draft-ietf-emu-eap-gpsk-17.txt   rfc5433.txt 
EMU Working Group T. Clancy Network Working Group T. Clancy
Internet-Draft LTS Request for Comments: 5433 LTS
Intended status: Standards Track H. Tschofenig Category: Standards Track H. Tschofenig
Expires: May 23, 2009 Nokia Siemens Networks Nokia Siemens Networks
November 19, 2008 February 2009
EAP Generalized Pre-Shared Key (EAP-GPSK) Method
draft-ietf-emu-eap-gpsk-17
Status of this Memo
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applicable patent or other IPR claims of which he or she is aware Generalized Pre-Shared Key (EAP-GPSK) Method
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Abstract Abstract
This Internet Draft defines an Extensible Authentication Protocol This memo defines an Extensible Authentication Protocol (EAP) method
(EAP) method called EAP Generalized Pre-Shared Key (EAP-GPSK). This called EAP Generalized Pre-Shared Key (EAP-GPSK). This method is a
method is a lightweight shared-key authentication protocol supporting lightweight shared-key authentication protocol supporting mutual
mutual authentication and key derivation. authentication and key derivation.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction ....................................................3
2. Terminology .....................................................4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Overview ........................................................6
4. Key Derivation ..................................................8
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5. Key Management .................................................11
6. Ciphersuites ...................................................11
4. Key Derivation . . . . . . . . . . . . . . . . . . . . . . . . 9 7. Generalized Key Derivation Function (GKDF) .....................12
8. Ciphersuites Processing Rules ..................................13
5. Key Management . . . . . . . . . . . . . . . . . . . . . . . . 11 8.1. Ciphersuite #1 ............................................13
8.1.1. Encryption .........................................13
6. Ciphersuites . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.1.2. Integrity ..........................................13
8.2. Ciphersuite #2 ............................................14
7. Generalized Key Derivation Function (GKDF) . . . . . . . . . . 13 8.2.1. Encryption .........................................14
8.2.2. Integrity ..........................................14
8. Ciphersuites Processing Rules . . . . . . . . . . . . . . . . 13 9. Packet Formats .................................................15
8.1. Ciphersuite #1 . . . . . . . . . . . . . . . . . . . . . 13 9.1. Header Format .............................................15
8.1.1. Encryption . . . . . . . . . . . . . . . . . . . . . . 14 9.2. Ciphersuite Formatting ....................................16
8.1.2. Integrity . . . . . . . . . . . . . . . . . . . . . . 14 9.3. Payload Formatting ........................................16
8.2. Ciphersuite #2 . . . . . . . . . . . . . . . . . . . . . 14 9.4. Protected Data ............................................21
8.2.1. Encryption . . . . . . . . . . . . . . . . . . . . . . 14 10. Packet Processing Rules .......................................24
8.2.2. Integrity . . . . . . . . . . . . . . . . . . . . . . 14 11. Example Message Exchanges .....................................25
12. Security Considerations .......................................28
9. Packet Formats . . . . . . . . . . . . . . . . . . . . . . . . 15 12.1. Security Claims ..........................................28
9.1. Header Format . . . . . . . . . . . . . . . . . . . . . . 15 12.2. Mutual Authentication ....................................29
9.2. Ciphersuite Formatting . . . . . . . . . . . . . . . . . 16 12.3. Protected Result Indications .............................29
9.3. Payload Formatting . . . . . . . . . . . . . . . . . . . 16 12.4. Integrity Protection .....................................29
9.4. Protected Data . . . . . . . . . . . . . . . . . . . . . 21 12.5. Replay Protection ........................................30
12.6. Reflection Attacks .......................................30
10. Packet Processing Rules . . . . . . . . . . . . . . . . . . . 24 12.7. Dictionary Attacks .......................................30
12.8. Key Derivation and Key Strength ..........................31
11. Example Message Exchanges . . . . . . . . . . . . . . . . . . 25 12.9. Denial-of-Service Resistance .............................31
12.10. Session Independence ....................................32
12. Security Considerations . . . . . . . . . . . . . . . . . . . 28 12.11. Compromise of the PSK ...................................32
12.1. Security Claims . . . . . . . . . . . . . . . . . . . . . 28 12.12. Fragmentation ...........................................32
12.2. Mutual Authentication . . . . . . . . . . . . . . . . . . 29 12.13. Channel Binding .........................................32
12.3. Protected Result Indications . . . . . . . . . . . . . . 29 12.14. Fast Reconnect ..........................................33
12.4. Integrity Protection . . . . . . . . . . . . . . . . . . 30 12.15. Identity Protection .....................................33
12.5. Replay Protection . . . . . . . . . . . . . . . . . . . . 30 12.16. Protected Ciphersuite Negotiation .......................33
12.6. Reflection attacks . . . . . . . . . . . . . . . . . . . 30 12.17. Confidentiality .........................................34
12.7. Dictionary Attacks . . . . . . . . . . . . . . . . . . . 30 12.18. Cryptographic Binding ...................................34
12.8. Key Derivation and Key Strength . . . . . . . . . . . . . 31 13. IANA Considerations ...........................................34
12.9. Denial of Service Resistance . . . . . . . . . . . . . . 31 14. Contributors ..................................................35
12.10. Session Independence . . . . . . . . . . . . . . . . . . 32 15. Acknowledgments ...............................................36
12.11. Compromise of the PSK . . . . . . . . . . . . . . . . . . 32 16. References ....................................................37
12.12. Fragmentation . . . . . . . . . . . . . . . . . . . . . . 32 16.1. Normative References .....................................37
12.13. Channel Binding . . . . . . . . . . . . . . . . . . . . . 32 16.2. Informative References ...................................38
12.14. Fast Reconnect . . . . . . . . . . . . . . . . . . . . . 33
12.15. Identity Protection . . . . . . . . . . . . . . . . . . . 33
12.16. Protected Ciphersuite Negotiation . . . . . . . . . . . . 33
12.17. Confidentiality . . . . . . . . . . . . . . . . . . . . . 34
12.18. Cryptographic Binding . . . . . . . . . . . . . . . . . . 34
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34
14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 35
15. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 35
16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 36
16.1. Normative References . . . . . . . . . . . . . . . . . . 36
16.2. Informative References . . . . . . . . . . . . . . . . . 37
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 37
Intellectual Property and Copyright Statements . . . . . . . . . . 39
1. Introduction 1. Introduction
EAP Generalized Pre-Shared Key (EAP-GPSK) is an EAP method defining a EAP Generalized Pre-Shared Key (EAP-GPSK) is an EAP method defining a
generalized pre-shared key authentication technique. Mutual generalized pre-shared key authentication technique. Mutual
authentication is achieved through a nonce-based exchange that is authentication is achieved through a nonce-based exchange that is
secured by a pre-shared key. secured by a pre-shared key.
EAP-GPSK addresses a large number of design goals with the intention EAP-GPSK addresses a large number of design goals with the intention
of being applicable in a broad range of usage scenarios. of being applicable in a broad range of usage scenarios.
The main design goals of EAP-GPSK are The main design goals of EAP-GPSK are:
Simplicity: Simplicity:
EAP-GPSK should be easy to implement. EAP-GPSK should be easy to implement.
Security Model: Security Model:
EAP-GPSK has been designed in a threat model where the attacker EAP-GPSK has been designed in a threat model where the attacker
has full control over the communication channel. This is the EAP has full control over the communication channel. This EAP threat
threat model that is presented in Section 7.1 of [RFC3748]. model is presented in Section 7.1 of [RFC3748].
Efficiency: Efficiency:
EAP-GPSK does not make use of public key cryptography and fully EAP-GPSK does not make use of public key cryptography and fully
relies of symmetric cryptography. The restriction of symmetric relies of symmetric cryptography. The restriction of symmetric
cryptographic computations allows for low computational overhead. cryptographic computations allows for low computational overhead.
Hence, EAP-GPSK is lightweight and well suited for any type of Hence, EAP-GPSK is lightweight and well suited for any type of
device, especially those with processing power, memory and battery device, especially those with processing power, memory, and
constraints. Additionally it seeks to minimize the number of battery constraints. Additionally, it seeks to minimize the
round trips. number of round trips.
Flexibility: Flexibility:
EAP-GPSK offers cryptographic flexibility. At the beginning, the EAP-GPSK offers cryptographic flexibility. At the beginning, the
EAP server proposes a list of ciphersuites. The client then EAP server proposes a list of ciphersuites. The client then
selects one. The current version of EAP-GPSK includes two selects one. The current version of EAP-GPSK includes two
ciphersuites, but additional ones can be easily added. ciphersuites, but additional ones can be easily added.
Extensibility: Extensibility:
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words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
"SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document
are to be interpreted as described in [RFC2119]. are to be interpreted as described in [RFC2119].
This section describes the various variables and functions used in This section describes the various variables and functions used in
the EAP-GPSK method. the EAP-GPSK method.
Variables: Variables:
CSuite_List: An octet array listing available ciphersuites (variable CSuite_List: An octet array listing available ciphersuites (variable
length) length).
CSuite_Sel: Ciphersuite selected by the peer (6 octets) CSuite_Sel: Ciphersuite selected by the peer (6 octets).
ID_Peer: Peer NAI [RFC4282] ID_Peer: Peer Network Access Identifier (NAI) [RFC4282].
ID_Server: Server identity as an opaque blob. ID_Server: Server identity as an opaque blob.
KS: Integer representing the input key size in octets of the KS: Integer representing the input key size, in octets, of the
selected ciphersuite CSuite_Sel. The key size is one of the selected ciphersuite CSuite_Sel. The key size is one of the
ciphersuite parameters. ciphersuite parameters.
ML: Integer representing the length of the MAC output, in octets, of ML: Integer representing the length of the Message Authentication
the selected ciphersuite CSuite_Sel. Code (MAC) output, in octets, of the selected ciphersuite
CSuite_Sel.
PD_Payload: Data carried within the protected data payload PD_Payload: Data carried within the protected data payload.
PD_Payload_Block: Block of possibly multiple PD_Payloads carried by PD_Payload_Block: Block of possibly multiple PD_Payloads carried by
a GPSK packet a GPSK packet.
PL: Integer representing the length of the PSK in octets (2 octets). PL: Integer representing the length of the PSK in octets (2 octets).
PL MUST be larger than or equal to KS. PL MUST be larger than or equal to KS.
RAND_Peer: Random integer generated by the peer (32 octets) RAND_Peer: Random integer generated by the peer (32 octets).
RAND_Server: Random integer generated by the server (32 octets) RAND_Server: Random integer generated by the server (32 octets).
Operations: Operations:
A || B: Concatenation of octet strings A and B A || B: Concatenation of octet strings A and B.
A**B: Integer exponentiation A**B: Integer exponentiation.
truncate(A,B): Returns the first B octets of A truncate(A,B): Returns the first B octets of A.
ENC_X(Y): Encryption of message Y with a symmetric key X, using a ENC_X(Y): Encryption of message Y with a symmetric key X, using a
defined block cipher defined block cipher.
KDF-X(Y): Key Derivation Function that generates an arbitrary number KDF-X(Y): Key Derivation Function that generates an arbitrary number
of octets of output using secret X and seed Y of octets of output using secret X and seed Y.
length(X): Function that returns the length of input X in octets, length(X): Function that returns the length of input X in octets,
encoded as a 2-octet integer in network byte order encoded as a 2-octet integer in network byte order.
