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RFC 4430
INTERNET-DRAFT KINK M. Froh
Cybersafe
M. Hur
Cybersafe
D. McGrew
Cisco
S. Medvinsky
Motorola
M. Thomas
Cisco
J. Vilhuber
Cisco
September 2000
Kerberized Internet Negotiation of Keys (KINK)
draft-ietf-kink-kink-00.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. 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 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.
Action Items:
Need to come to agreement on whether ACK is a MUST when respondent
changes cipher suite, keys, etc.
Need to determine whether a "stateful" mode is useful.
Better discussion of error scenarios
Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
The KINK Working Group will create a standards track protocol to
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facilitate centralized key exchange in an application independent
fashion. Participating systems will use the Kerberos architecture as
defined in RFC 1510 for key management and the KINK protocol between
applications. The goal of KINK is to produce a low-latency,
computationally inexpensive, easily managed, and cryptographically
sound protocol that is flexible enough to be able to be extended for
many applications.
The initial focus of the protocol will be keying IPsec security
associations as defined in RFC 2401. Future version of the KINK
protocol may define new objects and Domains of Interpretation to
extend KINK to be suitable for keying other kinds of applications.
Conventions used in this document
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.
1 Introduction
KINK is designed to provide a secure, scalable mechanism for
establishing keys between communicating entities within a centrally
managed environment in which it is important to maintain consistent
security policy. The security goals of KINK are to provide privacy,
authentication, and replay protection of key management messages, and
to avoid denial of service vulnerabilities whenever possible. The
performance goals of the protocol are to incur a low computational
cost, to have a low latency, to have a small footprint, and to avoid
or minimize the use of public key operations. In particular, the
protocol should provide the capability to establish SAs in two
messages with minimal computational effort.
Kerberos [KERB] and [RFC1510] provides an efficient mechanism for
trusted third party authentication for clients and servers. (Kerberos
also provides an efficient mechanism for inter-realm authentication
[PKCROSS].) Clients obtain tickets (a ticket is a symmetric key
certificate) from an online authentication server (the Key
Distribution Center or KDC). Tickets are used to construct
credentials for authenticating the client to the server. As a result
of this authentication, the client and the server share a secret (a
key, generated by the KDC, that is encrypted within the ticket).
The central key management provided by Kerberos is efficient, because
it limits computational cost and limits complexity. Initial
authentication to the KDC may be performed using either symmetric or
asymmetric keys [PKINIT]; however, subsequent requests for tickets
utilize symmetric cryptography, which is much more efficient than
public key cryptography. Therefore, public key operations are
limited and are amortized over the lifetime of the Kerberos tickets.
For example, a server may use a single public key exchange with the
KDC to efficiently establish multiple security associations with
other servers. Since Kerberos principal keys (used for initial
asymmetric authentication) are stored in the KDC, the number of
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principal keys is order of magnitude O(n) rather than O(n^2), as
would be required for a pre-shared key type of solution.
This document specifies the Kerberized Internet Negotiation of Keys
Protocol and its use to establish and maintain IPsec Security
Associations [RFC2401]. KINK could be used to maintain Security
Associations defined in other Domains of Interpretation, though such
use is outside of the scope of this document. It should be noted
that KINK is a complement to and not a replacement for the Internet
Key Exchange [IKE], as KINK requires the use of an online
authentication server and cannot provide identity protection nor
perfect forward secrecy (as described in [RFC2412]). There are many
situations in which centralized key management is desirable.
While Kerberos specifies a standard protocol between the client and
the KDC to get tickets, the actual ticket exchange between client and
server is application specific. KINK is intended to be an
alternative to requiring each application having its own method of
transporting and validating service tickets using a protocol which is
efficient and tailored to the specific needs of Kerberos and the
applications for which it provides keying and parameter negotiation.
KINK defines the "on the wire" protocol for establishing keys based
on Kerberos authentication. This is a general protocol that may be
used to securely establish keys for any purpose. This protocol is
ideally suited for environment in which efficiency, scalability, and
central management are important. This document defines the KINK
protocol and also defines a domain of interpretation to establish and
maintain IPsec security associations. Any other domains of
interpretation must be defined separately. The protocol takes full
advantage of the features of RFC 2401 but in the context of a
centralized keying authority.
2 Terminology
Ticket
A Kerberos term for a record that helps a client authenticate
itself to a server; it contains the client's identity, a session
key, a lifetime, and other information, all sealed using the
server's secret key. The combination of a ticket and an
authenticator (which proves freshness and knowledge of the key
within the ticket) creates an authentication credential.
Key Distribution Center (KDC)
Key Distribution Center, a network service that supplies tickets
and temporary session keys; or an instance of that service or the
host on which it runs. The KDC services both initial ticket and
Ticket-Granting Ticket (TGT) requests. The initial ticket portion
is referred to as the Authentication Server (or service). The
Ticket-Granting Ticket portion is referred to as the Ticket-
Granting Server (or service).
Realm
A Kerberos administrative domain. A single KDC may be responsible
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for one or more realms. A fully qualified principal name includes
a realm name along with a principal name unique within that realm.
3 Protocol Overview
This document specifies a protocol (KINK) that allows two peers to
directly establish symmetric keys, where one peer has already
obtained an authentication credential for the other peer from a
trusted third party known as the Kerberos KDC (Key Distribution
Center). An authentication credential for a server obtained from the
KDC is known as the Kerberos service ticket.
