computer science

Kerberized Internet Negotiation of Keys

Kerberized Internet Negotiation of Keys is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Kerberized Internet Negotiation of Keys rather than just read about it. In short: Kerberized Internet Negotiation of Keys (KINK) is a protocol defined in RFC 4430 used to set up an IPsec security association (SA), similar to Internet Key Exchange (IKE), utilizing the Kerberos protocol to allow trusted third parties to handle authentication of peers and management of security policies in a centralized fashion. Its motivation is given in RFC 3129 as an alternative to IKE, in which peers must each u…

Key takeaways

Kerberized Internet Negotiation of Keys belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Kerberized Internet Negotiation of Keys to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Kerberized Internet Negotiation of Keys from memory before moving on to harder problems.

Reference excerpt

Kerberized Internet Negotiation of Keys (KINK) is a protocol defined in RFC 4430 used to set up an IPsec security association (SA), similar to Internet Key Exchange (IKE), utilizing the Kerberos protocol to allow trusted third parties to handle authentication of peers and management of security policies in a centralized fashion. Its motivation is given in RFC 3129 as an alternative to IKE, in which peers must each use X.509 certificates for authentication, use Diffie–Hellman key exchange (DH) for encryption, know and implement a security policy for every peer with which it will connect, with authentication of the X.509 certificates either pre-arranged or using DNS, preferably with DNSSEC. Utilizing Kerberos, KINK peers must only mutually authenticate with the appropriate Authentication Server (AS), with a key distribution center (KDC) in turn controlling distribution of keying material for encryption and therefore controlling the IPsec security policy.

Protocol description KINK is a command/response protocol that can create, delete, and maintain IPsec SAs. Each command or response contains a common header along with a set of type-length-value payloads. The type of a command or a response constrains the payloads sent in the messages of the exchange. KINK itself is a stateless protocol in that each command or response does not require storage of hard state for KINK. This is in contrast to IKE, which uses Main Mode to first establish an Internet Security Association and Key Management Protocol (ISAKMP) SA followed by subsequent Quick Mode exchanges. KINK uses Kerberos mechanisms to provide mutual authentication and replay protection. For establishing SAs, KINK provides confidentiality for the payloads that follow the Kerberos AP-REQ payload. The design of KINK mitigates denial of service attacks by requiring authenticated exchanges before the use of any public key operations and the installation of any state. KINK also provides a means of using Kerberos User-to-User mechanisms when there is not a key shared between the server and the KDC. This is typically, but not limited to, the case with IPsec peers using PKINIT for initial authentication. KINK directly reuses Quick Mode payloads defined in section 5.5 of IKE, with some minor changes and omissions. In most cases, KINK exchanges are a single command and its response. An optional third message is required when creating SAs, only if the responder rejects the first proposal from the initiator or wants to contribute the keying materials. KINK also provides rekeying and Dead Peer Detection.

Packet format The KINK message includes the following fields:

type: CREATE, DELETE, REPLY, GETTGT, ACK, STATUS, or private use version: the major protocol version number length: length of the entire message domain of interpretation (DOI): a DOI as defined in the Internet Security Association and Key Management Protocol (ISAKMP) transaction ID (XID): identification the transaction, defined as a command, a reply, and an optional acknowledgement next payload: type of the first payload after the message header as KINK_DONE, KINK_AP_REQ, KINK_AP_REP, KINK_KRB_ERROR, KINK_TGT_REQ, KINK_TGT_REP, KINK_ISAKMP, KINK_ENCRYPT, or KINK_ERROR ACK or ACKREQ bit: 1 if responder requires an explicit acknowledgement that a REPLY was received otherwise 0 checksum length: length in bytes of the cryptographic checksum of the message payloads: a list of Type/Length/Value (TLV) payloads checksum: Kerberos keyed checksum over the entire message excluding the checksum field itself

Payloads KINK payloads are defined as:

next payload: type of the first payload length: length of the payload The following payloads are defined:

KINK_AP_REQ: a payload that relays a Kerberos AP-REQ to the responder KINK_AP_REP: a payload that relays a Kerberos AP-REP to the initiator KINK_KRB_ERROR: a payload that relays Kerberos type errors back to the initiator KINK_TGT_REQ: a payload that provides a means to get a TGT from the peer in order to obtain a User-to-User service ticket from the KDC KINK_TGT_REP: a payload that contains the TGT requested in a previous KINK_TGT_REQ payload of a GETTGT command KINK_ISAKMP: a payload to encapsulate the ISAKMP IKE Quick Mode (phase 2) payloads, to allow backward compatibility with IKE and ISAKMP if there are subsequent revisions KINK_ENCRYPT: a payload to encapsulate other KINK payloads and is encrypted using the session key and the algorithm specified by its etype KINK_ERROR: a payload that returns an error condition

Implementations The following open source implementations of KINK are currently available:

Racoon2 Archived 2008-10-15 at the Wayback Machine from the WIDE Project.

Worked examples

Example 1 — a first encounter with Kerberized Internet Negotiation of Keys

Start with the simplest possible case. Write down what Kerberized Internet Negotiation of Keys claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Kerberized Internet Negotiation of Keys before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Kerberized Internet Negotiation of Keys ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Kerberized Internet Negotiation of Keys

In research: Kerberized Internet Negotiation of Keys appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Kerberized Internet Negotiation of Keys in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Kerberized Internet Negotiation of Keys is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cryptographic protocols, IPsec, so understanding it makes those chapters shorter.
In everyday life: Look for Kerberized Internet Negotiation of Keys outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Kerberized Internet Negotiation of Keys in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kerberized Internet Negotiation of Keys means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Kerberized Internet Negotiation of Keys out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kerberized Internet Negotiation of Keys in simple terms?

Why does Kerberized Internet Negotiation of Keys matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Kerberized Internet Negotiation of Keys?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Kerberized Internet Negotiation of Keys.