . . . . . . . . . . . . . . . . 8
3.2. AT_KDF . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.2. AT_KDF . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.3. Key Generation . . . . . . . . . . . . . . . . . . . . . 12 3.3. Key Generation . . . . . . . . . . . . . . . . . . . . . 13
3.4. Hash Functions . . . . . . . . . . . . . . . . . . . . . 14 3.4. Hash Functions . . . . . . . . . . . . . . . . . . . . . 15
3.4.1. PRF' . . . . . . . . . . . . . . . . . . . . . . . . 14 3.4.1. PRF' . . . . . . . . . . . . . . . . . . . . . . . . 15
3.4.2. AT_MAC . . . . . . . . . . . . . . . . . . . . . . . 14 3.4.2. AT_MAC . . . . . . . . . . . . . . . . . . . . . . . 15
3.4.3. AT_CHECKCODE . . . . . . . . . . . . . . . . . . . . 14 3.4.3. AT_CHECKCODE . . . . . . . . . . . . . . . . . . . . 15
4. Bidding Down Prevention for EAP-AKA . . . . . . . . . . . . . 15 4. Bidding Down Prevention for EAP-AKA . . . . . . . . . . . . . 16
5. Identifier Usage in 5G . . . . . . . . . . . . . . . . . . . 16 5. Peer Identities . . . . . . . . . . . . . . . . . . . . . . . 17
5.1. Key Derivation . . . . . . . . . . . . . . . . . . . . . 17 5.1. Username Types in EAP-AKA' Identities . . . . . . . . . . 18
5.2. EAP Identity Response and EAP-AKA' AT_IDENTITY Attribute 18 5.2. Generating Pseudonyms and Fast Re-Authentication
6. Exported Parameters . . . . . . . . . . . . . . . . . . . . . 19 Identities . . . . . . . . . . . . . . . . . . . . . . . 18
7. Security Considerations . . . . . . . . . . . . . . . . . . . 19 5.3. Identifier Usage in 5G . . . . . . . . . . . . . . . . . 19
7.1. Security Properties of Binding Network Names . . . . . . 22 5.3.1. Key Derivation . . . . . . . . . . . . . . . . . . . 20
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 5.3.2. EAP Identity Response and EAP-AKA' AT_IDENTITY
8.1. Type Value . . . . . . . . . . . . . . . . . . . . . . . 23 Attribute . . . . . . . . . . . . . . . . . . . . . . 21
8.2. Attribute Type Values . . . . . . . . . . . . . . . . . . 23 6. Exported Parameters . . . . . . . . . . . . . . . . . . . . . 23
8.3. Key Derivation Function Namespace . . . . . . . . . . . . 23 7. Security Considerations . . . . . . . . . . . . . . . . . . . 24
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24 7.1. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 26
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24 7.2. Discovered Vulnerabilities . . . . . . . . . . . . . . . 28
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 24 7.3. Pervasive Monitoring . . . . . . . . . . . . . . . . . . 30
11.1. Normative References . . . . . . . . . . . . . . . . . . 24 7.4. Security Properties of Binding Network Names . . . . . . 31
11.2. Informative References . . . . . . . . . . . . . . . . . 26 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
Appendix A. Changes from RFC 5448 . . . . . . . . . . . . . . . 27 8.1. Type Value . . . . . . . . . . . . . . . . . . . . . . . 32
Appendix B. Changes from RFC 4187 to RFC 5448 . . . . . . . . . 27 8.2. Attribute Type Values . . . . . . . . . . . . . . . . . . 32
Appendix C. Changes from Previous Version of This Draft . . . . 28 8.3. Key Derivation Function Namespace . . . . . . . . . . . . 32
Appendix D. Importance of Explicit Negotiation . . . . . . . . . 28 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 33
Appendix E. Test Vectors . . . . . . . . . . . . . . . . . . . . 29 9.1. Normative References . . . . . . . . . . . . . . . . . . 33
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 33 9.2. Informative References . . . . . . . . . . . . . . . . . 34
Appendix A. Changes from RFC 5448 . . . . . . . . . . . . . . . 37
Appendix B. Changes from RFC 4187 to RFC 5448 . . . . . . . . . 38
Appendix C. Changes from Previous Version of This Draft . . . . 38
Appendix D. Importance of Explicit Negotiation . . . . . . . . . 38
Appendix E. Test Vectors . . . . . . . . . . . . . . . . . . . . 39
Appendix F. Contributors . . . . . . . . . . . . . . . . . . . . 43
Appendix G. Acknowledgments . . . . . . . . . . . . . . . . . . 44
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 44
1. Introduction 1. Introduction
This specification defines a new Extensible Authentication Protocol This specification defines a new Extensible Authentication Protocol
(EAP)[RFC3748] method, EAP-AKA', a small revision of the EAP-AKA (EAP)[RFC3748] method, EAP-AKA', a small revision of the EAP-AKA
method originally defined in [RFC4187]. What is new in EAP-AKA' is method originally defined in [RFC4187]. What is new in EAP-AKA' is
that it has a new key derivation function, specified in that it has a new key derivation function, specified in
[TS-3GPP.33.402]. This function binds the keys derived within the [TS-3GPP.33.402]. This function binds the keys derived within the
method to the name of the access network. This limits the effects of method to the name of the access network. This limits the effects of
compromised access network nodes and keys. This specification compromised access network nodes and keys. This specification
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function to SHA-256 [FIPS.180-4]. But it is otherwise equivalent to function to SHA-256 [FIPS.180-4]. But it is otherwise equivalent to
RFC 4187. Given that a different EAP method type value is used for RFC 4187. Given that a different EAP method type value is used for
EAP-AKA and EAP-AKA', a mutually supported method may be negotiated EAP-AKA and EAP-AKA', a mutually supported method may be negotiated
using the standard mechanisms in EAP [RFC3748]. using the standard mechanisms in EAP [RFC3748].
Note: Appendix D explains why it is important to be explicit about Note: Appendix D explains why it is important to be explicit about
the change of semantics for the keys, and why other approaches the change of semantics for the keys, and why other approaches
would lead to severe interoperability problems. would lead to severe interoperability problems.
This version of the EAP-AKA' specification obsoletes RFC 5448. The This version of the EAP-AKA' specification obsoletes RFC 5448. The
changes consist of three things: changes are as follows:
o Update the reference on how the Network Name field is constructed o Update the reference on how the Network Name field is constructed
in the protocol. The update helps ensure that EAP-AKA' becomes in the protocol. The update ensures that EAP-AKA' is compatible
compatible with 5G deployments as well. RFC 5448 referred to the with 5G deployments. RFC 5448 referred to the Release 8 version
Release 8 version of [TS-3GPP.24.302] and this update points to of [TS-3GPP.24.302] and this update points to the first 5G
the first 5G version, Release 15. version, Release 15.
o Specify how EAP and EAP-AKA' use identifiers in 5G, as additional o Specify how EAP and EAP-AKA' use identifiers in 5G. Additional
identifiers are introduced, and for interoperability, it is identifiers are introduced in 5G, and for interoperability, it is
important that implementations use the right ones. necessary that the right identifiers are used as inputs in the key
generation. In addition, for identity privacy it is important
that when privacy-friendly identifiers in 5G are used, no
trackable, permanent identifiers are passed in EAP-AKA' either.
o Specify session identifiers and other exported parameters, as o Specify session identifiers and other exported parameters, as
those were not specified in [RFC5448] despite requirements set those were not specified in [RFC5448] despite requirements set
forward in [RFC5247] to do so. Also, while [RFC5247] specified forward in [RFC5247] to do so. Also, while [RFC5247] specified
session identifiers for EAP-AKA, it only did so for the full session identifiers for EAP-AKA, it only did so for the full
authentication case, not for the case of fast re-authentication. authentication case, not for the case of fast re-authentication.
Arguably, the updates are small. For the first update, the 3GPP o Update the requirements on generating pseudonym usernames and fast
specification number for the updated calculation has not changed, re-authentication identities to ensure identity privacy.
o Describe what has been learned about any vulnerabilities in AKA or
EAP-AKA'.
o Describe the privacy and pervasive monitoring considerations
related to EAP-AKA'.
Some of the updates are small. For instance, for the first update,
the reference update does not change the 3GPP specification number,
only the version. But this reference is crucial in correct only the version. But this reference is crucial in correct
calculation of the keys resulting from running the EAP-AKA' method, calculation of the keys resulting from running the EAP-AKA' method,
so an update of the RFC with the newest version pointer may be so an update of the RFC with the newest version pointer may be
warranted. As always, feedback is welcome on that point as well as warranted.
on any other topic within this document.
Note: It is an open issue whether this update should refer to only
the 5G version of the definition, or be explicit that any further
update of that specification is something that EAP-AKA'
implementations should take into account. Note that one should
keep in mind that specification being automatically updated is
different from implementations taking notice of new things.
The second update is needed to ensure that implementations use the
correct identifiers in the context of 5G, as it introduces additional
privacy-protected identifiers, and it is no longer clear which
identifiers are used in EAP-AKA'.
The third update is necessary in order to fix a problem in previous Note: This specification refers only to the 5G specifications.
RFCs. Any further update that affects, for instance, key generation is
something that EAP-AKA' implementations should take into account.
Upon such updates there will be a need to both update the
specification and the implementations.
It is an explicit non-goal of this draft to include any other It is an explicit non-goal of this draft to include any other
technical modifications, addition of new features or other changes. technical modifications, addition of new features or other changes.
The EAP-AKA' base protocol is stable and needs to stay that way. If The EAP-AKA' base protocol is stable and needs to stay that way. If
there are any extensions or variants, those need to be proposed as there are any extensions or variants, those need to be proposed as
standalone extensions or even as different authentication methods. standalone extensions or even as different authentication methods.