The use of Kerberos tickets minimizes the amount of state that is
required for this key management protocol. It is possible for only
one of the peers to save Kerberos tickets, while the other peer can
remain completely stateless. KINK uses this property to allow
message exchanges to be stateless. That is, a secure session is not
required to exchange KINK messages as each message contains all of
the information required to authenticate the message. This is in
contrast to IKE [IKE] which requires a phase 1 security association
to be created and maintained in order to create subsequent security
associations.
Kerberos tickets utilize only symmetric key cryptography with
relatively small overhead required to process them (as compared to
public key-based protocols). However, an authentication mechanism
that is utilized between a KDC client and the KDC can be either
symmetric key based (as specified by the base Kerberos protocol
[RFC1510]) or public key based (as specified by PKINIT [PKINIT]).
KINK hosts are peers in the IPsec sense of the meaning that a KINK
host can initiate or respond to KINK commands. Messages come in three
varieties: commands, replies, and acknowledgments. In most
circumstances, a KINK security association can be installed in two
messages: a command and a reply. The method here is to use an
"optimistic" algorithm where negotiation proposals are prioritized
and the top choice is installed in the security association database.
If for some reason the respondent does not choose the first proposal,
the respondent may choose another but at the cost of a ACK message so
that it can be guaranteed of delivery.
Since the KDC does not possess a symmetric key PKINIT principals KINK
defines an unauthenticated request for getting a peer's ticket
granting ticket. This allows KINK peers to request a User to User
service ticket. Upon receipt of the User to User service ticket, all
messages exchanges are identical. Discovery issues are discussed in
section
KINK is intended as a generic key management protocol based on
Kerberos tickets. It can be used to provide key management for any
security layer above level 2 in the Internet protocol stack,
including application-layer security. This document includes an
IPSec DOI (Domain of Interpretation) that enables KINK to be used
directly as an IPSec key management protocol. Other DOI
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specifications may be used to apply KINK to other security protocols.
4 Message Flows
KINK message flows all follow the same pattern between the two peers:
a command, a response and an optional acknowledgement. The actual
Kerberos KDC traffic here is for illustrative purposes only. In
practice, when a principal obtains various tickets is a subject of
Kerberos and local policy consideration. In these flows, we assume
that A and B both have TGT's from their KDC.
4.1 Standard KINK Message Flow
A B KDC
------ ------ ---
1 COMMAND------------------->
2 <------------------REPLY
3 [ ACK---------------------> ]
Figure 1: KINK Message Flow
4.2 GETTGT Message Flow
If the initiator determines that it will not be able to directly get
a service ticket for the respondent (ie, B is a PKINIT principal), it
must fetch the TGT from the respondent first in order to get a User-
User service ticket:
A B KDC
------ ------ ---
1 GETTGT+KRB_TGT_REQ------->
2 <-------REPLY+KRB_TGT_REP
3 TGS-REQ+TGT(B)------------------------------------->
4 <--------------------------------------------TGS-REP
Figure 2: GETTGT Message Flow
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4.3 CREATE Security Association
This flow instantiates a security association. The CREATE command
takes an "optimistic" approach where security associations are
initially created on the expectation that the respondent will chose
the initial proposed payload.
A B KDC
------ ------ ---
A creates initial inbound SA
1 CREATE+ISAKMP------------>
B creates inbound SA to A. If it chooses A's first proposal,
it creates the outbound SA as well.
2 <------------REPLY+ISAKMP
A creates outbound SA and modifies inbound SA if first choice
wasn't acceptible.
3 [ ACK--------------------> ]
[ B creates the outbound SA to A. ]
Figure 3: CREATE Message Flow
The security associations are instantiated as follows: In step one
host A creates an inbound security association in its database from
B->A with the first proposal in the ISAKMP proposal. It is then ready
to receive any messages from B. A then sends the CREATE message to B.
B instantiates a security association in its database from A->B. If
it agreed to A's initial proposal sends a REPLY to A without
requesting an ACK and also instantiates the security association from
B->A. If B does not choose the first proposal, it sends the actual
choice in the REPLY and requests that the REPLY be acknowledged. Upon
receipt of the REPLY, A modifies the inbound security association as
necessary, instantiates the security association from A->B, If B
requested an ACK, A now sends the ACK message. Upon receipt of the
ACK, B installs the final security association from B->A.
4.3.1 CREATE Key Derivation Considerations
The CREATE command's optimistic approach allows a security
association to be created in two messages rather than three. The
implication of a two message exchange is that B will not contribute
to the key since A must set up the inbound security association
before it receives any additional keying material from B. Under
normal circumstances this may be suspect, however KINK takes
advantage of the fact that the KDC provides a reliable source of
randomness which is used in key derivation. In many cases, this will
provide an adequate session key so that B will not require an
acknowledgment. Since B is always at liberty to contribute to the
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keying material, this is strictly a key strength versus number of
messages tradeoff which KINK implementations may decide as a matter
of policy.
4.4 DELETE Security Association
The DELETE command deletes an existing security association. The DOI
specific payloads describe the actual security association to be
deleted. For the IPSEC DOI, those payloads will include an ISAKMP
payload contains the SPI to be deleted in each direction.
A B KDC
------ ------ ---
A deletes outbound SA to B
1 DELETE+ISAKMP------------>
B deletes outbound SA to A
2 <-------------REPLY+ISAKMP
A deletes inbound SA to B
3 ACK-------------------->
B deletes inbound SA to A
Figure 4: DELETE Message Flow
The DELETE command takes a "pessimistic approach" which does not
delete incoming security associations until it receives
acknowledgment that the other host has received the DELETE. The
exception to the pessimistic approach is if the initiator wants to
immediately cease all activity on an incoming SA. In this case, it
MAY delete the incoming SA as well in step one. The respondent MUST
NOT delete its incoming SA until it either receives the final ACK, or
the transaction times out.
