One document matched: draft-arkko-map-doi-07.txt

Differences from draft-arkko-map-doi-06.txt







Network Working Group                                           J. Arkko
INTERNET-DRAFT                                                   R. Blom
Category: Informational                                         Ericsson
<draft-arkko-map-doi-07.txt>                                 27 May 2002

    The MAP Security Domain of Interpretation for Internet Security
                 Association and Key Management Protocol

Status of this Memo

   This document is an Internet Draft and is in full conformance with
   all provisions of Section 10 of RFC2026 [STDS]. Internet Drafts are
   working documents of the Internet Engineering Task Force (IETF), its
   areas, and 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 obsoleted 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.

   To learn the current status of any Internet Draft, please check the
   "1id-abstracts.txt" listing contained in the Internet Drafts Shadow
   Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
   munnari.oz.au (Australia), ds.internic.net (US East Coast), or
   ftp.isi.edu (US West Coast).

   The distribution of this memo is unlimited. It is filed as <draft-
   arkko-map-doi-07.txt>, and expires November 27, 2002. Please send
   comments to the authors.

1. Abstract

   The Mobile Application Part (MAP) protocol is a signaling protocol
   for cellular networks. The MAP Security (MAPSEC) protocol provides
   a secure way to transport MAP messages. To use MAPSEC, however,
   Security Associations (SAs) are needed. This document defines how
   such SAs can be created automatically. We use the Internet
   Security Association and Key Management Protocol (ISAKMP) as a
   framework for managing SAs and establishing keys. The framework
   can be specialized to a particular task. Such a specialization is
   called a Domain of Interpretation (DOI), and this document defines



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   the MAPSEC DOI. This specialization is very similar to the
   Internet Key Exchange protocol and the ISAKMP specialization for
   IP Security, except that non-IP protocols are being negotiated.


Contents

   1. Abstract
   2. Terms and Definitions
   3. Introduction
      3.1. MAP and MAPSEC
      3.2. Domains of Interpretation
      3.3. Network Architecture
   4. MAPSEC DOI Phase 1
      4.1 MAPSEC DOI Number
   5. MAPSEC DOI Phase 2
      5.1 Naming Scheme
      5.2 MAPSEC Situation Definition
          4.2.1 SIT_IDENTITY_ONLY
      5.3 MAPSEC Policy Requirements
      5.4 MAPSEC Assigned Numbers
          5.4.1 MAPSEC Security Protocol Identifier
                4.5.1.1 PROTO_MAPSEC
          5.4.1 MAPSEC Transform Identifiers
      5.5 MAPSEC Security Association Attributes
          5.5.1 Required Attribute Support
          5.5.2 Attribute Negotiation
          5.5.3 Lifetime Matching
      5.6 MAP Security Payload Content
          5.6.1 Identification Payload Content
          5.6.2 Notify Message Types
      5.7 MAPSEC Key Exchange Requirements
   6. Security Considerations
   7. IANA Considerations
      7.1 MAPSEC Situation Definition
      7.2 MAPSEC Security Protocol Identifiers
      7.3 MAPSEC MAP Security Transform Identifiers
      7.4 MAPSEC Security Association Attributes
      7.5 MAPSEC Identification Type
   8. Key Derivation for MAP Security
   9. Intellectual property rights
   10. Acknowledgments
   11. References
       11.1 Normative References
       11.2 Informative References
   12. Author's Address

2. Terms and Definitions



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   In this document, the key words "MUST", "MUST NOT", "REQUIRED",
   "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT
   RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as
   described in RFC 2119 [WORDS].

3. Introduction

3.1. MAP and MAPSEC

   In the Global Mobile System (GSM) and Universal Mobile
   Telecommunication System (UMTS) networks, the MAP protocol plays a
   central role in the signaling communications between the Network
   Elements (NEs). User profile exchange, authentication, and mobility
   management are performed using MAP. MAP runs typically over the
   Signaling System number 7 (SS7) protocol stack. For a full
   description of the MAP protocol, see [MAP].

   The mobile networks are moving to IP-based solutions. Completely
   IP-based networks and new signaling protocols will replace MAP at
   some point. However, MAP and SS7 signaling networks have to be
   supported during the transition time, and beyond, due to the need
   to retain legacy equipment in networks.