The rest of this specification is structured as follows. Section 3 The rest of this specification is structured as follows. Section 3
defines the EAP-AKA' method. Section 4 adds support to EAP-AKA to defines the EAP-AKA' method. Section 4 adds support to EAP-AKA to
prevent bidding down attacks from EAP-AKA'. Section 7 explains the prevent bidding down attacks from EAP-AKA'. Section 5 specifies
security differences between EAP-AKA and EAP-AKA'. Section 8 requirements regarding the use of peer identities, including how how
describes the IANA considerations and Appendix A and Appendix B EAP-AKA' identifiers are used in 5G context. Section 6 specifies
explains what updates to RFC 5448 AKA' and RFC 4187 EAP-AKA have been what parameters EAP-AKA' exports out of the method. Section 7
made in this specification. Appendix D explains some of the design explains the security differences between EAP-AKA and EAP-AKA'.
rationale for creating EAP-AKA' Finally, Appendix E provides test Section 8 describes the IANA considerations and Appendix A and
vectors. Appendix B explains what updates to RFC 5448 EAP-AKA' and RFC 4187
EAP-AKA have been made in this specification. Appendix D explains
some of the design rationale for creating EAP-AKA' Finally,
Appendix E provides test vectors.
Editor's Note: The publication of this RFC depends on its Editor's Note: The publication of this RFC depends on its
normative references [TS-3GPP.24.302] and [TS-3GPP.33.501] normative references [TS-3GPP.24.302] and [TS-3GPP.33.501]
reaching a stable status for Release 15, as indicated by 3GPP. reaching a stable status for Release 15, as indicated by 3GPP.
This is expected to happen shortly. The RFC Editor should check This is expected to happen shortly. The RFC Editor should check
with the 3GPP liaisons that this has happened. RFC Editor: Please with the 3GPP liaisons that this has happened. RFC Editor: Please
delete this note upon publication of this specification as an RFC. delete this note upon publication of this specification as an RFC.
2. Requirements Language 2. Requirements Language
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| the network name from AT_KDF_INPUT attribute is | | | the network name from AT_KDF_INPUT attribute is | |
| used in running the AKA' algorithms, verifying AUTN | | | used in running the AKA' algorithms, verifying AUTN | |
| from AT_AUTN and MAC from AT_MAC attributes. The | | | from AT_AUTN and MAC from AT_MAC attributes. The | |
| peer then generates RES. The peer also derives | | | peer then generates RES. The peer also derives | |
| session keys from CK'/IK'. The AT_RES and AT_MAC | | | session keys from CK'/IK'. The AT_RES and AT_MAC | |
| attributes are constructed. | | | attributes are constructed. | |
+------------------------------------------------------+ | +------------------------------------------------------+ |
| EAP-Response/AKA'-Challenge | | EAP-Response/AKA'-Challenge |
| (AT_RES, AT_MAC) | | (AT_RES, AT_MAC) |
|------------------------------------------------------->| |------------------------------------------------------->|
| +-------------------------------------------------+ | +--------------------------------------------------+
| | Server checks the RES and MAC values received | | | Server checks the RES and MAC values received |
| | in AT_RES and AT_MAC, respectively. Success | | | in AT_RES and AT_MAC, respectively. Success |
| | requires both to be found correct. | | | requires both to be found correct. |
| +-------------------------------------------------+ | +--------------------------------------------------+
| EAP-Success | | EAP-Success |
|<-------------------------------------------------------| |<-------------------------------------------------------|
Figure 1: EAP-AKA' Authentication Process Figure 1: EAP-AKA' Authentication Process
EAP-AKA' can operate on the same credentials as EAP-AKA and employ EAP-AKA' can operate on the same credentials as EAP-AKA and employ
the same identities. However, EAP-AKA' employs different leading the same identities. However, EAP-AKA' employs different leading
characters than EAP-AKA for the conventions given in Section 4.1.1 of characters than EAP-AKA for the conventions given in Section 4.1.1 of
[RFC4187] for International Mobile Subscriber Identifier (IMSI) based [RFC4187] for International Mobile Subscriber Identifier (IMSI) based
usernames. EAP-AKA' MUST use the leading character "6" (ASCII 36 usernames. EAP-AKA' MUST use the leading character "6" (ASCII 36
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the peer over EAP-AKA'. The value of the AT_KDF_INPUT attribute from the peer over EAP-AKA'. The value of the AT_KDF_INPUT attribute from
the server MUST be non-empty. If it is empty, the peer behaves as if the server MUST be non-empty. If it is empty, the peer behaves as if
AUTN had been incorrect and authentication fails. See Section 3 and AUTN had been incorrect and authentication fails. See Section 3 and
Figure 3 of [RFC4187] for an overview of how authentication failures Figure 3 of [RFC4187] for an overview of how authentication failures
are handled. are handled.
Note: Currently, [TS-3GPP.24.302] or [TS-3GPP.33.501] specify Note: Currently, [TS-3GPP.24.302] or [TS-3GPP.33.501] specify
separate values. The former specifies what is called "Access separate values. The former specifies what is called "Access
Network ID" and the latter specifies what is called "Serving Network ID" and the latter specifies what is called "Serving
Network Name". However, from an EAP-AKA' perspective both occupy Network Name". However, from an EAP-AKA' perspective both occupy
the same field, and need to be distinghuishable from each other. the same field, and need to be distinguishable from each other.
Currently specified values are distinguishable, but it would be Currently specified values are distinguishable, but it would be
useful that this be specified explicitly in the 3GPP useful that this be specified explicitly in the 3GPP
specifications. specifications.
In addition, the peer MAY check the received value against its own In addition, the peer MAY check the received value against its own
understanding of the network name. Upon detecting a discrepancy, the understanding of the network name. Upon detecting a discrepancy, the
peer either warns the user and continues, or fails the authentication peer either warns the user and continues, or fails the authentication
process. More specifically, the peer SHOULD have a configurable process. More specifically, the peer SHOULD have a configurable
policy that it can follow under these circumstances. If the policy policy that it can follow under these circumstances. If the policy
indicates that it can continue, the peer SHOULD log a warning message indicates that it can continue, the peer SHOULD log a warning message
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authentication (see Figure 3 of [RFC4187]). A peer not supporting authentication (see Figure 3 of [RFC4187]). A peer not supporting
EAP-AKA' will simply ignore this attribute. In all cases, the EAP-AKA' will simply ignore this attribute. In all cases, the
attribute is protected by the integrity mechanisms of EAP-AKA, so it attribute is protected by the integrity mechanisms of EAP-AKA, so it
cannot be removed by a man-in-the-middle attacker. cannot be removed by a man-in-the-middle attacker.
Note that we assume (Section 7) that EAP-AKA' is always stronger than Note that we assume (Section 7) that EAP-AKA' is always stronger than
EAP-AKA. As a result, there is no need to prevent bidding "down" EAP-AKA. As a result, there is no need to prevent bidding "down"
attacks in the other direction, i.e., attackers forcing the endpoints attacks in the other direction, i.e., attackers forcing the endpoints
to use EAP-AKA'. to use EAP-AKA'.
5. Identifier Usage in 5G 5. Peer Identities
EAP-AKA' peer identities are as specified in [RFC4187] Section 4.1,
with the addition of some requirements specified in this section.
EAP-AKA' includes optional identity privacy support that can be used
to hide the cleartext permanent identity and thereby make the
subscriber's EAP exchanges untraceable to eavesdroppers. EAP-AKA'
can also use the privacy friendly identifiers specified for 5G
networks.
The permanent identity is usually based on the IMSI, which may
further help the tracking, because the same identifier may be used in
other contexts as well. Identity privacy is based on temporary
usernames, or pseudonym usernames. These are similar to but separate
from the Temporary Mobile Subscriber Identities (TMSI) that are used
on cellular networks.
5.1. Username Types in EAP-AKA' Identities
Section 4.1.1.3 of [RFC4187] specified that there are three types of
usernames: permanent, pseudonym, and fast re-authentication
usernames. This specification extends this definition as follows.
There are four types of usernames:
(1) Regular usernames. These are external names given to EAP-
AKA'. The regular usernames are further subdivided into to
categories:
(a) Permanent usernames, for instance IMSI-based usernames.
(b) Privacy-friendly temporary usernames, for instance 5G
privacy identifiers (see Section 5.3.2 and Section 5.3.2.1.
(2) EAP-AKA' pseudonym usernames. For example,
2s7ah6n9q@example.com might be a valid pseudonym identity. In
this example, 2s7ah6n9q is the pseudonym username.
(3) EAP-AKA' fast re-authentication usernames. For example,
43953754@example.com might be a valid fast re-authentication
identity and 43953754 the fast re-authentication username.
The permanent, privacy-friendly temporary, and pseudonym usernames
are only used on full authentication, and fast re-authentication
usernames only on fast re-authentication. Unlike permanent usernames
and pseudonym usernames, privacy friendly temporary usernames and
fast re-authentication usernames are one-time identifiers, which are
not re-used across EAP exchanges.
5.2. Generating Pseudonyms and Fast Re-Authentication Identities
As specified by [RFC4187] Section 4.1.1.7, pseudonym usernames and
fast re-authentication identities are generated by the EAP server, in
an implementation-dependent manner. RFC 4187 provides some general
requirements on how these identities are transported, how they map to
the NAI syntax, how they are distinguished from each other, and so
on.
However, to ensure privacy some additional requirements need to be
applied.
The pseudonym usernames and fast re-authentication identities MUST be
generated in a cryptographically secure way so that that it is
computationally infeasible for at attacker to differentiate two
identities belonging to the same user from two identities belonging
to different users. This can be achieved, for instance, by using
random or pseudo-random identifiers such as random byte strings or
ciphertexts.
