Spying by N.S.A. Ally Entangled U.S. Law Firm

In justifying the agency’s sweeping powers, the Obama administration often emphasizes the N.S.A.’s role in fighting terrorism and cyberattacks, but disclosures in recent months from the documents leaked by Mr. Snowden show the agency routinely spies on trade negotiations, communications of economic officials in other countries and even foreign corporations.

American intelligence officials do not deny that they collect economic information from overseas, but argue that they do not engage in industrial espionage by sharing that information with American businesses. China, for example, is often accused of stealing business secrets from Western corporations and passing them to Chinese corporations.

 .. The Australians have obtained nearly 1.8 million encrypted master keys, which are used to protect private communications, from the Telkomsel mobile telephone network in Indonesia, and developed a way to decrypt almost all of them, according to a 2013 N.S.A. document.