A final race condition with DELETE exists. Packets in flight while
the DELETE operation is taking place may, due to network reording,
etc, arrive after the diagrams above recommend deleting the incoming
security association. A KINK implementation MUST implement a grace
timer which SHOULD be set to a period of two times the average round
trip time, or to a configurable value. A KINK implementation MAY
chose to set the grace period to zero at appropriate times to
ungracefully delete a security association. The behavior described
here loosely mimics the behavior of the TCP [RFC793] flags FIN and
RST.
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4.4.1 Rekeying Security Associations
KINK requires the initiator of a security association to be
responsible for rekeying a security association. The reason is
twofold: we would like to prevent needless duplication of security
associations as the result of collisions due to an initiator and
respondent both trying to renew an existing security association. The
second reason is due to the client server nature of Kerberos
exchanges which expects the client to get and maintain tickets. While
KINK requires that a KINK host be able to get and maintain tickets,
in practice it probably advantageous for servers to wait for clients
to initiate sessions so that they do not need maintain a large ticket
cache.
There are no special semantics for rekeying security associations in
KINK. That is, in order to rekey an existing security association,
the initiator must CREATE a new security association followed by
either DETETE'ing the old security association or letting it just
time out. When identical flow selectors are available on different
security associations, KINK implementations SHOULD chose the security
association most recently created.
5 KINK Message Format
All values in KINK are formatted in the network byte order: Most
Significant Byte first.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | MjVer | MnVer | Length |
+---------------+---------------+---------------+---------------+
| Domain of Interpretation (DOI) |
+-------------------------------+-------------------------------+
| Transaction ID (XID) |
+---------------+---------------+-------------------------------+
| CksumLen | Flags | NextPayload |
+---------------+---------------+-------------------------------+
| |
~ Cksum ~
| |
+-------------------------------+-------------------------------+
| |
~ A series of payloads ~
| |
+-------------------------------+-------------------------------+
Figure 5: Format of a KINK message
Fields:
o Type (1 octet) - The type of message of this packet
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Type Value
----- -----
RESERVED 0
CREATE 1
DELETE 2
REPLY 3
GETTGT 4
ACK 5
o MjVer (4 bits) - Major protocol version number. This MUST be set
to 1. PacketCable IPSec key management MUST set this to 0.
o MnVer (4 bits) - Minor protocol version number. This MUST be set
to 0.
o Length (16 bits) - Length of the message in octets
o DOI (4 octets) - The domain of interpretation. All DOI's must be
registered with the IANA in the "Assigned Numbers" RFC [STD-2].
The IANA Assigned Number for the Internet IP Security DOI (IPSEC
DOI) is one (1). This field defines the context of all other sub-
payloads in this payloads. If other sub-payloads have a DOI field
(example: Security Association Payload), then the DOI in that
sub-payload MUST be checked against the DOI in this header, and
the values MUST be the same.
o XID (4 octets) - The transaction ID. A KINK transaction is bound
together by a transaction ID which is created by the command ini-
tiator and replicated in subsequent messages in the transaction. A
transaction is defined as a command, a reply, and an optional ack-
nowledgment. Transaction ID's are used by the initiator to
discriminate between multiple outstanding requests to a respon-
dent. It is not used for replay protection because that func-
tionality is provided by Kerberos.
o CksumLen (2 octets) -- CksumLen is the length in octets of the
keyed hash of the message. A CksumLen of zero implies that the
message is unauthenticated.
o Flags (8 bits)
bit 1: ACKREQ - ACK Request.
Set to one if the responder desires an
explicit acknowledgement that a REPLY was
received. An initiator MUST NOT set this flag.
bits 2-8: RSV - Reserved
o NextPayload (1 octet)- Indicates the type of the first payload
after the message header
o Cksum (variable) - Keyed checksum (HMAC) over the entire message.
This field MUST always be present whenever a key is available.
When a key is not available, this field is not present, and the
CksumLen field is set to zero. The hash algorithm used is the same
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as specified in the etype for the Kerberos session key in the Ker-
beros ticket. If the etype does not specify a hash algorithm, the
SHA1 MUST be used. The format of the Cksum field MUST mimic the
Kerberos checksum structure (without the ASN.1 encoding) as fol-
lows:
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
+---------------+---------------+---------------+---------------+
| Kerberos cksumtype | checksum (variable) |
+---------------+---------------+---------------+---------------+
Figure 6: KINK Checksum
The KINK header is followed immediately by a series of
Type/Length/Value fields, defined in the next section.
5.1 KINK Payloads
Immediately following the header, there is a list of
Type/Length/Value (TLV) payloads. There can be any number of payloads
following the header. Each payload MUST begin with a payload header.
Each payload header is built on the generic payload header. Any data
immediately follows the generic header.
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
+---------------+---------------+---------------+---------------+
| Next Payload | RESERVED | Payload Length |
+---------------+---------------+---------------+---------------+
| value (variable) |
+---------------+---------------+---------------+---------------+
Figure 7: Format of a KINK payload
Fields:
o NextPayload (2 octets) - The type of the next payload
NextPayload Number
---- ------
KINK_DONE 0
KRB_AP_REQ 1
KRB_AP_REP 2
KRB_ERROR 3
KRB_TGT_REQ 4
KRB_TGT_REP 5
ISAKMP_PAYLOAD 6
KINK_ENCRYPT 7
KINK_ERROR 8
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NextPayload type KINK_DONE denotes that the current payload is the
final payload in the message.
o RESERVED (1 octet) - Unused, MUST be set to 0.
o Length (2 octets) - The length of this payload, including the Type
and Length fields.
o Value (variable) - This field is depends on the Type.
