AT & T and Comcast cooperate in authenticating calls between the two networks, informing customers when a real caller – not a spammer – is on the phone. It does not handle every call that AT & T and Comcast customers receive, but it's a step in the right direction to tackle the scourge of Robocalls' SHAKEN / STIR protocol ("Secure Handling of Asserted Information using toKENs" and "Secure Telephony Identity Revisited"). The protocol informs consumers when a call they receive is actually made over the number specified in the caller ID. AT & T and Comcast hope the system will be operational for customers later this year.
The SHAKEN / STIR protocol uses digital certificates to verify that a call actually comes from where it is supposed to be. It's not clear how to tell if the call is spam, but it's likely that an identifier will be displayed when you receive a legitimate phone call.
The system has some limitations for now. It can only be used to identify legitimate calls ̵
In February, Federal Communications Commission chairman Ajit Pai praised carriers such as AT & T, Verizon and T-Mobile, which had committed to taking steps to implement the SHAKEN / STIR protocol into their networks. T-Mobile started in January with the slow launch of the system for calls on its network, and Sprint plans to test it later this year.
"American consumers are tired of suppressing unwanted attacks," Pai said. "Caller ID authentication will be a significant step toward stopping the misuse of fake robocalls. It's time for carriers to implement robust caller ID authentication. "