   MAP has a role in the authentication process of GSM phones, and
   operators are concerned about its lack of cryptographic security
   support. For this reason a new protocol header has been developed
   to protect MAP messages, much in the same way as the Encapsulating
   Security Payload (ESP) protocol protects IP packets. This new
   protocol is called MAPSEC [NDSEC]. A key management mechanism is
   also needed for MAPSEC. This key management mechanism runs over IP.



3.2. Domains of Interpretation

   The Internet Security Association and Key Management Protocol
   (ISAKMP) provides a common framework for protocols that manage
   Security Associations (SAs) and establish keys. This framework may
   be specialized to different tasks, with different requirements and
   security properties. Each such specialization results in a new
   task-specific protocol. ISAKMP provides a common message format
   for these protocols.

   A specialization of ISAKMP is called a Domain of Interpretation
   (DOI). A DOI defines the interpretation of task-specific parts in
   ISAKMP messages. These parts include the fields which are used to
   inform the peer about the supported cryptographic algorithms and
   protocols, and the fields which are used to carry the identities of



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   the parties. As ISAKMP is used in different tasks, the required
   algorithms and other parameters may be different.

   For instance, the IP Security DOI [IPSDOI] describes the use of
   ISAKMP in the context of IP Security protocols (AH, ESP) and IP
   Compression. The Internet Key Exchange (IKE) protocol uses IP
   Security DOI. The IKE protocol, and the parameters of the DOI are
   divided in two phases: In Phase 1, an authentication is performed
   and protection for ISAKMP itself is set up. In Phase 2, actual AH
   and ESP SAs are negotiated.

   This document defines the MAPSEC DOI for ISAKMP. This DOI can be
   used to negotiate MAPSEC SAs. Phase 1 related
   issues for the MAPSEC DOI are described in Section 4. Phase 2
   related issues are described in Section 5. In addition, 3GPP
   Technical Specifications [NDSEC] specify the actual MAPSEC
   authentication and encryption algorithms and the so called
   protection profiles. [NDSEC] defines also the values that are used
   in the MAPSEC DOI to refer to these algorithms and profiles. This
   ensures that the MAPSEC DOI document does not have to be modified
   upon the development of a new authentication algorithm, for
   instance.

   This new DOI is very similar to the IP Security DOI and IKE.
   The only technical differences are with respect to the Phase 2,
   otherwise a subset of the IP Security DOI and IKE is used. MAPSEC DOI
   is separated from IKE as a new DOI rather than an extension of the
   current one in order to allow the two protocols to have different
   port numbers, name spaces, and change control in the future.

   If IKE is developed further or replaced by new protocols, it is
   possible to update the MAPSEC DOI to use a new protocol. Such an
   update would involve extending the new protocol to allow other
   protocols than AH and ESP, and allowing certain new algorithm
   identifiers and other parameters.

3.3. Network Architecture

   The MAP Security protocol and its key management part provide
   authentication, confidentiality, integrity, and replay protection
   services to the MAP messages it transports.

   The purpose of the MAP Security header in the protocol is to
   provide enough information to determine the MAP Security
   Association and Protection Modes used in securing the MAP
   operation that follows the header.

   MAPSEC DOI and IKE are used to set up SAs for nodes implementing



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   MAPSEC. While the MAP protocol usually runs over SS7, the MAPSEC
   DOI and IKE are always run over IP. Therefore, it is assumed that
   nodes or networks implementing MAPSEC always have IP connectivity
   in addition to SS7 connectivity. Figure 1 below depicts the
   situation.

         _---------MAPSEC key management over IP-------_
        /                                               \
        |                                               |
    +-----------+                                 +-----------+
    |           |                                 |           |
    |  Node or  |                                 |  Node or  |
    | Network 1 |---------MAPSEC over SS7---------| Network 2 |
    |           |                                 |           |
    |           |                                 |           |
    +-----------+                                 +-----------+

        Figure 1: Network architecture for MAP Security


   The network architectures where the MAPSEC DOI can be run include
   but are not limited to the one defined by 3GPP [NDSEC]. In the 3GPP
   architecture the MAPSEC is typically run between two different
   network operators, and the same SAs are shared by a number of NEs.