5.1.1 KRB_AP_REQ Payload
The value field of this payload contains a raw Kerberos KRB_AP_REQ.
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
+---------------+---------------+---------------+---------------+
| Next Payload | RESERVED | Payload Length |
+---------------+---------------+---------------+---------------+
| |
~ AP_REQ ~
| |
+---------------------------------------------------------------+
Figure 8: KRB_AP_REQ Payload
5.1.2 KRB_AP_REP Payload
The value field of this payload contains a raw Kerberos KRB_AP_REP.
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
+---------------+---------------+---------------+---------------+
| Next Payload | RESERVED | Payload Length |
+---------------+---------------+---------------+---------------+
| |
~ AP_REP ~
| |
+---------------------------------------------------------------+
Figure 9: KRB_AP_REP Payload
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5.1.3 KRB_ERROR Payload
The value field of this payload contains a raw Kerberos KRB_ERROR.
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
+---------------+---------------+---------------+---------------+
| Next Payload | RESERVED | Payload Length |
+---------------+---------------+---------------+---------------+
| |
~ KRB_ERROR ~
| |
+---------------------------------------------------------------+
Figure 10: KRB_ERROR Payload
5.1.4 KRB_TGT_REQ Payload
The value field of this payload has the following 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
+---------------+---------------+---------------+---------------+
| Next Payload | RESERVED | Payload Length |
+---------------+---------------+---------------+---------------+
| RealmNameLen | RealmName (variable) ~
+---------------+---------------+---------------+---------------+
| |
~ RealmName(variable) ~
| |
+---------------------------------------------------------------+
Figure 11: KRB_TGT_REQ Payload
Fields:
o PrincipalNameLen - The length of the realm name that follows
o RealmName - The realm name that the responder should return a TGT
for.
If the responder is unable to get a TGT for the domain, it must reply
with a KRB_ERROR payload type.
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5.1.5 KRB_TGT_REP Payload
The value field of this payload contains the TGT requested in a
previous KRB_TGT_REP command.
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
+---------------+---------------+---------------+---------------+
| Next Payload | RESERVED | Payload Length |
+---------------+---------------+---------------+---------------+
| RealmNameLen | RealmName (variable) ~
+---------------+---------------+---------------+---------------+
| |
~ RealmName(variable) ~
| |
+---------------------------------------------------------------+
| |
~ TGT ~
| |
+---------------------------------------------------------------+
Figure 12: KRB_TGT_REQ Payload
Fields:
o RealmNameLen - The length of the realm name that follows
o RealmName - The realm that the initiator requested a TGT for.
o TGT - the DER encoded TGT of the responder
5.1.6 ISAKMP_PAYLOAD
The value field of this payload has the following 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
+---------------+---------------+---------------+---------------+
| Next Payload | RESERVED | Payload Length |
+---------------+---------------+---------------+---------------+
| InnerNextPload| RESERVED |
+---------------+---------------+---------------+---------------+
| Payload (variable) |
+---------------+---------------+---------------+---------------+
Figure 13: ISAKMP_PAYLOAD Payload
Fields:
o InnerNextPload (variable) - First payload type of the inner series of
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ISAKMP payloads.
5.1.7 KINK_ENCRYPT
The KINK_ENCRYPT payload encapsulates other payloads and is encrypted
using the encyption algorithm specified by the etype of the session
key. This payload MUST be the final payload in the message.
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
+---------------+---------------+---------------+---------------+
| Next Payload | RESERVED | Payload Length |
+---------------+---------------+---------------+---------------+
| InnerNextPload| RESERVED |
+---------------+---------------+---------------+---------------+
| Payload (variable) |
+---------------+---------------+---------------+---------------+
Figure 14: KINK_ENCRYPT Payload
Fields:
o InnerNextPload (variable) - First payload type of the inner series of
encrypted KINK payloads.
5.1.8 KINK_ERROR
The KINK_ERROR payload type provides a protocol level mechanism of
returning an error condition. This payload should not be used for
either Kerberos generated errors, or DOI specific errors which have
their own payloads defined. The error code is a an network order
integer.
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
+---------------+---------------+---------------+---------------+
| Next Payload | RESERVED | Payload Length |
+---------------+---------------+---------------+---------------+
| ErrorCode |
+---------------+---------------+---------------+---------------+
Figure 15: KINK_ERROR Payload
ErrorCode Number
--------- ------
KINK_OK 0
KINK_PROTOERR 1
KINK_INVDOI 2
KINK_INVMAJ 3
KINK_INVMIN 4
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RESERVED 5 - 8191
Private Use 8192 - 16383
o KINK_OK - No error detected
o KINK_PROTOERR - The message was malformed
o KINK_INVDOI - Invalid DOI
o KINK_INVMAJ - Invalid Major Version
o KINK_INVMIN - Invalid Minor Version
6 KINK Messages
KINK messages are either commands, replies, or acknowledgments. A
command is sent by an initiator to the respondent. A reply is sent
by the respondent to the initator. If the respondent desires confir-
mation of the reply, it sets the ACKREQ bit in the message header.