Note that the pseudonym and fast re-authentication usernames also
MUST NOT include substrings that can be used to relate the username
to a particular entity or a particular permanent identity. For
instance, the usernames can not include any subscriber-identifying
part of an IMSI or other permanent identifier. Similarly, no part of
the username can be formed by a fixed mapping that stays the same
across multiple different pseudonyms or fast re-authentication
identities for the same subscriber.
When the identifier used to identify a subscriber in an EAP-AKA'
authentication exchange is a privacy-friendly identifier that is used
only once, the EAP-AKA' peer MUST NOT use a pseudonym provided in
that authentication exchange in subsequent exchanges more than once.
To ensure that this does not happen, EAP-AKA' server MAY decline to
provide a pseudonym in such authentication exchanges. An important
case where such privacy-friendly identifiers are used is in 5G
networks (see Section 5.3)
5.3. Identifier Usage in 5G
In EAP-AKA', the peer identity may be communicated to the server in In EAP-AKA', the peer identity may be communicated to the server in
one of three ways: one of three ways:
o As a part of link layer establishment procedures, externally to o As a part of link layer establishment procedures, externally to
EAP. EAP.
o With the EAP-Response/Identity message in the beginning of the EAP o With the EAP-Response/Identity message in the beginning of the EAP
exchange, but before the selection of EAP-AKA'. exchange, but before the selection of EAP-AKA'.
o Transmitted from the peer to the server using EAP-AKA messages o Transmitted from the peer to the server using EAP-AKA messages
instead of EAP-Response/Identity. In this case, the server instead of EAP-Response/Identity. In this case, the server
includes an identity requesting attribute (AT_ANY_ID_REQ, includes an identity requesting attribute (AT_ANY_ID_REQ,
AT_FULLAUTH_ID_REQ or AT_PERMANENT_ID_REQ) in the EAP-Request/AKA- AT_FULLAUTH_ID_REQ or AT_PERMANENT_ID_REQ) in the EAP-Request/AKA-
Identity message; and the peer includes the AT_IDENTITY attribute, Identity message; and the peer includes the AT_IDENTITY attribute,
which contains the peer's identity, in the EAP-Response/AKA- which contains the peer's identity, in the EAP-Response/AKA-
Identity message. Identity message.
The identity carried above may be a permanent identity or a pseudonym The identity carried above may be a permanent identity, privacy
identity or fast re-authentication identity as defined in this RFC. friendly identity, pseudonym identity, or fast re-authentication
identity as defined in this RFC.
In networks where EAP is the only part handling such pseudonym or 5G supports the concept of privacy identifiers, and it is important
fast re-authentication identities, this usage is clear. However, 5G for interoperability that the right type of identifier is used.
supports the concept of pseudonym or privacy identifiers, and it is
important for interoperability that the right type of identifiers are
used in the right place.
5G defines the SUbscription Permanent Identifier (SUPI) and 5G defines the SUbscription Permanent Identifier (SUPI) and
SUbscription Concealed Identifier (SUCI) [TS-3GPP.23.501] SUbscription Concealed Identifier (SUCI) [TS-3GPP.23.501]
[TS-3GPP.33.501]. SUPI is globally unique and allocated to each [TS-3GPP.33.501] [TS-3GPP.23.003]. SUPI is globally unique and
subscriber. However, it is only used internally in the 5G network, allocated to each subscriber. However, it is only used internally in
and is privacy sensitive. The SUCI is a privacy preserving the 5G network, and is privacy sensitive. The SUCI is a privacy
identifier containing the concealed SUPI, using public key preserving identifier containing the concealed SUPI, using public key
cryptography to encrypt the SUPI. cryptography to encrypt the SUPI.
Given the choice between these two types of identifiers, two areas Given the choice between these two types of identifiers, two areas
need further specification in EAP-AKA' to ensure that different need further specification in EAP-AKA' to ensure that different
implementations understand each other and stay interoperable: implementations understand each other and stay interoperable:
o Where identifiers are used within EAP-AKA' -- such as key o Where identifiers are used within EAP-AKA' -- such as key
derivation -- specify what values exactly should be used, to avoid derivation -- specify what values exactly should be used, to avoid
ambiguity. ambiguity.
skipping to change at page 17, line 45 skipping to change at page 20, line 34
In 5G, the normal mode of operation is that identifiers are only In 5G, the normal mode of operation is that identifiers are only
transmitted outside EAP. However, in a system involving terminals transmitted outside EAP. However, in a system involving terminals
from many generations and several connectivity options via 5G and from many generations and several connectivity options via 5G and
other mechanisms, implementations and the EAP-AKA' specification need other mechanisms, implementations and the EAP-AKA' specification need
to prepare for many different situations, including sometimes having to prepare for many different situations, including sometimes having
to communicate identities within EAP. to communicate identities within EAP.
The following sections clarify which identifiers are used and how. The following sections clarify which identifiers are used and how.
5.1. Key Derivation 5.3.1. Key Derivation
In EAP-AKA', the peer identity is used in the Section 3.3 key In EAP-AKA', the peer identity is used in the Section 3.3 key
derivation formula. derivation formula.
If the AT_KDF_INPUT parameter contains the prefix "5G:", the AT_KDF If the AT_KDF_INPUT parameter contains the prefix "5G:", the AT_KDF
parameter has the value 1, and this authentication is not a fast re- parameter has the value 1, and this authentication is not a fast re-
authentication, then the peer identity used in the key derivation authentication, then the peer identity used in the key derivation
MUST be the 5G SUPI for the peer. This rule applies to all full EAP- MUST be the 5G SUPI for the peer. This rule applies to all full EAP-
AKA' authentication processes, even if the peer sent some other AKA' authentication processes, even if the peer sent some other
identifier at a lower layer or as a response to an EAP Identity identifier at a lower layer or as a response to an EAP Identity
Request or if no identity was sent. Request or if no identity was sent.
The identity MUST also be represented in the exact correct format for
the key derivation formula to produce correct results. For the SUPI,
this format is as defined Section 5.3.1.1.
In all other cases, the following applies: In all other cases, the following applies:
The identity used in the key derivation formula MUST be exactly The identity used in the key derivation formula MUST be exactly
the one sent in EAP-AKA' AT_IDENTITY attribute, if one was sent, the one sent in EAP-AKA' AT_IDENTITY attribute, if one was sent,
regardless of the kind of identity that it may have been. If no regardless of the kind of identity that it may have been. If no
AT_IDENTITY was sent, the identity MUST be the exactly the one AT_IDENTITY was sent, the identity MUST be the exactly the one
sent in the generic EAP Identity exchange, if one was made. sent in the generic EAP Identity exchange, if one was made.
Again, the identity MUST be used exactly as sent. Again, the identity MUST be used exactly as sent.
If no identity was communicated inside EAP, then the identity is If no identity was communicated inside EAP, then the identity is
the one communicated outside EAP in link layer messaging. the one communicated outside EAP in link layer messaging.
In this case, the used identity MUST be the identity most recently In this case, the used identity MUST be the identity most recently
communicated by the peer to the network, again regardless of what communicated by the peer to the network, again regardless of what
type of identity it may have been. type of identity it may have been.
5.2. EAP Identity Response and EAP-AKA' AT_IDENTITY Attribute 5.3.1.1. Format of the SUPI
A SUPI is either an IMSI or a Network Access Identifier [RFC4282].
The NAI string MUST be directly used in key derivation, and for IMSI,
the following string MUST be used:
o Three ASCII digits to represent the Mobile Country Code (MCC).
o Three ASCII digits to represent the Mobile Network Code (MNC). If
there are only 2 significant digits in the MNC, one "0" digit
shall be inserted at the left side to fill the 3 digits coding of
MNC.
o ASCII digits to represent the rest of the IMSI.
The component values are specified in more detail in
[TS-3GPP.23.003]. Note that no prefix ("0" or "6") in front of the
entire IMSI is used in the IMSI when used in the key derivation
function in 5G.
5.3.2. EAP Identity Response and EAP-AKA' AT_IDENTITY Attribute
The EAP authentication option is only available in 5G when the new 5G The EAP authentication option is only available in 5G when the new 5G
core network is also in use. However, in other networks an EAP-AKA' core network is also in use. However, in other networks an EAP-AKA'
peer may be connecting to other types of networks and existing peer may be connecting to other types of networks and existing
equipment. equipment.
When the EAP peer is connecting to a 5G access network and uses the When the EAP peer is connecting to a 5G access network and uses the
5G core network signalling mechanisms, it can assume that the EAP 5G Non-Access Stratum (NAS) protocol [TS-3GPP.24.501], the EAP server
server is in a 5G network. The EAP level identity exchanges are not is in a 5G network. The EAP identity exchanges are generally not
generally used in this case, but if there is, the EAP peer SHOULD used in this case, as the identity is already made available on
employ only the privacy preserving SUCI identifier within EAP (either previous link layer exchanges.
in EAP Identity Response or EAP-AKA' AT_IDENTITY attribute).
Similarly, if the peer is explicitly communicating through mechanisms In this situation, the EAP server SHOULD NOT request an additional
developed for 5G to connect to 5G networks over WLAN, it MUST assume identity from the peer. If the peer for some reason receives EAP-
that the EAP server is in a 5G network, and again employ the SUCI Request/Identity or EAP-Request/AKA-Identity messages, the peer
within EAP. should behave as follows.
Receive EAP-Request/Identity
In this case, the peer SHOULD respond with a EAP-Response/Identity
containing the privacy-friendly 5G identifier, the SUCI. The SUCI
SHOULD be represented as specified in Section 5.3.2.1.
EAP-Request/AKA-Identity with AT_PERMANENT_REQ
For privacy reasons, the peer should follow a "conservative"
policy and terminate the authentication exchange rather than risk
revaling its permanent identity.