   As in IKE, the MAPSEC DOI allows only symmetric SAs to be set
   up. That is, a pair of SAs is always created for the incoming and
   outgoing directions. These SAs differ only with respect to the
   keys, SPIs, and peer identities but all other parameters including
   the algorithms will have the same values.

4. MAPSEC DOI Phase 1

   For Phase 1, all IP Security DOI definitions [IPSDOI] and IKE
   procedures [ISAKMP, IKE] MUST be used unchanged in the MAPSEC DOI,
   including the way that peers are authenticated. However, with the
   MAPSEC DOI the following exceptions to the full requirements will
   apply:

     o  All MAPSEC DOI communications SHOULD run on port TBD instead
        of the standard IKE port 500. This applies to both Phase 1
        and 2. Additionally, MAPSEC DOI implementations MUST send
        the value zero in the port field of the identity payload
        during Phase 1 (standard IKE allows either 0 or 500).

     o  Support for Perfect Forward  Secrecy (PFS) is  not  required.
        An implementation that receives a Phase 2 negotiation request
        with PFS on MAY decline the negotiation.



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     o  Only one  identity  type,  ID_FQDN,  MUST  be implemented for
        Phase 1. Other identity types specified in [IPSDOI] SHOULD be
        implemented.

     o  Only the  AES  encryption  [AESESP]  and SHA-1 hash [IKE]
        algorithms MUST be implemented as ISAKMP encryption and hash
        operations.

   Implementer's note: IKE [IKE] specifies that all implementations
   MUST support authentication through pre-shared secrets and SHOULD
   support public key based authentication.  All implementations also
   MUST support Main Mode.

4.1 MAPSEC DOI Number

   Within ISAKMP, all DOI's MUST be registered with the IANA. This
   number is TBD.

5. MAPSEC DOI Phase 2

   IKE procedures regarding Phase 2 are used unchanged, with the
   following exceptions:

        o  Identity types used in Phase 2 are different.

        o  SA payloads are different.

        o  There are no MAPSEC-specific Phase 2 notifications.

   Note also that all implementations of this DOI MUST be able to
   handle the deletion of an existing SA (allowed also by IKE).

5.1 Naming Scheme

   Within the MAPSEC DOI, all well-known identifiers MUST be
   registered as explained in Section 7.

   All multi-octet binary values are stored in network byte order.

5.2 MAPSEC Situation Definition

   Within ISAKMP, the Situation field provides information that can
   be used by the responder to make a policy determination about how
   to process the incoming negotiation request. For the MAPSEC DOI,
   the Situation field in Phase 1 is handled as specified by the IP
   Security DOI [IPSDOI]. In Phase 2, the Situation field is a four
   (4) octet bitmask with the following value:




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       Situation                   Value
       ---------                   -----
       SIT_IDENTITY_ONLY           0x01

5.2.1 SIT_IDENTITY_ONLY

   The SIT_IDENTITY_ONLY type specifies that the SA will be
   identified by source identity information present in an associated
   Identification Payload. See Section 5.6.1 for a complete
   description of the various Identification types. All MAPSEC DOI
   implementations MUST support SIT_IDENTITY_ONLY by including two
   Identification Payloads in the Phase 2 exchange, and MUST abort
   any negotiation that fails to do so.

5.3 MAPSEC Policy Requirements

   The policy requirements for nodes implementing the MAPSEC DOI are
   beyond the scope of this document.  However, it is required that
   systems are able to specify their policies with respect to the MAP
   traffic in terms of Protection Profiles as defined in [NDSEC].
   These Protection Profiles indicate the need for a particular kind
   of protection based on the type of the MAP message.  For the
   purposes of this document a Protection Profile is a 16 bit number
   that is agreed during the SA negotiation.

5.4 MAPSEC Assigned Numbers

   The following sections list the Assigned Numbers for the MAPSEC
   DOI. Sections 5.4.1 to 5.5 describe Protocol Identifiers, MAPSEC
   Transform Identifiers and Security Association Attribute Type
   Values, which are a part of the MAPSEC SA Payloads. Section 5.6
   describes ID Payload Type Values and Notify Message Type Values.
   These are ISAKMP payloads whose data representations depend on the
   applicable DOI.

