Internet Key Exchange (IKE) is a key management protocol that is used in conjunction with the IPSec standard. It is not mandatory to implement IPSec with IKE. However, IKE enhances IPsec by providing additional features.
IKE is a hybrid protocol, which implements Oakley and Skeme key exchanges inside the Internet Security Association and Key Management Protocol (ISAKMP) framework. The ISAKMP defines a mechanism of implementing the key exchange protocol, which defines how to derive the authenticated keying material, whereas Skeme provides for secure and fast key refreshment.
Keying material is the data, such as keys and certificates, that is required to establish and maintain cryptographic keying relationships. ...