The peer SHOULD respond with EAP-Response/AKA-Client-Error with
the client error code 0, "unable to process packet".
EAP-Request/AKA-Identity with AT_FULLAUTH_REQ
In this case, the peer SHOULD respond with a EAP-Response/AKA-
Identity containing the SUCI. The SUCI SHOULD be represented as
specified in Section 5.3.2.1.
EAP-Request/AKA-Identity with AT_ANY_ID_REQ
If the peer supports fast re-authentication and has a fast re-
authentication identity available, the peer SHOULD respond with
EAP-Response/AKA-Identity containing the fast re-authentication
identity. Otherwise the peer SHOULD respond with a EAP-Response/
AKA-Identity containing the SUCI, and SHOULD represent the SUCI as
specified in Section 5.3.2.1.
Similarly, if the peer is communicating over a non-3GPP network but
carrying EAP inside 5G NAS protocol, it MUST assume that the EAP
server is in a 5G network, and again employ the SUCI within EAP.
Otherwise, the peer SHOULD employ IMSI, SUPI, or a NAI as it is Otherwise, the peer SHOULD employ IMSI, SUPI, or a NAI as it is
configured to use. configured to use.
5.3.2.1. Format of the SUCI
The SUCI format extends the format specified in [RFC4187]
Section 4.1.1.6 for IMSIs.
A SUCI SHOULD be represented by an ASCII string containing the
following components in sequence:
o A leading "6"
o Three ASCII digits to represent the Mobile Country Code (MCC).
o Three ASCII digits to represent the Mobile Network Code (MNC). If
there are only 2 significant digits in the MNC, one "0" digit
shall be inserted at the left side to fill the 3 digits coding of
MNC.
o Four ASCII digits to represent a routing indicator.
o One hex character ("0" through "9" and "a" through "f") to
represent the protection profile.
o Hex characters representing Home Network Public Key Identifier
(HNPKI). The number of hex characters needed for this depends on
the protection profile.
o Hex characters representing the encrypted identity. The number of
hex characters depends on the protection profile and identity
being encrypted.
The component values are specified in more detail in
[TS-3GPP.23.003].
6. Exported Parameters 6. Exported Parameters
The EAP-AKA' Session-Id is the concatenation of the EAP Type Code The EAP-AKA' Session-Id is the concatenation of the EAP Type Code
(50, one octet) with the contents of the RAND field from the AT_RAND (50, one octet) with the contents of the RAND field from the AT_RAND
attribute, followed by the contents of the AUTN field in the AT_AUTN attribute, followed by the contents of the AUTN field in the AT_AUTN
attribute: attribute:
Session-Id = 50 || RAND || AUTN Session-Id = 50 || RAND || AUTN
When using fast re-authentication, the EAP-AKA' Session-Id is the When using fast re-authentication, the EAP-AKA' Session-Id is the
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NONCE_S field from the AT_NONCE_S attribute, followed by the contents NONCE_S field from the AT_NONCE_S attribute, followed by the contents
of the MAC field from the AT_MAC attribute from EAP-Request/AKA- of the MAC field from the AT_MAC attribute from EAP-Request/AKA-
Reauthentication: Reauthentication:
Session-Id = 50 || NONCE_S || MAC Session-Id = 50 || NONCE_S || MAC
The Peer-Id is the contents of the Identity field from the The Peer-Id is the contents of the Identity field from the
AT_IDENTITY attribute, using only the Actual Identity Length octets AT_IDENTITY attribute, using only the Actual Identity Length octets
from the beginning. Note that the contents are used as they are from the beginning. Note that the contents are used as they are
transmitted, regardless of whether the transmitted identity was a transmitted, regardless of whether the transmitted identity was a
permanent, pseudonym, or fast EAP re-authentication identity. The permanent, pseudonym, or fast EAP re-authentication identity. If no
Server-Id is the null string (zero length). AT_IDENTITY attribute was exchanged, the exported Peer-Id is the
identity provided from the EAP Identity Response packet. If no EAP
Identity Response was provided either, the exported Peer-Id is null
string (zero length).
The Server-Id is the null string (zero length).
7. Security Considerations 7. Security Considerations
A summary of the security properties of EAP-AKA' follows. These A summary of the security properties of EAP-AKA' follows. These
properties are very similar to those in EAP-AKA. We assume that properties are very similar to those in EAP-AKA. We assume that
SHA-256 is at least as secure as SHA-1. This is called the SHA-256 SHA-256 is at least as secure as SHA-1. This is called the SHA-256
assumption in the remainder of this section. Under this assumption, assumption in the remainder of this section. Under this assumption,
EAP-AKA' is at least as secure as EAP-AKA. EAP-AKA' is at least as secure as EAP-AKA.
If the AT_KDF attribute has value 1, then the security properties of If the AT_KDF attribute has value 1, then the security properties of
skipping to change at page 20, line 49 skipping to change at page 25, line 35
K_aut, K_re), the MSK, and the EMSK are cryptographically K_aut, K_re), the MSK, and the EMSK are cryptographically
separate. If we make the assumption that SHA-256 behaves as a separate. If we make the assumption that SHA-256 behaves as a
pseudo-random function, an attacker is incapable of deriving any pseudo-random function, an attacker is incapable of deriving any
non-trivial information about any of these keys based on the other non-trivial information about any of these keys based on the other
keys. An attacker also cannot calculate the pre-shared secret keys. An attacker also cannot calculate the pre-shared secret
from IK, CK, IK', CK', K_encr, K_aut, K_re, MSK, or EMSK by any from IK, CK, IK', CK', K_encr, K_aut, K_re, MSK, or EMSK by any
practically feasible means. practically feasible means.
EAP-AKA' adds an additional layer of key derivation functions EAP-AKA' adds an additional layer of key derivation functions
within itself to protect against the use of compromised keys. within itself to protect against the use of compromised keys.
This is discussed further in Section 7.1. This is discussed further in Section 7.4.
EAP-AKA' uses a pseudo-random function modeled after the one used EAP-AKA' uses a pseudo-random function modeled after the one used
in IKEv2 [RFC4306] together with SHA-256. in IKEv2 [RFC4306] together with SHA-256.
Key strength Key strength
See above. See above.
Dictionary attack resistance Dictionary attack resistance
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EAP-AKA', like EAP-AKA, does not provide channel bindings as EAP-AKA', like EAP-AKA, does not provide channel bindings as
they're defined in [RFC3748] and [RFC5247]. New skippable they're defined in [RFC3748] and [RFC5247]. New skippable
attributes can be used to add channel binding support in the attributes can be used to add channel binding support in the
future, if required. future, if required.
However, including the Network Name field in the AKA' algorithms However, including the Network Name field in the AKA' algorithms
(which are also used for other purposes than EAP-AKA') provides a (which are also used for other purposes than EAP-AKA') provides a
form of cryptographic separation between different network names, form of cryptographic separation between different network names,
which resembles channel bindings. However, the network name does which resembles channel bindings. However, the network name does
not typically identify the EAP (pass-through) authenticator. See not typically identify the EAP (pass-through) authenticator. See
the following section for more discussion. Section 7.4 for more discussion.
7.1. Security Properties of Binding Network Names 7.1. Privacy
[RFC6973] suggests that the privacy considerations of IETF protocols
be documented.
The confidentiality properties of EAP-AKA' itself have been discussed
above under "Confidentiality".
EAP-AKA' uses several different types of identifiers to identify the
authenticating peer. It is strongly RECOMMENDED to use the privacy-
friendly temporary or hidden identifiers, i.e., the 5G SUCI,
pseudonym usernames, and fast re-authentication usernames. The use
of permanent identifiers such as the IMSI or SUPI may lead to an
ability to track the peer and/or user associated with the peer. The
use of permanent identifiers such as the IMSI or SUPI is strongly NOT
RECOMMENDED.
As discussed in Section 5.3, when authenticating to a 5G network,
only the 5G SUCI identifier should be used. The use of pseudonyms in
this situation is at best limited. In fact, the re-use of the same
pseudonym multiple times will result in a tracking opportunity for
observers that see the pseudonym pass by. To avoid this, the peer
and server need to follow the guidelines given in Section 5.2.
When authenticating to a 5G network, per Section 5.3.1, both the EAP-
AKA' peer and server need employ permanent identifier, SUPI, as an
input to key generation. However, this use of the SUPI is only
internal and the SUPI need not be communicated in EAP messages. SUCI
MUST NOT be communicated in EAP-AKA' when authenticating to a 5G
network.
While the use of SUCI in 5G networks generally provides identity
privacy, this is not true if the null-scheme encryption is used to
construct the SUCI (see [TS-3GPP.23.501] Annex C). The use of this
scheme turns the use of SUCI equivalent to the use of SUPI or IMSI.
The use of the null scheme is NOT RECOMMENDED where identity privacy
is important.
The use of fast re-authentication identities when authenticating to a
5G network does not have the same problems as the use of pseudonyms,
as long as the 5G authentication server generates the fast re-
authentication identifiers in a proper manner specified in
Section 5.2.
Outside 5G, there is a full choice to use permanent, pseudonym, or
fast re-authentication identifiers:
o A peer that has not yet performed any EAP-AKA' exchanges does not
typically have a pseudonym available. If the peer does not have a
pseudonym available, then the privacy mechanism cannot be used,
and the permanent identity will have to be sent in the clear.
The terminal SHOULD store the pseudonym in non-volatile memory so
that it can be maintained across reboots. An active attacker that
impersonates the network may use the AT_PERMANENT_ID_REQ attribute
([RFC4187] Section 4.1.2) to learn the subscriber's IMSI.
However, as discussed in [RFC4187] Section 4.1.2, the terminal can
refuse to send the cleartext permanent identity if it believes
that the network should be able to recognize the pseudonym.
o When pseudonyms and fast re-authentication identities are used,
the peer relies on the properly created identifiers by the server.
