Systems and methods for caller id 
authentication, spoof detection and 
list based call handling are disclosed. The caller ID 
authentication is performed by an 
authentication device connected to the calling party telephone transmitting the source and destination telephone numbers of the call to an 
authentication server. The called party authentication device extracts the caller ID of the incoming call and transmits the caller ID of the caller and the 
telephone number of the called party to the 
authentication server. The 
authentication server analyzes the transmitted information from both devices and replies with the authentication status of the caller ID to the called party authentication device. Other embodiments are disclosed where the authentication 
server is not available and caller ID authentication is performed in a peer-to-peer manner. In another embodiment, the concepts of active and passive certification passwords are used to maintain the integrity of the 
system. Other embodiments allow for authenticating blocked caller ID's, reveling blocked caller ID's, VoIP implementations, legitimate caller ID spoofing, and placing a blocked caller ID on private white or black lists. Another embodiment combines the described caller ID 
authentication system within a call 
handling system utilizing internal, global and private white and black lists. Applications of caller ID authentication methodology to other forms of 
communication source address authentication, such as email, SMS, and postal mail are envisioned.