MAC_X(Y): Keyed message authentication code computed over Y with MAC_X(Y): Keyed message authentication code computed over Y with
symmetric key X symmetric key X.
SEC_X(Y): SEC is a function that provides integrity protection based SEC_X(Y): SEC is a function that provides integrity protection based
on the chosen ciphersuite. The function SEC uses the algorithm on the chosen ciphersuite. The function SEC uses the algorithm
defined by the selected ciphersuite and applies it to the message defined by the selected ciphersuite and applies it to the message
content Y with key X. In short, SEC_X(Y) = Y || MAC_X(Y). content Y with key X. In short, SEC_X(Y) = Y || MAC_X(Y).
X[A..B]: Notation representing octets A through B of octet array X X[A..B]: Notation representing octets A through B of octet array X
where the first octet of the array has index zero where the first octet of the array has index zero.
The following abbreviations are used for the keying material: The following abbreviations are used for the keying material:
EMSK: Extended Master Session Key is exported by the EAP method (64 EMSK: Extended Master Session Key is exported by the EAP method (64
octets) octets).
MK: A session-specific Master Key between the peer and EAP server MK: A session-specific Master Key between the peer and EAP server
from which all other EAP method session keys are derived (KS from which all other EAP method session keys are derived (KS
octets) octets).
MSK: Master Session Key exported by the EAP method (64 octets) MSK: Master Session Key exported by the EAP method (64 octets).
PK: Session key generated from the MK and used during protocol PK: Session key generated from the MK and used during protocol
exchange to encrypt protected data (KS octets) exchange to encrypt protected data (KS octets).
PSK: Long-term key shared between the peer and the server (PL PSK: Long-term key shared between the peer and the server (PL
octets) octets).
SK: Session key generated from the MK and used during protocol SK: Session key generated from the MK and used during protocol
exchange to demonstrate knowledge of the PSK (KS octets) exchange to demonstrate knowledge of the PSK (KS octets).
3. Overview 3. Overview
The EAP framework (see Section 1.3 of [RFC3748]) defines three basic The EAP framework (see Section 1.3 of [RFC3748]) defines three basic
steps that occur during the execution of an EAP conversation between steps that occur during the execution of an EAP conversation between
the EAP peer, the Authenticator and the EAP server. the EAP peer, the Authenticator, and the EAP server.
1. The first phase, discovery, is handled by the underlying 1. The first phase, discovery, is handled by the underlying
protocol, e.g. IEEE 802.1X as utilized by IEEE 802.11 [80211]. protocol, e.g., IEEE 802.1X as utilized by IEEE 802.11 [80211].
2. The EAP authentication phase with EAP-GPSK is defined in this 2. The EAP authentication phase with EAP-GPSK is defined in this
document. document.
3. The secure association distribution and secure association phases 3. The secure association distribution and secure association phases
are handled differently depending on the underlying protocol. are handled differently depending on the underlying protocol.
EAP-GPSK performs mutual authentication between EAP peer ("Peer") and EAP-GPSK performs mutual authentication between the EAP peer ("Peer")
EAP server ("Server") based on a pre-shared key (PSK). The protocol and EAP server ("Server") based on a pre-shared key (PSK). The
consists of the message exchanges (GPSK-1, ..., GPSK-4), in which protocol consists of the message exchanges (GPSK-1, ..., GPSK-4) in
both sides exchange nonces and their identities, compute and exchange which both sides exchange nonces and their identities, and compute
a Message Authentication Code (MAC) over the previously exchanged and exchange a Message Authentication Code (MAC) over the previously
values, keyed with the pre-shared key. This MAC is considered as exchanged values, keyed with the pre-shared key. This MAC is
proof of possession of the pre-shared key. Two further messages, considered as proof of possession of the pre-shared key. Two further
namely GPSK-Fail and GPSK-Protected-Fail are used to deal with error messages, namely GPSK-Fail and GPSK-Protected-Fail, are used to deal
situations. with error situations.
A successful protocol exchange is shown in Figure 1. A successful protocol exchange is shown in Figure 1.
+--------+ +--------+ +--------+ +--------+
| | EAP-Request/Identity | | | | EAP-Request/Identity | |
| EAP |<------------------------------------| EAP | | EAP |<------------------------------------| EAP |
| peer | | server | | peer | | server |
| | EAP-Response/Identity | | | | EAP-Response/Identity | |
| |------------------------------------>| | | |------------------------------------>| |
| | | | | | | |
skipping to change at page 8, line 49 skipping to change at page 8, line 4
CSuite_Sel, [ ENC_PK(PD_Payload_Block) ] ) CSuite_Sel, [ ENC_PK(PD_Payload_Block) ] )
GPSK-3: GPSK-3:
SEC_SK(RAND_Peer, RAND_Server, ID_Server, CSuite_Sel, [ SEC_SK(RAND_Peer, RAND_Server, ID_Server, CSuite_Sel, [
ENC_PK(PD_Payload_Block) ] ) ENC_PK(PD_Payload_Block) ] )
GPSK-4: GPSK-4:
SEC_SK( [ ENC_PK(PD_Payload_Block) ] ) SEC_SK( [ ENC_PK(PD_Payload_Block) ] )
The EAP server begins EAP-GPSK by selecting a random number The EAP server begins EAP-GPSK by selecting a random number
RAND_Server and by encoding the supported ciphersuites into RAND_Server and encoding the supported ciphersuites into CSuite_List.
CSuite_List. A ciphersuite consists of an encryption algorithm, a A ciphersuite consists of an encryption algorithm, a key derivation
key derivation function and a message authentication code. function, and a message authentication code.
In GPSK-1, the EAP server sends its identity ID_Server, a random In GPSK-1, the EAP server sends its identity ID_Server, a random
number RAND_Server and a list of supported ciphersuites CSuite_List. number RAND_Server, and a list of supported ciphersuites CSuite_List.
The decision which ciphersuite to offer and which ciphersuite to pick The decision of which ciphersuite to offer and which ciphersuite to
is policy- and implementation-dependent and therefore outside the pick is policy- and implementation-dependent and, therefore, outside
scope of this document. the scope of this document.
In GPSK-2, the peer sends its identity ID_Peer and a random number In GPSK-2, the peer sends its identity ID_Peer and a random number
RAND_Peer. Furthermore, it repeats the received parameters of the RAND_Peer. Furthermore, it repeats the received parameters of the
GPSK-1 message (ID_Server, RAND_Server, CSuite_List) and the selected GPSK-1 message (ID_Server, RAND_Server, CSuite_List) and the selected
ciphersuite. It computes a Message Authentication Code over all the ciphersuite. It computes a Message Authentication Code over all the
transmitted parameters. transmitted parameters.
The EAP server verifies the received Message Authentication Code, and The EAP server verifies the received Message Authentication Code and
consistency of the identities, nonces, and ciphersuite parameters the consistency of the identities, nonces, and ciphersuite parameters
transmitted in GPSK-1. In case of successful verification, the EAP transmitted in GPSK-1. In case of successful verification, the EAP
server computes a Message Authentication Code over the session server computes a Message Authentication Code over the session
parameter and returns it to the peer (within GPSK-3). Within GPSK-2 parameter and returns it to the peer (within GPSK-3). Within GPSK-2
and GPSK-3, peer and EAP server have the possibility to exchange and GPSK-3, the EAP peer and EAP server have the possibility to
encrypted protected data parameters. exchange encrypted protected data parameters.
The peer verifies the received Message Authentication Code, and The peer verifies the received Message Authentication Code and the
consistency of the identities, nonces, and ciphersuite parameters consistency of the identities, nonces, and ciphersuite parameters
transmitted in GPSK-2. If the verification is successful, GPSK-4 is transmitted in GPSK-2. If the verification is successful, GPSK-4 is
prepared. This message can optionally contain the peer's protected prepared. This message can optionally contain the peer's protected
data parameters. data parameters.
Upon receipt of GPSK-4, the server processes any included Upon receipt of GPSK-4, the server processes any included
PD_Payload_Block. Then, the EAP server sends an EAP Success message PD_Payload_Block. Then, the EAP server sends an EAP Success message
to indicate the successful outcome of the authentication. to indicate the successful outcome of the authentication.
4. Key Derivation 4. Key Derivation
EAP-GPSK provides key derivation in compliance to the requirements of EAP-GPSK provides key derivation in compliance to the requirements of
[RFC3748] and [RFC5247]. Note that this section provides an abstract [RFC3748] and [RFC5247]. Note that this section provides an abstract
description for the key derivation procedure that needs to be description for the key derivation procedure that needs to be
instantiated with a specific ciphersuite. instantiated with a specific ciphersuite.
The long-term credential shared between EAP peer and EAP server The long-term credential shared between EAP peer and EAP server
SHOULD be a strong pre-shared key PSK of at least 16 octets, though SHOULD be a strong pre-shared key PSK of at least 16 octets, though
its length and entropy is variable. While it is possible to use a its length and entropy are variable. While it is possible to use a
password or passphrase, doing so is NOT RECOMMENDED as EAP-GPSK is password or passphrase, doing so is NOT RECOMMENDED as EAP-GPSK is
vulnerable to dictionary attacks. vulnerable to dictionary attacks.
During an EAP-GPSK authentication, a Master Key MK, a Session Key SK During an EAP-GPSK authentication, a Master Key MK, a Session Key SK,
and a Protected Data Encryption Key PK (if using an encrypting and a Protected Data Encryption Key PK (if using an encrypting
ciphersuite) are derived using the ciphersuite-specified KDF and data ciphersuite) are derived using the ciphersuite-specified KDF and data
exchanged during the execution of the protocol, namely 'RAND_Peer || exchanged during the execution of the protocol, namely 'RAND_Peer ||
ID_Peer || RAND_Server || ID_Server' referred as inputString as its ID_Peer || RAND_Server || ID_Server', referred to as inputString in
short-hand form. its short-hand form.
In case of successful completion, EAP-GPSK derives and exports an MSK In case of successful completion, EAP-GPSK derives and exports an MSK
and EMSK both in length of 64 octets. and an EMSK, each 64 octets in length.
The following notation is used: KDF-X(Y, Z)[A..B], whereby The following notation is used: KDF-X(Y, Z)[A..B], whereby
X is the length, in octets, of the desired output, X is the length, in octets, of the desired output,
Y is a secret key, Y is a secret key,
Z is the inputString, Z is the inputString,
[A..B] extracts the string of octets starting with octet A finishing
with octet B from the output of the KDF function. [A..B] extracts the string of octets starting with octet A and
finishing with octet B from the output of the KDF function.
