draft-ietf-emu-rfc5448bis-09.txt   draft-ietf-emu-rfc5448bis-10.txt 
Network Working Group J. Arkko Network Working Group J. Arkko
Internet-Draft V. Lehtovirta Internet-Draft V. Lehtovirta
Updates: 5448,4187 (if approved) V. Torvinen Updates: 5448,4187 (if approved) V. Torvinen
Intended status: Informational Ericsson Intended status: Informational Ericsson
Expires: July 15, 2021 P. Eronen Expires: November 11, 2021 P. Eronen
Independent Independent
January 11, 2021 May 10, 2021
Improved Extensible Authentication Protocol Method for 3GPP Mobile Improved Extensible Authentication Protocol Method for 3GPP Mobile
Network Authentication and Key Agreement (EAP-AKA') Network Authentication and Key Agreement (EAP-AKA')
draft-ietf-emu-rfc5448bis-09 draft-ietf-emu-rfc5448bis-10
Abstract Abstract
The 3GPP Mobile Network Authentication and Key Agreement (AKA) is an The 3GPP Mobile Network Authentication and Key Agreement (AKA) is an
authentication mechanism for devices wishing to access mobile authentication mechanism for devices wishing to access mobile
networks. RFC 4187 (EAP-AKA) made the use of this mechanism possible networks. RFC 4187 (EAP-AKA) made the use of this mechanism possible
within the Extensible Authentication Protocol (EAP) framework. RFC within the Extensible Authentication Protocol (EAP) framework. RFC
5448 (EAP-AKA') was an improved version of EAP-AKA. 5448 (EAP-AKA') was an improved version of EAP-AKA.
This memo is the most recent specification of EAP-AKA', including, This document is the most recent specification of EAP-AKA',
for instance, details and references about related to operating EAP- including, for instance, details and references about related to
AKA' in 5G networks. operating EAP-AKA' in 5G networks.
EAP-AKA' differs from EAP-AKA by providing a key derivation function EAP-AKA' differs from EAP-AKA by providing a key derivation function
that binds the keys derived within the method to the name of the that binds the keys derived within the method to the name of the
access network. The key derivation function has been defined in the access network. The key derivation function has been defined in the
3rd Generation Partnership Project (3GPP). EAP-AKA' allows its use 3rd Generation Partnership Project (3GPP). EAP-AKA' allows its use
in EAP in an interoperable manner. EAP-AKA' also updates the in EAP in an interoperable manner. EAP-AKA' also updates the
algorithm used in hash functions, as it employs SHA-256 / HMAC- algorithm used in hash functions, as it employs SHA-256 / HMAC-
SHA-256 instead of SHA-1 / HMAC-SHA-1 as in EAP-AKA. SHA-256 instead of SHA-1 / HMAC-SHA-1 as in EAP-AKA.
This version of EAP-AKA' specification specifies the protocol This version of EAP-AKA' specification specifies the protocol
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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 July 15, 2021. This Internet-Draft will expire on November 11, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 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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8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34
8.1. Type Value . . . . . . . . . . . . . . . . . . . . . . . 34 8.1. Type Value . . . . . . . . . . . . . . . . . . . . . . . 34
8.2. Attribute Type Values . . . . . . . . . . . . . . . . . . 34 8.2. Attribute Type Values . . . . . . . . . . . . . . . . . . 34
8.3. Key Derivation Function Namespace . . . . . . . . . . . . 34 8.3. Key Derivation Function Namespace . . . . . . . . . . . . 34
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 35 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 35
9.1. Normative References . . . . . . . . . . . . . . . . . . 35 9.1. Normative References . . . . . . . . . . . . . . . . . . 35
9.2. Informative References . . . . . . . . . . . . . . . . . 37 9.2. Informative References . . . . . . . . . . . . . . . . . 37
Appendix A. Changes from RFC 5448 . . . . . . . . . . . . . . . 40 Appendix A. Changes from RFC 5448 . . . . . . . . . . . . . . . 40
Appendix B. Changes to RFC 4187 . . . . . . . . . . . . . . . . 41 Appendix B. Changes to RFC 4187 . . . . . . . . . . . . . . . . 41
Appendix C. Changes from Previous Version of This Draft . . . . 41 Appendix C. Changes from Previous Version of This Draft . . . . 41
Appendix D. Importance of Explicit Negotiation . . . . . . . . . 44 Appendix D. Importance of Explicit Negotiation . . . . . . . . . 45
Appendix E. Test Vectors . . . . . . . . . . . . . . . . . . . . 45 Appendix E. Test Vectors . . . . . . . . . . . . . . . . . . . . 46
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 50 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 51
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 50 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 51
1. Introduction 1. Introduction
The 3GPP Mobile Network Authentication and Key Agreement (AKA) is an The 3GPP Mobile Network Authentication and Key Agreement (AKA) is an
authentication mechanism for devices wishing to access mobile authentication mechanism for devices wishing to access mobile
networks. [RFC4187] (EAP-AKA) made the use of this mechanism networks. [RFC4187] (EAP-AKA) made the use of this mechanism
possible within the Extensible Authentication Protocol (EAP) possible within the Extensible Authentication Protocol (EAP)
framework [RFC3748]. framework [RFC3748].
