Internet Draft P.Urien Document: draft-urien-eap-smartcard-01.txt A.J. Farrugia M.Groot G.Pujolle Expires: August 2003 EAP-Support in smartcard Status This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsolete by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract This document will describe the interface to the EAP protocol in smartcards, which could store multiple identities associated to Network Access Identifiers. Urien & All Informational - Expires August 2003 1 Integrating EAP in smartcards March 2003 Table of Contents Status.............................................................1 Abstract...........................................................1 Table of Contents..................................................2 Overview...........................................................2 Terms..............................................................3 Identification label...............................................4 Identification Label Coding Rules..................................4 Add-Identity.......................................................5 Delete-Identity....................................................5 Get-Preferred-Identity.............................................5 Get-Next-Identity..................................................5 Get-Subscriber-Profile.............................................6 Set-Identity.......................................................6 EAP-Packets........................................................6 Get-Pairwise-Master-Key (PMK)......................................6 ISO 7816-4 APDUs...................................................7 Add-Identity....................................................7 Delete-Identity.................................................7 Get-Preferred-Identity..........................................8 Get-Next-Identity...............................................8 Get-Subscriber-Profile..........................................8 Set-Identity....................................................8 EAP-Packets.....................................................8 Get-Pairwise-Master-Key.........................................9 State Machine Sequence............................................10 Security Considerations...........................................10 General Considerations.........................................10 PEAP Consideration.............................................10 Intellectual Property Right Notice................................11 Annex 1 (Informative) - EAP/SIM packet detail.....................11 Annex 2 (Informative) - EAP/MD5 packet details.................15 Annex 3 (Informative) TLS support.................................17 Fragment maximum size..........................................17 EAP/TLS messages format........................................17 Example of EAP/TLS Authentication..............................17 Annex 4 (Normative) ASN.1 BER Tag coding for the subscriber profile information.......................................................18 References........................................................18 Author's Addresses................................................19 Overview All technologies derived from 802.11 specifications such as 802.11a, 802.11b, 802.11g need a strong security protocols for data privacy, integrity and network access. Where the 802.1X [8] specification describes the risks and the protocols for the protection of the exchanged data during the network connection. The very same Urien & All Informational - Expires August 2003 2 Integrating EAP in smartcards March 2003 specification remains compatible with other standard for the authentication and the network access. 802.1X specification requires the Extensible Authentication Protocol (EAP) to be used as the framework for application dependent authentication processes with a mutual authentication between the supplicant and the authenticator. It is obvious that the role of the supplicant in this specification has partly been implemented in the smart card has an authentication processing mean. The flexibility of EAP (RFC 2284) specification does not provide a Mandatory-to- implement solution. The structure of the EAP frames allows the applications to identify the EAP type of consequently to operate the appropriate authentication. Terms The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119. Authentication Agent: A piece of software implemented in the supplicant that processes the authentication sequence. AS Authentication Server Authenticator: See the IEEE 802.1X specification for a definition of this concept. EAP Extensible Authentication Protocol. GSM Global System for Mobile communications. IMSI International Mobile Subscriber Identifier, used in GSM to identify subscribers. NAI Network Access Identifier PMK Pairwise Master Key SIM Subscriber Identity Mobile Supplicant: an IEEE 802.1X concept, which in the context of IEEE 802.11 represents a STA (station) seeking to attach to an IEEE 802 LAN via an IEEE 802.1X Port. See the IEEE 802.1X specification for a complete definition Urien & All Informational - Expires August 2003 3 Integrating EAP in smartcards March 2003 Identification label 802.1X specification [5] requires an authentication between the authenticator or the authentication server (AS) and the supplicant. The authentication is embedded in the Extensible Authentication Protocol (EAP) RFC2284 [1] specification. The authentication consists of a challenge response between both parties without consideration of the involved crypto-suite. Before starting the mutual authentication, the AS needs the supplicant identity to establish the session. The AS or the authenticator sends an EAP Request Identity to the supplicant that returns its system identity. A user may own several identities likely associated to the network operators. The identification label is a pointer to a system identity stored in smartcard; it may be of various types: 1. A network SSID as described in the 802.11 standard [4]. 