This keying material is derived using the ciphersuite-specified KDF This keying material is derived using the ciphersuite-specified KDF
as follows: as follows:
o inputString = RAND_Peer || ID_Peer || RAND_Server || ID_Server o inputString = RAND_Peer || ID_Peer || RAND_Server || ID_Server
o MK = KDF-KS(PSK[0..KS-1], PL || PSK || CSuite_Sel || o MK = KDF-KS(PSK[0..KS-1], PL || PSK || CSuite_Sel ||
inputString)[0..KS-1] inputString)[0..KS-1]
o MSK = KDF-{128+2*KS}(MK, inputString)[0..63] o MSK = KDF-{128+2*KS}(MK, inputString)[0..63]
o EMSK = KDF-{128+2*KS}(MK, inputString)[64..127] o EMSK = KDF-{128+2*KS}(MK, inputString)[64..127]
o SK = KDF-{128+2*KS}(MK, inputString)[128..127+KS] o SK = KDF-{128+2*KS}(MK, inputString)[128..127+KS]
o PK = KDF-{128+2*KS}(MK, inputString)[128+KS..127+2*KS] (if using o PK = KDF-{128+2*KS}(MK, inputString)[128+KS..127+2*KS] (if using
an encrypting ciphersuite) an encrypting ciphersuite)
The value for PL (the length of the PSK in octets) is encoded as a The value for PL (the length of the PSK in octets) is encoded as a
2-octet integer in network byte order. Recall that KS is the length 2-octet integer in network byte order. Recall that KS is the length
of the ciphersuite input key size in octets. of the ciphersuite input key size in octets.
Additionally, the EAP keying framework [RFC5247] requires the Additionally, the EAP keying framework [RFC5247] requires the
definition of a Method-ID, Session-ID, Peer-ID, and Server-ID. These definition of a Method-ID, Session-ID, Peer-ID, and Server-ID. These
values are defined as: values are defined as:
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2-octet integer in network byte order. Recall that KS is the length 2-octet integer in network byte order. Recall that KS is the length
of the ciphersuite input key size in octets. of the ciphersuite input key size in octets.
Additionally, the EAP keying framework [RFC5247] requires the Additionally, the EAP keying framework [RFC5247] requires the
definition of a Method-ID, Session-ID, Peer-ID, and Server-ID. These definition of a Method-ID, Session-ID, Peer-ID, and Server-ID. These
values are defined as: values are defined as:
o Method-ID = KDF-16(PSK[0..KS-1], "Method ID" || EAP_Method_Type || o Method-ID = KDF-16(PSK[0..KS-1], "Method ID" || EAP_Method_Type ||
CSuite_Sel || inputString)[0..15] CSuite_Sel || inputString)[0..15]
o Session-ID = EAP_Method_Type || Method_ID o Session-ID = EAP_Method_Type || Method_ID
o Peer-ID = ID_Peer o Peer-ID = ID_Peer
o Server-ID = ID_Server o Server-ID = ID_Server
EAP_Method_Type refers to the 1-octet IANA allocated EAP Type code EAP_Method_Type refers to the 1-octet, IANA-allocated EAP Type code
value. value.
Figure 2 depicts the key derivation procedure of EAP-GPSK. Figure 2 depicts the key derivation procedure of EAP-GPSK.
+-------------+ +-------------------------------+ +-------------+ +-------------------------------+
| PL-octet | | RAND_Peer || ID_Peer || | | PL-octet | | RAND_Peer || ID_Peer || |
| PSK | | RAND_Server || ID_Server | | PSK | | RAND_Server || ID_Server |
+-------------+ +-------------------------------+ +-------------+ +-------------------------------+
| | | | | |
| +------------+ | | | +------------+ | |
skipping to change at page 11, line 49 skipping to change at page 11, line 16
In order to be interoperable, PSKs must be entered in the same way on In order to be interoperable, PSKs must be entered in the same way on
both the peer and server. The management interface for entering PSKs both the peer and server. The management interface for entering PSKs
MUST support entering PSKs up to 64 octets in length as ASCII strings MUST support entering PSKs up to 64 octets in length as ASCII strings
and in hexadecimal encoding. and in hexadecimal encoding.
Additionally, the ID_Peer and ID_Server MUST be provisioned with the Additionally, the ID_Peer and ID_Server MUST be provisioned with the
PSK. Validation of these values is by an octet-wise comparison. The PSK. Validation of these values is by an octet-wise comparison. The
management interface SHOULD support entering non-ASCII octets for the management interface SHOULD support entering non-ASCII octets for the
ID_Peer and ID_Server up to 254 octets in length. For more ID_Peer and ID_Server up to 254 octets in length. For more
information the reader is advised to read Section 2.4 of RFC 4282 information, the reader is advised to read Section 2.4 of RFC 4282
[RFC4282]. [RFC4282].
6. Ciphersuites 6. Ciphersuites
The design of EAP-GPSK allows cryptographic algorithms and key sizes, The design of EAP-GPSK allows cryptographic algorithms and key sizes,
called ciphersuites, to be negotiated during the protocol run. The called ciphersuites, to be negotiated during the protocol run. The
ability to specify block-based and hash-based ciphersuites is ability to specify block-based and hash-based ciphersuites is
offered. Extensibility is provided with the introduction of new offered. Extensibility is provided with the introduction of new
ciphersuites; this document specifies an initial set. The CSuite/ ciphersuites; this document specifies an initial set. The CSuite/
Specifier column in Figure 3 uniquely identifies a ciphersuite. Specifier column in Figure 3 uniquely identifies a ciphersuite.
For a vendor-specific ciphersuite the first four octets are the For a vendor-specific ciphersuite, the first four octets are the
vendor-specific enterprise number contains the IANA assigned "SMI vendor-specific enterprise number that contains the IANA-assigned
Network Management Private Enterprise Codes" value (see [ENTNUM]), "SMI Network Management Private Enterprise Codes" value (see
encoded in network byte order. The last two octets are vendor [ENTNUM]), encoded in network byte order. The last two octets are
assigned for the specific ciphersuite. A vendor code of 0x00000000 vendor assigned for the specific ciphersuite. A vendor code of
indicates ciphersuites standardized by IETF in an IANA-maintained 0x00000000 indicates ciphersuites standardized by the IETF in an
registry. IANA-maintained registry.
The following ciphersuites are specified in this document (recall The following ciphersuites are specified in this document (recall
that KS is the length of the ciphersuite input key length in octets, that KS is the length of the ciphersuite input key length in octets,
and ML is the length of the MAC output in octets): and ML is the length of the MAC output in octets):
+-----------+----+-------------+----+--------------+----------------+ +-----------+----+-------------+----+--------------+----------------+
| CSuite/ | KS | Encryption | ML | Integrity / | Key Derivation | | CSuite/ | KS | Encryption | ML | Integrity / | Key Derivation |
| Specifier | | | | KDF MAC | Function | | Specifier | | | | KDF MAC | Function |
+-----------+----+-------------+----+--------------+----------------+ +-----------+----+-------------+----+--------------+----------------+
| 0x0001 | 16 | AES-CBC-128 | 16 | AES-CMAC-128 | GKDF | | 0x0001 | 16 | AES-CBC-128 | 16 | AES-CMAC-128 | GKDF |
+-----------+----+-------------+----+--------------+----------------+ +-----------+----+-------------+----+--------------+----------------+
| 0x0002 | 32 | NULL | 32 | HMAC-SHA256 | GKDF | | 0x0002 | 32 | NULL | 32 | HMAC-SHA256 | GKDF |
+-----------+----+-------------+----+--------------+----------------+ +-----------+----+-------------+----+--------------+----------------+
Figure 3: Ciphersuites Figure 3: Ciphersuites
Ciphersuite 1, which is based on the Advanced Encryption Standard
(AES) as a cryptographic primitive, MUST be implemented. This
document specifies also a second ciphersuite, which MAY be
implemented. Both ciphersuites defined in this document make use of
the Generalized Key Derivation Function (GKDF), as defined in
Section 7. The following aspects need to be considered to ensure
that the PSK that is used as input to the GKDF is sufficiently long:
Ciphersuite 1, which is based on AES as a cryptographic primitive, 1. The PSK used with ciphersuite 1 MUST be 128 bits in length. Keys
MUST be implemented. This document specifies also a second longer than 128 bits will be truncated.
ciphersuite, which MAY be implemented. Both ciphersuites defined in
this document make use of the GKDF, as defined in Section 7. The 2. The PSK used with ciphersuite 2 MUST be 256 bits in length. Keys
following aspects need to be considered to ensure that the PSK that longer than 256 bits will be truncated.
is used as input to the GKDF is sufficiently long (in case it is
longer it needs to be truncated):
1. The PSK used with ciphersuite 1 MUST be 128 bits in length or
longer.
2. The PSK used with ciphersuite 2 MUST be 256 bits in length or
longer.
3. It is RECOMMENDED that 256 bit keys be provisioned in all cases 3. It is RECOMMENDED that 256 bit keys be provisioned in all cases
to provide enough entropy for all current and many possible to provide enough entropy for all current and many possible
future ciphersuites. future ciphersuites.
Ciphersuites defined in the future that make use of the GKDF need to Ciphersuites defined in the future that make use of the GKDF need to
specify a minimum PSK size (as it is done with the ciphersuites specify a minimum PSK size (as is done with the ciphersuites listed
listed in this document). in this document).
7. Generalized Key Derivation Function (GKDF) 7. Generalized Key Derivation Function (GKDF)
Each ciphersuite needs to specify a key derivation function. The Each ciphersuite needs to specify a key derivation function. The
ciphersuites defined in this document make use of the Generalized Key ciphersuites defined in this document make use of the Generalized Key
Derivation Function (GKDF) that utilizes the MAC function defined in Derivation Function (GKDF) that utilizes the MAC function defined in
the ciphersuite. Future ciphersuites can use any other formally the ciphersuite. Future ciphersuites can use any other formally
specified KDF that takes as arguments a key and a seed value, and specified KDF that takes as arguments a key and a seed value, and
produces at least 128+2*KS octets of output. produces at least 128+2*KS octets of output.
skipping to change at page 14, line 7 skipping to change at page 13, line 22
Note that the variable 'i' in M_i is represented as a 2-octet value Note that the variable 'i' in M_i is represented as a 2-octet value
in network byte order. in network byte order.
8. Ciphersuites Processing Rules 8. Ciphersuites Processing Rules
8.1. Ciphersuite #1 8.1. Ciphersuite #1
8.1.1. Encryption 8.1.1. Encryption
With this ciphersuite all cryptography is built around a single With this ciphersuite, all cryptography is built around a single
cryptographic primitive, AES-128 ([AES]). Within the protected data cryptographic primitive, AES-128 ([AES]). Within the protected data
frames, AES-128 is used in Cipher Block Chaining (CBC) mode of frames, AES-128 is used in the Cipher Block Chaining (CBC) mode of
operation (see [CBC]). This EAP method uses encryption in a single operation (see [CBC]). This EAP method uses encryption in a single
payload, in the protected data payload (see Section 9.4). payload, in the protected data payload (see Section 9.4).
In a nutshell, the CBC mode proceeds as follows. The IV is XORed In a nutshell, the CBC mode proceeds as follows. The IV is XORed
with the first plaintext block before it is encrypted. Then for with the first plaintext block before it is encrypted. Then for
successive blocks, the previous ciphertext block is XORed with the successive blocks, the previous ciphertext block is XORed with the
current plaintext, before it is encrypted. current plaintext, before it is encrypted.
