From FOX News:

“We’ve learned that the surveillance that led to the unmasking of what started way before President Trump was even the GOP nominee,” reported Adam Housley. “The person who did the unmasking, I’m told, is very well known, very high up, very senior in the intelligence world and is not in the FBI.”

“This led to other surveillance which led to multiple names being unmasked. Again these are private citizens in the United States,” said Housley. “This had nothing to do with Russia, I’m told, or foreign intelligence of any kind.”

We know that NSA participates in Five Eyes and receives masked domestic intel from MI-6 and more recently, Sweden, according to Snowden.

Brennan’s animosity toward Trump is well established.

From Wikipedia:

Among those cleared to request and consume unmasked NSA-based intelligence reports about U.S. citizens were Obama’s national security adviser Susan Rice, his CIA Director John Brennan and then-Attorney General Loretta Lynch.

From Circa:

As his presidency drew to a close, Barack Obama’s top aides routinely reviewed intelligence reports gleaned from the National Security Agency’s incidental intercepts of Americans abroad…

Hannity is pushing this article, but Five Eyes provide enormous domestic intel, so this is disingenuous.  And let’s dispense with notions of masking as a quaint ruse to pretend 4th Amendment protections.  Indeed, a false narrative is being promulgated to deny the nature of domestic intel available to NSA.