Preshared Key Authentication

Preshared Key Authentication

With this method, the same preshared key is configured on each IPSec peer. These IKE peers can authenticate each other by generating a hash of their ID, plus the key appended to the ID before transmission. If the receiving peer can create the same hash value using its preshared key, it authenticates the source peer. Figure 9-18 shows the preshared key authentication exchange.

Figure 9-18: Preshared key authentication exchange

While preshared keys are easier to configure than configuring the IPSec policy values on each IPSec peer, they don’t scale well and potential security risks can be associated with getting the key to the peer.