8.1.2. Integrity 8.1.2. Integrity
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8.2. Ciphersuite #2 8.2. Ciphersuite #2
8.2.1. Encryption 8.2.1. Encryption
Ciphersuite 2 does not include an algorithm for encryption. With a Ciphersuite 2 does not include an algorithm for encryption. With a
NULL encryption algorithm, encryption is defined as: NULL encryption algorithm, encryption is defined as:
E_X(Y) = Y E_X(Y) = Y
When using this ciphersuite, the data exchanged inside the protected When using this ciphersuite, the data exchanged inside the protected
data block is not encrypted. Therefore this mode MUST NOT be used if data block is not encrypted. Therefore, this mode MUST NOT be used
confidential information appears inside the protected data block. if confidential information appears inside the protected data block.
8.2.2. Integrity 8.2.2. Integrity
Ciphersuite 2 uses the keyed MAC function HMAC, with the SHA256 hash Ciphersuite 2 uses the keyed MAC function HMAC, with the SHA256 hash
algorithm (see [RFC4634]). algorithm (see [RFC4634]).
For integrity protection the following instantiation is used: For integrity protection, the following instantiation is used:
HMAC-SHA256(SK, Input) denotes the MAC of Input under the key SK HMAC-SHA256(SK, Input) denotes the MAC of Input under the key SK
where Input refers to the following content: where Input refers to the following content:
o Parameter within SEC_SK(Parameter) in message GPSK-2 o Parameter within SEC_SK(Parameter) in message GPSK-2
o Parameter within SEC_SK(Parameter) in message GPSK-3 o Parameter within SEC_SK(Parameter) in message GPSK-3
o Parameter within SEC_SK(Parameter) in message GPSK-4 o Parameter within SEC_SK(Parameter) in message GPSK-4
9. Packet Formats 9. Packet Formats
This section defines the packet format of the EAP-GPSK messages. This section defines the packet format of the EAP-GPSK messages.
9.1. Header Format 9.1. Header Format
The EAP-GPSK header has the following structure: The EAP-GPSK header has the following structure:
skipping to change at page 15, line 33 skipping to change at page 15, line 26
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Identifier | Length | | Code | Identifier | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | OP-Code | | | Type | OP-Code | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| | | |
... Payload ... ... Payload ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4 Figure 4: EAP-GPSK Header
The Code, Identifier, Length, and Type fields are all part of the EAP The Code, Identifier, Length, and Type fields are all part of the EAP
header, and defined in [RFC3748]. The Type field in the EAP header header and are defined in [RFC3748]. The Type field in the EAP
MUST be the value allocated by IANA for EAP-GPSK. header MUST be the value allocated by IANA for EAP-GPSK.
The OP-Code field is one of four values: The OP-Code field is one of 6 values:
o 0x00 : Reserved o 0x00 : Reserved
o 0x01 : GPSK-1 o 0x01 : GPSK-1
o 0x02 : GPSK-2 o 0x02 : GPSK-2
o 0x03 : GPSK-3 o 0x03 : GPSK-3
o 0x04 : GPSK-4 o 0x04 : GPSK-4
o 0x05 : GPSK-Fail o 0x05 : GPSK-Fail
o 0x06 : GPSK-Protected-Fail o 0x06 : GPSK-Protected-Fail
All other values of this OP-Code field are available via IANA All other values of this OP-Code field are available via IANA
registration. registration.
9.2. Ciphersuite Formatting 9.2. Ciphersuite Formatting
Ciphersuites are encoded as 6-octet arrays. The first four octets Ciphersuites are encoded as 6-octet arrays. The first four octets
indicate the CSuite/Vendor field. For vendor-specific ciphersuites, indicate the CSuite/Vendor field. For vendor-specific ciphersuites,
this represents the vendor enterprise number and contains the IANA this represents the vendor enterprise number and contains the IANA-
assigned "SMI Network Management Private Enterprise Codes" value (see assigned "SMI Network Management Private Enterprise Codes" value (see
[ENTNUM]), encoded in network byte order. The last two octets [ENTNUM]), encoded in network byte order. The last two octets
indicate the CSuite/Specifier field, which identifies the particular indicate the CSuite/Specifier field, which identifies the particular
ciphersuite. The 4-octet CSuite/Vendor value 0x00000000 indicates ciphersuite. The 4-octet CSuite/Vendor value 0x00000000 indicates
ciphersuites allocated by the IETF. ciphersuites allocated by the IETF.
Graphically, they are represented as Graphically, they are represented as:
--- bit offset ---> --- bit offset --->
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CSuite/Vendor = 0x00000000 or enterprise number | | CSuite/Vendor = 0x00000000 or enterprise number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CSuite/Specifier | | CSuite/Specifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5 Figure 5: Ciphersuite Formatting
CSuite_Sel is encoded as a 6-octet ciphersuite CSuite/Vendor and CSuite_Sel is encoded as a 6-octet ciphersuite CSuite/Vendor and
CSuite/Specifier pair. CSuite/Specifier pair.
CSuite_List is a variable-length octet array of ciphersuites. It is CSuite_List is a variable-length octet array of ciphersuites. It is
encoded by concatenating encoded ciphersuite values. Its length in encoded by concatenating encoded ciphersuite values. Its length in
octets MUST be a multiple of 6. octets MUST be a multiple of 6.
9.3. Payload Formatting 9.3. Payload Formatting
skipping to change at page 18, line 49 skipping to change at page 19, line 4
| | | |
... optional PD_Payload_Block ... ... optional PD_Payload_Block ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... ML-octet payload MAC ... ... ML-octet payload MAC ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: GPSK-2 Payload Figure 7: GPSK-2 Payload
If the optional protected data payload is not included, then If the optional protected data payload is not included, then
length(PD_Payload_Block)=0 and the PD payload is excluded. The length(PD_Payload_Block)=0 and the PD payload is excluded. The
payload MAC covers the entire packet, from the ID_Peer length, up payload MAC covers the entire packet, from the ID_Peer length through
through the optional PD_Payload_Block. the optional PD_Payload_Block.
The GPSK-3 payload is defined as follows: The GPSK-3 payload is defined as follows:
--- bit offset ---> --- bit offset --->
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... 32-octet RAND_Peer ... ... 32-octet RAND_Peer ...
| | | |
skipping to change at page 19, line 43 skipping to change at page 19, line 46
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... ML-octet payload MAC ... ... ML-octet payload MAC ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: GPSK-3 Payload Figure 8: GPSK-3 Payload
If the optional protected data payload is not included, then If the optional protected data payload is not included, then
length(PD_Payload_Block)=0 and the PD payload is excluded. The length(PD_Payload_Block)=0 and the PD payload is excluded. The
payload MAC covers the entire packet, from the RAND_Peer, up through payload MAC covers the entire packet, from the RAND_Peer through the
the optional PD_Payload_Block. optional PD_Payload_Block.
The GPSK-4 payload format is defined as follows: The GPSK-4 payload format is defined as follows:
--- bit offset ---> --- bit offset --->
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| length(PD_Payload_Block) | | | length(PD_Payload_Block) | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| | | |
skipping to change at page 20, line 26 skipping to change at page 20, line 28
... ML-octet payload MAC ... ... ML-octet payload MAC ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: GPSK-4 Payload Figure 9: GPSK-4 Payload
If the optional protected data payload is not included, then If the optional protected data payload is not included, then
length(PD_Payload_Block)=0 and the PD payload is excluded. The MAC length(PD_Payload_Block)=0 and the PD payload is excluded. The MAC
MUST always be included, regardless of the presence of MUST always be included, regardless of the presence of
PD_Payload_Block. The payload MAC covers the entire packet, from the PD_Payload_Block. The payload MAC covers the entire packet, from the
PD_Payload_Block length up through the optional PD_Payload_Block. PD_Payload_Block length through the optional PD_Payload_Block.
The GPSK-Fail payload format is defined as follows: The GPSK-Fail payload format is defined as follows:
--- bit offset ---> --- bit offset --->
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Failure-Code | | Failure-Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 21, line 38 skipping to change at page 21, line 42
located, making authentication impossible. "Authentication Failure" located, making authentication impossible. "Authentication Failure"
indicates a MAC failure due to a PSK mismatch. "Authorization indicates a MAC failure due to a PSK mismatch. "Authorization
Failure" indicates that while the PSK being used is correct, the user Failure" indicates that while the PSK being used is correct, the user
is not authorized to connect. is not authorized to connect.
9.4. Protected Data 9.4. Protected Data
The protected data blocks are a generic mechanism for the peer and The protected data blocks are a generic mechanism for the peer and
server to securely exchange data. If the specified ciphersuite has a server to securely exchange data. If the specified ciphersuite has a
NULL encryption primitive, then this channel only offers NULL encryption primitive, then this channel only offers
authenticity, and not confidentiality. authenticity, not confidentiality.
These payloads are encoded as the concatenation of type-length-value These payloads are encoded as the concatenation of type-length-value
(TLV) triples called PD_Payloads. (TLV) triples called PD_Payloads.
Type values are encoded as a 6-octet string and represented by a Type values are encoded as a 6-octet string and represented by a
4-octet vendor and 2-octet specifier field. The vendor field 4-octet vendor and a 2-octet specifier field. The vendor field
indicates the type as either standards-specified or vendor-specific. indicates the type as either standards-specified or vendor-specific.
If these four octets are 0x00000000, then the value is standards- If these four octets are 0x00000000, then the value is standards-
specified, and any other value represents a vendor-specific specified, and any other value represents a vendor-specific
enterprise number. enterprise number.
The specifier field indicates the actual type. For vendor field The specifier field indicates the actual type. For vendor field
0x00000000, the specifier field is maintained by IANA. For any other 0x00000000, the specifier field is maintained by IANA. For any other
vendor field, the specifier field is maintained by the vendor. vendor field, the specifier field is maintained by the vendor.
Length fields are specified as 2-octet integers in network byte Length fields are specified as 2-octet integers in network byte
order, and reflect only the length of the value, and do not include order, reflect only the length of the value, and do not include the
the length of the type and length fields. length of the type and length fields.
