Description

Glossary

RFCs

Publications

Obsolete RFCs

Description:

IKE is a hybrid of the ISAKMP framework and the Oakley and SKEME protocols.

ISAKMP provides a framework for authentication and key exchange but does not define them. It is designed to be key exchange independant; that is, it is designed to support many different key exchanges.

Oakley describes a series of key exchanges, known as modes, and details the services provided by each (e.g. perfect forward secrecy for keys, identity protection, and authentication).

SKEME describes a versatile key exchange technique which provides anonymity, repudiability, and quick key refreshment.

Perfect Forward Secrecy is supported.

IKEv2 does not interoperate with IKEv1, but it has enough of the header format in common that both versions can unambiguously run over the same UDP port.

RFC 2409:

Oakley and SKEME each define a method to establish an authenticated key exchange. This includes payloads construction, the information payloads carry, the order in which they are processed and how they are used.

While Oakley defines "modes", ISAKMP defines "phases". The relationship between the two is very straightforward and IKE presents different exchanges as modes which operate in one of two phases.

Phase 1 is where the two ISAKMP peers establish a secure, authenticated channel with which to communicate. This is called the ISAKMP Security Association (SA). "Main Mode" and "Aggressive Mode" each accomplish a phase 1 exchange. "Main Mode" and "Aggressive Mode" MUST ONLY be used in phase 1.

Phase 2 is where Security Associations are negotiated on behalf of services such as IPsec or any other service which needs key material and/or parameter negotiation. "Quick Mode" accomplishes a phase 2 exchange. "Quick Mode" MUST ONLY be used in phase 2.

IKEv2 header:

Initiator SPI. 8 bytes.
A value chosen by the initiator to identify a unique IKE security association. This value MUST NOT be cleared to zero.

Responder SPI. 8 bytes.
A value chosen by the responder to identify a unique IKE security association. This value MUST be cleared to zero in the first message of an IKE Initial Exchange (including repeats of that message including a cookie) and MUST NOT be zero in any other message.

Next payload. 8 bits.
Indicates the type of payload that immediately follows the header.

Major ver. 4 bits.
Indicates the major version of the IKE protocol to use.

Minor ver. 4 bits.
Indicates the minor version of the IKE protocol to use.

Exchange type. 8 bits.
Indicates the type of exchange being used. This constrains the payloads sent in each message and orderings of messages in an exchange.

Flags. 8 bits.
Indicates specific options that are set for the message. The presence of options is indicated by the appropriate bit in the flags field being set.

I, Initiator. 1 bit.
Indicates the message was sent by the initiator if set.

V, Version. 1 bit.
Indicates that the sender is capable of speaking a higher major version number of the protocol than the one indicated in the major version number field. Implementations of IKEv2 must clear this bit when sending and MUST ignore it in incoming messages.

R, Response. 1 bit.
Indicates that this message is a response to a message containing the same message ID. This bit MUST be cleared in all request messages and MUST be set in all responses. An IKE endpoint MUST NOT generate a response to a message that is marked as being a response.

Attribute classes:

Encryption algorithms:

Hash algorithms:

Notify messages, message types:

Notify messages, status types:

Glossary:

Quick mode.

RFCs:

[RFC 3104] RSIP Support for End-to-end IPsec.

• Category: Experimental.

[RFC 3193] Securing L2TP using IPsec.

• Category: Standards Track.

[RFC 3526] More Modular Exponential (MODP) Diffie-Hellman groups for Internet Key Exchange (IKE).

• Category: Standards Track.

[RFC 3706] A Traffic-Based Method of Detecting Dead Internet Key Exchange (IKE) Peers.

• Category: Informational.

[RFC 3723] Securing Block Storage Protocols over IP.

• Category: Standards Track.

[RFC 3947] Negotiation of NAT-Traversal in the IKE.

• Category: Standards Track.
• Defines IKE payload types 20 (NAT Discovery Payload) and 21 (NAT Original Address Payload).

[RFC 4106] The Use of Galois/Counter Mode (GCM) in IPsec Encapsulating Security Payload (ESP).

• Category: Standards Track.

[RFC 4109] Algorithms for Internet Key Exchange version 1 (IKEv1).

• Category: Standards Track.
• Updates:
  RFC 2409.

[RFC 4301] Security Architecture for the Internet Protocol.

• Category: Standards Track.
• Obsoletes:
  RFC 2401.

[RFC 4306] Internet Key Exchange (IKEv2) Protocol.

• Category: Standards Track.
• Defines IKE version 2.
• Obsoletes:
  RFC 2407, RFC 2408, RFC 2409.
• Updated by:
  RFC 5282.

[RFC 4307] Cryptographic Algorithms for Use in the Internet Key Exchange Version 2 (IKEv2).

• Category: Standards Track.

[RFC 4308] Cryptographic Suites for IPsec.

• Category: Standards Track.

[RFC 4309] Using Advanced Encryption Standard (AES) CCM Mode with IPsec Encapsulating Security Payload (ESP).

• Category: Standards Track.

[RFC 4312] The Camellia Cipher Algorithm and Its Use With IPsec.

• Category: Standards Track.
• Defines IKE encryption algorithm 8 (Camellia-CBC).

[RFC 4322] Opportunistic Encryption using the Internet Key Exchange (IKE).

• Category: Informational.

[RFC 4434] The AES-XCBC-PRF-128 Algorithm for the Internet Key Exchange Protocol (IKE).

• Category: Standards Track.
• Obsoletes:
  RFC 3664.

[RFC 4478] Repeated Authentication in Internet Key Exchange (IKEv2) Protocol.

• Category: Experimental.
• Defines IKE notify message status type 16403 (AUTH_LIFETIME).

[RFC 4543] The Use of Galois Message Authentication Code (GMAC) in IPsec ESP and AH.

• Category: Standards Track.

[RFC 5282] Using Authenticated Encryption Algorithms with the Encrypted Payload of the Internet Key Exchange version 2 (IKEv2) Protocol.

• Category: Standards Track.
• Updates:
  RFC 4306.

[RFC 5386] Better-Than-Nothing Security: An Unauthenticated Mode of IPsec.

• Category: Standards Track.

Publications:

Obsolete RFCs:

[RFC 2409] The Internet Key Exchange (IKE).

• Category: Standards Track.
• Obsoleted by:
  RFC 4306.
• Updated by:
  RFC 4109.

[RFC 3664] The AES-XCBC-PRF-128 Algorithm for the Internet Key Exchange Protocol (IKE).

• Category: Standards Track.
• Obsoleted by:
  RFC 4434.

Description

Glossary

RFCs

Publications

Obsolete RFCs