The initiator will then respond with an ACK messages. All commands,
responses and acknowledgements are bound together by the XID field of
the message header. The XID is normally a monotonically incrementing
field, and is used by the initiator to differentiate between out-
standing requests to a responder. The XID field does not provide
replay protection as that functionality is provided by Kerberos
mechanisms. In addition, commands and responses MUST use a crypto-
graphic hash over the entire message if the two peers share a sym-
metric key via a ticket exchange.
6.1 CREATE
This message initiates an establishment of new Security
Association(s). The CREATE message must contain an AP-REQ payload and
any DOI specific payloads.
CREATE contains the following payloads:
KINK Header
KRB_AP_REQ Payload
[KINK_ENCRYPT]
[CREATE-PAYLOADS]
6.3 DELETE
This message indicates that the sending peer has deleted or will
shortly delete Security Association(s) with the other peer.
DELETE contains the following payloads:
KINK Header (with DOI)
KRB_AP_REQ Payload
[KINK_ENCRYPT]
[DELETE-PAYLOADS]
6.4 REPLY
The REPLY message is a generic reply which must contain either a
KRB_AP_REP or a KRB-ERROR payload. REPLY's may contain additional DOI
specific payloads such as ISAKMP payloads defined in this document.
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REPLY
KINK Header
KRB_AP_REP | KRB_ERROR Payload
[KINK_ENCRYPT]
[ KINK_ERROR ]
[REPLY-PAYLOADS]
All REPLY messages must contain either a KRB_AP_REP or KRB_ERROR. It
may optionally contain a KINK_ERROR. The checksum in the KRB-ERROR
message is not used, since the KINK header already contains a check-
sum field.
The server MUST return a KRB_AP_ERR_SKEW if the server clock and the
client clock are off by more than the policy-determined clock skew
limit (usually 5 minutes). The optional client's time in the KRB-
ERROR MUST be filled out, and the client MUST compute the difference
(in seconds) between the two clocks based upon the client and server
time contained in the KRB-ERROR message. The client SHOULD store
this clock difference and use it to adjust its clock in subsequent
messages.
6.5 ACK
This is an acknowledgment returned to the originator of a REPLY mes-
sage. This message MUST NOT contain any DOI specific payloads. ACK
MAY contain both KINK_ERROR's and KRB_ERROR's. In particular, if a
command initiator found an error in the AP_REP, it MUST send an ACK
with the proper Kerberos error regardless of the state of the ACKREQ
flag of the respondent. The respondent SHOULD be prepared to receive
an unexpected ACK from the initiator.
ACK
KINK Header
[KRB_AP_REQ]
[KINK_ERROR]
[KRB_ERROR]
7 IPSEC DOI-specific Payload Formats
These payloads follow the conventions and values established by
[ISAKMP]. In other words, each payload has a generic, well-
established header. Only certain payloads will be reused from
[ISAKMP], however. The rest of ISAKMP will not be used, since Ker-
beros provides the equivalent functionality.
Only the payloads listed in this document will be valid for KINK.
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7.1 Security Association Payload
When using the IP Domain of Interpretation, the protocol, transform
identifiers, and Security association Identifiers from section 4.4 in
[IPDOI] MUST be used.
7.1.1 Security Association Payload Format
The Security Association Payload header for IP is defined in [IPDOI]
section 4.6.1. For this memo, the Domain of Interpretation MUST be
set to 1 (IPSec) and the Situation bitmap MUST be set to 1
(SIT_IDENTITY_ONLY). All other fields are omitted (because
SIT_IDENTITY_ONLY is set).
Given this restriction, the Security Association Payload looks like
this:
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
+---------------+---------------+---------------+---------------+
! Next Payload ! RESERVED ! Payload Length !
+---------------+---------------+---------------+---------------+
! Domain of Interpretation (IPSec) |
+---------------+---------------+---------------+---------------+
! Situation !
+---------------+---------------+---------------+---------------+
! !
~ List of Proposal Payloads ~
! !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 16: Security Association Payload Format
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7.1.2 Proposal Payload Format
Immediately following the Security Association payload header is a
proposal payload header, as defined in [ISAKMP], section 3.6 (which
in turn contains transform payloads, which contains a set of
attributes as defined in [ISAKMP], section 3.3.
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
+---------------+---------------+---------------+---------------+
! Next Payload ! RESERVED ! Payload Length !
+---------------+---------------+---------------+---------------+
! Proposal # ! Protocol-Id ! SPI Size !# of Transforms!
+---------------+---------------+---------------+---------------+
! SPI (variable) !
+---------------+---------------+---------------+---------------+
! !
~ List of Transform Payloads ~
! !
+---------------+---------------+---------------+---------------+
Figure 17: Proposal Payload Format
7.1.3 Transform Payload 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
+---------------+---------------+---------------+---------------+
! Next Payload ! RESERVED ! Payload Length !
+---------------+---------------+---------------+---------------+
! Transform # ! Transform-Id ! RESERVED2 !
+---------------+---------------+---------------+---------------+
! !
~ List of SA Attributes ~
! !
+---------------+---------------+---------------+---------------+
Figure 18: Transform Payload Format
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7.1.4 Security Association Attributes
KINK supports the following security association attributes from
[IPDOI]:
class value type
-------------------------------------------------
SA Life Type 1 B
SA Life Duration 2 V
Encapsulation Mode 4 B
Authentication Algorithm 5 B
Key Length 6 B
Key Rounds 7 B
Refer to [IPDOI] for the actual definitions for these attributes.