Graphically, this can be depicted as follows: Graphically, this can be depicted as follows:
--- bit offset ---> --- bit offset --->
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PData/Vendor | | PData/Vendor |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
PData/Specifier | PData/Length | PData/Specifier | PData/Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... PData/Value ... ... PData/Value ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Protected Data Payload (PD_Payload) Formatting Figure 12: Protected Data Payload (PD_Payload) Formatting
These PD_Payloads are concatenated together to form a These PD_Payloads are concatenated together to form a
PD_Payload_Block. The If the CSuite_Sel includes support for PD_Payload_Block. If the CSuite_Sel includes support for encryption,
encryption, then the PD_Payload_Block includes fields specifying an then the PD_Payload_Block includes fields specifying an
initialization vector (IV), and the necessary padding. This can be Initialization Vector (IV) and the necessary padding. This can be
depicted as follows: depicted as follows:
--- bit offset ---> --- bit offset --->
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IV Length | | | IV Length | |
+-+-+-+-+-+-+-+-+ Initialization Vector + +-+-+-+-+-+-+-+-+ Initialization Vector +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... optional PD_Payload, etc ... ... optional PD_Payload, etc ...
| | | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Padding (0-255 octets) | | | Padding (0-255 octets) |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| | Pad Length | | | Pad Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Protected Data Block (PD_Payload_Block) Formatting if Encryption Figure 13: Protected Data Block (PD_Payload_Block)
Supported Formatting if Encryption is Supported
The Initialization Vector is a randomly chosen value whose length is The Initialization Vector is a randomly chosen value whose length is
equal to the specified IV Length. The required length is defined by equal to the specified IV Length. The required length is defined by
the ciphersuite. Recipients MUST accept any value. Senders SHOULD the ciphersuite. Recipients MUST accept any value. Senders SHOULD
either pick this value pseudo-randomly and independently for each either pick this value pseudo-randomly and independently for each
message or use the final ciphertext block of the previous message message or use the final ciphertext block of the previous message
sent. Senders MUST NOT use the same value for each message, use a sent. Senders MUST NOT use the same value for each message, use a
sequence of values with low hamming distance (e.g., a sequence sequence of values with low hamming distance (e.g., a sequence
number), or use ciphertext from a received message. IVs should be number), or use ciphertext from a received message. IVs should be
selected per the security requirements of the underlying cipher. If selected per the security requirements of the underlying cipher. If
the data is not being encrypted, then the IV Length MUST be 0. If the data is not being encrypted, then the IV Length MUST be 0. If
the ciphersuite does not require an IV, or has a self-contained way the ciphersuite does not require an IV, or has a self-contained way
of communicating the IV, then the IV Length field MUST be 0. In of communicating the IV, then the IV Length field MUST be 0. In
these cases the ciphersuite definition defines how the IV is these cases, the ciphersuite definition defines how the IV is
encapsulated in the PD_Payload. encapsulated in the PD_Payload.
The concatenation of PD_Payloads along with the padding and padding The concatenation of PD_Payloads along with the padding and padding
length are all encrypted using the negotiated block cipher. If no length are all encrypted using the negotiated block cipher. If no
block cipher is specified, then these fields are not encrypted. block cipher is specified, then these fields are not encrypted.
The Padding field MAY contain any value chosen by the sender. For The Padding field MAY contain any value chosen by the sender. For
block-based cipher modes, the padding MUST have a length that makes block-based cipher modes, the padding MUST have a length that makes
the combination of the concatenation of PD_Payloads, the Padding, and the combination of the concatenation of PD_Payloads, the Padding, and
the Pad Length to be a multiple of the encryption block size. If the the Pad Length to be a multiple of the encryption block size. If the
underlying ciphersuite does not require padding (e.g. a stream-based underlying ciphersuite does not require padding (e.g., a stream-based
cipher mode) or no encryption is being used, then the padding length cipher mode) or no encryption is being used, then the padding length
MUST still be present and be zero. MUST still be present and be 0.
The Pad Length field is the length of the Padding field. The sender The Pad Length field is the length of the Padding field. The sender
SHOULD set the Pad Length to the minimum value that makes the SHOULD set the Pad Length to the minimum value that makes the
combination of the PD_Payloads, the Padding, and the Pad Length a combination of the PD_Payloads, the Padding, and the Pad Length a
multiple of the block size (in the case of block-based cipher modes), multiple of the block size (in the case of block-based cipher modes),
but the recipient MUST accept any length that results in proper but the recipient MUST accept any length that results in proper
alignment. This field is encrypted with the negotiated cipher. alignment. This field is encrypted with the negotiated cipher.
If the negotiated ciphersuite does not support encryption, then the If the negotiated ciphersuite does not support encryption, then the
IV field MUST be of length zero and padding field MUST be of length IV field MUST be of length 0 and the padding field MUST be of length
zero. The IV length and padding length fields MUST still be present, 0. The IV length and padding length fields MUST still be present,
and contain the value zero. The rationale for still requiring the and contain the value 0. The rationale for still requiring the
length fields is to allow for modular implementations where the length fields is to allow for modular implementations where the
crypto processing is independent of the payload processing. This is crypto processing is independent of the payload processing. This is
depicted in the following figure. depicted in the following figure.
--- bit offset ---> --- bit offset --->
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | | | 0x00 | |
+-+-+-+-+-+-+-+-+ PD_Payload ... +-+-+-+-+-+-+-+-+ PD_Payload ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... optional PD_Payload, etc +-+-+-+-+-+-+-+-+ ... optional PD_Payload, etc +-+-+-+-+-+-+-+-+
| | 0x00 | | | 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Protected Data Block (PD_Payload_Block) Formatting Without Encryption Figure 14: Protected Data Block (PD_Payload_Block)
Formatting Without Encryption
For PData/Vendor field 0x00000000, the following PData/Specifier For PData/Vendor field 0x00000000, the following PData/Specifier
fields are defined: fields are defined:
o 0x0000 : Reserved o 0x0000 : Reserved
All other values of this field are available via IANA registration. All other values of this field are available via IANA registration.
10. Packet Processing Rules 10. Packet Processing Rules
This section defines how the EAP peer and EAP server MUST behave when This section defines how the EAP peer and EAP server MUST behave when
received packet is deemed invalid. a received packet is deemed invalid.
Any EAP-GPSK packet that cannot be parsed by the EAP peer or the EAP Any EAP-GPSK packet that cannot be parsed by the EAP peer or the EAP
server MUST be silently discarded. An EAP peer or EAP server server MUST be silently discarded. An EAP peer or EAP server
receiving any unexpected packet (e.g., an EAP peer receiving GPSK-3 receiving any unexpected packet (e.g., an EAP peer receiving GPSK-3
before receiving GPSK-1 or before transmitting GPSK-2) MUST silently before receiving GPSK-1 or before transmitting GPSK-2) MUST silently
discard the packet. discard the packet.
GPSK-1 contains no MAC protection, so provided it properly parses, it GPSK-1 contains no MAC protection, so provided it properly parses, it
MUST be accepted by the peer. If the EAP peer has no ciphersuites in MUST be accepted by the peer. If the EAP peer has no ciphersuites in
common with the server or decides the ID_Server is that of a AAA common with the server or decides the ID_Server is that of an
server to which it does not wish to authenticate, the EAP peer MUST Authentication, Authorization, and Accounting (AAA) server to which
respond with an EAP-NAK. it does not wish to authenticate, the EAP peer MUST respond with an
EAP-NAK.
For GPSK-2, if ID_Peer is for an unknown user, the EAP server MUST For GPSK-2, if the ID_Peer is for an unknown user, the EAP server
send either a "PSK Not Found" GPSK-Fail message, or an MUST send either a "PSK Not Found" GPSK-Fail message or an
"Authentication Failure" GPSK-Fail, depending on its policy. If the "Authentication Failure" GPSK-Fail, depending on its policy. If the
MAC validation fails, the server MUST transmit a GPSK-Fail message MAC validation fails, the server MUST transmit a GPSK-Fail message
specifying "Authentication Failure". If the RAND_Server or specifying "Authentication Failure". If the RAND_Server or
CSuite_List field in GPSK-2 does not match the values in GPSK-1, the CSuite_List field in GPSK-2 does not match the values in GPSK-1, the
server MUST silently discard the packet. If server policy determines server MUST silently discard the packet. If server policy determines
the peer is not authorized and the MAC is correct, the server MUST the peer is not authorized and the MAC is correct, the server MUST
transmit a GPSK-Protected-Fail message indicating "Authorization transmit a GPSK-Protected-Fail message indicating "Authorization
Failure" and discard the received packet. Failure", and discard the received packet.
A peer receiving a GPSK-Fail / GPSK-Protected-Fail message in A peer receiving a GPSK-Fail / GPSK-Protected-Fail message in
response to a GPSK-2 message MUST replay the received GPSK-Fail / response to a GPSK-2 message MUST replay the received GPSK-Fail /
GPSK-Protected-Fail message. Then, the EAP server returns an EAP- GPSK-Protected-Fail message. Then, the EAP server returns an EAP-
Failure after receiving the GPSK-Fail / GPSK-Protected-Fail message Failure after receiving the GPSK-Fail / GPSK-Protected-Fail message
to correctly finish the EAP conversation. If MAC validation on a to correctly finish the EAP conversation. If MAC validation on a
GPSK-Protected-Fail packet fails, then the received packet MUST be GPSK-Protected-Fail packet fails, then the received packet MUST be
silently discarded. silently discarded.
For GPSK-3, a peer MUST silently discard messages where the For GPSK-3, a peer MUST silently discard messages where the
skipping to change at page 25, line 47 skipping to change at page 26, line 22
| | EAP-Request/GPSK-1 | | | | EAP-Request/GPSK-1 | |
| |<------------------------------------| | | |<------------------------------------| |
| | | | | | | |
| | EAP-Response/EAP-NAK | | | | EAP-Response/EAP-NAK | |
| |------------------------------------>| | | |------------------------------------>| |
| | | | | | | |
| | EAP-Failure | | | | EAP-Failure | |
| |<------------------------------------| | | |<------------------------------------| |
+--------+ +--------+ +--------+ +--------+
EAP-GPSK: Unsuccessful Exchange (Unacceptable AAA server identity; Figure 15: EAP-GPSK: Unsuccessful Exchange
ID_Server) (Unacceptable AAA Server Identity; ID_Server)
+--------+ +--------+ +--------+ +--------+
| | EAP-Request/Identity | | | | EAP-Request/Identity | |
| EAP |<------------------------------------| EAP | | EAP |<------------------------------------| EAP |
| peer | | server | | peer | | server |
| | EAP-Response/Identity | | | | EAP-Response/Identity | |
| |------------------------------------>| | | |------------------------------------>| |
| | | | | | | |
| | EAP-Request/GPSK-1 | | | | EAP-Request/GPSK-1 | |
| |<------------------------------------| | | |<------------------------------------| |
| | | | | | | |
skipping to change at page 26, line 31 skipping to change at page 26, line 52
| | | | | | | |
| | EAP-Response/GPSK-Fail | | | | EAP-Response/GPSK-Fail | |
| | (PSK Not Found or Authentication | | | | (PSK Not Found or Authentication | |
| | Failure) | | | | Failure) | |
| |------------------------------------>| | | |------------------------------------>| |
| | | | | | | |
| | EAP-Failure | | | | EAP-Failure | |
| |<------------------------------------| | | |<------------------------------------| |
+--------+ +--------+ +--------+ +--------+
EAP-GPSK: Unsuccessful Exchange (Unknown user) Figure 16: EAP-GPSK: Unsuccessful Exchange (Unknown User)
+--------+ +--------+ +--------+ +--------+
| | EAP-Request/Identity | | | | EAP-Request/Identity | |
| EAP |<------------------------------------| EAP | | EAP |<------------------------------------| EAP |
| peer | | server | | peer | | server |
| | EAP-Response/Identity | | | | EAP-Response/Identity | |
| |------------------------------------>| | | |------------------------------------>| |
| | | | | | | |
| | EAP-Request/GPSK-1 | | | | EAP-Request/GPSK-1 | |
| |<------------------------------------| | | |<------------------------------------| |
| | | | | | | |
skipping to change at page 27, line 29 skipping to change at page 27, line 29
| |<------------------------------------| | | |<------------------------------------| |
| | | | | | | |
| | EAP-Response/GPSK-Fail | | | | EAP-Response/GPSK-Fail | |
| | (Authentication Failure) | | | | (Authentication Failure) | |
| |------------------------------------>| | | |------------------------------------>| |
| | | | | | | |
| | EAP-Failure | | | | EAP-Failure | |
| |<------------------------------------| | | |<------------------------------------| |
+--------+ +--------+ +--------+ +--------+
EAP-GPSK: Unsuccessful Exchange (Invalid MAC in GPSK-2) Figure 17: EAP-GPSK: Unsuccessful Exchange (Invalid MAC in GPSK-2)
+--------+ +--------+ +--------+ +--------+
| | EAP-Request/Identity | | | | EAP-Request/Identity | |
| EAP |<------------------------------------| EAP | | EAP |<------------------------------------| EAP |
| peer | | server | | peer | | server |
| | EAP-Response/Identity | | | | EAP-Response/Identity | |
| |------------------------------------>| | | |------------------------------------>| |
| | | | | | | |
| | EAP-Request/GPSK-1 | | | | EAP-Request/GPSK-1 | |
| |<------------------------------------| | | |<------------------------------------| |
| | | | | | | |
skipping to change at page 28, line 31 skipping to change at page 28, line 31
| | | | | | | |
| | EAP-Request/ | | | | EAP-Request/ | |
| | GPSK-Protected-Fail | | | | GPSK-Protected-Fail | |
| | (Authorization Failure) | | | | (Authorization Failure) | |
| |------------------------------------>| | | |------------------------------------>| |
| | | | | | | |
| | EAP-Failure | | | | EAP-Failure | |
| |<------------------------------------| | | |<------------------------------------| |
+--------+ +--------+ +--------+ +--------+
EAP-GPSK: Unsuccessful Exchange (Authorization failure) Figure 18: EAP-GPSK: Unsuccessful Exchange (Authorization Failure)
12. Security Considerations 12. Security Considerations
[RFC3748] highlights several attacks that are possible against EAP [RFC3748] highlights several attacks that are possible against EAP
since EAP itself does not provide any security. since EAP itself does not provide any security.