[RFC5448] (EAP-AKA') was an improved version of EAP-AKA. EAP-AKA' [RFC5448] (EAP-AKA') was an improved version of EAP-AKA. EAP-AKA'
was defined in RFC 5448 and updated EAP-AKA RFC 4187. was defined in RFC 5448 and updated EAP-AKA RFC 4187.
This memo is the most recent specification of EAP-AKA', including, This document is the most recent specification of EAP-AKA',
for instance, details and references about related to operating EAP- including, for instance, details and references about related to
AKA' in 5G networks. RFC 5448 is not obsole, but the most recent and operating EAP-AKA' in 5G networks. RFC 5448 is not obsole, but the
fully backwards compatible specification is in this memo. most recent and fully backwards compatible specification is in this
document.
EAP-AKA' is commonly implemented in mobile phones and network EAP-AKA' is commonly implemented in mobile phones and network
equipment. It can be used for authentication to gain network access equipment. It can be used for authentication to gain network access
via Wireless LAN networks and, with 5G, also directly to mobile via Wireless LAN networks and, with 5G, also directly to mobile
networks. networks.
EAP-AKA' differs from EAP-AKA by providing a different key derivation EAP-AKA' differs from EAP-AKA by providing a different key derivation
function. This function binds the keys derived within the method to function. This function binds the keys derived within the method to
the name of the access network. This limits the effects of the name of the access network. This limits the effects of
compromised access network nodes and keys. EAP-AKA' also updates the compromised access network nodes and keys. EAP-AKA' also updates the
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o Update the requirements on generating pseudonym usernames and fast o Update the requirements on generating pseudonym usernames and fast
re-authentication identities to ensure identity privacy. re-authentication identities to ensure identity privacy.
o Describe what has been learned about any vulnerabilities in AKA or o Describe what has been learned about any vulnerabilities in AKA or
EAP-AKA'. EAP-AKA'.
o Describe the privacy and pervasive monitoring considerations o Describe the privacy and pervasive monitoring considerations
related to EAP-AKA'. related to EAP-AKA'.
o Summaries of the attributes have been added.
Some of the updates are small. For instance, for the first update, Some of the updates are small. For instance, for the first update,
the reference update does not change the 3GPP specification number, 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. warranted.
Note: Any further updates in 3GPP specifications that affect, for Note: Any further updates in 3GPP specifications that affect, for
instance, key derivation is something that EAP-AKA' instance, key derivation is something that EAP-AKA'
implementations need to take into account. Upon such updates implementations need to take into account. Upon such updates
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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 5 specifies prevent bidding down attacks from EAP-AKA'. Section 5 specifies
requirements regarding the use of peer identities, including how EAP- requirements regarding the use of peer identities, including how 5G
AKA' identifiers are used in 5G context. Section 6 specifies what identifiers are used in the EAP-AKA' context. Section 6 specifies
parameters EAP-AKA' exports out of the method. Section 7 explains what parameters EAP-AKA' exports out of the method. Section 7
the security differences between EAP-AKA and EAP-AKA'. Section 8 explains the security differences between EAP-AKA and EAP-AKA'.
describes the IANA considerations and Appendix A and Appendix B Section 8 describes the IANA considerations and Appendix A and
explains what updates to RFC 5448 EAP-AKA' and RFC 4187 EAP-AKA have Appendix B explains what updates to RFC 5448 EAP-AKA' and RFC 4187
been made in this specification. Appendix D explains some of the EAP-AKA have been made in this specification. Appendix D explains
design rationale for creating EAP-AKA'. Finally, Appendix E provides some of the design rationale for creating EAP-AKA'. Finally,
test vectors. Appendix E provides test vectors.
2. Requirements Language 2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. EAP-AKA' 3. EAP-AKA'
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IK' and CK' are derived as specified in [TS-3GPP.33.402]. The IK' and CK' are derived as specified in [TS-3GPP.33.402]. The
functions that derive IK' and CK' take the following parameters: functions that derive IK' and CK' take the following parameters:
CK and IK produced by the AKA algorithm, and value of the Network CK and IK produced by the AKA algorithm, and value of the Network
Name field comes from the AT_KDF_INPUT attribute (without length Name field comes from the AT_KDF_INPUT attribute (without length
or padding). or padding).
The value "EAP-AKA'" is an eight-characters-long ASCII string. It The value "EAP-AKA'" is an eight-characters-long ASCII string. It
is used as is, without any trailing NUL characters. is used as is, without any trailing NUL characters.
Identity is the peer identity as specified in Section 7 of Identity is the peer identity as specified in Section 7 of
[RFC4187], and Section 5.3.2 in this memo for the 5G cases. [RFC4187], and Section 5.3.2 in this document for the 5G cases.