It is essential that an attacker cannot link a privacy-friendly
identifier to the user in any way or determine that two
identifiers belong to the same user as outlined in Section 5.2.
The pseudonym usernames and fast re-authentication identities MUST
also not be used for other purposes (e.g. in other protocols).
If the peer and server cannot guarantee that 5G SUCI can be used or
pseudonyms will available, generated properly, and maintained
reliably, and identity privacy is required then additional protection
from an external security mechanism such as tunneled EAP methods may
be used. The benefits and the security considerations of using an
external security mechanism with EAP-AKA are beyond the scope of this
document.
Finally, as with other EAP methods, even when privacy-friendly
identifiers or EAP tunneling is used, typically the domain part of an
identifier (e.g., the home operator) is visible to external parties.
7.2. Discovered Vulnerabilities
There have been no published attacks that violate the primary secrecy
or authentication properties defined for the anticipated
Authentication and Key Agreement (AKA) under the originally assumed
trust model. The same is true of EAP-AKA'.
However, there have been attacks when a different trust model is in
use, with characteristics not originally provided by the design, or
when participants in the protocol leak information to outsiders on
purpose, and there has been some privacy-related attacks.
For instance, the original AKA protocol does not prevent supplying
keys by an insider to a third party as done in, e.g., by Mjolsnes and
Tsay in [MT2012] where a serving network lets an authentication run
succeed, but then misuses the session keys to send traffic on the
authenticated user's behalf. This particular attack is not different
from any on-path entity (such as a router) pretending to send
traffic, but the general issue of insider attacks can be a problem,
particularly in a large group of collaborating operators.
Another class of attacks is the use of tunneling of traffic from one
place to another, e.g., as done by Zhang and Fang in [ZF2005] to
leverage security policy differences between different operator
networks, for instance. To gain something in such an attack, the
attacker needs to trick the user into believing it is in another
location where, for instance, it is not required to encrypt all
payload traffic after encryption. As an authentication mechanism,
EAP-AKA' is not directly affected by most such attacks. EAP-AKA'
network name binding can also help alleviate some of the attacks. In
any case, it is RECOMMENDED that EAP-AKA' configuration not be
dependent on the location of where a request comes from.
Zhang and Fang also looked at Denial-of-Service attacks [ZF2005]. A
serving network may request large numbers of authentication runs for
a particular subscriber from a home network. While resynchronization
process can help recover from this, eventually it is possible to
exhaust the sequence number space and render the subscriber's card
unusable. This attack is possible for both native AKA and EAP-AKA'.
However, it requires the collaboration of a serving network in an
attack. It is recommended that EAP-AKA' implementations provide
means to track, detect, and limit excessive authentication attempts
to combat this problem.
There has also been attacks related to the use of AKA without the
generated session keys (e.g., [BT2013]). Some of those attacks
relate to the use of originally man-in-the-middle vulnerable HTTP
Digest AKAv1 [RFC3310]. This has since then been corrected in
[RFC4169]. The EAP-AKA' protocol uses session keys and provides
channel binding, and as such, is resistant to the above attacks
except where the protocol participants leak information to outsiders.
Basin et al [Basin2018] have performed formal analysis and concluded
that the AKA protocol would have benefited from additional security
requirements, such as key confirmation.
In the context of pervasive monitoring revelations, there were also
reports of compromised long term pre-shared keys used in SIM and AKA
[Heist2015]. While no protocol can survive the theft of key material
associated with its credentials, there are some things that alleviate
the impacts in such situations. These are discussed further in
Section 7.3.
Arapinis et al ([Arapinis2012]) describe an attack that uses the AKA
resynchronization protocol to attempt to detect whether a particular
subscriber is on a given area. This attack depends on the ability of
the attacker to have a false base station on the given area, and the
subscriber performing at least one authentication between the time
the attack is set up and run.
Finally, while this is not a problem with the protocol itself, bad
implementations may not produce pseudonym usernames or fast re-
authentication identities in a manner that is sufficiently secure.
Recommendations from Section 5.2 need to be followed to avoid this.
7.3. Pervasive Monitoring
As required by [RFC7258], work on IETF protocols needs to consider
the effects of pervasive monitoring and mitigate them when possible.
As described Section 7.2, after the publication of RFC 5448, new
information has come to light regarding the use of pervasive
monitoring techniques against many security technologies, including
AKA-based authentication.
For AKA, these attacks relate to theft of the long-term shared secret
key material stored on the cards. Such attacks are conceivable, for
instance, during the manufacturing process of cards, through coercion
of the card manufacturers, or during the transfer of cards and
associated information to an operator. Since the publication of
reports about such attacks, manufacturing and provisioning processes
have gained much scrutiny and have improved.
In particular, it is crucial that manufacturers limit access to the
secret information and the cards only to necessary systems and
personnel. It is also crucial that secure mechanisms be used to
communicate the secrets between the manufacturer and the operator
that adopts those cards for their customers.
Beyond these operational considerations, there are also technical
means to improve resistance to these attacks. One approach is to
provide Perfect Forwards Secrecy (PFS). This would prevent any
passive attacks merely based on the long-term secrets and observation
of traffic. Such a mechanism can be defined as an backwards-
compatible extension of EAP-AKA', and is pursued separately from this
specification [I-D.arkko-eap-aka-pfs]. Alternatively, EAP-AKA'
authentication can be run inside a PFS-capable tunneled
authentication method. In any case, the use of some PFS-capable
mechanism is RECOMMENDED.
7.4. Security Properties of Binding Network Names
The ability of EAP-AKA' to bind the network name into the used keys The ability of EAP-AKA' to bind the network name into the used keys
provides some additional protection against key leakage to provides some additional protection against key leakage to
inappropriate parties. The keys used in the protocol are specific to inappropriate parties. The keys used in the protocol are specific to
a particular network name. If key leakage occurs due to an accident, a particular network name. If key leakage occurs due to an accident,
access node compromise, or another attack, the leaked keys are only access node compromise, or another attack, the leaked keys are only
useful when providing access with that name. For instance, a useful when providing access with that name. For instance, a
malicious access point cannot claim to be network Y if it has stolen malicious access point cannot claim to be network Y if it has stolen
keys from network X. Obviously, if an access point is compromised, keys from network X. Obviously, if an access point is compromised,
the malicious node can still represent the compromised node. As a the malicious node can still represent the compromised node. As a
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8.3. Key Derivation Function Namespace 8.3. Key Derivation Function Namespace
IANA has also created a new namespace for EAP-AKA' AT_KDF Key IANA has also created a new namespace for EAP-AKA' AT_KDF Key
Derivation Function Values. This namespace exists under the EAP-AKA Derivation Function Values. This namespace exists under the EAP-AKA
and EAP-SIM Parameters registry. The initial contents of this and EAP-SIM Parameters registry. The initial contents of this
namespace are given below; new values can be created through the namespace are given below; new values can be created through the
Specification Required policy [RFC8126]. Specification Required policy [RFC8126].
Value Description Reference Value Description Reference
--------- ---------------------- --------------- --------- ---------------------- -------------------------------
0 Reserved [RFC 5448] 0 Reserved [RFC Editor: Refer to this RFC]
1 EAP-AKA' with CK'/IK' [RFC 5448] 1 EAP-AKA' with CK'/IK' [RFC Editor: Refer to this RFC]
2-65535 Unassigned 2-65535 Unassigned
9. Contributors 9. References
The test vectors in Appendix C were provided by Yogendra Pal and
Jouni Malinen, based on two independent implementations of this
specification.
Jouni Malinen provided suggested text for Section 6.
10. Acknowledgments
The authors would like to thank Guenther Horn, Joe Salowey, Mats
Naslund, Adrian Escott, Brian Rosenberg, Laksminath Dondeti, Ahmad
Muhanna, Stefan Rommer, Miguel Garcia, Jan Kall, Ankur Agarwal, Jouni
Malinen, Brian Weis, Russ Housley, Alfred Hoenes, Vesa Torvinen,
Anand Palanigounder, and Mohit Sethi for their in-depth reviews and
interesting discussions in this problem space.
11. References 9.1. Normative References
11.1. Normative References [TS-3GPP.23.003]
3GPP, "3rd Generation Partnership Project; Technical
Specification Group Core Network and Terminals; Numbering,
addressing and identification (Release 15)", 3GPP Draft
Technical Specification 23.003, June 2018.
[TS-3GPP.23.501] [TS-3GPP.23.501]
3GPP, "3rd Generation Partnership Project; Technical 3GPP, "3rd Generation Partnership Project; Technical
Specification Group Services and System Aspects; 3G Specification Group Services and System Aspects; 3G
Security; Security architecture and procedures for 5G Security; Security architecture and procedures for 5G
System; (Release 15)", 3GPP Technical Specification System; (Release 15)", 3GPP Technical Specification
23.501, December 2017. 23.501, December 2017.
[TS-3GPP.24.302] [TS-3GPP.24.302]
3GPP, "3rd Generation Partnership Project; Technical 3GPP, "3rd Generation Partnership Project; Technical
Specification Group Core Network and Terminals; Access to Specification Group Core Network and Terminals; Access to
the 3GPP Evolved Packet Core (EPC) via non-3GPP access the 3GPP Evolved Packet Core (EPC) via non-3GPP access
networks; Stage 3; (Release 15)", 3GPP Draft Technical networks; Stage 3; (Release 15)", 3GPP Draft Technical
Specification 24.302, June 2018. Specification 24.302, June 2018.
[TS-3GPP.24.501]
3GPP, "3rd Generation Partnership Project; Technical
Specification Group Core Network and Terminals; Access to
the 3GPP Evolved Packet Core (EPC) via non-3GPP access
networks; Stage 3; (Release 15)", 3GPP Draft Technical
Specification 24.501, June 2018.