This section discusses the claimed security properties of EAP-GPSK as This section discusses the claimed security properties of EAP-GPSK as
well as vulnerabilities and security recommendations in the threat well as vulnerabilities and security recommendations in the threat
model of [RFC3748]. model of [RFC3748].
12.1. Security Claims 12.1. Security Claims
Auth. mechanism: Shared Keys Authentication mechanism: Shared Keys
Ciphersuite negotiation: Yes (Section 12.16) Ciphersuite negotiation: Yes (Section 12.16)
Mutual authentication: Yes (Section 12.2) Mutual authentication: Yes (Section 12.2)
Integrity protection: Yes (Section 12.4) Integrity protection: Yes (Section 12.4)
Replay protection: Yes (Section 12.5) Replay protection: Yes (Section 12.5)
Confidentiality: No (Section 12.17, Section 12.15) Confidentiality: No (Section 12.17, Section 12.15)
Key derivation: Yes (Section 12.8) Key derivation: Yes (Section 12.8)
Key strength: Varies (Section 12.8) Key strength: Varies (Section 12.8)
Dictionary attack prot.: No (Section 12.7) Dictionary attack protection: No (Section 12.7)
Fast reconnect: No (Section 12.14) Fast reconnect: No (Section 12.14)
Crypt. binding: N/A (Section 12.18) Cryptographic binding: N/A (Section 12.18)
Session independence: Yes (Section 12.10) Session independence: Yes (Section 12.10)
Fragmentation: No (Section 12.12) Fragmentation: No (Section 12.12)
Channel binding: Extensible (Section 12.13) Channel binding: Extensible (Section 12.13)
12.2. Mutual Authentication 12.2. Mutual Authentication
EAP-GPSK provides mutual authentication. EAP-GPSK provides mutual authentication.
The server believes that the peer is authentic when it successfully The server believes that the peer is authentic when it successfully
verifies the MAC in the GPSK-2 message and the peer believes that the verifies the MAC in the GPSK-2 message; the peer believes that the
server is authentic when it successfully verifies the MAC it receives server is authentic when it successfully verifies the MAC it receives
with the GPSK-3 message. with the GPSK-3 message.
The key used for mutual authentication is derived based on the long- The key used for mutual authentication is derived based on the long-
term secret PSK, nonces contributed by both parties and other term secret PSK, nonces contributed by both parties, and other
parameters. The long-term secret PSK has to provide sufficient parameters. The long-term secret PSK has to provide sufficient
entropy and therefore sufficient strength. The nonces (RAND_Peer and entropy and, therefore, sufficient strength. The nonces (RAND_Peer
RAND_Server) need to be fresh and unique for every session. In this and RAND_Server) need to be fresh and unique for every session. In
way EAP-GPSK is not different than other authentication protocols this way, EAP-GPSK is not different than other authentication
based on pre-shared keys. protocols based on pre-shared keys.
12.3. Protected Result Indications 12.3. Protected Result Indications
EAP-GPSK supports protected results indication via the GPSK- EAP-GPSK supports protected result indications via the GPSK-
Protected-Fail message. This allows a server to provide additional Protected-Fail message. This allows a server to provide additional
information to the peer as to why the session failed, and do so in an information to the peer as to why the session failed, and to do so in
authenticated way (if possible). In particular, the server can an authenticated way (if possible). In particular, the server can
indicate the lack of PSK (account not present), failed authentication indicate the lack of PSK (account not present), failed authentication
(PSK incorrect), or authorization failure (account disabled or (PSK incorrect), or authorization failure (account disabled or
unauthorized). Only the third message could be integrity protected. unauthorized). Only the third message could be integrity protected.
It should be noted that these options make debugging network and It should be noted that these options make debugging network and
account errors easier, but also leak information about accounts to account errors easier, but they also leak information about accounts
attackers. An attacker can determine if a particular ID_Peer is a to attackers. An attacker can determine if a particular ID_Peer is a
valid user on the network, or not. Thus implementers should use care valid user on the network or not. Thus, implementers should use care
in enabling this particular option on their servers. If they are in in enabling this particular option on their servers. If they are in
an environment where such attacks are of concern, then protected an environment where such attacks are of concern, then protected
result indication capabilities should be disabled. result indication capabilities should be disabled.
12.4. Integrity Protection 12.4. Integrity Protection
EAP-GPSK provides integrity protection based on the ciphersuites EAP-GPSK provides integrity protection based on the ciphersuites
suggested in this document. Integrity protection is a minimum suggested in this document. Integrity protection is a minimum
feature every ciphersuite must provide. feature every ciphersuite must provide.
12.5. Replay Protection 12.5. Replay Protection
EAP-GPSK provides replay protection of its mutual authentication part EAP-GPSK provides replay protection of its mutual authentication part
thanks to the use of random numbers RAND_Server and RAND_Peer. Since thanks to the use of random numbers RAND_Server and RAND_Peer. Since
RAND_Server is 32 octets long, one expects to have to record 2**64 RAND_Server is 32 octets long, one expects to have to record 2**64
(i.e., approximately 1.84*10**19) EAP-GPSK successful authentication (i.e., approximately 1.84*10**19) EAP-GPSK successful authentications
before an protocol run can be replayed. Hence, EAP-GPSK provides before a protocol run can be replayed. Hence, EAP-GPSK provides
replay protection of its mutual authentication part as long as replay protection of its mutual authentication part as long as
RAND_Server and RAND_Peer are chosen at random, randomness is RAND_Server and RAND_Peer are chosen at random; randomness is
critical for replay protection. RFC 4086 [RFC4086] describes critical for replay protection. RFC 4086 [RFC4086] describes
techniques for producing random quantities. techniques for producing random quantities.
12.6. Reflection attacks 12.6. Reflection Attacks
Reflection attacks occur in bi-directional, challenge-response, Reflection attacks occur in bi-directional, challenge-response,
mutual authentication protocols where an attacker, upon being issued mutual authentication protocols where an attacker, upon being issued
a challenge by an authenticator responds by issuing the same a challenge by an authenticator, responds by issuing the same
challenge back to the authenticator, obtaining the response, and then challenge back to the authenticator, obtaining the response, and then
"reflecting" that same response to the original challenge. "reflecting" that same response to the original challenge.
EAP-GPSK provides protection against reflection attacks because the EAP-GPSK provides protection against reflection attacks because the
message formats for the challenges differ. The protocol does not message formats for the challenges differ. The protocol does not
consist of two independent authentications, but rather the consist of two independent authentications, but rather the
authentications are tightly coupled. authentications are tightly coupled.
Also note that EAP-GPSK does not provide MAC protection of the OP- Also note that EAP-GPSK does not provide MAC protection of the OP-
Code field, but again since each message is constructed differently, Code field, but again since each message is constructed differently,
skipping to change at page 31, line 6 skipping to change at page 30, line 49
GPSK protocol makes no special provisions to ensure keys based on GPSK protocol makes no special provisions to ensure keys based on
passwords are used securely. Users who use passwords as the basis of passwords are used securely. Users who use passwords as the basis of
their PSK are not protected against dictionary attacks. Derivation their PSK are not protected against dictionary attacks. Derivation
of the long-term shared secret from a password is strongly of the long-term shared secret from a password is strongly
discouraged. discouraged.
The success of a dictionary attack against EAP-GPSK depends on the The success of a dictionary attack against EAP-GPSK depends on the
strength of the long-term shared secret (PSK) it uses. The PSK used strength of the long-term shared secret (PSK) it uses. The PSK used
by EAP-GPSK SHOULD be drawn from a pool of secrets that is at least by EAP-GPSK SHOULD be drawn from a pool of secrets that is at least
2^128 bits large and whose distribution is uniformly random. Note 2^128 bits large and whose distribution is uniformly random. Note
that this does not imply resistance to dictionary attack, only that that this does not imply resistance to dictionary attacks -- only
the probability of success in such an attack is acceptably remote. that the probability of success in such an attack is acceptably
remote.
12.8. Key Derivation and Key Strength 12.8. Key Derivation and Key Strength
EAP-GPSK supports key derivation as shown in Section 4. EAP-GPSK supports key derivation as shown in Section 4.
Keys used within EAP-GPSK are all based on the security of the Keys used within EAP-GPSK are all based on the security of the
originating PSK. PSKs SHOULD have at least 16 octets of entropy. originating PSK. PSKs SHOULD have at least 16 octets of entropy.
Independent of the protocol exchange (i.e. without knowing RAND_Peer Independent of the protocol exchange (i.e., without knowing RAND_Peer
and RAND_Server), the keys have been derived with sufficient input and RAND_Server), the keys have been derived with sufficient input
entropy to make them as secure as the underlying KDF output key entropy to make them as secure as the underlying KDF output key
length. length.
12.9. Denial of Service Resistance 12.9. Denial-of-Service Resistance
There are three forms of denial of service attacks relevant for this There are three forms of denial-of-service (DoS) attacks relevant for
document, namely (1) attacks that lead to vast amount of state being this document, namely (1) attacks that lead to a vast amount of state
allocated, (2) attacks that attempt to prevent communication between being allocated, (2) attacks that attempt to prevent communication
the peer and server, and (3) attacks against computational resources. between the peer and server, and (3) attacks against computational
resources.
