H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 844)

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Configuring IKE
Support for VPN depends on the device model. For more information, see About the H3C Access
Controllers Configuration Guides.
Overview
Built on a framework defined by the ISAKMP, IKE provides automatic key negotiation and SA
establishment services for IPsec. This simplifies the application, management, configuration and
maintenance of IPsec dramatically.
Instead of transmitting keys directly across a network, IKE peers transmit keying materials between them,
and calculate shared keys, respectively. Even if a third party captures all exchanged data for calculating
the keys, it cannot calculate the keys.
Unless otherwise specified, the term "IKE" in this chapter refers to the IKE version 1 protocol.
IKE security mechanism
IKE has a series of self-protection mechanisms, and it supports secure identity authentication, key
distribution, and IPsec SA establishment on insecure networks.
Data authentication
Data authentication involves the following concepts:
• Identity authentication—Mutual identity authentication between peers. Two authentication
methods are available: pre-shared key authentication and PKI-based digital signature
authentication (RSA signature).
• Identity protection—Encrypts the identity information with the generated keys before sending the
information.
DH
The DH algorithm is a public key algorithm. With this algorithm, two peers can exchange keying material
and then use the material to calculate the shared keys. Due to the decryption complexity, a third party
cannot decrypt the keys even after intercepting all keying materials.
PFS
The PFS feature is a security feature based on the DH algorithm. By making sure keys have no derivative
relations, it guarantees a broken key brings no threats to other keys. For IPsec, PFS is implemented by
adding an additional key exchange at IKE negotiation phase 2.
IKE operation
IKE negotiates keys and establishes SAs for IPsec in two phases:
1. Phase 1—Two peers establish an ISAKMP SA, a secure, authenticated channel for communication.
In this phase, two modes are available: main mode and aggressive mode.