7.2 Identification Payloads
The Identification payload carries information that is used to
identify the traffic that is to be protected using the keys exchanges
in this memo. (NB: The payload name is misleading, and should really
be called the selector payload).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Next Payload ! RESERVED ! Payload Length !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! ID Type ! DOI Specific ID Data !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Identification Data ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 19: Identification Payload Format
The Identification Payload fields are defined as follows:
o Next Payload (1 octet) - Identifier for the payload type of the next
payload in the message. If the current payload is the last in the
message, then this field will be 0.
o RESERVED (1 octet) - Unused, set to 0.
o Payload Length (2 octets) - Length in octets of the current payload,
including the generic payload header.
o ID Type (1 octet) - Specifies the type of Identification being used.
This field is DOI-dependent.
o DOI Specific ID Data (3 octets) - Contains DOI specific Identifica-
tion data. If unused, then this field MUST be set to 0.
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or IP DOI, this field has the following format:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Protocol ID ! Port !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Identification Data (variable length) - Contains identity informa-
tion. The values for this field are DOI-specific and the format is
specified by the ID Type field. Specific details for the IETF IP
Security DOI Identification Data are detailed in [IPDOI].
Valid ID-types for KINK are:
ID TypeValue
------------
ID_IPV4_ADDR 1
ID_IPV4_ADDR_SUBNET 4
ID_IPV6_ADDR 5
ID_IPV6_ADDR_SUBNET 6
ID_IPV4_ADDR_RANGE 7
ID_IPV6_ADDR_RANGE 8
Traffic selection is very Domain of Interpretation specific, so the
contents of ID's MUST depend on the DOI present in SA.
7.3 Nonce Payloads
The Nonce payload contains random data that SHOULD be used in key
generation by both sides. It also provides freshness of the exchange,
in addition to whatever freshness/replay-protection mechanisms the
transport mechanism may provide.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Next Payload ! RESERVED ! Payload Length !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! !
~ Nonce Data ~
! !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 20: Nonce Payload Format
The Nonce Payload fields are defined as follows:
o Next Payload (1 octet) - Identifier for the payload type of the next
payload in the message. If the current payload is the last in the
message, then this field will be 0.
o RESERVED (1 octet) - Unused, set to 0.
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o Payload Length (2 octets) - Length in octets of the current payload,
including the generic payload header.
o Nonce Data (variable length) - Contains the random data generated by
the transmitting entity.
7.4 Delete Payloads
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Next Payload ! RESERVED ! Payload Length !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Domain of Interpretation (DOI) !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Protocol-Id ! SPI Size ! # of SPIs !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! !
~ Security Parameter Index(es) (SPI) ~
! !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 21: Delete Payload Format
For IPSec, the Delete will always refer to a specific connection, and
therefore a specific SPI. The DOI field must therefore always be set to
1 (IP DOI), and the protocol and SPI fields will be set to the protocol
and SPI this deletion pertains to.
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7.4 Notify Payloads
Notification information can be error messages specifying why an SA
could not be established. It can also be status data that a process
managing an SA database wishes to communicate with a peer process.
For example, a secure front end or security gateway may use the
Notify message to synchronize SA communication. The table below
lists the Notification messages and their corresponding values.
Values in the Private Use range are expected to be DOI-specific
values.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Next Payload ! RESERVED ! Payload Length !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Domain of Interpretation (DOI) !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Protocol-ID ! SPI Size ! Notify Message Type !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! !
~ Security Parameter Index (SPI) ~
! !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! !
~ Notification Data ~
! !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 22: Notification Payload Format
The Notification Payload fields are defined as follows:
o Next Payload (1 octet) - Identifier for the payload type of the next
payload in the message. If the current payload is the last in the
message, then this field will be 0.
o RESERVED (1 octet) - Unused, set to 0.
o Payload Length (2 octets) - Length in octets of the current payload,
including the generic payload header.
o Domain of Interpretation (4 octets) - Identifies the DOI (as
described in Section 2.1) under which this notification is taking
place. For ISAKMP this value is zero (0) and for the IPSEC DOI it is
one (1). Other DOI's can be defined using the description in appen-
dix B.
o Protocol-Id (1 octet) - Specifies the protocol identifier for the
current notification. Examples might include ISAKMP, IPSEC ESP,
IPSEC AH, OSPF, TLS, etc.
o SPI Size (1 octet) - Length in octets of the SPI as defined by the
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Protocol-Id. In the case of ISAKMP, the Initiator and Responder
cookie pair from the ISAKMP Header is the ISAKMP SPI, therefore, the
SPI Size is irrelevant and MAY be from zero (0) to sixteen (16). If
the SPI Size is non-zero, the content of the SPI field MUST be
ignored. The Domain of Interpretation (DOI) will dictate the SPI
Size for other protocols.
o Notify Message Type (2 octets) - Specifies the type of notification
message (see section 3.14.1). Additional text, if specified by the
DOI, is placed in the Notification Data field.
o SPI (variable length) - Security Parameter Index. The receiving
entity's SPI. The use of the SPI field is described in section 2.4 of
[ISAKMP]. The length of this field is determined by the SPI Size
field and is not necessarily aligned to a 4 octet boundary.
o Notification Data (variable length) - Informational or error data
transmitted in addition to the Notify Message Type. Values for this
field are DOI-specific.
The following Notify Types are taken directly from [ISAKMP] with
unsupported values removed.
NOTIFY MESSAGES - ERROR TYPES
Errors Value
INVALID-PAYLOAD-TYPE 1
SITUATION-NOT-SUPPORTED 3 [?]
