NewBasicAuth returns an implementation of authenticator which does proxy authorization in a basic auth fashion.

NewIPWhitelist returns an implementation of authenicator which does auth based on a user IP address.

ErrAuthRequired means that user gave no credentials.

ErrFailedAuth is returned if authorization is failed.

NoopAuth is a dummy implementation which always welcomes everyone.

Interface defines a set of methods which are mandatory for each authenicator to implement.