An anonymous reader quotes a report from Wired: A little-known surveillance program tracks more than a trillion domestic phone records within the United States each year, according to a letter WIRED obtained that was sent by US senator Ron Wyden to the Department of Justice (DOJ) on Sunday, challenging the program’s legality. According to the letter, a surveillance program now known as Data Analytical Services (DAS) has for more than a decade allowed federal, state, and local law enforcement agencies to mine the details of Americans’ calls, analyzing the phone records of countless people who are not suspected of any crime, including victims. Using a technique known as chain analysis, the program targets not only those in direct phone contact with a criminal suspect but anyone with whom those individuals have been in contact as well.

The DAS program, formerly known as Hemisphere, is run in coordination with the telecom giant AT&T, which captures and conducts analysis of US call records for law enforcement agencies, from local police and sheriffs’ departments to US customs offices and postal inspectors across the country, according to a White House memo reviewed by WIRED. Records show that the White House has, for the past decade, provided more than $6 million to the program, which allows the targeting of the records of any calls that use AT&T’s infrastructure — a maze of routers and switches that crisscross the United States. In a letter to US attorney general Merrick Garland on Sunday, Wyden wrote that he had “serious concerns about the legality” of the DAS program, adding that “troubling information” he’d received “would justifiably outrage many Americans and other members of Congress.” That information, which Wyden says the DOJ confidentially provided to him, is considered “sensitive but unclassified” by the US government, meaning that while it poses no risk to national security, federal officials, like Wyden, are forbidden from disclosing it to the public, according to the senator’s letter. AT&T spokesperson Kim Hart Jonson said only that the company is required by law to comply with a lawful subpoena. However, “there is no law requiring AT&T to store decades’ worth of Americans’ call records for law enforcement purposes,” notes Wired. “Documents reviewed by WIRED show that AT&T officials have attended law enforcement conferences in Texas as recently as 2018 to train police officials on how best to utilize AT&T’s voluntary, albeit revenue-generating, assistance.”

“The collection of call record data under DAS is not wiretapping, which on US soil requires a warrant based on probable cause. Call records stored by AT&T do not include recordings of any conversations. Instead, the records include a range of identifying information, such as the caller and recipient’s names, phone numbers, and the dates and times they placed calls, for six months or more at a time.” It’s unclear exactly how far back the call records accessible under DAS go, although a slide deck released under the Freedom of Information Act in 2014 states that they can be queried for up to 10 years.