INVALID-MAJOR-VERSION 5
INVALID-MINOR-VERSION 6
INVALID-EXCHANGE-TYPE 7
INVALID-FLAGS 8
INVALID-MESSAGE-ID 9
INVALID-PROTOCOL-ID 10
INVALID-SPI 11
INVALID-TRANSFORM-ID 12
ATTRIBUTES-NOT-SUPPORTED 13
NO-PROPOSAL-CHOSEN 14
BAD-PROPOSAL-SYNTAX 15
PAYLOAD-MALFORMED 16
INVALID-KEY-INFORMATION 17
INVALID-ID-INFORMATION 18
ADDRESS-NOTIFICATION 26
NOTIFY-SA-LIFETIME 27
UNEQUAL-PAYLOAD-LENGTHS 30
RESERVED (Future Use) 31 - 8191
Private Use 8192 - 16383
NOTIFY MESSAGES - STATUS TYPES
Status Value
CONNECTED 16384
RESERVED (Future Use) 16385 - 24575
DOI-specific codes 24576 - 32767
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Private Use 32768 - 40959
RESERVED (Future Use) 40960 - 65535
8 IPsec DOI Message Formats
8.1 CREATE
This message initiates an establishment of new Security
Association(s). The CREATE message must contain an AP-REQ payload and
any DOI specific payloads.
CREATE contains the following payloads:
KINK Header
KRB_AP_REQ payload
[KINK_ENCRYPT]
ISAKMP_PAYLOAD payload
SA Payload
Proposal Payloads
Transform Payloads
Nonce Payload
[ ID Payloads ]
Replies are of the following forms:
REPLY
KINK Header
KRB_AP_REP payload
[KINK_ENCRYPT]
ISAKMP_PAYLOAD payload
SA Payload
Proposal Payload
Transform Payload
[ Nonce Payload ]
[ ID Payload ] Note that there MUST be a single proposal
payload and a single transform payload in REPLY messages.
If an IPspec DOI specific error is encountered, the respondent must
reply with a Notify payload describing the error:
REPLY
KINK Header
KRB_AP_REP payload
[KINK_ENCRYPT]
[ KINK_ERROR payload ]
ISAKMP_PAYLOAD payload
Notify payload
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If the respondent finds an Kerberos type of error it MUST reply with
a lone KRB_ERROR payload:
REPLY
KINK Header
KRB_ERROR payload
[KINK_ENCRYPT]
[ KINK_ERROR payload ]
8.2 DELETE
This message indicates that the sending peer has deleted or will
shortly delete Security Association(s) with the other peer.
DELETE contains the following payloads:
KINK Header (with DOI)
KRB_AP_REQ payload
[KINK_ENCRYPT]
[ KINK_ERROR payload ]
ISAKMP_PAYLOAD payload Delete Payload
There are three forms of replies for a DELETE
The normal form is:
REPLY
KINK Header
KRB_AP_REP | KRB_ERROR payload
[KINK_ENCRYPT]
[ KINK_ERROR payload ]
ISAKMP_PAYLOAD payload
Delete Payload
If an IPspec DOI specific error is encountered, the respondent must
reply with a Notify payload describing the error:
REPLY
KINK Header
KRB_AP_REP payload
[ KINK_ENCRYPT payload ]
[ KINK_ERROR payload ]
ISAKMP_PAYLOAD payload
Notify payload
If the respondent finds an Kerberos type of error it MUST reply with a
lone KRB_ERROR payload:
REPLY
KINK Header
KRB_ERROR payload
[ KINK_ENCRYPT payload ]
[ KINK_ERROR payload ]
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9 Key Derivation
During the establishment of SAs the initiator and responder each pro-
vide random nonces that add entropy to the KDC supplied session key
in order to derive the SA keying material (KEYMAT).
KEYMAT = HMAC(Secret, Ni [ | Nr ])
The function is initially called with the session key found in the
service ticket used for Secret and is called recursively with the
resulting KEYMAT until it has generated proper number of bits.
The initator MUST add entropy in the form of a random nonce to the
ticket session key when it instantiates the optimistic security asso-
ciation. The HMAC algorithm used is the same as specified in the
etype for the Kerberos session key in the Kerberos ticket. If the
etype does not specify a hash algorithm, the SHA1 MUST be used. The
results are placed in the subkey field of the AP-REQ. The number of
subkey bits MUST be large enough to generate keying material for the
largest encryption and integrity algorithms proposed.
Bits for the security association keys are taken from the generated
key in network order starting with the key for the initiator's
inbound security association with the integrity algorithm key first
followed by the encryption algorithm, and repeated for for the
initiator's outbound security association. There is no implied pad-
ding between the encryption and integrity keying material.
The respondent MAY choose to add more entropy to the key, but if it
does, it SHOULD request an ACK message before it sends data on the
newly created security association. It MUST place the concatenation
of the two nonces it choses in the subkey field of the AP-REP. The
nonce sizes MUST be the same size that the initiator chose. Upon
receipt of the AP-REP, the initiator MUST compare the second nonce to
determine if the respondent added entropy to the keying material. If
it has, the initiator MUST modify the keys for the initial security
association using the rules described above.
The following flow illustrates the derivation of keys:
A B
----- -----
K0=HMAC(SessKey, Nonce1, 0)
AP-REP(subkey=Nonce1)----------------> K1=HMAC(SessKey, Nonce1,
Nonce2)
K2=HMAC(SessKey, Nonce1,
Nonce3) [where Nonce3 MAY
be null]
<-------------------------------- AP-REQ(subkey=Nonce2|Nonce3)
Figure 23: Key Derivation
K0 is used to instantiate the optimistic incoming security associa-
tion from B->A. K1 is always the key that is used for the security
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association between A->B. The value of the subkey in the AP-REQ is
always Nonce1. The value of the subkey in the AP-REP is the concate-
nation of Nonce2 and Nonce3 where Nonce3 is equal to zero if B does
not desire to add entropy to the optimistic security association B-
>A.