When the server creates an AKA challenge and corresponding AUTN, When the server creates an AKA challenge and corresponding AUTN,
CK, CK', IK, and IK' values, it MUST set the Authentication CK, CK', IK, and IK' values, it MUST set the Authentication
Management Field (AMF) separation bit to 1 in the AKA algorithm Management Field (AMF) separation bit to 1 in the AKA algorithm
[TS-3GPP.33.102]. Similarly, the peer MUST check that the AMF [TS-3GPP.33.102]. Similarly, the peer MUST check that the AMF
separation bit is set to 1. If the bit is not set to 1, the peer separation bit is set to 1. If the bit is not set to 1, the peer
behaves as if the AUTN had been incorrect and fails the behaves as if the AUTN had been incorrect and fails the
authentication. authentication.
On fast re-authentication, the following keys are calculated: On fast re-authentication, the following keys are calculated:
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(9) EAP-Response/AKA-Reauthentication, (9) EAP-Response/AKA-Reauthentication,
(10) EAP-Response/AKA-Authentication-Reject, and (10) EAP-Response/AKA-Authentication-Reject, and
(11) EAP-Response/AKA-Synchronization-Failure. (11) EAP-Response/AKA-Synchronization-Failure.
The column denoted with "E" indicates whether the attribute is a The column denoted with "E" indicates whether the attribute is a
nested attribute that MUST be included within AT_ENCR_DATA. nested attribute that MUST be included within AT_ENCR_DATA.
In addition: In addition,the numbered columns indicate the quantity of the
attribute within the message as follows:
"0" indicates that the attribute MUST NOT be included in the "0" indicates that the attribute MUST NOT be included in the
message, message,
"1" indicates that the attribute MUST be included in the message, "1" indicates that the attribute MUST be included in the message,
"0-1" indicates that the attribute is sometimes included in the "0-1" indicates that the attribute is sometimes included in the
message, message,
"0+" indicates that zero or more copies of the attribute MAY be "0+" indicates that zero or more copies of the attribute MAY be
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message. If the peer supports EAP-AKA', it compares the received message. If the peer supports EAP-AKA', it compares the received
value to its own capabilities. If it turns out that both the server value to its own capabilities. If it turns out that both the server
and peer would have been able to use EAP-AKA' and preferred it over and peer would have been able to use EAP-AKA' and preferred it over
EAP-AKA, the peer behaves as if AUTN had been incorrect and fails the EAP-AKA, the peer behaves as if AUTN had been incorrect and fails the
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, this specification does not provide protection
attacks in the other direction, i.e., attackers forcing the endpoints against bidding "down" attacks in the other direction, i.e.,
to use EAP-AKA'. attackers forcing the endpoints to use EAP-AKA'.
4.1. Summary of Attributes for EAP-AKA 4.1. Summary of Attributes for EAP-AKA
The appearance of the AT_BIDDING attribute in EAP-AKA exchanges is The appearance of the AT_BIDDING attribute in EAP-AKA exchanges is
shown below, using the notation from Section 3.5: shown below, using the notation from Section 3.5:
Attribute (1) (2) (3) (4) (5) (6) (7) (8) (9) (10)(11) E Attribute (1) (2) (3) (4) (5) (6) (7) (8) (9) (10)(11) E
AT_BIDDING 0 0 1 0 0 0 0 0 0 0 0 N AT_BIDDING 0 0 1 0 0 0 0 0 0 0 0 N
5. Peer Identities 5. Peer Identities
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usernames. This specification extends this definition as follows. usernames. This specification extends this definition as follows.
There are four types of usernames: There are four types of usernames:
(1) Regular usernames. These are external names given to EAP-AKA' (1) Regular usernames. These are external names given to EAP-AKA'
peers. The regular usernames are further subdivided into to peers. The regular usernames are further subdivided into to
categories: categories:
(a) Permanent usernames, for instance IMSI-based usernames. (a) Permanent usernames, for instance IMSI-based usernames.
(b) Privacy-friendly temporary usernames, for instance 5G GUTI (b) Privacy-friendly temporary usernames, for instance 5G GUTI
or 5G privacy identifiers (see Section 5.3.2). (5G Globally Unique Temporary Identifier) or 5G privacy
identifiers (see Section 5.3.2), for instance SUCI
(Subscription Concealed Identifier).
(2) EAP-AKA' pseudonym usernames. For example, (2) EAP-AKA' pseudonym usernames. For example,
2s7ah6n9q@example.com might be a valid pseudonym identity. In 2s7ah6n9q@example.com might be a valid pseudonym identity. In
this example, 2s7ah6n9q is the pseudonym username. this example, 2s7ah6n9q is the pseudonym username.
(3) EAP-AKA' fast re-authentication usernames. For example, (3) EAP-AKA' fast re-authentication usernames. For example,
43953754@example.com might be a valid fast re-authentication 43953754@example.com might be a valid fast re-authentication
identity and 43953754 the fast re-authentication username. identity and 43953754 the fast re-authentication username.