2. A userĘs identification (userid) e.g. an ASCII string. A network access identifier, NAI [6] may be used as userid. 3. A pseudonym, e.g. a friendly name. According to the network environment, the supplicant software needs to set the appropriate identity and verifies if the smart card is able to mirror the authenticator. If the smart card is not able to process the authentication related to the identity then any setting process is rejected by the NAK code. The subsequent sections give the description of the methods used by a supplicant for processing an 802.1X authentication using the smart card. Annex one provides a reference implementation example for a SIM based authentication. Annex two provides a reference implementation example for a MD5 based authentication. Annex three provides a reference implementation for a TLS based authentication. Identification Label Coding Rules The Get-Next-Identity section didnĘt define the coding rules of the identification label. This section describes the structure and the architecture of the userid. A userid consists of 2 fields separated by the Internet symbol "@". The right hand side of the "@" symbol is the userid realms while the left hand side is an application dependent and unique identification number. EAP/SIM has defined the userid where the application identification is "1IMSI". Other userid such as email address can be used by the application. Urien & All Informational - Expires August 2003 4 Integrating EAP in smartcards March 2003 Add-Identity This command and the Delete-Identity are part of the userĘs identity management protocols. The smart card is initially manufactured without any identification label. The personalization or the supplicant software adds in the smart card userĘs identification label that can be retrieved by other smart card command. If the smart card manages pseudonyms the command does not allows setting the user pseudonyms. The smart card command only adds permanent identification label in the list. Delete-Identity This command and the add-Identity are part of the userĘs identity management protocols. The smart card contains a list of one or several identification labels that can be retrieved by the supplication software. The command deletes one entry of the smart card list. Get-Preferred-Identity The smart card contains at least one userĘs identity related to the userĘs network subscription. The supplicant software gets from the smart card the initial and preferred identification label. If the user has more than one identities the supplicant software uses the Get-Next-Identity to read all the available other userĘs identities. If the smart card manages pseudonyms and a pseudonym is available as preferred identity, the Get-Preferred-Identity shall return the pseudonym. Get-Next-Identity The smart card may contain one or more userĘs identities according to the userĘs network subscriptions. The supplicant software should prompt the userĘs identity and a subsequent selection allows the smart card to process the appropriate EAP authentication type. The method Get-Next-Identity allows the supplicant software to read all the available userĘs identities. The Get-Next-Identity method may inform the supplicant software when all userĘs identities have been read. Otherwise the supplicant software detects the identity list end when it gets again the first identity. If the smart card contains a pseudonym management and the pseudonym is (are) available the Get-Next-Identity returns the appropriate pseudonym. If the pseudonym management is not supported, the smart card returns the permanent Identity according to the previous section. Urien & All Informational - Expires August 2003 5 Integrating EAP in smartcards March 2003 Get-Subscriber-Profile The Authentication Agent or the authenticator may request the subscriber profile information. The Get-Subscriber-Profile returns all related information available in the smart card. This specification does not provide the detail of the subscriber profile information. The implementation of the information may be ruled but ASN.1 BER coding specification [9] or by an XML dialect [10]. Set-Identity Once the Identity selection is processed, the supplicant software needs to set the smart card EAP framework according to the selected userĘs identity. The Set-Identity sets or restarts the smart card EAP framework state machine for further processing using the EAP- Packets method. The supplicant software can set the EAP framework using the pseudonym if available in the smart