[TS-3GPP.33.102] [TS-3GPP.33.102]
3GPP, "3rd Generation Partnership Project; Technical 3GPP, "3rd Generation Partnership Project; Technical
Specification Group Services and System Aspects; 3G Specification Group Services and System Aspects; 3G
Security; Security architecture (Release 15)", 3GPP Draft Security; Security architecture (Release 15)", 3GPP Draft
Technical Specification 33.102, June 2018. Technical Specification 33.102, June 2018.
[TS-3GPP.33.402] [TS-3GPP.33.402]
3GPP, "3GPP System Architecture Evolution (SAE); Security 3GPP, "3GPP System Architecture Evolution (SAE); Security
aspects of non-3GPP accesses (Release 15)", 3GPP Draft aspects of non-3GPP accesses (Release 15)", 3GPP Draft
Technical Specification 33.402, June 2018. Technical Specification 33.402, June 2018.
skipping to change at page 25, line 43 skipping to change at page 34, line 31
[RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H. [RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
Levkowetz, Ed., "Extensible Authentication Protocol Levkowetz, Ed., "Extensible Authentication Protocol
(EAP)", RFC 3748, DOI 10.17487/RFC3748, June 2004, (EAP)", RFC 3748, DOI 10.17487/RFC3748, June 2004,
<https://www.rfc-editor.org/info/rfc3748>. <https://www.rfc-editor.org/info/rfc3748>.
[RFC4187] Arkko, J. and H. Haverinen, "Extensible Authentication [RFC4187] Arkko, J. and H. Haverinen, "Extensible Authentication
Protocol Method for 3rd Generation Authentication and Key Protocol Method for 3rd Generation Authentication and Key
Agreement (EAP-AKA)", RFC 4187, DOI 10.17487/RFC4187, Agreement (EAP-AKA)", RFC 4187, DOI 10.17487/RFC4187,
January 2006, <https://www.rfc-editor.org/info/rfc4187>. January 2006, <https://www.rfc-editor.org/info/rfc4187>.
[RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The
Network Access Identifier", RFC 4282,
DOI 10.17487/RFC4282, December 2005, <https://www.rfc-
editor.org/info/rfc4282>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
11.2. Informative References 9.2. Informative References
[TS-3GPP.23.003]
3GPP, "3rd Generation Partnership Project; Technical
Specification Group Core Network and Terminals; Numbering,
addressing and identification (Release 15)", 3GPP Draft
Technical Specification 23.003, June 2018.
[TS-3GPP.35.208] [TS-3GPP.35.208]
3GPP, "3rd Generation Partnership Project; Technical 3GPP, "3rd Generation Partnership Project; Technical
Specification Group Services and System Aspects; 3G Specification Group Services and System Aspects; 3G
Security; Specification of the MILENAGE Algorithm Set: An Security; Specification of the MILENAGE Algorithm Set: An
example algorithm set for the 3GPP authentication and key example algorithm set for the 3GPP authentication and key
generation functions f1, f1*, f2, f3, f4, f5 and f5*; generation functions f1, f1*, f2, f3, f4, f5 and f5*;
Document 4: Design Conformance Test Data (Release 14)", Document 4: Design Conformance Test Data (Release 14)",
3GPP Technical Specification 35.208, March 2017. 3GPP Technical Specification 35.208, March 2017.
skipping to change at page 26, line 33 skipping to change at page 35, line 25
National Institute of Standards and Technology, "Secure National Institute of Standards and Technology, "Secure
Hash Standard", FIPS PUB 180-1, April 1995, Hash Standard", FIPS PUB 180-1, April 1995,
<http://www.itl.nist.gov/fipspubs/fip180-1.htm>. <http://www.itl.nist.gov/fipspubs/fip180-1.htm>.
[FIPS.180-2] [FIPS.180-2]
National Institute of Standards and Technology, "Secure National Institute of Standards and Technology, "Secure
Hash Standard", FIPS PUB 180-2, August 2002, Hash Standard", FIPS PUB 180-2, August 2002,
<http://csrc.nist.gov/publications/fips/fips180-2/ <http://csrc.nist.gov/publications/fips/fips180-2/
fips180-2.pdf>. fips180-2.pdf>.
[RFC3310] Niemi, A., Arkko, J., and V. Torvinen, "Hypertext Transfer
Protocol (HTTP) Digest Authentication Using Authentication
and Key Agreement (AKA)", RFC 3310, DOI 10.17487/RFC3310,
September 2002, <https://www.rfc-editor.org/info/rfc3310>.
[RFC4169] Torvinen, V., Arkko, J., and M. Naslund, "Hypertext
Transfer Protocol (HTTP) Digest Authentication Using
Authentication and Key Agreement (AKA) Version-2",
RFC 4169, DOI 10.17487/RFC4169, November 2005,
<https://www.rfc-editor.org/info/rfc4169>.
[RFC4186] Haverinen, H., Ed. and J. Salowey, Ed., "Extensible [RFC4186] Haverinen, H., Ed. and J. Salowey, Ed., "Extensible
Authentication Protocol Method for Global System for Authentication Protocol Method for Global System for
Mobile Communications (GSM) Subscriber Identity Modules Mobile Communications (GSM) Subscriber Identity Modules
(EAP-SIM)", RFC 4186, DOI 10.17487/RFC4186, January 2006, (EAP-SIM)", RFC 4186, DOI 10.17487/RFC4186, January 2006,
<https://www.rfc-editor.org/info/rfc4186>. <https://www.rfc-editor.org/info/rfc4186>.
[RFC4284] Adrangi, F., Lortz, V., Bari, F., and P. Eronen, "Identity [RFC4284] Adrangi, F., Lortz, V., Bari, F., and P. Eronen, "Identity
Selection Hints for the Extensible Authentication Protocol Selection Hints for the Extensible Authentication Protocol
(EAP)", RFC 4284, DOI 10.17487/RFC4284, January 2006, (EAP)", RFC 4284, DOI 10.17487/RFC4284, January 2006,
<https://www.rfc-editor.org/info/rfc4284>. <https://www.rfc-editor.org/info/rfc4284>.
skipping to change at page 27, line 21 skipping to change at page 36, line 26
Authentication Protocol (EAP) Key Management Framework", Authentication Protocol (EAP) Key Management Framework",
RFC 5247, DOI 10.17487/RFC5247, August 2008, RFC 5247, DOI 10.17487/RFC5247, August 2008,
<https://www.rfc-editor.org/info/rfc5247>. <https://www.rfc-editor.org/info/rfc5247>.
[RFC5448] Arkko, J., Lehtovirta, V., and P. Eronen, "Improved [RFC5448] Arkko, J., Lehtovirta, V., and P. Eronen, "Improved
Extensible Authentication Protocol Method for 3rd Extensible Authentication Protocol Method for 3rd
Generation Authentication and Key Agreement (EAP-AKA')", Generation Authentication and Key Agreement (EAP-AKA')",
RFC 5448, DOI 10.17487/RFC5448, May 2009, RFC 5448, DOI 10.17487/RFC5448, May 2009,
<https://www.rfc-editor.org/info/rfc5448>. <https://www.rfc-editor.org/info/rfc5448>.
[RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
Morris, J., Hansen, M., and R. Smith, "Privacy
Considerations for Internet Protocols", RFC 6973,
DOI 10.17487/RFC6973, July 2013, <https://www.rfc-
editor.org/info/rfc6973>.
[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
2014, <https://www.rfc-editor.org/info/rfc7258>.
[I-D.arkko-eap-aka-pfs]
Arkko, J., Norrman, K., and V. Torvinen, "Perfect-Forward
Secrecy for the Extensible Authentication Protocol Method
for Authentication and Key Agreement (EAP-AKA' PFS)",
draft-arkko-eap-aka-pfs-02 (work in progress), July 2018.
[Heist2015]
Scahill, J. and J. Begley, "The great SIM heist", February
2015, in https://firstlook.org/theintercept/2015/02/19/
great-sim-heist/ .
[MT2012] Mjolsnes, S. and J-K. Tsay, "A vulnerability in the UMTS
and LTE authentication and key agreement protocols",
October 2012, in Proceedings of the 6th international
conference on Mathematical Methods, Models and
Architectures for Computer Network Security: computer
network security.
[BT2013] Beekman, J. and C. Thompson, "Breaking Cell Phone
Authentication: Vulnerabilities in AKA, IMS and Android",
August 2013, in 7th USENIX Workshop on Offensive
Technologies, WOOT '13.
[ZF2005] Zhang, M. and Y. Fang, "Breaking Cell Phone
Authentication: Vulnerabilities in AKA, IMS and Android",
March 2005, IEEE Transactions on Wireless Communications,
Vol. 4, No. 2.
[Basin2018]
Basin, D., Dreier, J., Hirsch, L., Radomirovic, S., Sasse,
R., and V. Stettle, "A Formal Analysis of 5G
Authentication", August 2018, arXiv:1806.10360.
[Arapinis2012]
Arapinis, M., Mancini, L., Ritter, E., Ryan, M., Golde,
N., and R. Borgaonkar, "New Privacy Issues in Mobile
Telephony: Fix and Verification", October 2012, CCS'12,
Raleigh, North Carolina, USA.
Appendix A. Changes from RFC 5448 Appendix A. Changes from RFC 5448
The changes consist first of all, referring to a newer version of The changes consist first of all, referring to a newer version of
[TS-3GPP.24.302]. The new version includes an updated definition of [TS-3GPP.24.302]. The new version includes an updated definition of
the Network Name field, to include 5G. the Network Name field, to include 5G.
Secondly, identifier usage for 5G has been specified in Section 5. Secondly, identifier usage for 5G has been specified in Section 5.3.
