4.3.3 Anonymous authentication

The anonymous key exchange offers encryption without any indication of the peer’s identity. This kind of authentication is vulnerable to a man in the middle attack, but can be used even if there is no prior communication or shared trusted parties with the peer. Moreover it is useful when complete anonymity is required. Unless in one of the above cases, do not use anonymous authentication.

The available key exchange algorithms for anonymous authentication are shown below, but note that few public servers support them. They typically have to be explicitly enabled.

ANON_DH:

This algorithm exchanges Diffie-Hellman parameters.

ANON_ECDH:

This algorithm exchanges elliptic curve Diffie-Hellman parameters. It is more efficient than ANON_DH on equivalent security levels.