5.4.1 MAPSEC Security Protocol Identifier

   The ISAKMP proposal syntax was specifically designed to allow for
   the simultaneous negotiation of multiple Phase 2 security protocol
   suites within a single negotiation.  As a result, the protocol
   suites listed below form the set of protocols that can be
   negotiated at the same time. The combination of protocol suites
   that may be negotiated together is a host policy decision.

   The following table lists the values for the Security Protocol
   Identifiers referenced in an ISAKMP Proposal Payload for the MAPSEC
   DOI.




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       Protocol ID                         Value
       -----------                         -----
       RESERVED                            0-1
       PROTO_MAPSEC                        TBD

5.4.1.1 PROTO_MAPSEC

   The PROTO_MAPSEC type specifies the use of the MAP Security to
   protect MAP messages.

5.4.2 MAPSEC Transform Identifiers

   The following table lists the reserved MAPSEC Transform
   Identifiers.

       Transform ID                        Value
       ------------                        -----
       RESERVED                            0-1

   Actual  MAP  Transform  Identifiers  are  defined in the 3GPP
   Technical Specification  [NDSEC].

5.5 MAPSEC Security Association Attributes

   The following SA attribute definitions are used in Phase 2 of an
   IKE negotiation. Attribute types can be either Basic (B) or
   Variable-Length (V). Encoding of these attributes is defined in
   the base ISAKMP specification.

   Attributes defined as Basic MUST NOT be encoded as Variable-Length.
   Variable-Length attributes MAY be encoded as Basic attributes if
   their value can fit into two octets. See [IKE] for further
   information on attribute encoding in the MAPSEC DOI. All
   restrictions listed in [IKE] also apply to the MAPSEC DOI.

   Implementer's note: The attributes described here behave exactly
   as the corresponding ones in the IP Security DOI, unless otherwise
   explicitly specified. For the purposes of reusing IP Security DOI
   code, the parameters not used by MAPSEC DOI are defined as class
   RESERVED (values 4, 8, and 9).

       Attribute Types

             class               value           type
       -------------------------------------------------
       SA Life Type                1               B
       SA Life Duration            2               V
       Group Description           3               B



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       RESERVED                    4               -
       Authentication Algorithm    5               B
       Key Length                  6               B
       Key Rounds                  7               B
       RESERVED                    8               -
       RESERVED                    9               -
       MAP Protection Profile      100             B
       MAP PP Version Indicator    101             B

       Class Definitions

         SA Life Type
         SA Duration

           Specifies the time-to-live for the SA. When the SA
           expires, the SA MUST be renegotiated. MAPSEC messages
           using the expired SA MUST no longer be either sent or
           accepted as input. The life type values are:

           RESERVED                0
           seconds                 1
           RESERVED                2

           For a given Life Type, the value of the Life Duration
           attribute defines the actual length of the component
           lifetime -- in seconds. If unspecified, the default value
           MUST be assumed to be 28800 seconds (8 hours).

           The SA Life Duration attribute MUST always follow the SA
           Life Type describing the units of duration.

           Implementer's note: The semantics and values for these
           attributes are exactly as defined in [IPSDOI], except that
           kilobyte lifetimes are not supported.

         Group Description

           Specifies the Oakley Group to be used in a PFS QM
           negotiation. For a list of supported values, see Appendix A
           of [IKE].

           Implementer's note: The semantics and values for these
           attributes are exactly as defined in [IPSDOI].

         Authentication Algorithm

           RESERVED                0-4




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           This specification only lists the reserved values. Actual
           Authentication Algorithm values are defined in the 3GPP
           Technical Specification [NDSEC].

           There is no default value for Authentication Algorithm.
           It MUST be always sent.

           Implementer's note: The first five values are reserved by
           the IP Security DOI.

         Key Length

           RESERVED                0

           There is no default value for Key Length. This attribute
           MUST be sent for transforms that use ciphers with variable
           key lengths. For fixed length ciphers, the Key Length
           attribute MUST NOT be sent. The definition of MAPSEC
           transforms in the 3GPP Technical Specifications such as
           [NDSEC] MUST specify if the use of Key Length is necessary
           and what the legal values are.

           Implementer's note: The semantics and values for these
           attributes are exactly as defined in [IPSDOI].