The permanent, privacy-friendly temporary, and pseudonym usernames The permanent, privacy-friendly temporary, and pseudonym usernames
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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, privacy The identity carried above may be a permanent identity, privacy
friendly identity, pseudonym identity, or fast re-authentication friendly identity, pseudonym identity, or fast re-authentication
identity as defined in this RFC. identity as defined in Section 5.1.
5G supports the concept of privacy identifiers, and it is important 5G supports the concept of privacy identifiers, and it is important
for interoperability that the right type of identifier is used. for interoperability that the right type of identifier is used.
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] [TS-3GPP.23.003]. SUPI is globally unique and [TS-3GPP.33.501] [TS-3GPP.23.003]. SUPI is globally unique and
allocated to each subscriber. However, it is only used internally in allocated to each subscriber. However, it is only used internally in
the 5G network, and is privacy sensitive. The SUCI is a privacy the 5G network, and is privacy sensitive. The SUCI is a privacy
preserving identifier containing the concealed SUPI, using public key preserving identifier containing the concealed SUPI, using public key
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For an example of the format of the identity, see Clause 2.2 of For an example of the format of the identity, see Clause 2.2 of
[TS-3GPP.23.003]. [TS-3GPP.23.003].
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.
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.
5.3.2. EAP Identity Response and EAP-AKA' AT_IDENTITY Attribute 5.3.2. EAP Identity Response and EAP-AKA' AT_IDENTITY Attribute
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identifier. identifier.
For an example of an IMSI in NAI format, see [TS-3GPP.23.003] For an example of an IMSI in NAI format, see [TS-3GPP.23.003]
Section 28.7.3. Section 28.7.3.
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.
6. Exported Parameters 6. Exported Parameters
The EAP-AKA' Session-Id is the concatenation of the EAP Type Code When not using fast re-authentication, the EAP-AKA' Session-Id is the
(0x32, one byte) with the contents of the RAND field from the AT_RAND concatenation of the EAP Type Code (0x32, one byte) with the contents
attribute, followed by the contents of the AUTN field in the AT_AUTN of the RAND field from the AT_RAND attribute, followed by the
attribute: contents of the AUTN field in the AT_AUTN attribute :
Session-Id = 0x32 || RAND || AUTN Session-Id = 0x32 || 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
concatenation of the EAP Type Code (0x32) with the contents of the concatenation of the EAP Type Code (0x32) with the contents of the
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 = 0x32 || NONCE_S || MAC Session-Id = 0x32 || 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 bytes AT_IDENTITY attribute, using only the Actual Identity Length bytes
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. If no permanent, pseudonym, or fast EAP re-authentication identity. If no
AT_IDENTITY attribute was exchanged, the exported Peer-Id is the AT_IDENTITY attribute was exchanged, the exported Peer-Id is the
identity provided from the EAP Identity Response packet. If no EAP identity provided from the EAP Identity Response packet. If no EAP
Identity Response was provided either, the exported Peer-Id is null Identity Response was provided either, the exported Peer-Id is the
string (zero length). null string (zero length).
The Server-Id is the 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 HMAC properties are very similar to those in EAP-AKA. We assume that HMAC
SHA-256 is at least as secure as HMAC SHA-1 (see also [RFC6194]. SHA-256 is at least as secure as HMAC SHA-1 (see also [RFC6194].
This is called the SHA-256 assumption in the remainder of this This is called the SHA-256 assumption in the remainder of this
section. Under this assumption, EAP-AKA' is at least as secure as section. Under this assumption, EAP-AKA' is at least as secure as
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Per assumptions in Section 4, there is no protection against Per assumptions in Section 4, there is no protection against
bidding down attacks from EAP-AKA to EAP-AKA', should EAP-AKA' bidding down attacks from EAP-AKA to EAP-AKA', should EAP-AKA'
somehow be considered less secure some day than EAP-AKA. Such somehow be considered less secure some day than EAP-AKA. Such
protection was not provided in RFC 5448 implementations and protection was not provided in RFC 5448 implementations and
consequently neither does this specification provide it. If such consequently neither does this specification provide it. If such
support is needed, it would have to be added as a separate new support is needed, it would have to be added as a separate new
feature. feature.
In general, it is expected that the current negotiation In general, it is expected that the current negotiation
capabilities in EAP-AKA' are sufficient for some types of capabilities in EAP-AKA' are sufficient for some types of
extensions and cryptographic agility, including adding Perfect extensions, including adding Perfect Forward Secrecy
Forward Secrecy ([I-D.ietf-emu-aka-pfs]) and perhaps others. But ([I-D.ietf-emu-aka-pfs]) and perhaps others. But as with how EAP-
as with how EAP-AKA' itself came about, some larger changes may AKA' itself came about, some larger changes may require a new EAP
require a new EAP method type. method type. One example of such change would be the introduction
of new algorithms.
