AT&T originally launched its Call Protect spam blocking service back in 2016, and it's been improving it ever since. Today Call Protect is getting another boost with STIR and SHAKEN.

AT&T has activated the STIR and SHAKEN standards for the Samsung Galaxy S10, Galaxy S10+, and LG V40 ThinQ as part of its Call Protect service. Support for more devices will be added in 2020. Customers with AT&T Phone digital home phone service can get this feature, too.

STIR and SHAKEN aim to protect you from spoofed calls by labeling legitimate calls with a green checkmark and the words "Valid Number". Incoming calls without the "Valid Number" label may still be legitimate. More calls will be labeled as legitimate over time as more carriers implement the STIR and SHAKEN standards and link to each other.

If you've got a Galaxy S10, S10+, or LG V40, you should get Call Protect and STIR/SHAKEN automatically and for free. If you're not seeing the feature on your phone, you can download the AT&T Call Protect app or activate it from your AT&T account settings.

The STIR and SHAKEN technologies help to fight phone number spoofing by verifying that an incoming call is actually coming from the number that it says it is. Spoofing is a tactic used by scammers who use the same area code and three-digit prefix of the person they're calling to make their call appear legitimate.