Also, the requirements on generating pseudonym usernames and fast re-
authentication identities have been updated from the original
definition in RFC 5448, which referenced RFC 4187. See Section 5.
Thirdly, exported parameters for EAP-AKA' have been defined in Thirdly, exported parameters for EAP-AKA' have been defined in
Section 6, as required by [RFC5247], including the definition of Section 6, as required by [RFC5247], including the definition of
those parameters for both full authentication and fast re- those parameters for both full authentication and fast re-
authentication. authentication.
The security, privacy, and pervasive monitoring considerations have
been updated or added. See Section 7.
Finally, the references to [RFC2119], [RFC5226], [FIPS.180-1] and Finally, the references to [RFC2119], [RFC5226], [FIPS.180-1] and
[FIPS.180-2] have been updated to their most recent versions and [FIPS.180-2] have been updated to their most recent versions and
language in this document changed accordingly. Similarly, references language in this document changed accordingly. Similarly, references
to all 3GPP technical specifications have been updated to their 5G to all 3GPP technical specifications have been updated to their 5G
(Release 15) versions or otherwise most recent version when there has (Release 15) versions or otherwise most recent version when there has
not been a 5G-related update. not been a 5G-related update.
Appendix B. Changes from RFC 4187 to RFC 5448 Appendix B. Changes from RFC 4187 to RFC 5448
The changes to RFC 4187 relate only to the bidding down prevention The changes to RFC 4187 relate only to the bidding down prevention
skipping to change at page 28, line 12 skipping to change at page 38, line 20
and IK, not CK' and IK'); neither is any processing of the AMF bit and IK, not CK' and IK'); neither is any processing of the AMF bit
added to RFC 4187. added to RFC 4187.
Appendix C. Changes from Previous Version of This Draft Appendix C. Changes from Previous Version of This Draft
RFC Editor: Please delete this section at the time of publication. RFC Editor: Please delete this section at the time of publication.
The -00 version of the working group draft is merely a republication The -00 version of the working group draft is merely a republication
of an earlier individual draft. of an earlier individual draft.
The -01 version of the working group clarifies updates relationship The -01 version of the working group draft clarifies updates
to RFC 4187, clarifies language relating to obsoleting RFC 5448, relationship to RFC 4187, clarifies language relating to obsoleting
clarifies when the 3GPP references are expected to be stable, updates RFC 5448, clarifies when the 3GPP references are expected to be
several past references to their more recently published versions, stable, updates several past references to their more recently
specifies what identifiers should be used in key derivation formula published versions, specifies what identifiers should be used in key
for 5G, specifies how to construct the network name in manner that is derivation formula for 5G, specifies how to construct the network
compatible with both 5G and previous versions, and has some minor name in manner that is compatible with both 5G and previous versions,
editorial changes. and has some minor editorial changes.
The -02 version of the working group draft added specification of
peer identity usage in EAP-AKA', added requirements on the generation
of pseudonym and fast re-authentication identifiers, specified the
format of 5G-identifiers when they are used within EAP-AKA', defined
privacy and pervasive surveillance considerations, clarified when 5G-
related procedures apply, specified what Peer-Id value is exported
when no AT_IDENTITY is exchanged within EAP-AKA', and made a number
of other clarifications and editorial improvements. The security
considerations section also includes a summary of vulnerabilities
brought up in the context of AKA or EAP-AKA', and discusses their
applicability and impacts in EAP-AKA'.
Appendix D. Importance of Explicit Negotiation Appendix D. Importance of Explicit Negotiation
Choosing between the traditional and revised AKA key derivation Choosing between the traditional and revised AKA key derivation
functions is easy when their use is unambiguously tied to a functions is easy when their use is unambiguously tied to a
particular radio access network, e.g., Long Term Evolution (LTE) as particular radio access network, e.g., Long Term Evolution (LTE) as
defined by 3GPP or evolved High Rate Packet Data (eHRPD) as defined defined by 3GPP or evolved High Rate Packet Data (eHRPD) as defined
by 3GPP2. There is no possibility for interoperability problems if by 3GPP2. There is no possibility for interoperability problems if
this radio access network is always used in conjunction with new this radio access network is always used in conjunction with new
protocols that cannot be mixed with the old ones; clients will always protocols that cannot be mixed with the old ones; clients will always
skipping to change at page 29, line 16 skipping to change at page 39, line 38
provide all features of the current release. And obviously, there provide all features of the current release. And obviously, there
are many EAP and even some EAP-AKA implementations that are not are many EAP and even some EAP-AKA implementations that are not
bundled with the 3GPP network offerings. In general, these bundled with the 3GPP network offerings. In general, these
approaches are expected to lead to hard-to-diagnose problems and approaches are expected to lead to hard-to-diagnose problems and
increased support calls. increased support calls.
Appendix E. Test Vectors Appendix E. Test Vectors
Test vectors are provided below for four different cases. The test Test vectors are provided below for four different cases. The test
vectors may be useful for testing implementations. In the first two vectors may be useful for testing implementations. In the first two
cases, we employ the Milenage algorithm and the algorithm cases, we employ the MILENAGE algorithm and the algorithm
configuration parameters (the subscriber key K and operator algorithm configuration parameters (the subscriber key K and operator algorithm
variant configuration value OP) from test set 19 in [TS-3GPP.35.208]. variant configuration value OP) from test set 19 in [TS-3GPP.35.208].
The last two cases use artificial values as the output of AKA, and is The last two cases use artificial values as the output of AKA, and is
useful only for testing the computation of values within EAP-AKA', useful only for testing the computation of values within EAP-AKA',
not AKA itself. not AKA itself.
Case 1 Case 1
The parameters for the AKA run are as follows: The parameters for the AKA run are as follows:
Identity: "0555444333222111" Identity: "0555444333222111"
Network name: "WLAN" Network name: "WLAN"
RAND: 81e9 2b6c 0ee0 e12e bceb a8d9 2a99 dfa5 RAND: 81e9 2b6c 0ee0 e12e bceb a8d9 2a99 dfa5
AUTN: bb52 e91c 747a c3ab 2a5c 23d1 5ee3 51d5 AUTN: bb52 e91c 747a c3ab 2a5c 23d1 5ee3 51d5
IK: 9744 871a d32b f9bb d1dd 5ce5 4e3e 2e5a IK: 9744 871a d32b f9bb d1dd 5ce5 4e3e 2e5a
CK: 5349 fbe0 9864 9f94 8f5d 2e97 3a81 c00f CK: 5349 fbe0 9864 9f94 8f5d 2e97 3a81 c00f
RES: 28d7 b0f2 a2ec 3de5 RES: 28d7 b0f2 a2ec 3de5
Then the derived keys are generated as follows: Then the derived keys are generated as follows:
CK': 0093 962d 0dd8 4aa5 684b 045c 9edf fa04 CK': 0093 962d 0dd8 4aa5 684b 045c 9edf fa04
IK': ccfc 230c a74f cc96 c0a5 d611 64f5 a76c IK': ccfc 230c a74f cc96 c0a5 d611 64f5 a76c
K_encr: 766f a0a6 c317 174b 812d 52fb cd11 a179 K_encr: 766f a0a6 c317 174b 812d 52fb cd11 a179
K_aut: 0842 ea72 2ff6 835b fa20 3249 9fc3 ec23 K_aut: 0842 ea72 2ff6 835b fa20 3249 9fc3 ec23
c2f0 e388 b4f0 7543 ffc6 77f1 696d 71ea c2f0 e388 b4f0 7543 ffc6 77f1 696d 71ea
K_re: cf83 aa8b c7e0 aced 892a cc98 e76a 9b20 K_re: cf83 aa8b c7e0 aced 892a cc98 e76a 9b20
95b5 58c7 795c 7094 715c b339 3aa7 d17a 95b5 58c7 795c 7094 715c b339 3aa7 d17a
MSK: 67c4 2d9a a56c 1b79 e295 e345 9fc3 d187 MSK: 67c4 2d9a a56c 1b79 e295 e345 9fc3 d187
