-- Microsoft is suing federal officials for the right to be able to tell customers when law enforcement officials request their emails and other data, the latest instance of a Silicon Valley giant settling in for a battle with the government over privacy issues.
Mark Bartholomew, a law professor at the University of Buffalo who studies encryption and cyber law, said major Silicon Valley players are trying to make their brands stand for privacy.
"One way to do that is to take these very public stances against the government," he told ABC News.
The Justice Department has 60 days to respond and is "reviewing the filing," according to a spokesperson.
The lawsuit, which was filed Thursday in federal court in the Western District of Washington, comes the same week Senate Intelligence Committee Chairman Sen. Richard Burr and the panel’s Vice Chair Sen. Dianne Feinstein circulated proposed legislation that would compel companies to help authorities access data on the power of a warrant or court order.
Federal officials announced last month they successfully cracked into an iPhone belonging to one of the San Bernardino shooters and no longer needed Apple's help in unlocking the device. Apple and the FBI had engaged in a very public battle over privacy rights leading up to the FBI's announcement.
Only days after abandoning that case, the Justice Department said earlier this month it is still pushing Apple to help break into an iPhone seized in a New York drug case, according to a notice to a federal judge in the Eastern District of New York.
At issue is whether Microsoft can tell customers when law enforcement requests their emails or other data.
Microsoft argues it is unconstitutional to prevent the company from notifying its customers of these requests, writing in the lawsuit: "Microsoft brings this case because its customers have a right to know when the government obtains a warrant to read their emails, and because Microsoft has a right to tell them."
Brad Smith, Microsoft's president and chief legal officer, said in a blog post that Microsoft has been sworn to secrecy by the U.S. government regarding 2,576 legal demands. Of those secrecy orders, Smith said 1,752 had no fixed end date, meaning "we effectively are prohibited forever from telling our customers that the government has obtained their data."
The Fourth Amendment provides the "right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures of property by the government" -- a right, Microsoft said, should extend to cloud storage as well as physical storage.
"People do not give up their rights when they move their private information from physical storage to the cloud," the suit says. The government is exploiting the "transition to cloud computing as a means of expanding its power to conduct secret investigations."
Smith said it also violates Microsoft's First Amendment right to speak freely to its customers about "how government action is affecting their data."
The Case For Secrecy
While the Justice Department has yet to respond to the lawsuit, Smith said Microsoft understands the need for secrecy in some cases but the tech giant does not believe a gag order applies to every request it receives from officials.
"To be clear, we appreciate that there are times when secrecy around a government warrant is needed. This is the case, for example, when disclosure of the government’s warrant would create a real risk of harm to another individual or when disclosure would allow people to destroy evidence and thwart an investigation," Smith wrote in a blog post. "But based on the many secrecy orders we have received, we question whether these orders are grounded in specific facts that truly demand secrecy. To the contrary, it appears that the issuance of secrecy orders has become too routine."
ABC News' Mike Levine and Margaret Chadbourn contributed to this report.