In an EAP-GPSK conversation the server has to maintain state, namely In an EAP-GPSK conversation the server has to maintain state, namely
the 32-octet RAND_Server, when transmitting the GPSK-1 message to the the 32-octet RAND_Server, when transmitting the GPSK-1 message to the
peer. An adversary could therefore flood a server with a large peer. An adversary could therefore flood a server with a large
number of EAP-GPSK communication attempts. An EAP server may number of EAP-GPSK communication attempts. An EAP server may
therefore ensure that established state times out after a relatively therefore ensure that an established state times out after a
short period of time when no further messages are received. This relatively short period of time when no further messages are
enables a sort of garbage collection. received. This enables a sort of garbage collection.
The client has to keep state information after receiving the GPSK-1 The client has to keep state information after receiving the GPSK-1
message. To prevent a replay attack, all the client needs to do is message. To prevent a replay attack, all the client needs to do is
to ensure that the value of RAND_Peer is consistent between GPSK-2 ensure that the value of RAND_Peer is consistent between GPSK-2 and
and GPSK-3. Message GPSK-3 contains all the material required to re- GPSK-3. Message GPSK-3 contains all the material required to
compute the keying material. Thus, if a client chooses to implement re-compute the keying material. Thus, if a client chooses to
this client-side DoS protection mechanism it may manage RAND_Peer and implement this client-side DoS protection mechanism, it may manage
CSuite_Sel on a per-server basis for servers it knows instead of on a RAND_Peer and CSuite_Sel on a per-server basis for servers it knows,
per-message basis. instead of on a per-message basis.
Attacks that disrupt communication between the peer and server are Attacks that disrupt communication between the peer and server are
mitigated by silently discarding messages with invalid MACs. Attacks mitigated by silently discarding messages with invalid MACs. Attacks
against computational resources are mitigated by having very light- against computational resources are mitigated by having very light-
weight cryptographic operations required during each protocol round. weight cryptographic operations required during each protocol round.
The security considerations of EAP itself, see Section 5.2 and The security considerations of EAP itself, see Sections 5.2 and 7 of
Section 7 of RFC 3748 [RFC3748], are also applicable to this RFC 3748 [RFC3748], are also applicable to this specification (e.g.,
specification (e.g., for example concerning EAP-based notifications). for example concerning EAP-based notifications).
12.10. Session Independence 12.10. Session Independence
Thanks to its key derivation mechanisms, EAP-GPSK provides session Thanks to its key derivation mechanisms, EAP-GPSK provides session
independence: passive attacks (such as capture of the EAP independence: passive attacks (such as capture of the EAP
conversation) or active attacks (including compromise of the MSK or conversation) or active attacks (including compromise of the MSK or
EMSK) do not enable compromise of subsequent or prior MSKs or EMSKs. EMSK) do not enable compromise of subsequent or prior MSKs or EMSKs.
The assumption that RAND_Peer and RAND_Server are random is central The assumption that RAND_Peer and RAND_Server are random is central
for the security of EAP-GPSK in general and session independence in for the security of EAP-GPSK in general and session independence in
particular. particular.
12.11. Compromise of the PSK 12.11. Compromise of the PSK
EAP-GPSK does not provide perfect forward secrecy. Compromise of the EAP-GPSK does not provide perfect forward secrecy. Compromise of the
PSK leads to compromise of recorded past sessions. PSK leads to compromise of recorded past sessions.
Compromise of the PSK enables the attacker to impersonate the peer Compromise of the PSK enables the attacker to impersonate the peer
and the server and it allows the adversary to compromise future and the server, and it allows the adversary to compromise future
sessions. sessions.
EAP-GPSK provides no protection against a legitimate peer sharing its EAP-GPSK provides no protection against a legitimate peer sharing its
PSK with a third party. Such protection may be provided by PSK with a third party. Such protection may be provided by
appropriate repositories for the PSK, which choice is outside the appropriate repositories for the PSK, the choice of which is outside
scope of this document. The PSK used by EAP-GPSK must only be shared the scope of this document. The PSK used by EAP-GPSK must only be
between two parties: the peer and the server. In particular, this shared between two parties: the peer and the server. In particular,
PSK must not be shared by a group of peers (e.g. those with different this PSK must not be shared by a group of peers (e.g., those with
ID_Peer values) communicating with the same server. different ID_Peer values) communicating with the same server.
The PSK used by EAP-GPSK must be cryptographically separated from The PSK used by EAP-GPSK must be cryptographically separated from
keys used by other protocols, otherwise the security of EAP-GPSK may keys used by other protocols, otherwise the security of EAP-GPSK may
be compromised. be compromised.
12.12. Fragmentation 12.12. Fragmentation
EAP-GPSK does not support fragmentation and reassembly since the EAP-GPSK does not support fragmentation and reassembly since the
message size is relatively small. However it should be noted that message size is relatively small. However, it should be noted that
this impacts the length of protected data payloads that can be this impacts the length of protected data payloads that can be
attached to messages. Also if the EAP frame is larger than the MTU attached to messages. Also, if the EAP frame is larger than the MTU
of the underlying transport, and that transport does not support of the underlying transport, and that transport does not support
fragmentation, the frame will most likely not be transported. fragmentation, the frame will most likely not be transported.
Consequently implementors and deployers should take care to ensure Consequently, implementers and deployers should take care to ensure
EAP-GPSK frames are short enough to work properly on the target EAP-GPSK frames are short enough to work properly on the target
underlying transport mechanism. underlying transport mechanism.
12.13. Channel Binding 12.13. Channel Binding
This document enables the ability to exchange channel binding This document enables the ability to exchange channel binding
information. It does not, however, define the encoding of channel information. It does not, however, define the encoding of channel
binding information in the document. binding information in the document.
12.14. Fast Reconnect 12.14. Fast Reconnect
EAP-GPSK does not provide the fast reconnect capability since this EAP-GPSK does not provide fast reconnect capability since this method
method is already at (or close to) the lower limit of the number of is already at (or close to) the lower limit of the number of
roundtrips and the cryptographic operations. roundtrips and the cryptographic operations.
12.15. Identity Protection 12.15. Identity Protection
Identity protection is not specified in this document. Extensions Identity protection is not specified in this document. Extensions
can be defined that enhance this protocol to provide this feature. can be defined that enhance this protocol to provide this feature.
12.16. Protected Ciphersuite Negotiation 12.16. Protected Ciphersuite Negotiation
EAP-GPSK provides protected ciphersuite negotiation via the EAP-GPSK provides protected ciphersuite negotiation via the
indication of available ciphersuites by the server in the first indication of available ciphersuites by the server in the first
message and a confirmation by the peer in the subsequent message. message, and a confirmation by the peer in the subsequent message.
Note, however, that the GPSK-2 message may optionally contain a Note, however, that the GPSK-2 message may optionally contain a
payload, ENC_PK(PD_Payload_Block), protected with an algorithm based payload, ENC_PK(PD_Payload_Block), protected with an algorithm based
on a selected ciphersuite before the ciphersuite list has actually on a selected ciphersuite before the ciphersuite list has actually
been authenticated. In the classical downgrading attack an adversary been authenticated. In the classical downgrading attack, an
would chose a ciphersuite that it weak enough to that it could break adversary would choose a ciphersuite that is so weak that it can be
it in real-time or to turn security off. The latter is not possible broken in real time or would attempt to disable cryptographic
since any ciphersuite defined for EAP-GPSK must at least provide protection altogether. The latter is not possible since any
authentication and integrity protection. Confidentiality protection ciphersuite defined for EAP-GPSK must at least provide authentication
is optional. When, some time in the future, a ciphersuite contains and integrity protection. Confidentiality protection is optional.
algorithms that can be broken in real-time then a policy on peers and When, at some time in the future, a ciphersuite contains algorithms
the server needs to indicate that such a ciphersuite must not be that can be broken in real-time, then a policy on peers and the
selected by any of parties. server needs to indicate that such a ciphersuite must not be selected
by any of parties.
Furthermore, an adversary may modify the selection of the ciphersuite Furthermore, an adversary may modify the selection of the ciphersuite
to for the client to select a ciphersuite that does not provide for the client to select a ciphersuite that does not provide
confidentiality protection. As a result this would cause the content confidentiality protection. As a result, this would cause the
of PD_Payload_Block to be transmitted in cleartext. When protocol content of PD_Payload_Block to be transmitted in cleartext. When
designers extend EAP-GPSK to carry information in the protocol designers extend EAP-GPSK to carry information in the
PD_Payload_Block of the GPSK-2 message then it must be indicated PD_Payload_Block of the GPSK-2 message, then it must be indicated
whether confidentiality protection is mandatory. In case such an whether confidentiality protection is mandatory. In case such an
extension requires a ciphersuite with confidentiality protection then extension requires a ciphersuite with confidentiality protection,
the policy at the peer must not transmit information of that then the policy at the peer must be to not transmit information of
extension in the PD_Payload_Block of the GPSK-2 message. The peer that extension in the PD_Payload_Block of the GPSK-2 message. The
may, if possible, delay the transmission of this information element peer may, if possible, delay the transmission of this information
to the GPSK-4 message where the ciphersuite negotiation has been element to the GPSK-4 message where the ciphersuite negotiation has
confirmed already. In general, when a ciphersuite is selected that been confirmed already. In general, when a ciphersuite is selected
does not provide confidentiality protection then information that that does not provide confidentiality protection, then information
demands confidentiality protection must not be included in any of the that demands confidentiality protection must not be included in any
PD_Payload_Block objects. of the PD_Payload_Block objects.
12.17. Confidentiality 12.17. Confidentiality
Although EAP-GPSK provides confidentiality in its protected data Although EAP-GPSK provides confidentiality in its protected data
payloads, it cannot claim to do so as per Section 7.2.1 of [RFC3748] payloads, it cannot claim to do so, per Section 7.2.1 of [RFC3748],
since it does not support identity protection. since it does not support identity protection.
12.18. Cryptographic Binding 12.18. Cryptographic Binding
Since EAP-GPSK does not tunnel another EAP method, it does not Since EAP-GPSK does not tunnel another EAP method, it does not
implement cryptographic binding. implement cryptographic binding.
13. IANA Considerations 13. IANA Considerations
This document requires IANA to allocate a new EAP Type for EAP-GPSK. IANA has allocated a new EAP Type for EAP-GPSK (51).
This document requires IANA to create a new registry for IANA has created a new registry for ciphersuites, protected data
ciphersuites, protected data types, failure codes and op-codes. IANA types, failure codes, and op-codes. IANA has added the specified
is furthermore instructed to add the specified ciphersuites, ciphersuites, protected data types, failure codes, and op-codes to
protected data types, failure codes and op-codes to these registries these registries as defined below. Values defining ciphersuites
as defined below. Values can be added or modified per IETF REVIEW (block-based or hash-based), protected data payloads, failure codes,
[RFC5226] defining either block-based or hash-based ciphersuites, and op-codes can be added or modified per IETF Review [RFC5226].
protected data payloads, failure codes and op-codes. Each
Figure 3 represents the initial contents of the "EAP-GPSK
Ciphersuites" registry. The CSuite/Specifier field is 16 bits long.
All other values are available via IANA registration. Each
ciphersuite needs to provide processing rules and needs to specify ciphersuite needs to provide processing rules and needs to specify
how the following algorithms are instantiated: encryption, integrity, how the following algorithms are instantiated: encryption, integrity,
key derivation and key length. key derivation, and key length.
