Digital certificates can be used to authenticate network devices and users on the network. They can be used to negotiate IPSec
sessions between network nodes.
A third party uses a Certificate Authority certificate to validate and authenticate two or more nodes that are attempting
to communicate. Each node has a public and private key. The public key encrypts data. The private key decrypts data. Because
the nodes have obtained their certificates from the same source, they are assured of their respective identities.
The device can use digital certificates provided by a third-party Certificate Authority (CA) to authenticate IPSec connections.
The phones support a set of preloaded Root Certificate Authority embedded in the firmware:
Cisco Small Business CA Certificate
CyberTrust CA Certificate
Verisign CA certificate
Sipura Root CA Certificate
Linksys Root CA Certificate