Mutual authentication Mutual authentication
Under the SHA-256 assumption, the properties of EAP-AKA' are at Under the SHA-256 assumption, the properties of EAP-AKA' are at
least as good as those of EAP-AKA in this respect. Refer to least as good as those of EAP-AKA in this respect. Refer to
[RFC4187], Section 12 for further details. [RFC4187], Section 12 for further details.
Integrity protection Integrity protection
Under the SHA-256 assumption, the properties of EAP-AKA' are at Under the SHA-256 assumption, the properties of EAP-AKA' are at
skipping to change at page 28, line 35 skipping to change at page 28, line 38
7.1. Privacy 7.1. Privacy
[RFC6973] suggests that the privacy considerations of IETF protocols [RFC6973] suggests that the privacy considerations of IETF protocols
be documented. be documented.
The confidentiality properties of EAP-AKA' itself have been discussed The confidentiality properties of EAP-AKA' itself have been discussed
above under "Confidentiality". above under "Confidentiality".
EAP-AKA' uses several different types of identifiers to identify the EAP-AKA' uses several different types of identifiers to identify the
authenticating peer. It is strongly RECOMMENDED to use the privacy- authenticating peer. It is strongly RECOMMENDED to use the privacy-
friendly temporary or hidden identifiers, i.e., the 5G SUCI, friendly temporary or hidden identifiers, i.e., the 5G GUTI or SUCI,
pseudonym usernames, and fast re-authentication usernames. The use pseudonym usernames, and fast re-authentication usernames. The use
of permanent identifiers such as the IMSI or SUPI may lead to an 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 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 use of permanent identifiers such as the IMSI or SUPI is strongly NOT
RECOMMENDED. RECOMMENDED.
As discussed in Section 5.3, when authenticating to a 5G network, As discussed in Section 5.3, when authenticating to a 5G network,
only the 5G SUCI identifier is normally used. The use of EAP-AKA' only the SUCI identifier is normally used. The use of EAP-AKA'
pseudonyms in this situation is at best limited, because the 5G SUCI pseudonyms in this situation is at best limited, because the SUCI
already provides a stronger mechanism. In fact, the re-use of the already provides a stronger mechanism. In fact, the re-use of the
same pseudonym multiple times will result in a tracking opportunity same pseudonym multiple times will result in a tracking opportunity
for observers that see the pseudonym pass by. To avoid this, the 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. 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- When authenticating to a 5G network, per Section 5.3.1, both the EAP-
AKA' peer and server need to employ the permanent identifier, SUPI, AKA' peer and server need to employ the permanent identifier, SUPI,
as an input to key derivation. However, this use of the SUPI is only as an input to key derivation. However, this use of the SUPI is only
internal. As such, the SUPI need not be communicated in EAP internal. As such, the SUPI need not be communicated in EAP
messages. Therefore, SUPI MUST NOT be communicated in EAP-AKA' when messages. Therefore, SUPI MUST NOT be communicated in EAP-AKA' when
authenticating to a 5G network. authenticating to a 5G network.
While the use of SUCI in 5G networks generally provides identity While the use of SUCI in 5G networks generally provides identity
privacy, this is not true if the null-scheme encryption is used to 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 construct the SUCI (see [TS-3GPP.33.501] Annex C). The use of this
scheme turns the use of SUCI equivalent to the use of SUPI or IMSI. 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 The use of the null scheme is NOT RECOMMENDED where identity privacy
is important. is important.
The use of fast re-authentication identities when authenticating to a The use of fast re-authentication identities when authenticating to a
5G network does not have the same problems as the use of pseudonyms, 5G network does not have the same problems as the use of pseudonyms,
as long as the 5G authentication server generates the fast re- as long as the 5G authentication server generates the fast re-
authentication identifiers in a proper manner specified in authentication identifiers in a proper manner specified in
Section 5.2. Section 5.2.
skipping to change at page 29, line 44 skipping to change at page 29, line 48
refuse to send the cleartext permanent identity if it believes refuse to send the cleartext permanent identity if it believes
that the network should be able to recognize the pseudonym. that the network should be able to recognize the pseudonym.
o When pseudonyms and fast re-authentication identities are used, o When pseudonyms and fast re-authentication identities are used,
the peer relies on the properly created identifiers by the server. the peer relies on the properly created identifiers by the server.
It is essential that an attacker cannot link a privacy-friendly It is essential that an attacker cannot link a privacy-friendly
identifier to the user in any way or determine that two identifier to the user in any way or determine that two
identifiers belong to the same user as outlined in Section 5.2. identifiers belong to the same user as outlined in Section 5.2.
The pseudonym usernames and fast re-authentication identities MUST The pseudonym usernames and fast re-authentication identities MUST
also not be used for other purposes (e.g. in other protocols). 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 If the peer and server cannot guarantee that SUCI can be used or
pseudonyms will available, generated properly, and maintained pseudonyms will be available, generated properly, and maintained
reliably, and identity privacy is required then additional protection reliably, and identity privacy is required then additional protection
from an external security mechanism such as tunneled EAP methods may from an external security mechanism such as tunneled EAP methods such
be used. The benefits and the security considerations of using an as TTLS [RFC5281] or TEAP [RFC7170] may be used. The benefits and
external security mechanism with EAP-AKA are beyond the scope of this the security considerations of using an external security mechanism
document. with EAP-AKA are beyond the scope of this document.