d42b e0bf 818d 3070 e362 c5e9 67a4 d544 d42b e0bf 818d 3070 e362 c5e9 67a4 d544
e8ec fe19 358a b303 9aff 03b7 c930 588c e8ec fe19 358a b303 9aff 03b7 c930 588c
055b abee 58a0 2650 b067 ec4e 9347 c75a 055b abee 58a0 2650 b067 ec4e 9347 c75a
EMSK: f861 703c d775 590e 16c7 679e a387 4ada EMSK: f861 703c d775 590e 16c7 679e a387 4ada
8663 11de 2907 64d7 60cf 76df 647e a01c 8663 11de 2907 64d7 60cf 76df 647e a01c
313f 6992 4bdd 7650 ca9b ac14 1ea0 75c4 313f 6992 4bdd 7650 ca9b ac14 1ea0 75c4
ef9e 8029 c0e2 90cd bad5 638b 63bc 23fb ef9e 8029 c0e2 90cd bad5 638b 63bc 23fb
Case 2 Case 2
The parameters for the AKA run are as follows: The parameters for the AKA run are as follows:
Identity: "0555444333222111" Identity: "0555444333222111"
Network name: "HRPD" Network name: "HRPD"
RAND: 81e9 2b6c 0ee0 e12e bceb a8d9 2a99 dfa5 RAND: 81e9 2b6c 0ee0 e12e bceb a8d9 2a99 dfa5
AUTN: bb52 e91c 747a c3ab 2a5c 23d1 5ee3 51d5 AUTN: bb52 e91c 747a c3ab 2a5c 23d1 5ee3 51d5
IK: 9744 871a d32b f9bb d1dd 5ce5 4e3e 2e5a IK: 9744 871a d32b f9bb d1dd 5ce5 4e3e 2e5a
CK: 5349 fbe0 9864 9f94 8f5d 2e97 3a81 c00f CK: 5349 fbe0 9864 9f94 8f5d 2e97 3a81 c00f
RES: 28d7 b0f2 a2ec 3de5 RES: 28d7 b0f2 a2ec 3de5
Then the derived keys are generated as follows: Then the derived keys are generated as follows:
CK': 3820 f027 7fa5 f777 32b1 fb1d 90c1 a0da CK': 3820 f027 7fa5 f777 32b1 fb1d 90c1 a0da
IK': db94 a0ab 557e f6c9 ab48 619c a05b 9a9f IK': db94 a0ab 557e f6c9 ab48 619c a05b 9a9f
K_encr: 05ad 73ac 915f ce89 ac77 e152 0d82 187b K_encr: 05ad 73ac 915f ce89 ac77 e152 0d82 187b
K_aut: 5b4a caef 62c6 ebb8 882b 2f3d 534c 4b35 K_aut: 5b4a caef 62c6 ebb8 882b 2f3d 534c 4b35
2773 37a0 0184 f20f f25d 224c 04be 2afd 2773 37a0 0184 f20f f25d 224c 04be 2afd
K_re: 3f90 bf5c 6e5e f325 ff04 eb5e f653 9fa8 K_re: 3f90 bf5c 6e5e f325 ff04 eb5e f653 9fa8
cca8 3981 94fb d00b e425 b3f4 0dba 10ac cca8 3981 94fb d00b e425 b3f4 0dba 10ac
MSK: 87b3 2157 0117 cd6c 95ab 6c43 6fb5 073f MSK: 87b3 2157 0117 cd6c 95ab 6c43 6fb5 073f
f15c f855 05d2 bc5b b735 5fc2 1ea8 a757 f15c f855 05d2 bc5b b735 5fc2 1ea8 a757
57e8 f86a 2b13 8002 e057 5291 3bb4 3b82 57e8 f86a 2b13 8002 e057 5291 3bb4 3b82
f868 a961 17e9 1a2d 95f5 2667 7d57 2900 f868 a961 17e9 1a2d 95f5 2667 7d57 2900
EMSK: c891 d5f2 0f14 8a10 0755 3e2d ea55 5c9c EMSK: c891 d5f2 0f14 8a10 0755 3e2d ea55 5c9c
b672 e967 5f4a 66b4 bafa 0273 79f9 3aee b672 e967 5f4a 66b4 bafa 0273 79f9 3aee
539a 5979 d0a0 042b 9d2a e28b ed3b 17a3 539a 5979 d0a0 042b 9d2a e28b ed3b 17a3
1dc8 ab75 072b 80bd 0c1d a612 466e 402c 1dc8 ab75 072b 80bd 0c1d a612 466e 402c
Case 3 Case 3
The parameters for the AKA run are as follows: The parameters for the AKA run are as follows:
Identity: "0555444333222111" Identity: "0555444333222111"
Network name: "WLAN" Network name: "WLAN"
RAND: e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 RAND: e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 e0e0
AUTN: a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 AUTN: a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 a0a0
IK: b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 IK: b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 b0b0
CK: c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 CK: c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 c0c0
RES: d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 RES: d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 d0d0
Then the derived keys are generated as follows: Then the derived keys are generated as follows:
CK': cd4c 8e5c 68f5 7dd1 d7d7 dfd0 c538 e577 CK': cd4c 8e5c 68f5 7dd1 d7d7 dfd0 c538 e577
IK': 3ece 6b70 5dbb f7df c459 a112 80c6 5524 IK': 3ece 6b70 5dbb f7df c459 a112 80c6 5524
K_encr: 897d 302f a284 7416 488c 28e2 0dcb 7be4 K_encr: 897d 302f a284 7416 488c 28e2 0dcb 7be4
K_aut: c407 00e7 7224 83ae 3dc7 139e b0b8 8bb5 K_aut: c407 00e7 7224 83ae 3dc7 139e b0b8 8bb5
58cb 3081 eccd 057f 9207 d128 6ee7 dd53 58cb 3081 eccd 057f 9207 d128 6ee7 dd53
K_re: 0a59 1a22 dd8b 5b1c f29e 3d50 8c91 dbbd K_re: 0a59 1a22 dd8b 5b1c f29e 3d50 8c91 dbbd
b4ae e230 5189 2c42 b6a2 de66 ea50 4473 b4ae e230 5189 2c42 b6a2 de66 ea50 4473
MSK: 9f7d ca9e 37bb 2202 9ed9 86e7 cd09 d4a7 MSK: 9f7d ca9e 37bb 2202 9ed9 86e7 cd09 d4a7
0d1a c76d 9553 5c5c ac40 a750 4699 bb89 0d1a c76d 9553 5c5c ac40 a750 4699 bb89
61a2 9ef6 f3e9 0f18 3de5 861a d1be dc81 61a2 9ef6 f3e9 0f18 3de5 861a d1be dc81
ce99 1639 1b40 1aa0 06c9 8785 a575 6df7 ce99 1639 1b40 1aa0 06c9 8785 a575 6df7
EMSK: 724d e00b db9e 5681 87be 3fe7 4611 4557 EMSK: 724d e00b db9e 5681 87be 3fe7 4611 4557
d501 8779 537e e37f 4d3c 6c73 8cb9 7b9d d501 8779 537e e37f 4d3c 6c73 8cb9 7b9d
c651 bc19 bfad c344 ffe2 b52c a78b d831 c651 bc19 bfad c344 ffe2 b52c a78b d831
6b51 dacc 5f2b 1440 cb95 1552 1cc7 ba23 6b51 dacc 5f2b 1440 cb95 1552 1cc7 ba23
Case 4 Case 4
The parameters for the AKA run are as follows: The parameters for the AKA run are as follows:
Identity: "0555444333222111" Identity: "0555444333222111"
Network name: "HRPD" Network name: "HRPD"
RAND: e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 RAND: e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 e0e0 e0e0
AUTN: a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 AUTN: a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 a0a0 a0a0
IK: b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 IK: b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 b0b0 b0b0
CK: c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 CK: c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 c0c0 c0c0
RES: d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 RES: d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 d0d0 d0d0
Then the derived keys are generated as follows: Then the derived keys are generated as follows:
CK': 8310 a71c e6f7 5488 9613 da8f 64d5 fb46 CK': 8310 a71c e6f7 5488 9613 da8f 64d5 fb46
IK': 5adf 1436 0ae8 3819 2db2 3f6f cb7f 8c76 IK': 5adf 1436 0ae8 3819 2db2 3f6f cb7f 8c76
K_encr: 745e 7439 ba23 8f50 fcac 4d15 d47c d1d9 K_encr: 745e 7439 ba23 8f50 fcac 4d15 d47c d1d9
K_aut: 3e1d 2aa4 e677 025c fd86 2a4b e183 61a1 K_aut: 3e1d 2aa4 e677 025c fd86 2a4b e183 61a1
3a64 5765 5714 63df 833a 9759 e809 9879 3a64 5765 5714 63df 833a 9759 e809 9879
K_re: 99da 835e 2ae8 2462 576f e651 6fad 1f80 K_re: 99da 835e 2ae8 2462 576f e651 6fad 1f80
2f0f a119 1655 dd0a 273d a96d 04e0 fcd3 2f0f a119 1655 dd0a 273d a96d 04e0 fcd3
MSK: c6d3 a6e0 ceea 951e b20d 74f3 2c30 61d0 MSK: c6d3 a6e0 ceea 951e b20d 74f3 2c30 61d0
680a 04b0 b086 ee87 00ac e3e0 b95f a026 680a 04b0 b086 ee87 00ac e3e0 b95f a026
83c2 87be ee44 4322 94ff 98af 26d2 cc78 83c2 87be ee44 4322 94ff 98af 26d2 cc78
3bac e75c 4b0a f7fd feb5 511b a8e4 cbd0 3bac e75c 4b0a f7fd feb5 511b a8e4 cbd0
EMSK: 7fb5 6813 838a dafa 99d1 40c2 f198 f6da EMSK: 7fb5 6813 838a dafa 99d1 40c2 f198 f6da
cebf b6af ee44 4961 1054 02b5 08c7 f363 cebf b6af ee44 4961 1054 02b5 08c7 f363
352c b291 9644 b504 63e6 a693 5415 0147 352c b291 9644 b504 63e6 a693 5415 0147
ae09 cbc5 4b8a 651d 8787 a689 3ed8 536d ae09 cbc5 4b8a 651d 8787 a689 3ed8 536d
Appendix F. Contributors
The test vectors in Appendix C were provided by Yogendra Pal and
Jouni Malinen, based on two independent implementations of this
specification.
Jouni Malinen provided suggested text for Section 6. John Mattsson
provided much of the text for Section 7.1. Karl Norrman was the
source of much of the information in Section 7.2.
Appendix G. Acknowledgments
The authors would like to thank Guenther Horn, Joe Salowey, Mats
Naslund, Adrian Escott, Brian Rosenberg, Laksminath Dondeti, Ahmad
Muhanna, Stefan Rommer, Miguel Garcia, Jan Kall, Ankur Agarwal, Jouni
Malinen, John Mattsson, Brian Weis, Russ Housley, Alfred Hoenes,
Anand Palanigounder, and Mohit Sethi for their in-depth reviews and
interesting discussions in this problem space.
Authors' Addresses Authors' Addresses
Jari Arkko Jari Arkko
Ericsson Ericsson
Jorvas 02420 Jorvas 02420
Finland Finland
Email: jari.arkko@piuha.net Email: jari.arkko@piuha.net
Vesa Lehtovirta Vesa Lehtovirta
Ericsson Ericsson
Jorvas 02420 Jorvas 02420
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