         Key Rounds

           RESERVED                0

           There is no default value for Key Rounds, as it must be
           specified for transforms using ciphers with varying numbers
           of rounds.

           Implementer's note: The semantics and values for these
           attributes are exactly as defined in [IPSDOI].

         MAP Protection Profile

           The value of this attribute is a 16-bit entity as defined
           in [NDSEC].

         MAP PP Version Indicator

           The Protection Profile Version Indicator allows different
           versions of protection profiles to be used. The value of
           this attribute is a 16-bit entity as defined in [NDSEC].

5.5.1 Required Attribute Support



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   To ensure basic interoperability, all implementations MUST be able
   to negotiate all of the following attributes:

           SA Life Type
           SA Duration
           Authentication Algorithm
           Key Length
           MAP Protection Profile
           MAP PP Version Indicator

5.5.2 Attribute Negotiation

   If an implementation receives a defined MAPSEC DOI attribute (or
   attribute value) which it does not support, an ATTRIBUTES-NOT-
   SUPPORTED Notification Payload SHOULD be returned and the
   negotiation MUST be aborted, unless the attribute value is in the
   reserved range.

   If an implementation receives an attribute value in the reserved
   range, an implementation MAY choose to continue based on local
   policy.

   Implementer's note: This follows exactly the IP Security DOI.
   However, there are no special lifetime attribute parsing
   requirements, since only time-based lifetimes are supported.

5.5.3 Lifetime Matching

   Offered and locally acceptable SA lifetimes must match exactly
   under MAPSEC in order for the responder to select an SA.

   Implementer's note: This is simplified from the IP Security DOI
   which required notifications. In the MAPSEC DOI lifetime
   notifications are not defined and hence not used.

5.6 MAP Security Payload Content

   The SA Payloads that the Initiator and the Responder exchange
   control the SAs that actually get installed. The attributes
   discussed above are a part of the SA Payloads. For a definition of
   a MAPSEC SA, see [NDSEC].

   The following sections describe those ISAKMP payloads whose data
   representations are dependent on the applicable DOI.

5.6.1 Identification Payload Content

   The initiator of the negotiation is identified using the



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   Identification Payload. The responder SHOULD use the initiator's
   identity to determine the correct security policy for creating
   SAs.

   During Phase 1, the ID port and protocol fields MUST be set to zero
   or to the UDP port that the MAPSEC DOI is running on. If an
   implementation receives any other values, this MUST be treated as
   an error and the negotiation MUST be aborted.

   The following diagram illustrates the content of the Identification
   Payload.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   !  Next Payload !   RESERVED    !        Payload Length         !
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   !   ID Type     !  Protocol ID  !             Port              !
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                     Identification Data                       ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 2: Identification Payload Format

   The Identification Payload fields are defined as follows:

     o  Next Payload (1 octet) - Identifier for the type of the next
        payload in the message. If the current payload is the last in
        the message, this field will be zero (0).

     o  RESERVED (1 octet) - Unused, must be zero (0).

     o  Payload  Length  (2 octets) -  Length, in octets, of the
        identification data, including the generic header.

     o  Identification Type (1 octet) - Value describing the identity
        information found in the Identification Data field.

     o  Protocol ID (1 octet) - Value specifying an associated
        Transport Layer Protocol ID (e.g. UDP/TCP). Value zero means
        that the Protocol ID field should be ignored. In the MAPSEC
        DOI Phase 2, the Protocol field MUST always be zero (0).

     o Port (2 octets) - Value specifying an associated port. A value
        of zero means that the Port field should be ignored. In the
        MAPSEC DOI, value of zero MUST always be used in Phase 2.
        Unlike in IP traffic protected by IP Security, the concept of
        a port is not used in MAP.




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     o  Identification Data (variable length) - Value, as indicated by
        the Identification Type.

   The legal Identification Type field values in Phase 1 are as
   defined in [IPSDOI].  Phase 2 identities MUST conform to the
   following table. The table lists the assigned values for the
   Identification Type field found in the Identification
   Payload. (Values from 0 to 11 are reserved by the IP Security DOI
   for the purposes of code reuse.)