card. If the pseudonym is not available the supplicant software uses the permanent identity to set the EAP framework according to the previous section. EAP-Packets The EAP process is described in the RFC 2284 specification [1] and involves several EAP requests and responses packets, 1. EAP request/response Identity; 2. A suite of EAP request/response related to a particular authentication scenario; and 3. EAP success or failure. The Set-Identity restarts the smart card EAP framework state machine for further processing using the EAP-Packets method. The smart card receives the RFC 2284 frames. It retrieves the appropriate EAP authentication type in the frame and the identifier. The smart card maintains the EAP state machine and returns an EAP NAK packet if the state sequence is broken. Any EAP request is silently ignored if the state machine was not started. The last step of the protocol retrieving the Pairwise Master Key from the smart card can be accomplished only if the last EAP packet received from the authentication is an EAP success packet. Get-Pairwise-Master-Key (PMK) At the end of a successful authentication the supplicant needs to update the appropriate crypto suite using the master session key. The Get-Pairwise-Master-Key returns to the supplicant software the key to initialize radio security protocols like TKIP, WRAP or CCMP. Urien & All Informational - Expires August 2003 6 Integrating EAP in smartcards March 2003 For obvious security reasons the Get-Pairwise-Master-Key is available only if the smart card has received an EAP success packet. ISO 7816-4 APDUs This section of the document provides an implementation of the previous descriptions for an ISO 78176-4 compatible smart card. The section does not preclude of the transport protocol used between the smart card and the reader. Thus, this specification does not mandate-to-implement any transport protocol such as T=0 or T=1, which are not in the scope of this document. It should be noted that all values are in hex representation. The restriction and security related descriptions are not present in the document. Annexes of this document give implementation examples. Add-Identity This command adds an identification label as described in the section: Identification Label Coding Rules. The smart card list is managed by the smart card. The identification label is appended as the last element of the list if the parameter Po is 0x00. If this parameter has any value, it represents the identification label position. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 16 | 81 | Po | 00 | XX | +--------+-----+-----+----+----+----+----+ Delete-Identity This command deletes the identification label as described in the section: Identification Label Coding Rules. The command parameter gives the identification label to be deleted and the smart card leave the space empty. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 16 | 82 | Po | 00 | 00 | +--------+-----+-----+----+----+----+----+ Urien & All Informational - Expires August 2003 7 Integrating EAP in smartcards March 2003 Get-Preferred-Identity This command returns the userĘs preferred identification label as described in the section: Identification Label Coding Rules +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 16 | 02 | 00 | 00 | XX | +--------+-----+-----+----+----+----+----+ Get-Next-Identity This command returns a user identification label as described in the section: Identification Label Coding Rules. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 16 | 01 | 00 | 00 | XX | +--------+-----+-----+----+----+----+----+ Get-Subscriber-Profile The command returns the related subscriber profile information according to the application requirements and format. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 16 | 08 | 00 | 00 | YY | +--------+-----+-----+----+----+----+----+ Set-Identity The command resets and initializes the state machine for processing the EAP Packets. The first step after this command is an EAP request identity packet. If a different EAP packet is sent to the smart card the smart card return an EAP NAK response. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 16 | 80 | 00 | XX | 00 | +--------+-----+-----+----+----+----+----+ EAP-Packets The command is the method for EAP packet management. The smart card identifies the EAP packet type and processes the EAP authentication according to current state machine. The state machine sequences have Urien & All Informational - Expires August 2003 8 Integrating EAP in smartcards March 2003 to be respected and the smart card enforces the EAP sequence processing. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 80 | 00 | 00 | XX | YY | +--------+-----+-----+----+----+----+----+ The EAP request or response packet lengths are represented by the unknown value XX and YY. The supplicant software should set these elements in accordance with the EAP packet types. EAP Identity packets are independent of the authentication type and can be the same for any type of authentications. This section of the document provides the packet details. The rest of the EAP packet being authentication protocol dependent, they are detailed in the informative annex of this document. The description of the EAP/Request/identity is detailed according to the IETF RFC 2284 [1]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Request | Identifier | Length = 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 01 | +-+-+-+-+-+-+-+-+ The description of the EAP/Response/identity is detailed according to the IETF RFC 2284 [1]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Response | Identifier | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 01 | | +-+-+-+-+-+-+-+-+ | | | | User Identity | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Get-Pairwise-Master-Key Once the state machine has received the EAP Success packet the smartcard process is able to send the Master Key used by the 802.1X specification for the crypto-suite. Urien & All Informational - Expires August 2003 9 Integrating EAP in smartcards March 2003 As an illustration the EAP SIM authentication [2] specifies the Pairwise Master Key usage according to the system cryptographic suite. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | A6 | 00 | 00 | 00 | 20 | +--------+-----+-----+----+----+----+----+ State Machine Sequence +----------------------+ +----------------------+ | Get userĘs identity |>>>| Set userĘs identity |>>> +----------------------+ +----------------------+ +----------------------+ +----------------------+ | EAP request/response |>>>| EAP request/response |>>> | Get identity | | | +----------------------+ +----------------------+ +----------------------+ +----------------------+ | EAP request/response |>>>| EAP Notification | | | | Success | +----------------------+ +----------------------+ Security Considerations General Considerations As a reference implementation the previous section provides the details of the EAP authentication using the GSM SIM. This section of the document highlights the new potential risks providers of application may face by re-using deployed networks for other purposes. From the document [7] fatal flaw does exist when have physical access to the smart card. The nature of the Internet network does no longer require getting physical access to the smart card. Worms, Trojan horses or viruses can move to the computing platforms and performs the jobs. It is important for a reference implementation to provide the relevant level of protection for the new applications but not to create other flaws. Other consideration have been introduced in [2] to protect the smart card against crypto attack and recommends the authentication should take place in a PROTECTED ENVIRONMENT. PEAP Consideration Urien & All Informational - Expires August 2003 10 Integrating EAP in smartcards March 2003 Protected Extensible Authentication Protocol (PEAP) [12] is a pre- processing protocol that allows the privacy of data when processing EAP [1] protocol. EAP protocol, as defined in [1], starts by an EAP packet request/Identity. The EAP packet response Identity returns the userĘs identification label with no privacy being not part of [1]. PEAP protocol allows both part of the EAP packet exchange creating a session key that can be for privacy over the subsequent execution of the EAP protocol. This implementation of EAP in the smart card shall allow performing a PEAP tunnel for privacy. Once PEAP first phase has been successfully preformed, the EAP protocol has defined shall be performed according the EAP smart card requirements. Intellectual Property Right Notice To be specify according to the author and participant. Annex 1 (Informative) - EAP/SIM packet detail. The protocol implementation is out of the scope of this document but as a reference implementation this section gives details using the SIM as specified by [3]. Other protocol can be implemented using ISO 7816-3 TPDU. This section of the document gives the APDU syntax and coding which makes the specification protocol free. The first EAP packet is the EAP Request Identity. This initial packet format complies with [1]. The smart card returns an EAP response identity according to the IMSI length and the supported version according to [2]. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 80 | 00 | 00 | 05 | YY | +--------+-----+-----+----+----+----+----+ The description of the EAP/Request/identity is detailed according to the IETF RFC 2284 [1]. This EAP packet doesnĘt respect the EAP/SIM format since it is only part of [1]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Request | Identifier | Length = 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 01 | +-+-+-+-+-+-+-+-+ Urien & All Informational - Expires August 2003 11 Integrating EAP in smartcards March 2003 The description of the EAP/Response/identity is detailed according to the IETF RFC 2284 [1]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Response | Identifier | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 01 | | +-+-+-+-+-+-+-+-+ | | | | User Identity | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Note the EAP/Response/Identity when returning the userĘs identity that includes the IMSI includes the real coded IMSI in the EAP packet and not the IMSI coded for GSM network. Further information can be retrieved in [3] for the IMSI coding in the SIM during the SIM setting. The user Identity field can contains the userĘs permanent pseudonym or re-authentication identity. The second EAP Packet is the EAP request SIM start as represented in the IETF draft document [2]. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 80 | 00 | 00 | XX | YY | +--------+-----+-----+----+----+----+----+ The description of the EAP/Request/SIM/Start is detailed according to [2] incoming SIM data where further information can be retrieved. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Request | Identifier | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 18 | Subtype = 10 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_PERM..._REQ | Length = 1 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_FULL..._RES | Length = 1 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_ANY_ID_REQ | Length = 1 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_VERSION_L...| Length | Actual Version List Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Supported version 1 | Supported version 2 | Urien & All Informational - Expires August 2003 12 Integrating EAP in smartcards March 2003 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Supported version 3 | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The description of the EAP/Response/SIM/Start is detailed according to [2] outgoing SIM data where further information can be retrieved. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Response | Identifier | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 18 | Subtype = 10 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_NONCE_MT | Length = 5 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | NONCE_MT | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AT_SELECTED | Length = 1 | Select Version | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AT_IDENTITY | Length | Actual Identity Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | User Identity (Optional) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The description of the EAP/Response/SIM/Start is detailed according to [2] outgoing SIM data where further information can be retrieved. The third EAP Packet is the EAP request SIM Challenge as represented in the IETF draft document [2]. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 80 | 00 | 00 | XX | 1C | +--------+-----+-----+----+----+----+----+ The description of the EAP/Request/SIM/Challenge is detailed according to [2] incoming SIM data where further information can be retrieved. Urien & All Informational - Expires August 2003 13 Integrating EAP in smartcards March 2003 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Request | Identifier | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 18 | Subtype = 11 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AT_RAND | Length | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | n*RAND | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AT_MAC | Length = 5 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | MAC | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AT_IV | Length = 5 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Initialization Vector (Optional) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AT_ENCR_DATA | Length | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Encrypted Data (Optional) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The description of the EAP/Response/SIM/Challenge is detailed according to [2] outgoing SIM data where further information can be retrieved. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Response | Identifier | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 18 | Subtype = 11 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AT_MAC | Length = 5 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | MAC | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Urien & All Informational - Expires August 2003 14 Integrating EAP in smartcards March 2003 The last EAP Packet is the EAP success notification as represented in the IETF RFC 2284 [2]. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 80 | 00 | 00 | 04 | 00 | +--------+-----+-----+----+----+-- -+----+ 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Success | Identifier | Length = 04 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Annex 2 (Informative) - EAP/MD5 packet details The first EAP packet is the EAP Request Identity. This initial packet format complies with the RFC 2284. The smart card returns an EAP response identity according to the NAI length. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 80 | 00 | 00 | 05 | YY | +--------+-----+-----+----+----+----+----+ The description of the EAP/Request/identity is detailed according to the IETF RFC 2284 [1]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Request | Identifier | Length = 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 01 | +-+-+-+-+-+-+-+-+ The description of the EAP/Response/identity is detailed according to the IETF RFC 2284 [1]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Response | Identifier | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 01 | | |-+-+-+-+-+-+-+-+ Identity Value | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Urien & All Informational - Expires August 2003 15 Integrating EAP in smartcards March 2003 The second EAP Packet is the EAP/request/MD5/challenge as represented in the IETF RFC 2284 [1]. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 80 | 00 | 00 | XX | 16 | +--------+-----+-----+----+----+----+----+ The description of the EAP/Request/MD5/challenge is detailed according to the IETF RFC 2284 [1]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Request | Identifier | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 04 | | |-+-+-+-+-+-+-+-+ MD5-Challenge.Value | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The description of the EAP/Response/MD5/challenge is detailed according to the IETF RFC 2284 [1]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Response | Identifier | Length = 16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 04 | Type_Size=10 | | |-+-+-+-+-+-+-+-+---------------+ MD5 Digest Value | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The third EAP Packet is the EAP success notification as represented in the IETF RFC 2284 [1]. +--------+-----+-----+----+----+----+----+ |Command |Class| INS | P1 | P2 | Lc | Le | +--------+-----+-----+----+----+----+----+ | | A0 | 80 | 00 | 00 | 04 | 00 | +--------+-----+-----+----+----+-- -+----+ 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Success | Identifier | Length = 04 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Urien & All Informational - Expires August 2003 16 Integrating EAP in smartcards March 2003 Further information can be retrieved from the IETF draft document [2]. Annex 3 (Informative) TLS support Fragment maximum size. A single TLS record may be up to 16384 octets in length, but a TLS message may span multiple TLS records, and a TLS certificate message may in principle be as long as 16MB. The group of EAP-TLS messages sent in a single round may thus be larger than the maximum RADIUS packet size of 4096 octets, or the maximum 802 LAN frame size. Due to smartcard constraints, the maximum EAP message length of a no fragmented packet is set to 240 bytes. For a fragmented EAP message, the maximum length value is 240 bytes. When the smartcard receives an EAP-Request packet with the M bit set, it MUST respond with an EAP-Response with EAP-Type=EAP-TLS and no data. This serves as a fragment ACK. EAP/TLS messages format. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Code | Identifier | Length <= 240 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 13 | Flag | TLS Message Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLS Message Length | TLS DATA | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Flags 0 1 2 3 4 5 6 7 8 +-+-+-+-+-+-+-+-+ |L M S R R R R R| +-+-+-+-+-+-+-+-+ L = Length included. M = More fragments S = EAP-TLS start, set in an EAP-TLS Start message. R = Reserved Example of EAP/TLS Authentication Smartcard Authentication Server <- EAP-Request/ Identity Urien & All Informational - Expires August 2003 17 Integrating EAP in smartcards March 2003 EAP-Response/ Identity (MyID) -> <- EAP-Request/ EAP-Type=EAP-TLS (TLS Start) EAP-Response/ EAP-Type=EAP-TLS TLS client_hello)-> <- EAP-Request/ EAP-Type=EAP-TLS (TLS server_hello, TLS certificate, TLS certificate_request, TLS server_hello_done) EAP-Response/ EAP-Type=EAP-TLS (TLS certificate, TLS client_key_exchange, TLS certificate_verify, TLS change_cipher_spec, TLS finished) -> <- EAP-Request/ EAP-Type=EAP-TLS (TLS change_cipher_spec, TLS finished) EAP-Response/ EAP-Type=EAP-TLS -> <- EAP-Success Annex 4 (Normative) ASN.1 BER Tag coding for the subscriber profile information To be defined according to the EAP type. References [1] L. Blunk, J. Vollbrecht, "PPP Extensible Authentication Protocol (EAP)", RFC 2284, March 1998. (NORMATIVE) [2] EAP SIM Authentication draft version 8 (NORMATIVE) [3] GSM Technical Specification GSM 11.11. Digital cellular telecommunications system (Phase 2+); Specification of the Subscriber Identity Module - Mobile Equipment (SIM - ME) [4] Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications [5] Standards for Local and Metropolitan Area Networks: Standard for Port based Network Access Control. Urien & All Informational - Expires August 2003 18 Integrating EAP in smartcards March 2003 [6] "The Network Access Identifier" rfc 2486 [7] "Can you Clone a GSM Smart Card (SIM)? " From Charles Brookson Chairman GSM Association Security Group [8] Part 11: Wireless Medium Access Control (MAC) and physical layer (PHY) specifications: Specification for Enhanced Security [9] ASN.1 standard 2002 edition ISO/IEC 8825.1. http://asn1.elibel.tm.fr/en/standards/index.htm [10] Extensible Markup Language (XML) 1.0 (Second Edition), W3C Recommendation 6 October 2000 [11] B. Aboba, D. Simon, EAP TLS Authentication Protocol RFC 2716, October 1999. [12] H. Andersson, S. Josefsson, G. Zorn, D. Simon, A. Palekar, "Protected EAP Protocol (PEAP)", draft-josefsson-pppext-eap-tls-eap- 05.txt, work-in-progress, September 2002. (INFORMATIVE) Author's Addresses Pascal Urien ENST 46 rue Barrault 75013 Paris Phone: NA France Email: Pascal.Urien@enst.fr Augustin J. Farrugia Impasse des CAMEGIERS Phone: NA Ceyreste, 13600 France Email: afarrugia@csi.com Max de Groot Gemplus Avenue du Pic de Bertagne BP 100, 13881 Gemenos Phone: +33 442 365 036 France Email: max.de-groot@gemplus.com Guy Pujolle LIP6 - University Paris 6 8 rue Capitaine Scott Phone: NA Paris 75015 France Email: Guy.Pujolle@lip6.fr Urien & All Informational - Expires August 2003 19