Finally, as with other EAP methods, even when privacy-friendly Finally, as with other EAP methods, even when privacy-friendly
identifiers or EAP tunneling is used, typically the domain part of an identifiers or EAP tunneling is used, typically the domain part of an
identifier (e.g., the home operator) is visible to external parties. identifier (e.g., the home operator) is visible to external parties.
7.2. Discovered Vulnerabilities 7.2. Discovered Vulnerabilities
There have been no published attacks that violate the primary secrecy There have been no published attacks that violate the primary secrecy
or authentication properties defined for Authentication and Key or authentication properties defined for Authentication and Key
Agreement (AKA) under the originally assumed trust model. The same Agreement (AKA) under the originally assumed trust model. The same
is true of EAP-AKA'. is true of EAP-AKA'.
However, there have been attacks when a different trust model is in However, there have been attacks when a different trust model is in
use, with characteristics not originally provided by the design, or use, with characteristics not originally provided by the design, or
when participants in the protocol leak information to outsiders on when participants in the protocol leak information to outsiders on
purpose, and there has been some privacy-related attacks. purpose, and there have been some privacy-related attacks.
For instance, the original AKA protocol does not prevent supplying 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 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 Tsay in [MT2012] where a serving network lets an authentication run
succeed, but then misuses the session keys to send traffic on the succeed, but then misuses the session keys to send traffic on the
authenticated user's behalf. This particular attack is not different authenticated user's behalf. This particular attack is not different
from any on-path entity (such as a router) pretending to send from any on-path entity (such as a router) pretending to send
traffic, but the general issue of insider attacks can be a problem, traffic, but the general issue of insider attacks can be a problem,
particularly in a large group of collaborating operators. particularly in a large group of collaborating operators.
skipping to change at page 31, line 11 skipping to change at page 31, line 13
serving network may request large numbers of authentication runs for serving network may request large numbers of authentication runs for
a particular subscriber from a home network. While resynchronization a particular subscriber from a home network. While resynchronization
process can help recover from this, eventually it is possible to process can help recover from this, eventually it is possible to
exhaust the sequence number space and render the subscriber's card exhaust the sequence number space and render the subscriber's card
unusable. This attack is possible for both native AKA and EAP-AKA'. unusable. This attack is possible for both native AKA and EAP-AKA'.
However, it requires the collaboration of a serving network in an However, it requires the collaboration of a serving network in an
attack. It is recommended that EAP-AKA' implementations provide attack. It is recommended that EAP-AKA' implementations provide
means to track, detect, and limit excessive authentication attempts means to track, detect, and limit excessive authentication attempts
to combat this problem. to combat this problem.
There has also been attacks related to the use of AKA without the There have also been attacks related to the use of AKA without the
generated session keys (e.g., [BT2013]). Some of those attacks generated session keys (e.g., [BT2013]). Some of those attacks
relate to the use of originally man-in-the-middle vulnerable HTTP relate to the use of originally man-in-the-middle vulnerable HTTP
Digest AKAv1 [RFC3310]. This has since then been corrected in Digest AKAv1 [RFC3310]. This has since then been corrected in
[RFC4169]. The EAP-AKA' protocol uses session keys and provides [RFC4169]. The EAP-AKA' protocol uses session keys and provides
channel binding, and as such, is resistant to the above attacks channel binding, and as such, is resistant to the above attacks
except where the protocol participants leak information to outsiders. except where the protocol participants leak information to outsiders.
Basin et al [Basin2018] have performed formal analysis and concluded Basin et al [Basin2018] have performed formal analysis and concluded
that the AKA protocol would have benefited from additional security that the AKA protocol would have benefited from additional security
requirements, such as key confirmation. requirements, such as key confirmation.
skipping to change at page 32, line 17 skipping to change at page 32, line 17
short messages or make phone calls to the intended victim and observe short messages or make phone calls to the intended victim and observe
the air-interface (e.g., [Kune2012] and [Shaik2016]). Hussain et. the air-interface (e.g., [Kune2012] and [Shaik2016]). Hussain et.
al. demonstrated a slightly more sophisticated version of the attack al. demonstrated a slightly more sophisticated version of the attack
that exploits the fact that 4G paging protocol uses the IMSI to that exploits the fact that 4G paging protocol uses the IMSI to
calculate the paging timeslot [Hussain2019]. As this attack is calculate the paging timeslot [Hussain2019]. As this attack is
outside AKA, it does not impact EAP-AKA'. outside AKA, it does not impact EAP-AKA'.
Finally, bad implementations of EAP-AKA' may not produce pseudonym Finally, bad implementations of EAP-AKA' may not produce pseudonym
usernames or fast re-authentication identities in a manner that is usernames or fast re-authentication identities in a manner that is
sufficiently secure. While it is not a problem with the protocol sufficiently secure. While it is not a problem with the protocol
itself, recommendations from Section 5.2 need to be followed to avoid itself, following the recommendations in Section 5.2 mitigate this
this. concern.