       ID Type                   Value
       -------                   -----
       RESERVED                  0-11
       ID_PLMN_ID                12

   In MAPSEC DOI, the ID_PLMN_ID type specifies PLMN ID of the
   Initiator or the Responder.  The PLMN ID MUST be represented as
   defined in section 17.7.8 of [MAP], i.e. as a three octet data item
   with the Mobile Country Code (MCC) followed by the Mobile Network
   Code (MNC).  The size of the PLMN ID MUST correspond to the size in
   the ID payload header.

5.6.2 Notify Message Types

   There are no DOI-specific Notify Message types for the MAPSEC DOI
   in Phase 2.

   Note however that Phase 1 uses the standard ISAKMP and IP Security
   DOI notifications that are defined in section 3.14.1 of [ISAKMP]
   and section 4.6.3 of [IPSDOI], respectively.  Even Phase 2 of the
   MAPSEC DOI uses standard ISAKMP notifications.

   Implementer's note: The reason why MAPSEC DOI does not need the
   same Phase 2 DOI-specific notifications is the following. MAPSEC
   does not allow turning replay protection on or off, which makes the
   use of REPLAY-STATUS unnecessary. Responder lifetimes are required
   to be exactly the same as the initiator lifetimes, which makes the
   use of RESPONDER-LIFETIME unnecessary. INITIAL-CONTACT
   notification on the other hand is used exclusively in Phase 1, and
   is therefore applicable also for MAPSEC DOI in Phase 1.

5.7 MAPSEC Key Exchange Requirements

   The MAPSEC DOI introduces no additional Key Exchange types.

6. Security Considerations

   This entire memo relates to the Internet Key Exchange protocol



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   ([IKE]), which combines ISAKMP ([ISAKMP]) and Oakley ([OAKLEY]) to
   provide the derivation of cryptographic keying material in a secure
   and authenticated manner. Specific discussion of the various
   security protocols and transforms identified in this document can
   be found in the associated base documents and in the cipher
   references.

7. IANA Considerations

   This document contains many parameters to be maintained by the the
   standardization bodies. In the case of the MAPSEC DOI, 3GPP will
   assign many of the parameters normally maintained by IANA.  This
   section explains how 3GPP will assign new values for different
   MAPSEC DOI related parameters. All values not explicitly defined in
   previous sections will be assigned by 3GPP. IANA will still define
   the DOI numbers, including the DOI number for this DOI.

7.1 MAPSEC Situation Definition

   The Situation Definition is a 32-bit bitmask which represents the
   environment under which the MAPSEC SA proposal and negotiation is
   carried out. Requests for new Situation Definition values must be
   accompanied by a 3GPP Technical Specification which describes the
   new Situation.

   The upper two bits are reserved for private use between cooperating
   systems.

7.2 MAPSEC Security Protocol Identifiers

   The Security Protocol Identifier is an 8-bit value which identifies
   a security protocol suite being negotiated. Requests for new
   security protocol identifiers must be accompanied by a 3GPP
   Technical Specification which describes the security protocol.

   The values 249-255 are reserved for private use between cooperating
   systems.

7.3 MAPSEC MAP Security Transform Identifiers

   The MAP Security Transform Identifier is an 8-bit value which
   identifies the algorithm to be used to protect for MAP messages.
   Requests for new Transform Identifiers must be accompanied by a
   3GPP Technical Specification describing the use of the algorithm
   within the MAPSEC DOI framework.

   The values 249-255 are reserved for private use between cooperating
   systems.



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7.4 MAPSEC Security Association Attributes

   The MAPSEC Security Association Attribute consists of a 16-bit type
   definition and its associated value. MAPSEC SA attributes are used
   to pass miscellaneous values between ISAKMP peers. Requests for
   new MAPSEC SA attributes must be accompanied by a 3GPP Technical
   Specification describing the attribute semantics, its type encoding
   (Basic/Variable-Length) and its legal values.  Section 5.5 of this
   document provides an example of such a description.

   The values 32001-32767 are reserved for private use between
   cooperating systems.

   Requests for new values for existing attributes must be accompanied
   also by a 3GPP Technical Specification. Such specifications describe
   the semantics of the new values.

7.5 MAPSEC Identification Type

   The MAPSEC Identification Type is an 8-bit value which is used as a
   discriminant for the interpretation of the variable-length
   Identification Payload. Requests for new Identification Types must
   be accompanied by a 3GPP Technical Specification which describes
   how to use the identification type.