Figure 3 represents the initial ciphersuite CSuite/Specifier registry
setup. The CSuite/Specifier field is 16 bits long. All other values
are available via IANA registration. This registry should be named
"EAP-GPSK Ciphersuites".
The following is the initial protected data PData/Specifier registry The following are the initial contents of the "EAP-GPSK Protected
setup, which should be named "EAP-GPSK Protected Data Payloads": Data Payloads" registry:
o 0x0000 : Reserved o 0x0000 : Reserved
The PData/Specifier field is 16 bits long and all other values are The PData/Specifier field is 16 bits long, and all other values are
available via IANA registration. Each extension needs to indicate available via IANA registration. Each extension needs to indicate
whether confidentiality protection for transmission between the EAP whether confidentiality protection for transmission between the EAP
peer and the EAP server is mandatory. peer and the EAP server is mandatory.
The following layout represents the initial Failure-Code registry The following are the initial contents of the "EAP-GPSK Failure
setup, which should be named "EAP-GPSK Failure Codes": Codes" registry:
o 0x00000000 : Reserved o 0x00000000 : Reserved
o 0x00000001 : PSK Not Found o 0x00000001 : PSK Not Found
o 0x00000002 : Authentication Failure o 0x00000002 : Authentication Failure
o 0x00000003 : Authorization Failure o 0x00000003 : Authorization Failure
The Failure-Code field is 32 bits long and all other values are The Failure-Code field is 32 bits long, and all other values are
available via IANA registration. available via IANA registration.
The following layout represents the initial OP-Code registry setup, The following are the initial contents of the "EAP-GPSK OP Codes"
which should be named "EAP-GPSK OP Codes": registry:
o 0x00 : Reserved o 0x00 : Reserved
o 0x01 : GPSK-1 o 0x01 : GPSK-1
o 0x02 : GPSK-2 o 0x02 : GPSK-2
o 0x03 : GPSK-3 o 0x03 : GPSK-3
o 0x04 : GPSK-4 o 0x04 : GPSK-4
o 0x05 : GPSK-Fail o 0x05 : GPSK-Fail
o 0x06 : GPSK-Protected-Fail o 0x06 : GPSK-Protected-Fail
The OP-Code field is 8 bits long and all other values are available The OP-Code field is 8 bits long, and all other values are available
via IANA registration. via IANA registration.
14. Contributors 14. Contributors
This work is a joint effort of the EAP Method Update (EMU) design This work is a joint effort of the EAP Method Update (EMU) design
team of the EMU Working Group that was created to develop a mechanism team of the EMU Working Group that was created to develop a mechanism
based on strong shared secrets that meets RFC 3748 [RFC3748] and RFC based on strong shared secrets that meets RFC 3748 [RFC3748] and RFC
4017 [RFC4017] requirements. The design team members (in 4017 [RFC4017] requirements. The design team members (in
alphabetical order) were: alphabetical order) were:
skipping to change at page 35, line 34 skipping to change at page 35, line 38
14. Contributors 14. Contributors
This work is a joint effort of the EAP Method Update (EMU) design This work is a joint effort of the EAP Method Update (EMU) design
team of the EMU Working Group that was created to develop a mechanism team of the EMU Working Group that was created to develop a mechanism
based on strong shared secrets that meets RFC 3748 [RFC3748] and RFC based on strong shared secrets that meets RFC 3748 [RFC3748] and RFC
4017 [RFC4017] requirements. The design team members (in 4017 [RFC4017] requirements. The design team members (in
alphabetical order) were: alphabetical order) were:
o Jari Arkko o Jari Arkko
o Mohamad Badra o Mohamad Badra
o Uri Blumenthal o Uri Blumenthal
o Charles Clancy o Charles Clancy
o Lakshminath Dondeti o Lakshminath Dondeti
o David McGrew o David McGrew
o Joe Salowey o Joe Salowey
o Sharma Suman o Sharma Suman
o Hannes Tschofenig o Hannes Tschofenig
o Jesse Walker o Jesse Walker
Finally, we would like to thank Thomas Otto for his draft reviews, Finally, we would like to thank Thomas Otto for his reviews,
feedback and text contributions. feedback, and text contributions.
15. Acknowledgments 15. Acknowledgments
We would like to thank We would like to thank:
o Jouni Malinen and Bernard Aboba for their early draft comments in
June 2006. Jouni Malinen developed the first prototype o Jouni Malinen and Bernard Aboba for their early comments on the
implementation. It can be found at: document in June 2006. Jouni Malinen developed the first
http://hostap.epitest.fi/releases/snapshots/ prototype implementation.
o Lakshminath Dondeti, David McGrew, Bernard Aboba, Michaela o Lakshminath Dondeti, David McGrew, Bernard Aboba, Michaela
Vanderveen and Ray Bell for their input to the ciphersuite Vanderveen, and Ray Bell for their input to the ciphersuite
discussions between July and August 2006. discussions between July and August 2006.
o Lakshminath Dondeti for his detailed draft review (sent to the EMU
ML on the 12th July 2006). o Lakshminath Dondeti for his detailed review (sent to the EMU
o Based on a review requested from NIST Quynh Dang suggested changes mailing list on 12 July 2006).
to the GKDF function (December 2006).
o Based on a review requested from NIST, Quynh Dang suggested
changes to the GKDF function (December 2006).
o Jouni Malinen and Victor Fajardo for their review in January 2007. o Jouni Malinen and Victor Fajardo for their review in January 2007.
o Jouni Malinen for his suggestions regarding the examples and the o Jouni Malinen for his suggestions regarding the examples and the
key derivation function in February 2007. key derivation function in February 2007.
o Bernard Aboba and Jouni Malinen for their review in February 2007. o Bernard Aboba and Jouni Malinen for their review in February 2007.
o Vidya Narayanan for her review in March 2007. o Vidya Narayanan for her review in March 2007.
o Pasi Eronen for his IESG review in March and July 2008. o Pasi Eronen for his IESG review in March and July 2008.
o Dan Harkins for his review in June 2008. o Dan Harkins for his review in June 2008.
o Joe Salowey, the EMU working group chair, provided a document o Joe Salowey, the EMU working group chair, provided a document
review in April 2007. Jouni Malinen also reviewed the document review in April 2007. Jouni Malinen also reviewed the document
during the same month. during the same month.
o We would like to thank Paul Rowe, Arnab Roy, Prof. Andre Scedrov
and Prof. John C. Mitchell for their analysis of EAP-GPSK and for o We would like to thank Paul Rowe, Arnab Roy, Prof. Andre Scedrov,
pointing us to a client-side DoS attack, a downgrading attack and and Prof. John C. Mitchell for their analysis of EAP-GPSK, for
their input to the key derivation function. Based on their input their input to the key derivation function, and for pointing us to
the key derivation function has been modified and the text in the a client-side DoS attack and to a downgrading attack. Based on
security consideration section has been updated. their input, the key derivation function has been modified and the
text in the security considerations section has been updated.
o Finally, we would like to thank our working group chair, Joe o Finally, we would like to thank our working group chair, Joe
Salowey, for his support and for the time he spend on discussing Salowey, for his support and for the time he spent discussing open
open issues with us. issues with us.
16. References 16. References
16.1. Normative References 16.1. Normative References
[AES] National Institute of Standards and Technology,
"Specification for the Advanced Encryption Standard
(AES)", Federal Information Processing Standards
(FIPS) 197, November 2001.
[CBC] National Institute of Standards and Technology,
"Recommendation for Block Cipher Modes of Encryption --
Methods and Techniques", Special Publication (SP) 800-38A,
December 2001.
[CMAC] National Institute of Standards and Technology,
"Recommendation for Block Cipher Modes of Operation: The
CMAC Mode for Authentication", Special Publication
(SP) 800-38B, May 2005.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H. [RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
Levkowetz, "Extensible Authentication Protocol (EAP)", Levkowetz, "Extensible Authentication Protocol (EAP)",
RFC 3748, June 2004. RFC 3748, June 2004.
[RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The [RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The
Network Access Identifier", RFC 4282, December 2005. Network Access Identifier", RFC 4282, December 2005.
skipping to change at page 37, line 13 skipping to change at page 38, line 5
(SHA and HMAC-SHA)", RFC 4634, July 2006. (SHA and HMAC-SHA)", RFC 4634, July 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. May 2008.
[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, August 2008. RFC 5247, August 2008.
[AES] National Institute of Standards and Technology, 16.2. Informative References
"Specification for the Advanced Encryption Standard
(AES)", Federal Information Processing Standards
(FIPS) 197, November 2001.
[CMAC] National Institute of Standards and Technology,
"Recommendation for Block Cipher Modes of Operation: The
CMAC Mode for Authentication", Special Publication
(SP) 800-38B, May 2005.
[CBC] National Institute of Standards and Technology, [80211] "Information technology - Telecommunications and
"Recommendation for Block Cipher Modes of Encryption. Information Exchange Between Systems - Local and
Methods and Techniques.", Special Publication (SP) 800- Metropolitan Area Networks - Specific Requirements - Part
38A, December 2001. 11: Wireless LAN Medium Access Control (MAC) and Physical
Layer (PHY) Specifications", IEEE Standard 802.11-2007,
March 2007.
16.2. Informative References [ENTNUM] IANA, "SMI Network Management Private Enterprise Codes",
Private Enterprise Numbers, <http://www.iana.org>.
[RFC4017] Stanley, D., Walker, J., and B. Aboba, "Extensible [RFC4017] Stanley, D., Walker, J., and B. Aboba, "Extensible
Authentication Protocol (EAP) Method Requirements for Authentication Protocol (EAP) Method Requirements for
Wireless LANs", RFC 4017, March 2005. Wireless LANs", RFC 4017, March 2005.
[RFC4086] Eastlake, D., Schiller, J., and S. Crocker, "Randomness [RFC4086] Eastlake, D., Schiller, J., and S. Crocker, "Randomness
Requirements for Security", BCP 106, RFC 4086, June 2005. Requirements for Security", BCP 106, RFC 4086, June 2005.
[ENTNUM] IANA, "SMI Network Management Private Enterprise Codes",
IANA Assignments enterprise-numbers.
[80211] "Information technology - Telecommunications and
Information Exchange Between Systems - Local and
Metropolitan Area Networks - Specific Requirements - Part
11: Wireless LAN Medium Access Control (MAC) and Physical
Layer (PHY) Specifications", IEEE Standard 802.11-2007,
March 2007.
Authors' Addresses Authors' Addresses
T. Charles Clancy T. Charles Clancy
DoD Laboratory for Telecommunications Sciences DoD Laboratory for Telecommunications Sciences
8080 Greenmead Drive 8080 Greenmead Drive
College Park, MD 20740 College Park, MD 20740
USA USA
Email: clancy@ltsnet.net EMail: clancy@ltsnet.net
Hannes Tschofenig Hannes Tschofenig
Nokia Siemens Networks Nokia Siemens Networks
Linnoitustie 6 Linnoitustie 6
Espoo 02600 Espoo 02600
Finland Finland
Email: Hannes.Tschofenig@gmx.net EMail: Hannes.Tschofenig@gmx.net
Full Copyright Statement
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