Yahoo's secret email scans helped the FBI probe terrorists

The scanning program used a reconfigured spam filter, not a whole new system, the New York Times says

What Yahoo was looking for with its alleged email scanning program may have been signs of code used by a foreign terrorist group. 

The company was searching for a digital "signature" of a communication method used by a state-sponsored terrorist group, according to a new report from The New York Times that provided more details on Yahoo's email scanning.  

The report on Wednesday report didn't identify the signature or say if it involved any cryptographic computer code. But the article said it was the U.S. Department of Justice, and not the National Security Agency, that had obtained a court order forcing Yahoo to comply. A Reuters report on Tuesday wasn't clear about what agencies were involved in the probe.

During the project, Yahoo made copies of any messages found to contain the signature and handed them over to the Federal Bureau of Investigation, according to the Times story, which cited an unnamed government official. The report said the email collection is no longer taking place.

To conduct the searches, Yahoo reportedly modified an existing system that already scanned incoming emails for spam, malware and child pornography. 

The Reuters story said Yahoo had created a custom software program to search through the incoming emails of all its users at the behest of the U.S. government.

The Reuters story also said U.S. intelligence officials were using Yahoo to find a "set of characters," possibly a phrase in an email or an attachment. It also said hundreds of millions of Yahoo mail accounts had been scanned. This sparked outrage among privacy advocates, who said such an email scanning program would be unconstitutional.

On Wednesday, Yahoo called the Reuters report misleading.

"We narrowly interpret every government request for user data to minimize disclosure," the company said in a statement. "The mail scanning described in the article does not exist on our systems."

Yahoo declined to comment on The New York Times's report.

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