   The values 249-255 are reserved for private use between cooperating
   systems.

8. Key Derivation for MAP Security

   MAP Security requires two sets of keys, one for each direction,
   just as in the case of IP Security SAs. Separate authentication and
   encryption keys are also needed for each direction. For one
   direction, these two keys are taken from the keying material in
   following order: first the authentication key, and then the
   encryption key.

   The keys are derived with the procedure described in Section 5.5 of
   [IKE].

   Implementer's note: The same procedure is used in order to simplify
   specification and implementation. Note also that one of the
   parameters needed for the derivation process is constant, i.e. the
   protocol is always PROTO_MAPSEC.


9. Intellectual property rights




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   Ericsson has patent applications which may cover parts of this
   technology.  Should such applications become actual patents and be
   determined to cover parts of this specification, Ericsson intends
   to provide licensing when implementing, using or distributing the
   technology under openly specified, reasonable, non-discriminatory
   terms.

10. Acknowledgments

   This document is derived from the work done by the SA3 group of
   3GPP.  The authors wish to thank in particular David Castellanos-
   Zamora, Krister Boman, Anders Liljekvist, Eeva Munter and others at
   Ericsson, and Tatu Ylonen and others at SSH Communications Security
   Corp, Marc Blommaert, Dirk Kroeselberg, and Ulrich Wiehe at
   Siemens, and Olivier Paridaens at Alcatel.

11. References

11.1 Normative References

   [AESESP]  S. Frankel, S. Kelly, R. Glenn, "The AES Cipher Algorithm
             and  Its Use With IPsec", draft-ietf-ipsec-ciph-aes-cbc-03.
             txt. Work In Progress, IETF, November 2001.

   [AESMAC]  M. Dworkin, "Recommendation for Block Cipher Modes of
             Operation", NIST Special Publication 800-38A, December
             2001.

   [IKE]     D. Harkins and D. Carrel, "The Internet Key Exchange
             (IKE)", RFC 2409, November 1998.

   [IPSDOI]  D.  Piper,  "The   Internet   IP   Security   Domain   of
             Interpretation for ISAKMP", RFC 2407, November 1998.

   [ISAKMP]  D. Maughan, M. Schertler, M. Schneider and J. Turner,
             "Internet Security Association and Key Management Protocol
             (ISAKMP)", RFC 2408, November 1998.

   [MAP]     3rd Generation Partnership Project, Technical Specification
             Group Core Network, "Mobile Application Part (MAP)
             Specification (Release 5)", 3GPP TS 29.002, 2002.

   [NDSEC]   3rd Generation Partnership Project, Technical Specification
             Group   SA3,   Security   "Network   Domain  Security;  MAP
             Application  Layer  Security  (Release 5)", 3GPP TS 33.200,
             2002.

   [STDS]    S. Bradner, "The Internet Standards Process -- Revision 3",



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             RFC 2026, October 1996.

   [WORDS]   S. Bradner,  "Key  Words  for  Use  in  RFCs  to  Indicate
             Requirement  Levels",  BCP 14,  RFC 2119,  March 1997.


11.2 Informative References

   [AH]      S. Kent, and R. Atkinson, "IP Authentication Header", RFC
             2402, November 1998.

   [ARCH]    S. Kent and R. Atkinson, "Security Architecture for the
             Internet Protocol", RFC 2401, November 1998.

   [ESP]     S. Kent and R. Atkinson, "IP Encapsulating Security
             Payload (ESP)", RFC 2406, November 1998.

   [OAKLEY]  H. Orman, "The OAKLEY Key Determination Protocol", RFC
             2412, November 1998.


12. Authors' Addresses

   Jari Arkko
   Oy LM Ericsson Ab
   02420 Jorvas
   Finland

   Phone: +358 40 5079256
   EMail: jari.arkko@ericsson.com

   Rolf Blom
   Ericsson Radio Systems AB
   SE-16480 Stockholm
   Sweden

   Phone: +46 8 58531707
   EMail: rolf.blom@era.ericsson.se

Full Copyright Statement

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   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are



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   included on all such copies and derivative works.  However, this
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