10 Transport Considerations
KINK uses UDP on port XXX to transport its messages. There is one
timer T which SHOULD take into consideration round trip considera-
tions and MUST implement a truncated exponential backoff mechanism.
The state machines is simple: any message which expects a response
must retransmit the request using timer T. Since Kerberos requires
that messages be retransmitted with new times for replay protection,
the message must be recreated each time including the checksum of the
message.
11 Security Considerations
12 Protocol Considerations
12.1 Security Policy Database Considerations
KINK leaves the population of the IPsec security policy database out
of scope. There are, however, considerations which should be pointed
out. Firstly, even though when and when not to initiate a user to
user flow is left to the discretion of the KINK implemention, a Ker-
beros client which initially authenticated using a symmetric key
SHOULD NOT use a user-user flow if the respondent is also in the same
realm. Likewise, a KINK initiator which authenticated in a public
key realm SHOULD use a user-user flow if the respondent is in the
same realm.
KINK does not define the cross realm behavior. At a minimum a the
security policy database for a KINK implementation SHOULD contain a
logical record of the KDC to contact, principal name for the respon-
dent, and whether the KINK implementation should use a direct AP-
REQ/AP-REP flow, or a User-User flow to CREATE/DELETE the security
association.
That said, there is considerable room for improvement on how a KINK
initiator could auto-discover how a respondent in a different realm
initially authenticated. This is left as an implementation detail as
well as the subject of possible future standardization efforts which
are outside of the scope of the KINK working group.
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13 Related Work
The IPsec working group has defined a number of protocols that pro-
vide the ability to create and maintain cryptographically secure
security associations at layer three (ie, the IP layer). This effort
has produced two distinct protocols:
o a mechanism for encrypting and authenticating IP datagram
payloads which assumes a shared secret between the sender and
receiver
o a mechanism for IPsec peers to perform mutual authentication
and exchange keying material
The IPsec working group has defined a peer to peer authentication and
keying mechanism, IKE (RFC 2409). One of the drawbacks of a peer to
peer protocol is that each peer must know and implement a site's
security policy which in practice can be quite complex. In addition,
the peer to peer nature of IKE requires the use of Diffie Hellman
(DH) to establish a shared secret. DH, unfortunately, is computation-
ally quite expensive and prone to denial of service attacks. IKE also
relies on X.509 certificates to realize scalable authentication of
peers. Digital signatures are also computationally expensive and cer-
tificate based trust models are difficult to deploy in practice.
While IKE does allow for pre-shared symmetric keys, key distribution
is required between all peers -- an O(n2) problem -- which is prob-
lematic for large deployments.
14 References
[RFC1510]
J. Kohl, C. Neuman. The Kerberos Network Authentication Service
(V5). Request for Comments 1510.
[KERB]
B.C. Neuman, Theodore Ts'o. Kerberos: An Authentication Service for
Computer Networks, IEEE Communications, 32(9):33-38. September 1994.
[PKINIT]
B. Tung, C. Neuman, M. Hur, A. Medvinsky, S.Medvinsky, J. Wray, J.
Trostle. Public Key Cryptography for Initial Authentication in Ker-
beros. draft-ietf-cat-kerberos-pk-init-11.txt
[PKCROSS]
M.Hur, B. Tung, T. Ryutov, C. Neuman, G. Tsudik, A. Medvinsky, B.
Sommerfeld. Public Key Cryptography for Cross-Realm Authentication
in Kerberos. draft-ietf-cat-kerberos-pk-cross-06.txt
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INTERNET DRAFT KINK September 2000
[RFC2401]
S. Kent, R. Atkinson. Security Architecture for the Internet Proto-
col. Request for Comments 2401.
[IKE]
D. Harkins, D. Carrel. The Internet Key Exchange (IKE). Request for
Comments 2409.
[ISAKMP]
Maughhan, D., Schertler, M., Schneider, M., and J. Turner, "Internet
Security Association and Key Management Protocol (ISAKMP)", RFC 2408,
November 1998.
[IPDOI]
Piper, D., "The Internet IP Security Domain Of Interpretation for
ISAKMP", RFC 2407, November 1998.
15 Mailing List
Please send comments to the KINK mailing list (ietf-kink@vpnc.org).
You can subscribe by sending mail to ietf-kink-request@vpnc.org with
a line in the body of the mail with the word SUBSCRIBE in it.
16 Author's Addresses
Mike Froh
CyberSafe Corporation
180 Elgin Street
Ottawa, Ontario K2P 2K3
Phone: +1 613 234 7300
E-mail: mike.froh@cybersafe.com
Matthew Hur
CyberSafe Corporation
1605 NW Sammamish Road
Issaquah WA 98027-5378
Phone: +1 425 391 6000
E-mail: matt.hur@cybersafe.com
David McGrew
Mike Thomas
Jan Vilhuber
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
E-mail: {mcgrew,mat,vilhuber}@cisco.com
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Sasha Medvinsky
Motorola
6450 Sequence Drive
San Diego, CA 92121
+1 858 404 2367
E-mail: smedvinsky@gi.com
17 Expiration
This memo is filed as <draft-ietf-kink-kink-00.txt>, and expires
February, 2001.
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