7.3. Pervasive Monitoring 7.3. Pervasive Monitoring
As required by [RFC7258], work on IETF protocols needs to consider As required by [RFC7258], work on IETF protocols needs to consider
the effects of pervasive monitoring and mitigate them when possible. the effects of pervasive monitoring and mitigate them when possible.
As described Section 7.2, after the publication of RFC 5448, new As described in Section 7.2, after the publication of RFC 5448, new
information has come to light regarding the use of pervasive information has come to light regarding the use of pervasive
monitoring techniques against many security technologies, including monitoring techniques against many security technologies, including
AKA-based authentication. AKA-based authentication.
For AKA, these attacks relate to theft of the long-term shared secret For AKA, these attacks relate to theft of the long-term shared secret
key material stored on the cards. Such attacks are conceivable, for key material stored on the cards. Such attacks are conceivable, for
instance, during the manufacturing process of cards, through coercion instance, during the manufacturing process of cards, through coercion
of the card manufacturers, or during the transfer of cards and of the card manufacturers, or during the transfer of cards and
associated information to an operator. Since the publication of associated information to an operator. Since the publication of
reports about such attacks, manufacturing and provisioning processes reports about such attacks, manufacturing and provisioning processes
have gained much scrutiny and have improved. have gained much scrutiny and have improved.
In particular, it is crucial that manufacturers limit access to the In particular, it is crucial that manufacturers limit access to the
secret information and the cards only to necessary systems and secret information and the cards only to necessary systems and
personnel. It is also crucial that secure mechanisms be used to personnel. It is also crucial that secure mechanisms be used to
communicate the secrets between the manufacturer and the operator store and communicate the secrets between the manufacturer and the
that adopts those cards for their customers. operator that adopts those cards for their customers.
Beyond these operational considerations, there are also technical Beyond these operational considerations, there are also technical
means to improve resistance to these attacks. One approach is to means to improve resistance to these attacks. One approach is to
provide Perfect Forwards Secrecy (PFS). This would prevent any provide Perfect Forward Secrecy (PFS). This would prevent any
passive attacks merely based on the long-term secrets and observation passive attacks merely based on the long-term secrets and observation
of traffic. Such a mechanism can be defined as a backwards- of traffic. Such a mechanism can be defined as a backwards-
compatible extension of EAP-AKA', and is pursued separately from this compatible extension of EAP-AKA', and is pursued separately from this
specification [I-D.ietf-emu-aka-pfs]. Alternatively, EAP-AKA' specification [I-D.ietf-emu-aka-pfs]. Alternatively, EAP-AKA'
authentication can be run inside a PFS-capable tunneled authentication can be run inside a PFS-capable tunneled
authentication method. In any case, the use of some PFS-capable authentication method. In any case, the use of some PFS-capable
mechanism is recommended. mechanism is recommended.
7.4. Security Properties of Binding Network Names 7.4. Security Properties of Binding Network Names
skipping to change at page 38, line 24 skipping to change at page 38, line 24
[RFC5113] Arkko, J., Aboba, B., Korhonen, J., Ed., and F. Bari, [RFC5113] Arkko, J., Aboba, B., Korhonen, J., Ed., and F. Bari,
"Network Discovery and Selection Problem", RFC 5113, "Network Discovery and Selection Problem", RFC 5113,
DOI 10.17487/RFC5113, January 2008, <https://www.rfc- DOI 10.17487/RFC5113, January 2008, <https://www.rfc-
editor.org/info/rfc5113>. editor.org/info/rfc5113>.
[RFC5247] Aboba, B., Simon, D., and P. Eronen, "Extensible [RFC5247] Aboba, B., Simon, D., and P. Eronen, "Extensible
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>.
[RFC5281] Funk, P. and S. Blake-Wilson, "Extensible Authentication
Protocol Tunneled Transport Layer Security Authenticated
Protocol Version 0 (EAP-TTLSv0)", RFC 5281,
DOI 10.17487/RFC5281, August 2008, <https://www.rfc-
editor.org/info/rfc5281>.
[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>.
[RFC6194] Polk, T., Chen, L., Turner, S., and P. Hoffman, "Security [RFC6194] Polk, T., Chen, L., Turner, S., and P. Hoffman, "Security
Considerations for the SHA-0 and SHA-1 Message-Digest Considerations for the SHA-0 and SHA-1 Message-Digest
Algorithms", RFC 6194, DOI 10.17487/RFC6194, March 2011, Algorithms", RFC 6194, DOI 10.17487/RFC6194, March 2011,
<https://www.rfc-editor.org/info/rfc6194>. <https://www.rfc-editor.org/info/rfc6194>.
[RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., [RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
Morris, J., Hansen, M., and R. Smith, "Privacy Morris, J., Hansen, M., and R. Smith, "Privacy
Considerations for Internet Protocols", RFC 6973, Considerations for Internet Protocols", RFC 6973,
DOI 10.17487/RFC6973, July 2013, <https://www.rfc- DOI 10.17487/RFC6973, July 2013, <https://www.rfc-
editor.org/info/rfc6973>. editor.org/info/rfc6973>.
[RFC7170] Zhou, H., Cam-Winget, N., Salowey, J., and S. Hanna,
"Tunnel Extensible Authentication Protocol (TEAP) Version
1", RFC 7170, DOI 10.17487/RFC7170, May 2014,
<https://www.rfc-editor.org/info/rfc7170>.
[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an [RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
2014, <https://www.rfc-editor.org/info/rfc7258>. 2014, <https://www.rfc-editor.org/info/rfc7258>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2 Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>. 2014, <https://www.rfc-editor.org/info/rfc7296>.
[I-D.ietf-emu-aka-pfs] [I-D.ietf-emu-aka-pfs]
Arkko, J., Norrman, K., and V. Torvinen, "Perfect-Forward Arkko, J., Norrman, K., and V. Torvinen,"Perfect-Forward Secrecy
Secrecy for the Extensible Authentication Protocol Method for the Extensible Authentication Protocol Method for
for Authentication and Key Agreement (EAP-AKA' PFS)", Authentication and Key Agreement (EAP-AKA' PFS)", draft-
draft-ietf-emu-aka-pfs-05 (work in progress), October ietf-emu-aka-pfs-05 (work in progress), October 2020.
2020.
[Heist2015] [Heist2015]
Scahill, J. and J. Begley, "The great SIM heist", February Scahill, J. and J. Begley, "The great SIM heist", February
2015, in https://firstlook.org/theintercept/2015/02/19/ 2015, in https://firstlook.org/theintercept/2015/02/19/
great-sim-heist/ . great-sim-heist/ .
[MT2012] Mjolsnes, S. and J-K. Tsay, "A vulnerability in the UMTS [MT2012] Mjolsnes, S. and J-K. Tsay, "A vulnerability in the UMTS
and LTE authentication and key agreement protocols", and LTE authentication and key agreement protocols",
October 2012, in Proceedings of the 6th international October 2012, in Proceedings of the 6th international
conference on Mathematical Methods, Models and conference on Mathematical Methods, Models and
skipping to change at page 44, line 46 skipping to change at page 45, line 5
o Clarified that the Section 5.2 text does not impact backwards o Clarified that the Section 5.2 text does not impact backwards
compatibility. compatibility.
o Corrected the characterization of the attack from [ZF2005]. o Corrected the characterization of the attack from [ZF2005].
o Mentioned 5G GUTIs as one possible 5G-identifier in Section 5.1. o Mentioned 5G GUTIs as one possible 5G-identifier in Section 5.1.
o Updated the references to Release 16. These specifications are o Updated the references to Release 16. These specifications are
stable in 3GPP. stable in 3GPP.
Version -10 is the final version and made changes per IESG and
directorate review comments. These changes were editorial. One
duplicate requirement in Section 5.3.1 was removed, and some
references were added for tunnel methods discussion in Section 7.1.
The language about exported parameters was clarified in Section 6.
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
know whether they are connecting to the old or new system. know whether they are connecting to the old or new system.
skipping to change at page 50, line 16 skipping to change at page 51, line 16
provided much of the text for Section 7.1. Karl Norrman was the provided much of the text for Section 7.1. Karl Norrman was the
source of much of the information in Section 7.2. source of much of the information in Section 7.2.
Acknowledgments Acknowledgments
The authors would like to thank Guenther Horn, Joe Salowey, Mats The authors would like to thank Guenther Horn, Joe Salowey, Mats
Naslund, Adrian Escott, Brian Rosenberg, Laksminath Dondeti, Ahmad Naslund, Adrian Escott, Brian Rosenberg, Laksminath Dondeti, Ahmad
Muhanna, Stefan Rommer, Miguel Garcia, Jan Kall, Ankur Agarwal, Jouni Muhanna, Stefan Rommer, Miguel Garcia, Jan Kall, Ankur Agarwal, Jouni
Malinen, John Mattsson, Jesus De Gregorio, Brian Weis, Russ Housley, Malinen, John Mattsson, Jesus De Gregorio, Brian Weis, Russ Housley,
Alfred Hoenes, Anand Palanigounder, Michael Richardsson, Roman Alfred Hoenes, Anand Palanigounder, Michael Richardsson, Roman
Danyliw, Dan Romascanu, Kyle Rose, Marcus Wong, Kalle Jarvinen, Danyliw, Dan Romascanu, Kyle Rose, Benjamin Kaduk, Alissa Cooper,
Daniel Migault, and Mohit Sethi for their in-depth reviews and Erik Kline, Murray Kucherawy, Robert Wilton, Warren Kumari, Andreas
interesting discussions in this problem space. Kunz, Marcus Wong, Kalle Jarvinen, Daniel Migault, 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
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